BARCELONA – Obesity, more so than having a poor lifestyle, significantly raised the odds of developing type 2 diabetes, independent of individuals’ genetic susceptibility, according to data from a Danish population-based, case-cohort study.

In fact, having a body mass index (BMI) of more than 30 kg/m2 was linked with a 480% risk of incident type 2 diabetes, compared with being of normal weight (BMI, 18.5-24.9 kg/m2). The 95% confidence interval was 5.16-6.55. Being overweight (BMI, 25-29.9 kg/m2) also carried a 100% increased risk of type 2 diabetes (hazard ratio, 2.37; 95% CI, 2.15-2.62).

Having an unfavorable lifestyle – which was defined as having no or only one of several healthy-living characteristics, from not smoking and moderating alcohol use to eating a well-balanced, nutritious diet and exercising regularly – increased the risk of diabetes by 18%, compared with having a favorable lifestyle (HR, 1.18; 95% CI, 1.06-1.30).

Individuals with a high genetic risk score (GRS) had a 100% increased risk of developing the disease versus those with a low GRS (HR, 2.0; 95% CI, 1.1-1.3).

“High genetic risk, obesity, and [an] unfavorable lifestyle increase the individual-level risk of incident type 2 diabetes,” Hermina Jakupovic and associates reported in a poster presentation at the annual meeting of the European Association for the Study of Diabetes. Their results suggest that “the effect of obesity on type 2 diabetes risk is dominant over other risk factors, highlighting the importance of weight management in type 2 diabetes prevention.”

Ms. Jakupovic, a PhD student at the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen, and coauthors examined data on 9,555 participants of the Diet, Cancer, and Health cohort, a large, prospective study that has been running since the early 1990s.

Around half of the study sample were women and the mean age was 52 years. Just over one-fifth (22.8%) were obese, 43% were overweight, and the remaining 35.2% were of normal weight. A quarter (25.4%) had an unfavorable lifestyle, 40% a favorable lifestyle, and the remainder an “intermediate” lifestyle. Over a follow-up of almost 15 years, nearly half (49.5%) developed type 2 diabetes.

Genetic risk was assessed by a GRS comprising 193 genetic variants known to be strongly associated with type 2 diabetes, Ms. Jakupovic explained, adding that, using the GRS, patients were categorized into being at low (the lowest 20%), intermediate (middle 60%) and high risk (top 20%) of type 2 diabetes.

Considering individuals’ GRS and lifestyle score together showed an increasing risk of developing type 2 diabetes from the low GRS/favorable-lifestyle category (HR, 1.0; reference) upward to the high GRS/unfavorable lifestyle (HR, 2.22; 95% CI, 1.76-2.81).

The Diet, Cancer, and Health cohort is supported by the Danish Cancer Society. The Novo Nordisk Foundation Center for Basic Metabolic Research is an independent research center at the University of Copenhagen partially funded by an unrestricted donation from the Novo Nordisk Foundation. Ms. Jakupovic and associates are funded either directly or indirectly by the Novo Nordisk Foundation.

SOURCE: Jakupovic H et al. EASD 2019, Abstract 376.

BARCELONA – Obesity, more so than having a poor lifestyle, significantly raised the odds of developing type 2 diabetes, independent of individuals’ genetic susceptibility, according to data from a Danish population-based, case-cohort study.

In fact, having a body mass index (BMI) of more than 30 kg/m2 was linked with a 480% risk of incident type 2 diabetes, compared with being of normal weight (BMI, 18.5-24.9 kg/m2). The 95% confidence interval was 5.16-6.55. Being overweight (BMI, 25-29.9 kg/m2) also carried a 100% increased risk of type 2 diabetes (hazard ratio, 2.37; 95% CI, 2.15-2.62).

Having an unfavorable lifestyle – which was defined as having no or only one of several healthy-living characteristics, from not smoking and moderating alcohol use to eating a well-balanced, nutritious diet and exercising regularly – increased the risk of diabetes by 18%, compared with having a favorable lifestyle (HR, 1.18; 95% CI, 1.06-1.30).

Individuals with a high genetic risk score (GRS) had a 100% increased risk of developing the disease versus those with a low GRS (HR, 2.0; 95% CI, 1.1-1.3).

“High genetic risk, obesity, and [an] unfavorable lifestyle increase the individual-level risk of incident type 2 diabetes,” Hermina Jakupovic and associates reported in a poster presentation at the annual meeting of the European Association for the Study of Diabetes. Their results suggest that “the effect of obesity on type 2 diabetes risk is dominant over other risk factors, highlighting the importance of weight management in type 2 diabetes prevention.”

Ms. Jakupovic, a PhD student at the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen, and coauthors examined data on 9,555 participants of the Diet, Cancer, and Health cohort, a large, prospective study that has been running since the early 1990s.

Around half of the study sample were women and the mean age was 52 years. Just over one-fifth (22.8%) were obese, 43% were overweight, and the remaining 35.2% were of normal weight. A quarter (25.4%) had an unfavorable lifestyle, 40% a favorable lifestyle, and the remainder an “intermediate” lifestyle. Over a follow-up of almost 15 years, nearly half (49.5%) developed type 2 diabetes.

Genetic risk was assessed by a GRS comprising 193 genetic variants known to be strongly associated with type 2 diabetes, Ms. Jakupovic explained, adding that, using the GRS, patients were categorized into being at low (the lowest 20%), intermediate (middle 60%) and high risk (top 20%) of type 2 diabetes.

Considering individuals’ GRS and lifestyle score together showed an increasing risk of developing type 2 diabetes from the low GRS/favorable-lifestyle category (HR, 1.0; reference) upward to the high GRS/unfavorable lifestyle (HR, 2.22; 95% CI, 1.76-2.81).

The Diet, Cancer, and Health cohort is supported by the Danish Cancer Society. The Novo Nordisk Foundation Center for Basic Metabolic Research is an independent research center at the University of Copenhagen partially funded by an unrestricted donation from the Novo Nordisk Foundation. Ms. Jakupovic and associates are funded either directly or indirectly by the Novo Nordisk Foundation.

SOURCE: Jakupovic H et al. EASD 2019, Abstract 376.

BARCELONA – Obesity, more so than having a poor lifestyle, significantly raised the odds of developing type 2 diabetes, independent of individuals’ genetic susceptibility, according to data from a Danish population-based, case-cohort study.

In fact, having a body mass index (BMI) of more than 30 kg/m2 was linked with a 480% risk of incident type 2 diabetes, compared with being of normal weight (BMI, 18.5-24.9 kg/m2). The 95% confidence interval was 5.16-6.55. Being overweight (BMI, 25-29.9 kg/m2) also carried a 100% increased risk of type 2 diabetes (hazard ratio, 2.37; 95% CI, 2.15-2.62).

Having an unfavorable lifestyle – which was defined as having no or only one of several healthy-living characteristics, from not smoking and moderating alcohol use to eating a well-balanced, nutritious diet and exercising regularly – increased the risk of diabetes by 18%, compared with having a favorable lifestyle (HR, 1.18; 95% CI, 1.06-1.30).

Individuals with a high genetic risk score (GRS) had a 100% increased risk of developing the disease versus those with a low GRS (HR, 2.0; 95% CI, 1.1-1.3).

“High genetic risk, obesity, and [an] unfavorable lifestyle increase the individual-level risk of incident type 2 diabetes,” Hermina Jakupovic and associates reported in a poster presentation at the annual meeting of the European Association for the Study of Diabetes. Their results suggest that “the effect of obesity on type 2 diabetes risk is dominant over other risk factors, highlighting the importance of weight management in type 2 diabetes prevention.”

Ms. Jakupovic, a PhD student at the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen, and coauthors examined data on 9,555 participants of the Diet, Cancer, and Health cohort, a large, prospective study that has been running since the early 1990s.

Around half of the study sample were women and the mean age was 52 years. Just over one-fifth (22.8%) were obese, 43% were overweight, and the remaining 35.2% were of normal weight. A quarter (25.4%) had an unfavorable lifestyle, 40% a favorable lifestyle, and the remainder an “intermediate” lifestyle. Over a follow-up of almost 15 years, nearly half (49.5%) developed type 2 diabetes.

Genetic risk was assessed by a GRS comprising 193 genetic variants known to be strongly associated with type 2 diabetes, Ms. Jakupovic explained, adding that, using the GRS, patients were categorized into being at low (the lowest 20%), intermediate (middle 60%) and high risk (top 20%) of type 2 diabetes.

Considering individuals’ GRS and lifestyle score together showed an increasing risk of developing type 2 diabetes from the low GRS/favorable-lifestyle category (HR, 1.0; reference) upward to the high GRS/unfavorable lifestyle (HR, 2.22; 95% CI, 1.76-2.81).

The Diet, Cancer, and Health cohort is supported by the Danish Cancer Society. The Novo Nordisk Foundation Center for Basic Metabolic Research is an independent research center at the University of Copenhagen partially funded by an unrestricted donation from the Novo Nordisk Foundation. Ms. Jakupovic and associates are funded either directly or indirectly by the Novo Nordisk Foundation.

SOURCE: Jakupovic H et al. EASD 2019, Abstract 376.

Patients with type 1 diabetes who used a closed-loop insulin delivery system spent a greater percentage of time in their target blood glucose range, compared with patients using a sensor-augmented insulin pump.

The significant, between-group, mean-adjusted difference of 11 percentage points between the two groups translated into the closed-loop patients spending an additional 2.6 hr/day in the target range of 70-180 mg/dL, Susan A. Brown, MD, and colleagues wrote in the New England Journal of Medicine.

Most of the benefit occurred in the early morning hours, at 5 am, when 89% of patients using the closed-loop system remained in the target range, compared with 62% of those using the pump system, said Dr. Brown of the University of Virginia, Charlottesville, and colleagues.

The randomized study comprised 168 patients with a mean age of 33 years, although the age range was wide (14-71 years). The patients had a mean disease duration of 16 years. Their baseline glycated hemoglobin level ranged between 5.4% and 10.6%. At enrollment, 79% of patients used insulin pumps, and 21% used multiple daily insulin injections; 70% were using continuous glucose monitoring, of whom 86% were using pumps. Patients in both groups had follow-up visits at 2, 6, 13, and 26 weeks.

There were no dropouts in this study – 100% of clinical and telephone follow-ups were completed.

During the 6-month trial, the mean percentage of time spent in the glucose target range rose from 61% at baseline to 71% in the closed-loop group, but remained unchanged at 59% in the pump group. The difference became apparent very early in the study and remained consistent over its course.

“The mean percentage of time that the glucose level was in the target range was 70% in the closed-loop group and 59% in the control [pump] group during the daytime (6 a.m. to midnight) and 76% and 59%, respectively, during the nighttime (midnight to 6 am) ... and the greatest differences in the mean glucose level occurred at 5 a.m. and 6 a.m. [139 mg/dL in the closed-loop group vs. 166 mg/dL in the control group at both time points]. This diurnal pattern is a result of the increased aggressiveness of the algorithm to meet a lower glucose target during the second half of the night,” the authors noted.

The closed-loop system was also better than the pump system on all secondary endpoints, including the following:
 

• Glycated hemoglobin at 26 weeks: mean difference, –0.33 percentage points.
• Percentage of time with glucose higher than 180 mg/dL: mean difference, –10 percentage points (a difference of 2.4 hr/day).
• Percentage of time with glucose less than 70 mg/dL: mean difference, –0.88 percentage points (a difference of 13 min/day).

The other secondary endpoints – mean glucose level and mean glycated hemoglobin level – were also significantly better in those using the closed-loop system.

The benefits “consistently favored the closed-loop system across a broad range of baseline characteristics, including age, sex, body mass index, income, educational level, insulin pump or infection use, previous use of continuous glucose monitor, and glycated hemoglobin,” the authors said.

There were 17 adverse events in 16 patients in the closed-loop group, and 2 events in 2 patients in the pump group, but no incidents of severe hypoglycemia. One person in the closed-loop system experienced ketoacidosis because of a failure in the pump infusion set. There were 13 hyperglycemic or ketosis episodes in 12 patients in the closed-loop group, and 2 in 2 patients the pump group, but none of them met the criteria for diabetic ketoacidosis. All of these episodes were deemed related to infusion set failures.

There were three serious adverse events in the closed-loop group, and none related to the device. Blood ketones exceeding 1 mmol/L occurred in 11 closed-loop patients and 8 pump patients.

The results should be interpreted with consideration of potential group bias, the authors noted. “In our trial, 70% of the patients were using a continuous glucose monitor, and 79% were using an insulin pump at the time of enrollment, percentages that are substantially higher than the reported usage in the general population of type 1 diabetes. These data may reflect an interest in and willingness to use a closed-loop system among patients who were already using devices as part of diabetes management.”

Dr. Brown reported receiving grant support from Tandem Diabetes Care, Dexcom, and Roche Diagnostics. Other authors reported a range of support from numerous pharmaceutical and medical technology companies. Several reported patents on diabetes-related devices.

SOURCE: Brown SA et al. New Engl J Med. 2019 Oct 16. doi: 10.1056/NEJMoa1907863.

Patients with type 1 diabetes who used a closed-loop insulin delivery system spent a greater percentage of time in their target blood glucose range, compared with patients using a sensor-augmented insulin pump.

The significant, between-group, mean-adjusted difference of 11 percentage points between the two groups translated into the closed-loop patients spending an additional 2.6 hr/day in the target range of 70-180 mg/dL, Susan A. Brown, MD, and colleagues wrote in the New England Journal of Medicine.

Most of the benefit occurred in the early morning hours, at 5 am, when 89% of patients using the closed-loop system remained in the target range, compared with 62% of those using the pump system, said Dr. Brown of the University of Virginia, Charlottesville, and colleagues.

The randomized study comprised 168 patients with a mean age of 33 years, although the age range was wide (14-71 years). The patients had a mean disease duration of 16 years. Their baseline glycated hemoglobin level ranged between 5.4% and 10.6%. At enrollment, 79% of patients used insulin pumps, and 21% used multiple daily insulin injections; 70% were using continuous glucose monitoring, of whom 86% were using pumps. Patients in both groups had follow-up visits at 2, 6, 13, and 26 weeks.

There were no dropouts in this study – 100% of clinical and telephone follow-ups were completed.

During the 6-month trial, the mean percentage of time spent in the glucose target range rose from 61% at baseline to 71% in the closed-loop group, but remained unchanged at 59% in the pump group. The difference became apparent very early in the study and remained consistent over its course.

“The mean percentage of time that the glucose level was in the target range was 70% in the closed-loop group and 59% in the control [pump] group during the daytime (6 a.m. to midnight) and 76% and 59%, respectively, during the nighttime (midnight to 6 am) ... and the greatest differences in the mean glucose level occurred at 5 a.m. and 6 a.m. [139 mg/dL in the closed-loop group vs. 166 mg/dL in the control group at both time points]. This diurnal pattern is a result of the increased aggressiveness of the algorithm to meet a lower glucose target during the second half of the night,” the authors noted.

The closed-loop system was also better than the pump system on all secondary endpoints, including the following:
 

• Glycated hemoglobin at 26 weeks: mean difference, –0.33 percentage points.
• Percentage of time with glucose higher than 180 mg/dL: mean difference, –10 percentage points (a difference of 2.4 hr/day).
• Percentage of time with glucose less than 70 mg/dL: mean difference, –0.88 percentage points (a difference of 13 min/day).

The other secondary endpoints – mean glucose level and mean glycated hemoglobin level – were also significantly better in those using the closed-loop system.

The benefits “consistently favored the closed-loop system across a broad range of baseline characteristics, including age, sex, body mass index, income, educational level, insulin pump or infection use, previous use of continuous glucose monitor, and glycated hemoglobin,” the authors said.

There were 17 adverse events in 16 patients in the closed-loop group, and 2 events in 2 patients in the pump group, but no incidents of severe hypoglycemia. One person in the closed-loop system experienced ketoacidosis because of a failure in the pump infusion set. There were 13 hyperglycemic or ketosis episodes in 12 patients in the closed-loop group, and 2 in 2 patients the pump group, but none of them met the criteria for diabetic ketoacidosis. All of these episodes were deemed related to infusion set failures.

There were three serious adverse events in the closed-loop group, and none related to the device. Blood ketones exceeding 1 mmol/L occurred in 11 closed-loop patients and 8 pump patients.

The results should be interpreted with consideration of potential group bias, the authors noted. “In our trial, 70% of the patients were using a continuous glucose monitor, and 79% were using an insulin pump at the time of enrollment, percentages that are substantially higher than the reported usage in the general population of type 1 diabetes. These data may reflect an interest in and willingness to use a closed-loop system among patients who were already using devices as part of diabetes management.”

Dr. Brown reported receiving grant support from Tandem Diabetes Care, Dexcom, and Roche Diagnostics. Other authors reported a range of support from numerous pharmaceutical and medical technology companies. Several reported patents on diabetes-related devices.

SOURCE: Brown SA et al. New Engl J Med. 2019 Oct 16. doi: 10.1056/NEJMoa1907863.

Patients with type 1 diabetes who used a closed-loop insulin delivery system spent a greater percentage of time in their target blood glucose range, compared with patients using a sensor-augmented insulin pump.

The significant, between-group, mean-adjusted difference of 11 percentage points between the two groups translated into the closed-loop patients spending an additional 2.6 hr/day in the target range of 70-180 mg/dL, Susan A. Brown, MD, and colleagues wrote in the New England Journal of Medicine.

Most of the benefit occurred in the early morning hours, at 5 am, when 89% of patients using the closed-loop system remained in the target range, compared with 62% of those using the pump system, said Dr. Brown of the University of Virginia, Charlottesville, and colleagues.

The randomized study comprised 168 patients with a mean age of 33 years, although the age range was wide (14-71 years). The patients had a mean disease duration of 16 years. Their baseline glycated hemoglobin level ranged between 5.4% and 10.6%. At enrollment, 79% of patients used insulin pumps, and 21% used multiple daily insulin injections; 70% were using continuous glucose monitoring, of whom 86% were using pumps. Patients in both groups had follow-up visits at 2, 6, 13, and 26 weeks.

There were no dropouts in this study – 100% of clinical and telephone follow-ups were completed.

During the 6-month trial, the mean percentage of time spent in the glucose target range rose from 61% at baseline to 71% in the closed-loop group, but remained unchanged at 59% in the pump group. The difference became apparent very early in the study and remained consistent over its course.

“The mean percentage of time that the glucose level was in the target range was 70% in the closed-loop group and 59% in the control [pump] group during the daytime (6 a.m. to midnight) and 76% and 59%, respectively, during the nighttime (midnight to 6 am) ... and the greatest differences in the mean glucose level occurred at 5 a.m. and 6 a.m. [139 mg/dL in the closed-loop group vs. 166 mg/dL in the control group at both time points]. This diurnal pattern is a result of the increased aggressiveness of the algorithm to meet a lower glucose target during the second half of the night,” the authors noted.

The closed-loop system was also better than the pump system on all secondary endpoints, including the following:
 

• Glycated hemoglobin at 26 weeks: mean difference, –0.33 percentage points.
• Percentage of time with glucose higher than 180 mg/dL: mean difference, –10 percentage points (a difference of 2.4 hr/day).
• Percentage of time with glucose less than 70 mg/dL: mean difference, –0.88 percentage points (a difference of 13 min/day).

The other secondary endpoints – mean glucose level and mean glycated hemoglobin level – were also significantly better in those using the closed-loop system.

The benefits “consistently favored the closed-loop system across a broad range of baseline characteristics, including age, sex, body mass index, income, educational level, insulin pump or infection use, previous use of continuous glucose monitor, and glycated hemoglobin,” the authors said.

There were 17 adverse events in 16 patients in the closed-loop group, and 2 events in 2 patients in the pump group, but no incidents of severe hypoglycemia. One person in the closed-loop system experienced ketoacidosis because of a failure in the pump infusion set. There were 13 hyperglycemic or ketosis episodes in 12 patients in the closed-loop group, and 2 in 2 patients the pump group, but none of them met the criteria for diabetic ketoacidosis. All of these episodes were deemed related to infusion set failures.

There were three serious adverse events in the closed-loop group, and none related to the device. Blood ketones exceeding 1 mmol/L occurred in 11 closed-loop patients and 8 pump patients.

The results should be interpreted with consideration of potential group bias, the authors noted. “In our trial, 70% of the patients were using a continuous glucose monitor, and 79% were using an insulin pump at the time of enrollment, percentages that are substantially higher than the reported usage in the general population of type 1 diabetes. These data may reflect an interest in and willingness to use a closed-loop system among patients who were already using devices as part of diabetes management.”

Dr. Brown reported receiving grant support from Tandem Diabetes Care, Dexcom, and Roche Diagnostics. Other authors reported a range of support from numerous pharmaceutical and medical technology companies. Several reported patents on diabetes-related devices.

SOURCE: Brown SA et al. New Engl J Med. 2019 Oct 16. doi: 10.1056/NEJMoa1907863.

AUSTIN, TEX. – Patients with suspected myasthenia gravis are more likely to have positive repetitive nerve stimulation (RNS) findings if they undergo testing in an inpatient setting, are seropositive, or are classified as Myasthenia Gravis Foundation of America (MGFA) Class III or higher, according to research presented at the annual meeting of the American Association of Neuromuscular and Electrodiagnostic Medicine.

Low-frequency RNS is a common test that neurologists perform to evaluate a patient for myasthenia gravis. The effects of various clinical factors on the diagnostic yield of this test are unknown, however.

Myasthenia gravis is “mostly a clinical diagnosis,” study first author Tingting Hua, a medical student at the University of Missouri in Columbia, said in an interview. “RNS is just one of the helpful diagnostic tests for it. If we can find out in what kind of populations of patients this test is more helpful, maybe that would help cut down unnecessary tests in patients for whom it’s not necessarily helpful.”

Ms. Hua and her colleagues conducted research to assess the effects of clinical, serologic, and demographic factors on the diagnostic yield of RNS. They retrospectively analyzed patients with an established diagnosis of myasthenia gravis and at least 1 year of follow-up. The variables that the investigators examined were demographic characteristics, MGFA class, RNS study results, antibody test results, thymoma status, and treatments received.

Ms. Hua and her colleagues included 65 patients in their analysis. Thirty-one patients were female. Fifty-five patients were white, eight were black, and two were categorized as “unknown.” Of this population, 32 patients (49.2%) were in MGFA Class I, 14 (21.5%) were in MGFA Class IIa, 13 (20.0%) were in MGFA Class IIb, and the remaining 6 (9.2%) were in MGFA Classes IIIa through V. Twenty-seven patients (42%) had positive RNS studies. Twenty-one patients (32%) were seropositive for myasthenia gravis antibodies.

Eleven patients underwent RNS in an inpatient setting, and 54 were tested in an outpatient setting. Acetylcholine receptor (AChR) binding antibody titer ranged from 0.12 nmol/L to 118 nmol/L. The RNS results were significantly more likely to be positive for seropositive patients, compared with seronegative patients. Patients with MGFA Class III or higher also had higher likelihood of positive RNS results, compared with patients in lower classes. Finally, the diagnostic yield was highest for patients with MGFA Class III or higher who were tested in an inpatient setting.

The study was supported by a Missouri School of Medicine Summer Research Fellowship.

[email protected]

SOURCE: Hua T et al. AANEM 2019, Abstract 9.

AUSTIN, TEX. – Patients with suspected myasthenia gravis are more likely to have positive repetitive nerve stimulation (RNS) findings if they undergo testing in an inpatient setting, are seropositive, or are classified as Myasthenia Gravis Foundation of America (MGFA) Class III or higher, according to research presented at the annual meeting of the American Association of Neuromuscular and Electrodiagnostic Medicine.

Low-frequency RNS is a common test that neurologists perform to evaluate a patient for myasthenia gravis. The effects of various clinical factors on the diagnostic yield of this test are unknown, however.

Myasthenia gravis is “mostly a clinical diagnosis,” study first author Tingting Hua, a medical student at the University of Missouri in Columbia, said in an interview. “RNS is just one of the helpful diagnostic tests for it. If we can find out in what kind of populations of patients this test is more helpful, maybe that would help cut down unnecessary tests in patients for whom it’s not necessarily helpful.”

Ms. Hua and her colleagues conducted research to assess the effects of clinical, serologic, and demographic factors on the diagnostic yield of RNS. They retrospectively analyzed patients with an established diagnosis of myasthenia gravis and at least 1 year of follow-up. The variables that the investigators examined were demographic characteristics, MGFA class, RNS study results, antibody test results, thymoma status, and treatments received.

Ms. Hua and her colleagues included 65 patients in their analysis. Thirty-one patients were female. Fifty-five patients were white, eight were black, and two were categorized as “unknown.” Of this population, 32 patients (49.2%) were in MGFA Class I, 14 (21.5%) were in MGFA Class IIa, 13 (20.0%) were in MGFA Class IIb, and the remaining 6 (9.2%) were in MGFA Classes IIIa through V. Twenty-seven patients (42%) had positive RNS studies. Twenty-one patients (32%) were seropositive for myasthenia gravis antibodies.

Eleven patients underwent RNS in an inpatient setting, and 54 were tested in an outpatient setting. Acetylcholine receptor (AChR) binding antibody titer ranged from 0.12 nmol/L to 118 nmol/L. The RNS results were significantly more likely to be positive for seropositive patients, compared with seronegative patients. Patients with MGFA Class III or higher also had higher likelihood of positive RNS results, compared with patients in lower classes. Finally, the diagnostic yield was highest for patients with MGFA Class III or higher who were tested in an inpatient setting.

The study was supported by a Missouri School of Medicine Summer Research Fellowship.

[email protected]

SOURCE: Hua T et al. AANEM 2019, Abstract 9.

AUSTIN, TEX. – Patients with suspected myasthenia gravis are more likely to have positive repetitive nerve stimulation (RNS) findings if they undergo testing in an inpatient setting, are seropositive, or are classified as Myasthenia Gravis Foundation of America (MGFA) Class III or higher, according to research presented at the annual meeting of the American Association of Neuromuscular and Electrodiagnostic Medicine.

Low-frequency RNS is a common test that neurologists perform to evaluate a patient for myasthenia gravis. The effects of various clinical factors on the diagnostic yield of this test are unknown, however.

Myasthenia gravis is “mostly a clinical diagnosis,” study first author Tingting Hua, a medical student at the University of Missouri in Columbia, said in an interview. “RNS is just one of the helpful diagnostic tests for it. If we can find out in what kind of populations of patients this test is more helpful, maybe that would help cut down unnecessary tests in patients for whom it’s not necessarily helpful.”

Ms. Hua and her colleagues conducted research to assess the effects of clinical, serologic, and demographic factors on the diagnostic yield of RNS. They retrospectively analyzed patients with an established diagnosis of myasthenia gravis and at least 1 year of follow-up. The variables that the investigators examined were demographic characteristics, MGFA class, RNS study results, antibody test results, thymoma status, and treatments received.

Ms. Hua and her colleagues included 65 patients in their analysis. Thirty-one patients were female. Fifty-five patients were white, eight were black, and two were categorized as “unknown.” Of this population, 32 patients (49.2%) were in MGFA Class I, 14 (21.5%) were in MGFA Class IIa, 13 (20.0%) were in MGFA Class IIb, and the remaining 6 (9.2%) were in MGFA Classes IIIa through V. Twenty-seven patients (42%) had positive RNS studies. Twenty-one patients (32%) were seropositive for myasthenia gravis antibodies.

Eleven patients underwent RNS in an inpatient setting, and 54 were tested in an outpatient setting. Acetylcholine receptor (AChR) binding antibody titer ranged from 0.12 nmol/L to 118 nmol/L. The RNS results were significantly more likely to be positive for seropositive patients, compared with seronegative patients. Patients with MGFA Class III or higher also had higher likelihood of positive RNS results, compared with patients in lower classes. Finally, the diagnostic yield was highest for patients with MGFA Class III or higher who were tested in an inpatient setting.

The study was supported by a Missouri School of Medicine Summer Research Fellowship.

[email protected]

SOURCE: Hua T et al. AANEM 2019, Abstract 9.

AUSTIN, TEX. – During a 3-year period, 5.7% of patients referred to an electromyography laboratory returned for at least one additional electrodiagnostic study, according to research presented at the annual meeting of the American Association of Neuromuscular and Electrodiagnostic Medicine. A preliminary analysis suggests that repeat testing for the same indication does not change symptom or disease management in about one-third of cases.

Jake Remaly/MDedge News

Physicians may request repeat electrodiagnostic studies to monitor previous, new, or progressing symptoms in the same or different body segments. “While the utility of [electrodiagnostic] studies for clinical care has been established, testing is associated with some patient risk, time, and cost,” the researchers wrote. “To date, there have been no known studies investigating the utility of repeat [electrodiagnostic] testing in the outpatient setting.”

To study referral patterns and outcomes following repeat electrodiagnostic testing, Aimee K. Boegle, MD, PhD, an instructor in neurology at Beth Israel Deaconess Medical Center in Boston, and colleagues examined all outpatient electromyography and nerve conduction studies performed between 2015 and 2017 in the neurology department at their institution. The investigators excluded patients who underwent inpatient electrodiagnostic studies from their analysis.

Approximately 4,800 patients underwent electrodiagnostic testing, 276 of whom underwent testing more than once.

Among patients who underwent two studies, 55% were referred by a different physician for the second study. Median neuropathy was the most common referring and final diagnosis among patients who underwent repeat electrodiagnostic testing, Dr. Boegle said. This finding was not surprising because carpal tunnel syndrome is among the most common reasons for referral overall.

Median neuropathy was the referring diagnosis in 31% and the final diagnosis in 30%, cervical radiculopathy in 15% and 14%, ulnar neuropathy in 14% and 17%, lumbosacral radiculopathy in 12% and 10%, and polyneuropathy in 8% and 10%.

The neurology and orthopedics departments made the most referrals for repeat electrodiagnostic studies (49.4% and 29.3%, respectively), followed by primary care physicians/internal medicine (13%).

About 24% of the returning patients underwent testing for the same indication as their initial referral.

A preliminary analysis of 26 patients who underwent a repeat study for the same indication found no change in treatment in 34%. When a study prompted intervention, a conservative course of management such as a splint or physical therapy was used in 42%. About 8% received a pharmacologic intervention, such as a medication change or steroid injections. Another 8% received a surgical intervention and about 8% received further work-up.

The researchers had no relevant disclosures.
 

[email protected]

SOURCE: Boegle AK et al. AANEM 2019, Abstract 85.

AUSTIN, TEX. – During a 3-year period, 5.7% of patients referred to an electromyography laboratory returned for at least one additional electrodiagnostic study, according to research presented at the annual meeting of the American Association of Neuromuscular and Electrodiagnostic Medicine. A preliminary analysis suggests that repeat testing for the same indication does not change symptom or disease management in about one-third of cases.

Jake Remaly/MDedge News

Physicians may request repeat electrodiagnostic studies to monitor previous, new, or progressing symptoms in the same or different body segments. “While the utility of [electrodiagnostic] studies for clinical care has been established, testing is associated with some patient risk, time, and cost,” the researchers wrote. “To date, there have been no known studies investigating the utility of repeat [electrodiagnostic] testing in the outpatient setting.”

To study referral patterns and outcomes following repeat electrodiagnostic testing, Aimee K. Boegle, MD, PhD, an instructor in neurology at Beth Israel Deaconess Medical Center in Boston, and colleagues examined all outpatient electromyography and nerve conduction studies performed between 2015 and 2017 in the neurology department at their institution. The investigators excluded patients who underwent inpatient electrodiagnostic studies from their analysis.

Approximately 4,800 patients underwent electrodiagnostic testing, 276 of whom underwent testing more than once.

Among patients who underwent two studies, 55% were referred by a different physician for the second study. Median neuropathy was the most common referring and final diagnosis among patients who underwent repeat electrodiagnostic testing, Dr. Boegle said. This finding was not surprising because carpal tunnel syndrome is among the most common reasons for referral overall.

Median neuropathy was the referring diagnosis in 31% and the final diagnosis in 30%, cervical radiculopathy in 15% and 14%, ulnar neuropathy in 14% and 17%, lumbosacral radiculopathy in 12% and 10%, and polyneuropathy in 8% and 10%.

The neurology and orthopedics departments made the most referrals for repeat electrodiagnostic studies (49.4% and 29.3%, respectively), followed by primary care physicians/internal medicine (13%).

About 24% of the returning patients underwent testing for the same indication as their initial referral.

A preliminary analysis of 26 patients who underwent a repeat study for the same indication found no change in treatment in 34%. When a study prompted intervention, a conservative course of management such as a splint or physical therapy was used in 42%. About 8% received a pharmacologic intervention, such as a medication change or steroid injections. Another 8% received a surgical intervention and about 8% received further work-up.

The researchers had no relevant disclosures.
 

[email protected]

SOURCE: Boegle AK et al. AANEM 2019, Abstract 85.

AUSTIN, TEX. – During a 3-year period, 5.7% of patients referred to an electromyography laboratory returned for at least one additional electrodiagnostic study, according to research presented at the annual meeting of the American Association of Neuromuscular and Electrodiagnostic Medicine. A preliminary analysis suggests that repeat testing for the same indication does not change symptom or disease management in about one-third of cases.

Jake Remaly/MDedge News

Physicians may request repeat electrodiagnostic studies to monitor previous, new, or progressing symptoms in the same or different body segments. “While the utility of [electrodiagnostic] studies for clinical care has been established, testing is associated with some patient risk, time, and cost,” the researchers wrote. “To date, there have been no known studies investigating the utility of repeat [electrodiagnostic] testing in the outpatient setting.”

To study referral patterns and outcomes following repeat electrodiagnostic testing, Aimee K. Boegle, MD, PhD, an instructor in neurology at Beth Israel Deaconess Medical Center in Boston, and colleagues examined all outpatient electromyography and nerve conduction studies performed between 2015 and 2017 in the neurology department at their institution. The investigators excluded patients who underwent inpatient electrodiagnostic studies from their analysis.

Approximately 4,800 patients underwent electrodiagnostic testing, 276 of whom underwent testing more than once.

Among patients who underwent two studies, 55% were referred by a different physician for the second study. Median neuropathy was the most common referring and final diagnosis among patients who underwent repeat electrodiagnostic testing, Dr. Boegle said. This finding was not surprising because carpal tunnel syndrome is among the most common reasons for referral overall.

Median neuropathy was the referring diagnosis in 31% and the final diagnosis in 30%, cervical radiculopathy in 15% and 14%, ulnar neuropathy in 14% and 17%, lumbosacral radiculopathy in 12% and 10%, and polyneuropathy in 8% and 10%.

The neurology and orthopedics departments made the most referrals for repeat electrodiagnostic studies (49.4% and 29.3%, respectively), followed by primary care physicians/internal medicine (13%).

About 24% of the returning patients underwent testing for the same indication as their initial referral.

A preliminary analysis of 26 patients who underwent a repeat study for the same indication found no change in treatment in 34%. When a study prompted intervention, a conservative course of management such as a splint or physical therapy was used in 42%. About 8% received a pharmacologic intervention, such as a medication change or steroid injections. Another 8% received a surgical intervention and about 8% received further work-up.

The researchers had no relevant disclosures.
 

[email protected]

SOURCE: Boegle AK et al. AANEM 2019, Abstract 85.

MADRID – A placebo-controlled trial has confirmed that amoxicillin/clavulanate is beneficial for resolution of acute exacerbations in nonsevere bronchiectasis while also demonstrating a greater relative effect than azithromycin, based on data presented at the annual congress of the European Respiratory Society.

“We now have robust data with which to support our guidelines,” reported Vikas Goyal, MD, of the Children’s Health Clinical Unit, University of Queensland, Brisbane, Australia.

The study addresses a knowledge gap. Antibiotics are already recommended by many guidelines for treatment of acute exacerbations in children with bronchiectasis, but Dr. Goyal said that no controlled trials have ever been performed in this age group to confirm superiority to placebo.

In this multicenter study, called BEST-1, 197 children with bronchiectasis were randomized at the start of an exacerbation to placebo, 45 mg/kg per day of amoxicillin/clavulanate, or 5 mg/kg per day of azithromycin. To maintain blinding, patients in the active treatment groups received a dummy for the opposite antibiotic while patients on placebo received dummies for both active agents.

For the primary outcome, 65% of children randomized to amoxicillin/clavulanate had resolution of their exacerbation by day 14 versus 61% of those randomized to azithromycin and 43% of those randomized to placebo. On the basis of relative risk for reaching this end point, the outcome was superior to placebo for amoxicillin/clavulanate (RR, 1.5; P = .015).

Although the relative risk for azithromycin (RR, 1.4; P = .042) was only slightly lower, it did not reach a prespecified level of significance set at P = .025. Dr. Goyal did report that the resolution rate at 14 days in the placebo group was “higher than expected.”

In this trial, 53% of the 154 children who were tested for respiratory viruses with nasal swabs on day 1 of the exacerbation were found to have respiratory viruses. Of these viruses, rhinovirus was the most common, according to Dr. Goyal, whose data were published just prior to his presentation (Lancet Respir Med. 2019;7:791-801).

The median durations of the exacerbations were 7 days, 8 days, and 10 days for those treated with amoxicillin/clavulanate, azithromycin, and placebo, respectively. The difference between amoxicillin/clavulanate and placebo, but not that between azithromycin and placebo, reached statistical significance, Dr. Goyal said.

There were no between group differences in the time to next exacerbation.

In discussing limitations of this study, Dr. Goyal pointed out that the optimal doses of amoxicillin/clavulanate or azithromycin have never been established for the treatment of exacerbations in children with bronchiectasis. He noted that some infectious disease specialists have advocated higher doses of both than those employed in this trial, but dose-ranging studies have never been conducted in this age group.

In this study, adverse events were less common on azithromycin than amoxicillin/clavulanate (21% vs. 30%), but none were severe, according to Dr. Goyal. He said treatment with azithromycin was associated with increased macrolide-resistant bacteria.

On the basis of these data, Dr. Goyal concluded that amoxicillin/clavulanate should remain, as already specified in some guidelines, the standard first-line therapy for nonsevere exacerbations in nonhospitalized children with bronchiectasis. He recommended reserving azithromycin as an alternative therapy.

Dr. Goyal reports no potential conflicts of interest.

SOURCE: Goyal V et al. Lancet Respir Med. 2019;7:791-801.

MADRID – A placebo-controlled trial has confirmed that amoxicillin/clavulanate is beneficial for resolution of acute exacerbations in nonsevere bronchiectasis while also demonstrating a greater relative effect than azithromycin, based on data presented at the annual congress of the European Respiratory Society.

“We now have robust data with which to support our guidelines,” reported Vikas Goyal, MD, of the Children’s Health Clinical Unit, University of Queensland, Brisbane, Australia.

The study addresses a knowledge gap. Antibiotics are already recommended by many guidelines for treatment of acute exacerbations in children with bronchiectasis, but Dr. Goyal said that no controlled trials have ever been performed in this age group to confirm superiority to placebo.

In this multicenter study, called BEST-1, 197 children with bronchiectasis were randomized at the start of an exacerbation to placebo, 45 mg/kg per day of amoxicillin/clavulanate, or 5 mg/kg per day of azithromycin. To maintain blinding, patients in the active treatment groups received a dummy for the opposite antibiotic while patients on placebo received dummies for both active agents.

For the primary outcome, 65% of children randomized to amoxicillin/clavulanate had resolution of their exacerbation by day 14 versus 61% of those randomized to azithromycin and 43% of those randomized to placebo. On the basis of relative risk for reaching this end point, the outcome was superior to placebo for amoxicillin/clavulanate (RR, 1.5; P = .015).

Although the relative risk for azithromycin (RR, 1.4; P = .042) was only slightly lower, it did not reach a prespecified level of significance set at P = .025. Dr. Goyal did report that the resolution rate at 14 days in the placebo group was “higher than expected.”

In this trial, 53% of the 154 children who were tested for respiratory viruses with nasal swabs on day 1 of the exacerbation were found to have respiratory viruses. Of these viruses, rhinovirus was the most common, according to Dr. Goyal, whose data were published just prior to his presentation (Lancet Respir Med. 2019;7:791-801).

The median durations of the exacerbations were 7 days, 8 days, and 10 days for those treated with amoxicillin/clavulanate, azithromycin, and placebo, respectively. The difference between amoxicillin/clavulanate and placebo, but not that between azithromycin and placebo, reached statistical significance, Dr. Goyal said.

There were no between group differences in the time to next exacerbation.

In discussing limitations of this study, Dr. Goyal pointed out that the optimal doses of amoxicillin/clavulanate or azithromycin have never been established for the treatment of exacerbations in children with bronchiectasis. He noted that some infectious disease specialists have advocated higher doses of both than those employed in this trial, but dose-ranging studies have never been conducted in this age group.

In this study, adverse events were less common on azithromycin than amoxicillin/clavulanate (21% vs. 30%), but none were severe, according to Dr. Goyal. He said treatment with azithromycin was associated with increased macrolide-resistant bacteria.

On the basis of these data, Dr. Goyal concluded that amoxicillin/clavulanate should remain, as already specified in some guidelines, the standard first-line therapy for nonsevere exacerbations in nonhospitalized children with bronchiectasis. He recommended reserving azithromycin as an alternative therapy.

Dr. Goyal reports no potential conflicts of interest.

SOURCE: Goyal V et al. Lancet Respir Med. 2019;7:791-801.

MADRID – A placebo-controlled trial has confirmed that amoxicillin/clavulanate is beneficial for resolution of acute exacerbations in nonsevere bronchiectasis while also demonstrating a greater relative effect than azithromycin, based on data presented at the annual congress of the European Respiratory Society.

“We now have robust data with which to support our guidelines,” reported Vikas Goyal, MD, of the Children’s Health Clinical Unit, University of Queensland, Brisbane, Australia.

The study addresses a knowledge gap. Antibiotics are already recommended by many guidelines for treatment of acute exacerbations in children with bronchiectasis, but Dr. Goyal said that no controlled trials have ever been performed in this age group to confirm superiority to placebo.

In this multicenter study, called BEST-1, 197 children with bronchiectasis were randomized at the start of an exacerbation to placebo, 45 mg/kg per day of amoxicillin/clavulanate, or 5 mg/kg per day of azithromycin. To maintain blinding, patients in the active treatment groups received a dummy for the opposite antibiotic while patients on placebo received dummies for both active agents.

For the primary outcome, 65% of children randomized to amoxicillin/clavulanate had resolution of their exacerbation by day 14 versus 61% of those randomized to azithromycin and 43% of those randomized to placebo. On the basis of relative risk for reaching this end point, the outcome was superior to placebo for amoxicillin/clavulanate (RR, 1.5; P = .015).

Although the relative risk for azithromycin (RR, 1.4; P = .042) was only slightly lower, it did not reach a prespecified level of significance set at P = .025. Dr. Goyal did report that the resolution rate at 14 days in the placebo group was “higher than expected.”

In this trial, 53% of the 154 children who were tested for respiratory viruses with nasal swabs on day 1 of the exacerbation were found to have respiratory viruses. Of these viruses, rhinovirus was the most common, according to Dr. Goyal, whose data were published just prior to his presentation (Lancet Respir Med. 2019;7:791-801).

The median durations of the exacerbations were 7 days, 8 days, and 10 days for those treated with amoxicillin/clavulanate, azithromycin, and placebo, respectively. The difference between amoxicillin/clavulanate and placebo, but not that between azithromycin and placebo, reached statistical significance, Dr. Goyal said.

There were no between group differences in the time to next exacerbation.

In discussing limitations of this study, Dr. Goyal pointed out that the optimal doses of amoxicillin/clavulanate or azithromycin have never been established for the treatment of exacerbations in children with bronchiectasis. He noted that some infectious disease specialists have advocated higher doses of both than those employed in this trial, but dose-ranging studies have never been conducted in this age group.

In this study, adverse events were less common on azithromycin than amoxicillin/clavulanate (21% vs. 30%), but none were severe, according to Dr. Goyal. He said treatment with azithromycin was associated with increased macrolide-resistant bacteria.

On the basis of these data, Dr. Goyal concluded that amoxicillin/clavulanate should remain, as already specified in some guidelines, the standard first-line therapy for nonsevere exacerbations in nonhospitalized children with bronchiectasis. He recommended reserving azithromycin as an alternative therapy.

Dr. Goyal reports no potential conflicts of interest.

SOURCE: Goyal V et al. Lancet Respir Med. 2019;7:791-801.

Read the full Cutis article, “Quality of Life in Patients With Atopic Dermatitis.”

Read the full Cutis article, “Quality of Life in Patients With Atopic Dermatitis.”

Read the full Cutis article, “Quality of Life in Patients With Atopic Dermatitis.”

SEATTLE – While current treatments for actinic keratosis include variations on light therapy and strategies such as field cancerization, the nitrogen tank in the corner of the office is likely to stay, David Pariser, MD, said during a presentation at the annual Coastal Dermatology Symposium.

“My personal view is that, no matter how good other treatments are eventually going to be, we’re never going to give that up,” Dr. Pariser, professor of dermatology at Eastern Virginia Medical School, Norfolk, said at the meeting, jointly presented by the University of Louisville and Global Academy for Medical Education.

During the presentation, he emphasized that it isn’t always clear which actinic keratosis (AK) should be treated and which can be left alone, since most AKs don’t progress to squamous cell carcinoma (SCC). “We know that most squamous cell carcinomas arise near AKs, and many of them have histologic evidence” of AK/SCC continuum at the periphery, he said. Sun protection reduces the incidence of AKs and the incidence of nonmelanoma skin cancer, “so it’s a logical conclusion that treating AKs reduces the development of SCCs, but there are no data to show that.”

Generally, treatment decisions are made based on the presence of symptoms, location, or appearance; if the area is irritated; or there is a progressive or unusual appearance, especially if hyperkeratotic. Physician or patient concerns about cancer can prompt treatment, as should a history of multiple skin cancers or the presence of immunosuppression, he said.

Treatment options include cryosurgery, surgery, topical agents, and photodynamic therapy (PDT); Dr. Pariser focused on the latter because it is a special interest of his.

Field cancerization is based on the idea that a broad area of cells may be at risk for developing into SCC, rather than just individual AKs. Treatment with methyl 5-aminolevulinate (MAL) can reveal the extent of a problem. In some patients, “you can see a lot of fluorescence in areas that look reasonably clinically normal. So this is a piece of evidence of this field cancerization, that maybe we shouldn’t be treating individual AKs, but larger areas,” Dr. Pariser said.

With PDT, there has been some debate about how long to leave the photosensitizer on the skin before applying the light. The longer it remains, the more it spreads to nerves, which can lead to pain during the procedure. A clinical trial comparing 1-, 2-, and 3-hour wait times showed no difference in efficacy. “So 1 hour is what I do for AKs, that’s it,” Dr. Pariser said.

There are two Food and Drug Administration–approved PDT systems, a blue-light system combined with aminolevulinic acid (ALA) and a newer red-light system combined with a nanoemulsion of ALA 7.8% and a proprietary 635-nm red LED light. The nanoemulsion has the theoretical advantage in that it can penetrate more deeply into the epidermis, though this isn’t really an issue when treating AKs, according to Dr. Pariser.

A study comparing nanoemulsion of ALA, compared with a MAL cream, found the nanoemulsion to be superior in achieving complete clearance of all lesions at 12 weeks (78.2% vs. 64.2%; P less than .05). Both treatments achieved best efficacy with LED lamps, and the proprietary red light may reduce pain by allowing use of lower light intensity (Br J Dermatol. 2012 Jan; 166[1]:137-46).

Another study, Dr. Pariser said, looked at whether occlusion during drug incubation improves outcomes of blue light ALA-PDT (J Drugs Dermatol. 2012;11[12]:1483-9). Patients underwent split occlusion on the upper extremities before undergoing blue-light treatment. The median clearance rate of AKs at 8 weeks was higher with occlusion, compared with the nonoccluded areas (75% vs. 47%; P = .006), and at 12 weeks, after a second treatment (89% vs. 70%; P = .00029). There was a higher efficacy with a 3-hour incubation period, compared with studies using a 2-hour incubation period.

Application of heat can also boost success rates by increasing the synthesis of the photoactive agent, Dr. Pariser said. One study found that a simple heating pad applied to the area treated with ALA-PDT and blue light led to an 88% reduction in lesions at 8 and 24 weeks, compared with a reduction of 71% at 8 weeks and 68% at 24 weeks without heat (P less than .0001). “So if you want to give PDT a little extra oomph, add occlusion and heat,” he commented.

He also pointed out the availability of a new 4% 5-fluorouracil cream that contains peanut oil, which has similar efficacy to 5% 5-fluorouracil cream but has been associated with less pruritus, stinging/burning, edema, crusting, scaling/dryness, erosion, and erythema (J Drugs Dermatol. 2016 Oct 1;15[10]: 1218-24).

Dr. Pariser is an investigator and consultant for DUSA/Sun Pharma, Photocure, LEO Pharma, and Biofrontera. This publication and Global Academy for Medical Education are owned by the same parent company.

SEATTLE – While current treatments for actinic keratosis include variations on light therapy and strategies such as field cancerization, the nitrogen tank in the corner of the office is likely to stay, David Pariser, MD, said during a presentation at the annual Coastal Dermatology Symposium.

“My personal view is that, no matter how good other treatments are eventually going to be, we’re never going to give that up,” Dr. Pariser, professor of dermatology at Eastern Virginia Medical School, Norfolk, said at the meeting, jointly presented by the University of Louisville and Global Academy for Medical Education.

During the presentation, he emphasized that it isn’t always clear which actinic keratosis (AK) should be treated and which can be left alone, since most AKs don’t progress to squamous cell carcinoma (SCC). “We know that most squamous cell carcinomas arise near AKs, and many of them have histologic evidence” of AK/SCC continuum at the periphery, he said. Sun protection reduces the incidence of AKs and the incidence of nonmelanoma skin cancer, “so it’s a logical conclusion that treating AKs reduces the development of SCCs, but there are no data to show that.”

Generally, treatment decisions are made based on the presence of symptoms, location, or appearance; if the area is irritated; or there is a progressive or unusual appearance, especially if hyperkeratotic. Physician or patient concerns about cancer can prompt treatment, as should a history of multiple skin cancers or the presence of immunosuppression, he said.

Treatment options include cryosurgery, surgery, topical agents, and photodynamic therapy (PDT); Dr. Pariser focused on the latter because it is a special interest of his.

Field cancerization is based on the idea that a broad area of cells may be at risk for developing into SCC, rather than just individual AKs. Treatment with methyl 5-aminolevulinate (MAL) can reveal the extent of a problem. In some patients, “you can see a lot of fluorescence in areas that look reasonably clinically normal. So this is a piece of evidence of this field cancerization, that maybe we shouldn’t be treating individual AKs, but larger areas,” Dr. Pariser said.

With PDT, there has been some debate about how long to leave the photosensitizer on the skin before applying the light. The longer it remains, the more it spreads to nerves, which can lead to pain during the procedure. A clinical trial comparing 1-, 2-, and 3-hour wait times showed no difference in efficacy. “So 1 hour is what I do for AKs, that’s it,” Dr. Pariser said.

There are two Food and Drug Administration–approved PDT systems, a blue-light system combined with aminolevulinic acid (ALA) and a newer red-light system combined with a nanoemulsion of ALA 7.8% and a proprietary 635-nm red LED light. The nanoemulsion has the theoretical advantage in that it can penetrate more deeply into the epidermis, though this isn’t really an issue when treating AKs, according to Dr. Pariser.

A study comparing nanoemulsion of ALA, compared with a MAL cream, found the nanoemulsion to be superior in achieving complete clearance of all lesions at 12 weeks (78.2% vs. 64.2%; P less than .05). Both treatments achieved best efficacy with LED lamps, and the proprietary red light may reduce pain by allowing use of lower light intensity (Br J Dermatol. 2012 Jan; 166[1]:137-46).

Another study, Dr. Pariser said, looked at whether occlusion during drug incubation improves outcomes of blue light ALA-PDT (J Drugs Dermatol. 2012;11[12]:1483-9). Patients underwent split occlusion on the upper extremities before undergoing blue-light treatment. The median clearance rate of AKs at 8 weeks was higher with occlusion, compared with the nonoccluded areas (75% vs. 47%; P = .006), and at 12 weeks, after a second treatment (89% vs. 70%; P = .00029). There was a higher efficacy with a 3-hour incubation period, compared with studies using a 2-hour incubation period.

Application of heat can also boost success rates by increasing the synthesis of the photoactive agent, Dr. Pariser said. One study found that a simple heating pad applied to the area treated with ALA-PDT and blue light led to an 88% reduction in lesions at 8 and 24 weeks, compared with a reduction of 71% at 8 weeks and 68% at 24 weeks without heat (P less than .0001). “So if you want to give PDT a little extra oomph, add occlusion and heat,” he commented.

He also pointed out the availability of a new 4% 5-fluorouracil cream that contains peanut oil, which has similar efficacy to 5% 5-fluorouracil cream but has been associated with less pruritus, stinging/burning, edema, crusting, scaling/dryness, erosion, and erythema (J Drugs Dermatol. 2016 Oct 1;15[10]: 1218-24).

Dr. Pariser is an investigator and consultant for DUSA/Sun Pharma, Photocure, LEO Pharma, and Biofrontera. This publication and Global Academy for Medical Education are owned by the same parent company.

SEATTLE – While current treatments for actinic keratosis include variations on light therapy and strategies such as field cancerization, the nitrogen tank in the corner of the office is likely to stay, David Pariser, MD, said during a presentation at the annual Coastal Dermatology Symposium.

“My personal view is that, no matter how good other treatments are eventually going to be, we’re never going to give that up,” Dr. Pariser, professor of dermatology at Eastern Virginia Medical School, Norfolk, said at the meeting, jointly presented by the University of Louisville and Global Academy for Medical Education.

During the presentation, he emphasized that it isn’t always clear which actinic keratosis (AK) should be treated and which can be left alone, since most AKs don’t progress to squamous cell carcinoma (SCC). “We know that most squamous cell carcinomas arise near AKs, and many of them have histologic evidence” of AK/SCC continuum at the periphery, he said. Sun protection reduces the incidence of AKs and the incidence of nonmelanoma skin cancer, “so it’s a logical conclusion that treating AKs reduces the development of SCCs, but there are no data to show that.”

Generally, treatment decisions are made based on the presence of symptoms, location, or appearance; if the area is irritated; or there is a progressive or unusual appearance, especially if hyperkeratotic. Physician or patient concerns about cancer can prompt treatment, as should a history of multiple skin cancers or the presence of immunosuppression, he said.

Treatment options include cryosurgery, surgery, topical agents, and photodynamic therapy (PDT); Dr. Pariser focused on the latter because it is a special interest of his.

Field cancerization is based on the idea that a broad area of cells may be at risk for developing into SCC, rather than just individual AKs. Treatment with methyl 5-aminolevulinate (MAL) can reveal the extent of a problem. In some patients, “you can see a lot of fluorescence in areas that look reasonably clinically normal. So this is a piece of evidence of this field cancerization, that maybe we shouldn’t be treating individual AKs, but larger areas,” Dr. Pariser said.

With PDT, there has been some debate about how long to leave the photosensitizer on the skin before applying the light. The longer it remains, the more it spreads to nerves, which can lead to pain during the procedure. A clinical trial comparing 1-, 2-, and 3-hour wait times showed no difference in efficacy. “So 1 hour is what I do for AKs, that’s it,” Dr. Pariser said.

There are two Food and Drug Administration–approved PDT systems, a blue-light system combined with aminolevulinic acid (ALA) and a newer red-light system combined with a nanoemulsion of ALA 7.8% and a proprietary 635-nm red LED light. The nanoemulsion has the theoretical advantage in that it can penetrate more deeply into the epidermis, though this isn’t really an issue when treating AKs, according to Dr. Pariser.

A study comparing nanoemulsion of ALA, compared with a MAL cream, found the nanoemulsion to be superior in achieving complete clearance of all lesions at 12 weeks (78.2% vs. 64.2%; P less than .05). Both treatments achieved best efficacy with LED lamps, and the proprietary red light may reduce pain by allowing use of lower light intensity (Br J Dermatol. 2012 Jan; 166[1]:137-46).

Another study, Dr. Pariser said, looked at whether occlusion during drug incubation improves outcomes of blue light ALA-PDT (J Drugs Dermatol. 2012;11[12]:1483-9). Patients underwent split occlusion on the upper extremities before undergoing blue-light treatment. The median clearance rate of AKs at 8 weeks was higher with occlusion, compared with the nonoccluded areas (75% vs. 47%; P = .006), and at 12 weeks, after a second treatment (89% vs. 70%; P = .00029). There was a higher efficacy with a 3-hour incubation period, compared with studies using a 2-hour incubation period.

Application of heat can also boost success rates by increasing the synthesis of the photoactive agent, Dr. Pariser said. One study found that a simple heating pad applied to the area treated with ALA-PDT and blue light led to an 88% reduction in lesions at 8 and 24 weeks, compared with a reduction of 71% at 8 weeks and 68% at 24 weeks without heat (P less than .0001). “So if you want to give PDT a little extra oomph, add occlusion and heat,” he commented.

He also pointed out the availability of a new 4% 5-fluorouracil cream that contains peanut oil, which has similar efficacy to 5% 5-fluorouracil cream but has been associated with less pruritus, stinging/burning, edema, crusting, scaling/dryness, erosion, and erythema (J Drugs Dermatol. 2016 Oct 1;15[10]: 1218-24).

Dr. Pariser is an investigator and consultant for DUSA/Sun Pharma, Photocure, LEO Pharma, and Biofrontera. This publication and Global Academy for Medical Education are owned by the same parent company.

About 100,000 people in America have sickle cell disease. Of those, an estimated 27 people have undergone experimental gene therapy using conventional vectors—virus-based vehicles for delivering “therapeutic genes.” Now National Institutes of Health researchers have taken the vector idea and revved it up, bringing the possibility of curing sickle cell disease a bit closer.

With gene therapy, doctors add a normal copy of the β-globin gene to the patient’s hematopoietic stem cells, then reinfuse the modified stem cells into the patient to produce normal disc-shaped red blood cells. In animal studies, the new vector was up to 10 times more efficient at incorporating corrective genes into bone marrow stem cells with a carrying capacity of up to 6 times greater viral load than current vectors. The new vectors also can be produced in much higher amounts, saving time and lowering costs.

The researchers call it a “forward-oriented” vector because it changes the usual direction of how gene sequences in globin-containing vectors are read: from right to left. That backward orientation—globin-containing vectors are the only therapeutic vectors in clinical development that use it—the researchers say, “has remained unchallenged for decades despite its negative impacts on efficiency.”

The right-to-left orientation was dictated by the need to prevent the loss of a key molecular component, intron 2, by RNA splicing during the vector preparation. The redesigned forward-reading method crucially leaves intron 2 intact and makes the gene-translation approach less complicated, says John Tisdale, MD, chief of the Cellular and Molecular Therapeutic Branch at the National Heart, Lung, and Blood Institute, who, with Naoya Uchida, MD, PhD, came up with the idea.

In testing, the new vectors also proved longer lasting, remaining in place 4 years after transplantation.

National Institutes of Health is working to accelerate research and development through the Cure Sickle Cell Initiative, launched by NHLBI in 2018 to identify and support the most promising genetic therapies for the more than 20 million people worldwide who have sickle cell disease. NIH holds the patent for the new vector, which still will need clinical testing in humans. Clinical trials are actively enrolling.

About 100,000 people in America have sickle cell disease. Of those, an estimated 27 people have undergone experimental gene therapy using conventional vectors—virus-based vehicles for delivering “therapeutic genes.” Now National Institutes of Health researchers have taken the vector idea and revved it up, bringing the possibility of curing sickle cell disease a bit closer.

With gene therapy, doctors add a normal copy of the β-globin gene to the patient’s hematopoietic stem cells, then reinfuse the modified stem cells into the patient to produce normal disc-shaped red blood cells. In animal studies, the new vector was up to 10 times more efficient at incorporating corrective genes into bone marrow stem cells with a carrying capacity of up to 6 times greater viral load than current vectors. The new vectors also can be produced in much higher amounts, saving time and lowering costs.

The researchers call it a “forward-oriented” vector because it changes the usual direction of how gene sequences in globin-containing vectors are read: from right to left. That backward orientation—globin-containing vectors are the only therapeutic vectors in clinical development that use it—the researchers say, “has remained unchallenged for decades despite its negative impacts on efficiency.”

The right-to-left orientation was dictated by the need to prevent the loss of a key molecular component, intron 2, by RNA splicing during the vector preparation. The redesigned forward-reading method crucially leaves intron 2 intact and makes the gene-translation approach less complicated, says John Tisdale, MD, chief of the Cellular and Molecular Therapeutic Branch at the National Heart, Lung, and Blood Institute, who, with Naoya Uchida, MD, PhD, came up with the idea.

In testing, the new vectors also proved longer lasting, remaining in place 4 years after transplantation.

National Institutes of Health is working to accelerate research and development through the Cure Sickle Cell Initiative, launched by NHLBI in 2018 to identify and support the most promising genetic therapies for the more than 20 million people worldwide who have sickle cell disease. NIH holds the patent for the new vector, which still will need clinical testing in humans. Clinical trials are actively enrolling.

About 100,000 people in America have sickle cell disease. Of those, an estimated 27 people have undergone experimental gene therapy using conventional vectors—virus-based vehicles for delivering “therapeutic genes.” Now National Institutes of Health researchers have taken the vector idea and revved it up, bringing the possibility of curing sickle cell disease a bit closer.

With gene therapy, doctors add a normal copy of the β-globin gene to the patient’s hematopoietic stem cells, then reinfuse the modified stem cells into the patient to produce normal disc-shaped red blood cells. In animal studies, the new vector was up to 10 times more efficient at incorporating corrective genes into bone marrow stem cells with a carrying capacity of up to 6 times greater viral load than current vectors. The new vectors also can be produced in much higher amounts, saving time and lowering costs.

The researchers call it a “forward-oriented” vector because it changes the usual direction of how gene sequences in globin-containing vectors are read: from right to left. That backward orientation—globin-containing vectors are the only therapeutic vectors in clinical development that use it—the researchers say, “has remained unchallenged for decades despite its negative impacts on efficiency.”

The right-to-left orientation was dictated by the need to prevent the loss of a key molecular component, intron 2, by RNA splicing during the vector preparation. The redesigned forward-reading method crucially leaves intron 2 intact and makes the gene-translation approach less complicated, says John Tisdale, MD, chief of the Cellular and Molecular Therapeutic Branch at the National Heart, Lung, and Blood Institute, who, with Naoya Uchida, MD, PhD, came up with the idea.

In testing, the new vectors also proved longer lasting, remaining in place 4 years after transplantation.

National Institutes of Health is working to accelerate research and development through the Cure Sickle Cell Initiative, launched by NHLBI in 2018 to identify and support the most promising genetic therapies for the more than 20 million people worldwide who have sickle cell disease. NIH holds the patent for the new vector, which still will need clinical testing in humans. Clinical trials are actively enrolling.

Autoimmune hemolytic anemia (AIHA) is mediated by antibodies, and in most cases immunoglobulin (Ig) G is the mediating antibody. This type of AIHA is referred to as "warm" AIHA because IgG antibodies bind best at body temperature. "Cold" AIHA is mediated by IgM antibodies, which bind maximally at temperatures below 37°C. AIHA caused by a drug reaction is rare, with an estimated annual incidence of 1:1,000,000 for severe drug-related AIHA.¹ This article reviews the management of the more common types of AIHA, with a focus on warm, cold, and drug-induced AIHA; the evaluation and diagnosis of AIHA is reviewed in a separate article.

Warm Autoimmune Hemolytic Anemia

In AIHA, hemolysis is mediated by antibodies that bind to the surface of red blood cells. AIHA in which IgG antibodies are the offending antibodies is referred to as warm AIHA. “Warm” refers to the fact that the antibody binds best at body temperature (37°C). In warm AIHA, testing will show IgG molecules attached to the surface of the red cells, with 50% of patients also showing C3. Between 50% and 90% of AIHA cases are due to warm antibodies.^2,3 The incidence of warm AIHA varies by series but is approximately 1 case per 100,000 patients per year; this form of hemolysis affects women more frequently than men.^4,5

Therapeutic Options

First Line

Steroids. The goal of therapy in warm AIHA can be hard to define. However, most would agree that a hematocrit above 30% (or higher to prevent symptoms) with a minimal increase in the reticulocyte count—reflective of a significantly slowed hemolytic process—is a reasonable goal. Initial management of warm AIHA is prednisone at a standard dose of 1 mg/kg daily (Table 1).^6,7 Patients should be also started on proton-pump inhibitors to prevent ulcers. It can take up to 3 weeks for patients to respond to prednisone therapy. Once the patient’s hematocrit is above 30%, the prednisone is slowly tapered. Although approximately 80% of patients will respond to steroids, only 30% can be fully tapered off steroids. For patients who can be maintained on a daily steroid dose of 10 mg or less, steroids may be the most reasonable long-term therapy. In addition, because active hemolysis leads to an increased demand for folic acid, patients with warm AIHA are often prescribed folic acid 1 mg daily to prevent megaloblastic anemia due to folic acid deficiency.

Rituximab. Increasingly, rituximab (anti-CD20) therapy is added to the initial steroids. Two clinical trials showed both increased long-term and short-term responses with the use of rituximab.^8,9 An important consideration is that most patients respond gradually to rituximab over weeks, so a rapid response should not be expected. Most studies have used the traditional dosing of 375 mg/m² weekly for 4 weeks. These responses appear to be durable, but as in immune thrombocytopenia (ITP), repeat treatment with rituximab is effective.

The major side effects of rituximab are infusion reactions, which are often worse with the first dose. These reactions can be controlled with antihistamines, steroids, and, for severe rigors, meperidine. Rarely, patients can develop neutropenia (approximately 1:500) that appears to be autoimmune in nature. Infections appear to be only minimally increased with the use of rituximab.¹⁰ One group at risk is chronic carriers of hepatitis B virus, who may experience a reactivation of the virus that can be fatal. Thus, patients being considered for rituximab need to be screened for hepatitis B virus carrier state.¹¹ Patients receiving rituximab are at very slight risk for progressive multifocal leukoencephalopathy, which is more common in patients with cancer and in heavily immunosuppressed patients. The overall risk is unknown but is less than 1:50,000.

Second Line

Splenectomy. For patients who cannot be weaned from steroids or in whom steroid therapy fails, there is no standard therapy. Currently, the 2 main choices are splenectomy or rituximab (anti-CD20) therapy if the patient did not receive it first line. Splenectomy is the classic therapy for warm AIHA. Reported response rates in the literature range from 50% to 80%, with 50% to 60% remaining in remission.^12-16 Timing of the procedure is a balance between allowing time for the steroids to work and the risk of toxicity of steroids. In a patient who has low presurgical risk and has either refractory disease or cannot be weaned from high doses of steroids, splenectomy should be done sooner. Splenectomy can be delayed or other therapy tried first in patients who require lower doses of steroids or have medical risk factors for surgery. Most splenectomies are performed via laparoscopy. The small incisions allow for quicker healing, and the laparoscopic approach provides better visualization of the abdomen to find and remove accessory spleens. When splenectomy is performed by experienced surgeons, the mortality rate is low (< 0.5%).¹⁷

The most concerning complication of splenectomy is overwhelming post-splenectomy infection (OPSI).¹⁸ In adults, the spleen appears to play a minimal role in immunity except for protecting against certain encap-sulated organisms. Splenectomized patients infected with an encapsulated organism (eg, Pneumococcus) will develop overwhelming sepsis within hours. These patients will often have disseminated intravascular coagulation and will rapidly progress to purpura fulminans. Approximately 40% to 50% of patients will die of sepsis even when the infection is detected early. The overall lifetime risk of sepsis may be as high as 1:500. The organism that most commonly causes sepsis in splenectomized patients is Streptococcus pneumoniae, reported in over 50% of cases. Neisseria meningitidis and Haemophilus influenzae have also been implicated in many cases.¹⁹ Overwhelming sepsis after dog bites has been reported due to Capnocytophaga canimorsus infections. Patients are also at increased risk of developing severe malaria and severe babesiosis.¹⁸

Patients who have undergone splenectomy need to be warned about the risk of OPSI and instructed to report to the emergency department readily if they develop a fever greater than 101°F (38.3°C) or shaking chills. Once in the emergency department, blood cultures should be obtained rapidly and the patient started on antibiotic coverage with vancomycin and ceftriaxone (or levofloxacin if allergic to beta-lactams).²⁰ For patients in remote areas, some physicians will prescribe prophylactic antibiotics to take while they are traveling to a health care provider or even recommend a “standby” antibiotic dose to take while traveling to health care.⁵ This usually consists of amoxicillin or a macrolide for penicillin-allergic patients.

Patients in whom splenectomy is being planned or considered should be vaccinated for pneumococcal, meningococcal, and influenza infections (Table 2).¹⁸ If there is a plan to treat with rituximab, patients should first be vaccinated since they will not be able to mount an immune response after being treated with rituximab.

Third Line

The therapeutic options for patients who do not respond to either splenectomy or rituximab are much less certain.^5,6 Although intravenous immune globulin is a standard therapy for ITP, response rates are low in warm AIHA.¹⁷ Numerous therapies have been reported in small series, but no clear approach has emerged. Options include azathioprine, cyclophosphamide, mycophenolate, cyclosporine, danazol, and alemtuzumab. Our approach has been to use mycophenolate for patients requiring high doses of steroids or transfusions. Patients who respond to lower doses of steroids may be good candidates for danazol to help wean them off steroids.

Warm AIHA can complicate several diseases. Patients with systemic lupus erythematosus (SLE) can develop warm AIHA as part of their disease complex. The initial treatment approach is the same, but data suggest that splenectomy may not be as effective.^13,17 Also, many SLE patients have complex medical conditions, making surgeries riskier. For SLE patients who are refractory or cannot be weaned from steroids, rituximab may be the better choice. Babesiosis, particularly in asplenic patients, has been associated with the development of AIHA.^21,22

Of the malignances associated with AIHA, chronic lymphocytic leukemia (CLL) has the strongest association.^4,23 Series show that 5% to 10% of patients with CLL will have warm AIHA. AIHA can appear concurrent with CLL or develop during the course of the disease. The introduction of purine analogs such as fludarabine led to a dramatic increase in the incidence of warm AIHA in treated patients.²⁴ It is speculated that these powerful agents reduce the number and effectiveness of T cells that hold in check the autoantibody response, leading to warm AIHA.²⁵ However, when these purine analogs are used in com-bination with agents such as cyclophosphamide or rituximab (with their immunosuppressive effects), the rates of warm AIHA have been lower.²³

The approach to patients with CLL and warm AIHA depends on the state of their CLL.²³ For patients who have low-stage CLL that does not need treatment, the standard approach to warm AIHA should be steroids, splenectomy, and rituximab.²⁴ For patients with higher-stage CLL, the treatment for the leukemia will often provide therapy for the warm AIHA. The combination of rituximab-cyclophosphamide-dexamethasone has been reported to be effective for both the AIHA and CLL components.²⁶ The use of ibrutinib has also been reported to be effective.²⁷

A rare but important variant of warm AIHA is Evans syndrome.^28,29 This is the combination of AIHA and ITP. Approximately 1% to 3% of AIHA cases are the Evans variant. The ITP can precede, be concurrent with, or develop after the AIHA. The diagnosis of Evans syndrome should raise concern for underlying disorders. In young adults, immunodeficiency disorders such as autoimmune lymphoproliferative disease (ALPS) need to be considered. In older patients, Evans syndrome is often associated with T cell lymphomas. The sparse literature on Evans syndrome suggests that it can be more refractory to standard therapy, with response rates to splenectomy in the 50% range.^28,30 In patients with lymphoma, antineoplastic therapy is crucial. There is increasing data showing that mycophenolate or sirolimus may be effective for patients with ALPS in whom splenectomy or rituximab therapy is unsuccessful.³¹

Warm AIHA with IgA or IgM Antibodies

In rare patients with warm AIHA, IgA or IgM is the implicated antibody. The literature suggests that patients with IgA AIHA may have more severe hemolysis.³² Patients with IgM AIHA often have a severe course with a fatal outcome.³³ In such cases, the patient’s plasma may show spontaneous hemolysis and agglutination. The DAT may not be strongly positive or may show C3 reactivity only. The clinical clues are C3 reactivity with no cold agglutinins and severe hemolysis, sometimes with an intravascular component. Treatment is the same as for warm AIHA, including the use of rituximab.³⁴

In cold AIHA, the hemolysis is mediated by IgM antibodies directed against red cells.³⁵ As discussed earlier, the term “cold” refers to the fact that the antibody binds maximally at temperatures below 37°C. The most efficient temperature for binding is called the “thermal amplitude,” and, in theory, the higher the thermal amplitude, the more virulent the antibody. An antibody titer can be calculated at each reaction temperature from 4°C to 37°C by serial dilutions of the patient’s serum prior to incubating with reagent red cells. Rarely, the IgM can fix complement rapidly, leading to intravascular hemolysis. In most patients, complement is fixed through C3, and the C3-coated red cells are taken up by macrophages in the mononuclear phagocyte system, primarily in the liver.³

The DAT in patients with cold AIHA will show cells coated with C3. The blood smear will often show ag-glutination of the blood, and if the blood cools before being analyzed, the agglutination will interfere with the analysis. Titers of cold agglutinin can range from 1:1000 to over 1 million. The IgM autoantibodies are most often directed against the I/i antigens on the red blood cell membrane, with 90% against I antigen.³⁵ The I antigen specificity is typical with primary cold agglutinin disease and after Mycoplasma infection. The i antigen specificity is most typical of Epstein-Barr virus and cytomegalovirus infections in children. In young patients, cold AIHA often occurs following an infection, including viral and Mycoplasma infections, and the course is self-limited.^35,36 The hemolysis usually starts 2 to 3 weeks after the illness and will last for 4 to 6 weeks. In older patients, the etiology in over 90% of cases is a B-cell lymphoproliferative disorder, usually with monoclonal kappa B-cells.³⁷ The most common disorders are marginal zone lymphoma, small lymphocytic lymphoma, and lymphoplasmacytic lymphoma.³

Therapeutic Options

It is important to diagnose cold AIHA because the standard therapy for warm AIHA (steroids) is ineffective in cold AIHA. Because C3-coated red cells are taken up primarily in the liver, removing the spleen is also an ineffective therapy. Simple measures to help with cold AIHA should be employed.³⁷ Patients should be kept in a warm environment and should try to avoid the cold. If transfusions are needed, they should be infused via blood warmers to prevent hemolysis. In rare patients with severe hemolysis, therapeutic plasma exchange (TPE) can be considered.³⁸ Given that the culprit antibody is IgM—mostly intravascular—use of TPE may slow the hemolysis to give time for other therapies to take effect.

Treatment of cold AIHA remains difficult (Table 3). Because most patients with primary AIHA have underlying lymphoproliferative diseases, chlorambucil has been used in the past to treat cold AIHA. However, responses were rare and the drug could worsen the anemia.³⁸ Currently, the drug of choice is rituximab. Response is seen in 45% to 75% of patients, but is almost always a partial response and retreatment is often necessary.^17,37,39 As with other autoimmune hematologic diseases, there can be a delay in response that ranges from 2 weeks to 4 months (median time, 1.5 months).³⁷ Given the lack of robust response (complete and durable) with rituximab, the Berentsen group has explored adding bendamustine to rituximab.⁴⁰ In a prospective trial, 71% of patients responded with a 40% complete response rate. Therapy was well tolerated, with only 29% of patients needing dose reduction Although more toxic, this combination can be considered in patients with aggressive disease. A small study of the use of bortezomib showed a good response in one-third of patients.⁴¹ There is increasing use of the C5 complement inhibitor eculizumab to halt the hemolysis, but further study of this agent is also required.^36,42,43 Blockers of C1s complement, which block hemolysis by preventing complement activation, are currently being studied in clinical trials.⁴⁴

Since most patients with cold AIHA are older, a frequent issue that must be considered is cardiac surgery. The concern is that the hypothermia involved with most heart bypass procedures will lead to agglutination and hemolysis. The development of normothermic bypass has expanded treatment options. A recommended approach in patients who have known cold agglutinins is to measure the thermal amplitude of the antibody preoperatively. If the thermal amplitude is above 18°C, normothermic bypass should be done, if feasible.⁴⁵ If not feasible, preoperative TPE should be considered.

Paroxysmal Cold Hemoglobinuria

A unique cold AIHA is paroxysmal cold hemoglobinuria (PCH).^3,46 This cold hemolytic syndrome most often occurs in children following a viral infection, but in the past it complicated any stage of syphilis.⁴⁷ The mediating antibody in PCH is an IgG antibody directed against the P antigen on the red blood cell. This antibody binds best at temperatures below 37°C, fixing complement at cold temperatures, but then activates the complement cascade at body temperature.⁴⁸ Because this antibody can fix complement, hemolysis can be rapid and severe, leading to extreme anemia. The DAT is often weakly positive but can be negative. The diagnostic test for PCH is the Donath–Landsteiner test. This complex test is performed by incubating 3 blood samples, 1 at 0° to 4°C, another at 37°C, and a third at 0° to 4°C and then at 37°C. The diagnosis of PCH is made if only the third tube shows hemolysis.³⁵ PCH can persist for 1 to 3 months but is almost always self-limiting. In severe case, steroids may be of benefit.

Drug-Induced Hemolytic Anemia

AIHA caused by a drug reaction is rare, with a lower incidence than drug-related ITP. The rate of severe drug-related AIHA is estimated at 1:1,000,000, but less severe cases may be missed.¹ Most patients will have a positive DAT without signs of hemolysis, but in rare cases patients will have relentless hemolysis resulting in death.

Mechanisms

Multiple mechanisms for drug-induced immune hemolysis have been proposed, including drug-absorption (hapten-induced) and immune complex mechanisms.^1,49 The hapten mechanism is most often associated with the use of high-dose penicillin.⁵⁰ High doses of penicillin or similar drugs such as piperacillin lead to incorporation of the drug into the red cell membrane by binding to proteins. Patients will manifest a positive DAT with IgG antibody but not complement.⁵¹ The patient’s plasma will be reactive only with penicillin-coated red cells and not with normal cells. As mentioned, very few patients will have hemolysis, and if they have hemolysis, it will resolve in a few days after discontinuation of the offending drug.⁵²

Binding of a drug-antibody complex to the red cell membrane may cause hemolysis via the immune com-plex mechanism.⁵³ Again, most often the patient will have just a positive DAT, but rarely patients will have life-threatening hemolysis upon exposure or reexposure to the drug. The onset of hemolysis is rapid, with signs of acute illness and intravascular hemolysis. The paradigm drug is quinine, but many other drugs have been implicated. Testing shows a positive Coombs test with anti-complement but not anti-IgG.⁵⁰ This pattern is due to the effectiveness of the tertiary complex at fixing complement. The patient’s plasma reacts with red cells only when the drug is added.

A form of immune complex hemolysis associated with both disseminated intravascular coagulation (DIC) and brisk hemolysis has been recognized. Patients who receive certain second- and third-generation cephalosporins (especially cefotetan and ceftriaxone.^53,54) have developed this syndrome.^50,55-59 The clinical symptoms start 7 to 10 days after the drug is administered; often the patient has only received the antibiotic for surgical prophylaxis. Immune hemolysis with acute hematocrit drop, hypotension, and DIC ensues. The patients are often believed to have sepsis and are often reexposed to the cephalosporin, resulting in worsening of the clinical status. The outcome is often fatal due to massive hemolysis and thrombosis.^56,60,62

Finally, 8% to 36% of patients taking methyldopa will develop a positive DAT after 6 months of therapy, with less than 1% showing hemolysis.^52,63 The hemolysis in these patients is indistinguishable from warm AIHA, consistent with the notion that methyldopa induces an AIHA. The hemolysis often resolves rapidly after the methyldopa is stopped, but the Coombs test may remain positive for months.⁶³ This type of drug-induced hemolytic anemia has been reported with levodopa, procainamide, and chlorpromazine, but fludarabine is the most common cause currently. This form of AIHA is now being seen with increased use of checkpoint inhibitors.⁶⁴

Diagnosis

In many patients, the first clue to the presence of drug AIHA is the finding of a positive DAT. Rarely, patients will have severe hemolysis, but in many patients the hemolytic process is mild and may be wrongly assumed to be part of the underlying illness. Finding the offending drug can be a challenge, unless a patient has recently started a new drug; in a hospitalized patient on multiple agents, identifying the problem drug is difficult. Patients recently started on “suspect drugs,” especially the most common agents cefotetan, ceftriaxone, and piperacillin, should have these agents stopped (Table 4).^1,49,65 Specialty laboratories such as the Blood Center of Wisconsin or the Los Angeles Red Cross can perform in vitro studies of drug interactions that can confirm the clinical diagnosis of drug-induced AIHA.

Treatment

Therapy for patients with positive DAT without signs of hemolysis is uncertain. If the drug is essential, then the patient can be observed. If the patient has hemolysis, the drug needs to be stopped and the patient observed for signs of end-organ damage. It is doubtful that steroids or other autoimmune-directed therapy is effective. For patients with the DIC-hemolysis syndrome, there are anecdotal reports that TPE may be helpful.¹

Summary

AIHA can range from an abnormal laboratory test (positive DAT and signs of hemolysis) to an acute, life-threatening illness. Treatment is guided by the laboratory work-up and evaluation of the patient’s clinical status. While rituximab is promising for many patients, the lack of robust clinical trials hinders the treatment of patients who fail standard therapies.

Autoimmune hemolytic anemia (AIHA) is mediated by antibodies, and in most cases immunoglobulin (Ig) G is the mediating antibody. This type of AIHA is referred to as "warm" AIHA because IgG antibodies bind best at body temperature. "Cold" AIHA is mediated by IgM antibodies, which bind maximally at temperatures below 37°C. AIHA caused by a drug reaction is rare, with an estimated annual incidence of 1:1,000,000 for severe drug-related AIHA.¹ This article reviews the management of the more common types of AIHA, with a focus on warm, cold, and drug-induced AIHA; the evaluation and diagnosis of AIHA is reviewed in a separate article.

Warm Autoimmune Hemolytic Anemia

In AIHA, hemolysis is mediated by antibodies that bind to the surface of red blood cells. AIHA in which IgG antibodies are the offending antibodies is referred to as warm AIHA. “Warm” refers to the fact that the antibody binds best at body temperature (37°C). In warm AIHA, testing will show IgG molecules attached to the surface of the red cells, with 50% of patients also showing C3. Between 50% and 90% of AIHA cases are due to warm antibodies.^2,3 The incidence of warm AIHA varies by series but is approximately 1 case per 100,000 patients per year; this form of hemolysis affects women more frequently than men.^4,5

Therapeutic Options

First Line

Steroids. The goal of therapy in warm AIHA can be hard to define. However, most would agree that a hematocrit above 30% (or higher to prevent symptoms) with a minimal increase in the reticulocyte count—reflective of a significantly slowed hemolytic process—is a reasonable goal. Initial management of warm AIHA is prednisone at a standard dose of 1 mg/kg daily (Table 1).^6,7 Patients should be also started on proton-pump inhibitors to prevent ulcers. It can take up to 3 weeks for patients to respond to prednisone therapy. Once the patient’s hematocrit is above 30%, the prednisone is slowly tapered. Although approximately 80% of patients will respond to steroids, only 30% can be fully tapered off steroids. For patients who can be maintained on a daily steroid dose of 10 mg or less, steroids may be the most reasonable long-term therapy. In addition, because active hemolysis leads to an increased demand for folic acid, patients with warm AIHA are often prescribed folic acid 1 mg daily to prevent megaloblastic anemia due to folic acid deficiency.

Rituximab. Increasingly, rituximab (anti-CD20) therapy is added to the initial steroids. Two clinical trials showed both increased long-term and short-term responses with the use of rituximab.^8,9 An important consideration is that most patients respond gradually to rituximab over weeks, so a rapid response should not be expected. Most studies have used the traditional dosing of 375 mg/m² weekly for 4 weeks. These responses appear to be durable, but as in immune thrombocytopenia (ITP), repeat treatment with rituximab is effective.

The major side effects of rituximab are infusion reactions, which are often worse with the first dose. These reactions can be controlled with antihistamines, steroids, and, for severe rigors, meperidine. Rarely, patients can develop neutropenia (approximately 1:500) that appears to be autoimmune in nature. Infections appear to be only minimally increased with the use of rituximab.¹⁰ One group at risk is chronic carriers of hepatitis B virus, who may experience a reactivation of the virus that can be fatal. Thus, patients being considered for rituximab need to be screened for hepatitis B virus carrier state.¹¹ Patients receiving rituximab are at very slight risk for progressive multifocal leukoencephalopathy, which is more common in patients with cancer and in heavily immunosuppressed patients. The overall risk is unknown but is less than 1:50,000.

Second Line

Splenectomy. For patients who cannot be weaned from steroids or in whom steroid therapy fails, there is no standard therapy. Currently, the 2 main choices are splenectomy or rituximab (anti-CD20) therapy if the patient did not receive it first line. Splenectomy is the classic therapy for warm AIHA. Reported response rates in the literature range from 50% to 80%, with 50% to 60% remaining in remission.^12-16 Timing of the procedure is a balance between allowing time for the steroids to work and the risk of toxicity of steroids. In a patient who has low presurgical risk and has either refractory disease or cannot be weaned from high doses of steroids, splenectomy should be done sooner. Splenectomy can be delayed or other therapy tried first in patients who require lower doses of steroids or have medical risk factors for surgery. Most splenectomies are performed via laparoscopy. The small incisions allow for quicker healing, and the laparoscopic approach provides better visualization of the abdomen to find and remove accessory spleens. When splenectomy is performed by experienced surgeons, the mortality rate is low (< 0.5%).¹⁷

The most concerning complication of splenectomy is overwhelming post-splenectomy infection (OPSI).¹⁸ In adults, the spleen appears to play a minimal role in immunity except for protecting against certain encap-sulated organisms. Splenectomized patients infected with an encapsulated organism (eg, Pneumococcus) will develop overwhelming sepsis within hours. These patients will often have disseminated intravascular coagulation and will rapidly progress to purpura fulminans. Approximately 40% to 50% of patients will die of sepsis even when the infection is detected early. The overall lifetime risk of sepsis may be as high as 1:500. The organism that most commonly causes sepsis in splenectomized patients is Streptococcus pneumoniae, reported in over 50% of cases. Neisseria meningitidis and Haemophilus influenzae have also been implicated in many cases.¹⁹ Overwhelming sepsis after dog bites has been reported due to Capnocytophaga canimorsus infections. Patients are also at increased risk of developing severe malaria and severe babesiosis.¹⁸

Patients who have undergone splenectomy need to be warned about the risk of OPSI and instructed to report to the emergency department readily if they develop a fever greater than 101°F (38.3°C) or shaking chills. Once in the emergency department, blood cultures should be obtained rapidly and the patient started on antibiotic coverage with vancomycin and ceftriaxone (or levofloxacin if allergic to beta-lactams).²⁰ For patients in remote areas, some physicians will prescribe prophylactic antibiotics to take while they are traveling to a health care provider or even recommend a “standby” antibiotic dose to take while traveling to health care.⁵ This usually consists of amoxicillin or a macrolide for penicillin-allergic patients.

Patients in whom splenectomy is being planned or considered should be vaccinated for pneumococcal, meningococcal, and influenza infections (Table 2).¹⁸ If there is a plan to treat with rituximab, patients should first be vaccinated since they will not be able to mount an immune response after being treated with rituximab.

Third Line

The therapeutic options for patients who do not respond to either splenectomy or rituximab are much less certain.^5,6 Although intravenous immune globulin is a standard therapy for ITP, response rates are low in warm AIHA.¹⁷ Numerous therapies have been reported in small series, but no clear approach has emerged. Options include azathioprine, cyclophosphamide, mycophenolate, cyclosporine, danazol, and alemtuzumab. Our approach has been to use mycophenolate for patients requiring high doses of steroids or transfusions. Patients who respond to lower doses of steroids may be good candidates for danazol to help wean them off steroids.

Warm AIHA can complicate several diseases. Patients with systemic lupus erythematosus (SLE) can develop warm AIHA as part of their disease complex. The initial treatment approach is the same, but data suggest that splenectomy may not be as effective.^13,17 Also, many SLE patients have complex medical conditions, making surgeries riskier. For SLE patients who are refractory or cannot be weaned from steroids, rituximab may be the better choice. Babesiosis, particularly in asplenic patients, has been associated with the development of AIHA.^21,22

Of the malignances associated with AIHA, chronic lymphocytic leukemia (CLL) has the strongest association.^4,23 Series show that 5% to 10% of patients with CLL will have warm AIHA. AIHA can appear concurrent with CLL or develop during the course of the disease. The introduction of purine analogs such as fludarabine led to a dramatic increase in the incidence of warm AIHA in treated patients.²⁴ It is speculated that these powerful agents reduce the number and effectiveness of T cells that hold in check the autoantibody response, leading to warm AIHA.²⁵ However, when these purine analogs are used in com-bination with agents such as cyclophosphamide or rituximab (with their immunosuppressive effects), the rates of warm AIHA have been lower.²³

The approach to patients with CLL and warm AIHA depends on the state of their CLL.²³ For patients who have low-stage CLL that does not need treatment, the standard approach to warm AIHA should be steroids, splenectomy, and rituximab.²⁴ For patients with higher-stage CLL, the treatment for the leukemia will often provide therapy for the warm AIHA. The combination of rituximab-cyclophosphamide-dexamethasone has been reported to be effective for both the AIHA and CLL components.²⁶ The use of ibrutinib has also been reported to be effective.²⁷

A rare but important variant of warm AIHA is Evans syndrome.^28,29 This is the combination of AIHA and ITP. Approximately 1% to 3% of AIHA cases are the Evans variant. The ITP can precede, be concurrent with, or develop after the AIHA. The diagnosis of Evans syndrome should raise concern for underlying disorders. In young adults, immunodeficiency disorders such as autoimmune lymphoproliferative disease (ALPS) need to be considered. In older patients, Evans syndrome is often associated with T cell lymphomas. The sparse literature on Evans syndrome suggests that it can be more refractory to standard therapy, with response rates to splenectomy in the 50% range.^28,30 In patients with lymphoma, antineoplastic therapy is crucial. There is increasing data showing that mycophenolate or sirolimus may be effective for patients with ALPS in whom splenectomy or rituximab therapy is unsuccessful.³¹

Warm AIHA with IgA or IgM Antibodies

In rare patients with warm AIHA, IgA or IgM is the implicated antibody. The literature suggests that patients with IgA AIHA may have more severe hemolysis.³² Patients with IgM AIHA often have a severe course with a fatal outcome.³³ In such cases, the patient’s plasma may show spontaneous hemolysis and agglutination. The DAT may not be strongly positive or may show C3 reactivity only. The clinical clues are C3 reactivity with no cold agglutinins and severe hemolysis, sometimes with an intravascular component. Treatment is the same as for warm AIHA, including the use of rituximab.³⁴

In cold AIHA, the hemolysis is mediated by IgM antibodies directed against red cells.³⁵ As discussed earlier, the term “cold” refers to the fact that the antibody binds maximally at temperatures below 37°C. The most efficient temperature for binding is called the “thermal amplitude,” and, in theory, the higher the thermal amplitude, the more virulent the antibody. An antibody titer can be calculated at each reaction temperature from 4°C to 37°C by serial dilutions of the patient’s serum prior to incubating with reagent red cells. Rarely, the IgM can fix complement rapidly, leading to intravascular hemolysis. In most patients, complement is fixed through C3, and the C3-coated red cells are taken up by macrophages in the mononuclear phagocyte system, primarily in the liver.³

The DAT in patients with cold AIHA will show cells coated with C3. The blood smear will often show ag-glutination of the blood, and if the blood cools before being analyzed, the agglutination will interfere with the analysis. Titers of cold agglutinin can range from 1:1000 to over 1 million. The IgM autoantibodies are most often directed against the I/i antigens on the red blood cell membrane, with 90% against I antigen.³⁵ The I antigen specificity is typical with primary cold agglutinin disease and after Mycoplasma infection. The i antigen specificity is most typical of Epstein-Barr virus and cytomegalovirus infections in children. In young patients, cold AIHA often occurs following an infection, including viral and Mycoplasma infections, and the course is self-limited.^35,36 The hemolysis usually starts 2 to 3 weeks after the illness and will last for 4 to 6 weeks. In older patients, the etiology in over 90% of cases is a B-cell lymphoproliferative disorder, usually with monoclonal kappa B-cells.³⁷ The most common disorders are marginal zone lymphoma, small lymphocytic lymphoma, and lymphoplasmacytic lymphoma.³

Therapeutic Options

It is important to diagnose cold AIHA because the standard therapy for warm AIHA (steroids) is ineffective in cold AIHA. Because C3-coated red cells are taken up primarily in the liver, removing the spleen is also an ineffective therapy. Simple measures to help with cold AIHA should be employed.³⁷ Patients should be kept in a warm environment and should try to avoid the cold. If transfusions are needed, they should be infused via blood warmers to prevent hemolysis. In rare patients with severe hemolysis, therapeutic plasma exchange (TPE) can be considered.³⁸ Given that the culprit antibody is IgM—mostly intravascular—use of TPE may slow the hemolysis to give time for other therapies to take effect.

Treatment of cold AIHA remains difficult (Table 3). Because most patients with primary AIHA have underlying lymphoproliferative diseases, chlorambucil has been used in the past to treat cold AIHA. However, responses were rare and the drug could worsen the anemia.³⁸ Currently, the drug of choice is rituximab. Response is seen in 45% to 75% of patients, but is almost always a partial response and retreatment is often necessary.^17,37,39 As with other autoimmune hematologic diseases, there can be a delay in response that ranges from 2 weeks to 4 months (median time, 1.5 months).³⁷ Given the lack of robust response (complete and durable) with rituximab, the Berentsen group has explored adding bendamustine to rituximab.⁴⁰ In a prospective trial, 71% of patients responded with a 40% complete response rate. Therapy was well tolerated, with only 29% of patients needing dose reduction Although more toxic, this combination can be considered in patients with aggressive disease. A small study of the use of bortezomib showed a good response in one-third of patients.⁴¹ There is increasing use of the C5 complement inhibitor eculizumab to halt the hemolysis, but further study of this agent is also required.^36,42,43 Blockers of C1s complement, which block hemolysis by preventing complement activation, are currently being studied in clinical trials.⁴⁴

Since most patients with cold AIHA are older, a frequent issue that must be considered is cardiac surgery. The concern is that the hypothermia involved with most heart bypass procedures will lead to agglutination and hemolysis. The development of normothermic bypass has expanded treatment options. A recommended approach in patients who have known cold agglutinins is to measure the thermal amplitude of the antibody preoperatively. If the thermal amplitude is above 18°C, normothermic bypass should be done, if feasible.⁴⁵ If not feasible, preoperative TPE should be considered.

Paroxysmal Cold Hemoglobinuria

A unique cold AIHA is paroxysmal cold hemoglobinuria (PCH).^3,46 This cold hemolytic syndrome most often occurs in children following a viral infection, but in the past it complicated any stage of syphilis.⁴⁷ The mediating antibody in PCH is an IgG antibody directed against the P antigen on the red blood cell. This antibody binds best at temperatures below 37°C, fixing complement at cold temperatures, but then activates the complement cascade at body temperature.⁴⁸ Because this antibody can fix complement, hemolysis can be rapid and severe, leading to extreme anemia. The DAT is often weakly positive but can be negative. The diagnostic test for PCH is the Donath–Landsteiner test. This complex test is performed by incubating 3 blood samples, 1 at 0° to 4°C, another at 37°C, and a third at 0° to 4°C and then at 37°C. The diagnosis of PCH is made if only the third tube shows hemolysis.³⁵ PCH can persist for 1 to 3 months but is almost always self-limiting. In severe case, steroids may be of benefit.

Drug-Induced Hemolytic Anemia

AIHA caused by a drug reaction is rare, with a lower incidence than drug-related ITP. The rate of severe drug-related AIHA is estimated at 1:1,000,000, but less severe cases may be missed.¹ Most patients will have a positive DAT without signs of hemolysis, but in rare cases patients will have relentless hemolysis resulting in death.

Mechanisms

Multiple mechanisms for drug-induced immune hemolysis have been proposed, including drug-absorption (hapten-induced) and immune complex mechanisms.^1,49 The hapten mechanism is most often associated with the use of high-dose penicillin.⁵⁰ High doses of penicillin or similar drugs such as piperacillin lead to incorporation of the drug into the red cell membrane by binding to proteins. Patients will manifest a positive DAT with IgG antibody but not complement.⁵¹ The patient’s plasma will be reactive only with penicillin-coated red cells and not with normal cells. As mentioned, very few patients will have hemolysis, and if they have hemolysis, it will resolve in a few days after discontinuation of the offending drug.⁵²

Binding of a drug-antibody complex to the red cell membrane may cause hemolysis via the immune com-plex mechanism.⁵³ Again, most often the patient will have just a positive DAT, but rarely patients will have life-threatening hemolysis upon exposure or reexposure to the drug. The onset of hemolysis is rapid, with signs of acute illness and intravascular hemolysis. The paradigm drug is quinine, but many other drugs have been implicated. Testing shows a positive Coombs test with anti-complement but not anti-IgG.⁵⁰ This pattern is due to the effectiveness of the tertiary complex at fixing complement. The patient’s plasma reacts with red cells only when the drug is added.

A form of immune complex hemolysis associated with both disseminated intravascular coagulation (DIC) and brisk hemolysis has been recognized. Patients who receive certain second- and third-generation cephalosporins (especially cefotetan and ceftriaxone.^53,54) have developed this syndrome.^50,55-59 The clinical symptoms start 7 to 10 days after the drug is administered; often the patient has only received the antibiotic for surgical prophylaxis. Immune hemolysis with acute hematocrit drop, hypotension, and DIC ensues. The patients are often believed to have sepsis and are often reexposed to the cephalosporin, resulting in worsening of the clinical status. The outcome is often fatal due to massive hemolysis and thrombosis.^56,60,62

Finally, 8% to 36% of patients taking methyldopa will develop a positive DAT after 6 months of therapy, with less than 1% showing hemolysis.^52,63 The hemolysis in these patients is indistinguishable from warm AIHA, consistent with the notion that methyldopa induces an AIHA. The hemolysis often resolves rapidly after the methyldopa is stopped, but the Coombs test may remain positive for months.⁶³ This type of drug-induced hemolytic anemia has been reported with levodopa, procainamide, and chlorpromazine, but fludarabine is the most common cause currently. This form of AIHA is now being seen with increased use of checkpoint inhibitors.⁶⁴

Diagnosis

In many patients, the first clue to the presence of drug AIHA is the finding of a positive DAT. Rarely, patients will have severe hemolysis, but in many patients the hemolytic process is mild and may be wrongly assumed to be part of the underlying illness. Finding the offending drug can be a challenge, unless a patient has recently started a new drug; in a hospitalized patient on multiple agents, identifying the problem drug is difficult. Patients recently started on “suspect drugs,” especially the most common agents cefotetan, ceftriaxone, and piperacillin, should have these agents stopped (Table 4).^1,49,65 Specialty laboratories such as the Blood Center of Wisconsin or the Los Angeles Red Cross can perform in vitro studies of drug interactions that can confirm the clinical diagnosis of drug-induced AIHA.

Treatment

Therapy for patients with positive DAT without signs of hemolysis is uncertain. If the drug is essential, then the patient can be observed. If the patient has hemolysis, the drug needs to be stopped and the patient observed for signs of end-organ damage. It is doubtful that steroids or other autoimmune-directed therapy is effective. For patients with the DIC-hemolysis syndrome, there are anecdotal reports that TPE may be helpful.¹

Summary

AIHA can range from an abnormal laboratory test (positive DAT and signs of hemolysis) to an acute, life-threatening illness. Treatment is guided by the laboratory work-up and evaluation of the patient’s clinical status. While rituximab is promising for many patients, the lack of robust clinical trials hinders the treatment of patients who fail standard therapies.

Autoimmune hemolytic anemia (AIHA) is mediated by antibodies, and in most cases immunoglobulin (Ig) G is the mediating antibody. This type of AIHA is referred to as "warm" AIHA because IgG antibodies bind best at body temperature. "Cold" AIHA is mediated by IgM antibodies, which bind maximally at temperatures below 37°C. AIHA caused by a drug reaction is rare, with an estimated annual incidence of 1:1,000,000 for severe drug-related AIHA.¹ This article reviews the management of the more common types of AIHA, with a focus on warm, cold, and drug-induced AIHA; the evaluation and diagnosis of AIHA is reviewed in a separate article.

Warm Autoimmune Hemolytic Anemia

In AIHA, hemolysis is mediated by antibodies that bind to the surface of red blood cells. AIHA in which IgG antibodies are the offending antibodies is referred to as warm AIHA. “Warm” refers to the fact that the antibody binds best at body temperature (37°C). In warm AIHA, testing will show IgG molecules attached to the surface of the red cells, with 50% of patients also showing C3. Between 50% and 90% of AIHA cases are due to warm antibodies.^2,3 The incidence of warm AIHA varies by series but is approximately 1 case per 100,000 patients per year; this form of hemolysis affects women more frequently than men.^4,5

Therapeutic Options

First Line

Steroids. The goal of therapy in warm AIHA can be hard to define. However, most would agree that a hematocrit above 30% (or higher to prevent symptoms) with a minimal increase in the reticulocyte count—reflective of a significantly slowed hemolytic process—is a reasonable goal. Initial management of warm AIHA is prednisone at a standard dose of 1 mg/kg daily (Table 1).^6,7 Patients should be also started on proton-pump inhibitors to prevent ulcers. It can take up to 3 weeks for patients to respond to prednisone therapy. Once the patient’s hematocrit is above 30%, the prednisone is slowly tapered. Although approximately 80% of patients will respond to steroids, only 30% can be fully tapered off steroids. For patients who can be maintained on a daily steroid dose of 10 mg or less, steroids may be the most reasonable long-term therapy. In addition, because active hemolysis leads to an increased demand for folic acid, patients with warm AIHA are often prescribed folic acid 1 mg daily to prevent megaloblastic anemia due to folic acid deficiency.

Rituximab. Increasingly, rituximab (anti-CD20) therapy is added to the initial steroids. Two clinical trials showed both increased long-term and short-term responses with the use of rituximab.^8,9 An important consideration is that most patients respond gradually to rituximab over weeks, so a rapid response should not be expected. Most studies have used the traditional dosing of 375 mg/m² weekly for 4 weeks. These responses appear to be durable, but as in immune thrombocytopenia (ITP), repeat treatment with rituximab is effective.

The major side effects of rituximab are infusion reactions, which are often worse with the first dose. These reactions can be controlled with antihistamines, steroids, and, for severe rigors, meperidine. Rarely, patients can develop neutropenia (approximately 1:500) that appears to be autoimmune in nature. Infections appear to be only minimally increased with the use of rituximab.¹⁰ One group at risk is chronic carriers of hepatitis B virus, who may experience a reactivation of the virus that can be fatal. Thus, patients being considered for rituximab need to be screened for hepatitis B virus carrier state.¹¹ Patients receiving rituximab are at very slight risk for progressive multifocal leukoencephalopathy, which is more common in patients with cancer and in heavily immunosuppressed patients. The overall risk is unknown but is less than 1:50,000.

Second Line

Splenectomy. For patients who cannot be weaned from steroids or in whom steroid therapy fails, there is no standard therapy. Currently, the 2 main choices are splenectomy or rituximab (anti-CD20) therapy if the patient did not receive it first line. Splenectomy is the classic therapy for warm AIHA. Reported response rates in the literature range from 50% to 80%, with 50% to 60% remaining in remission.^12-16 Timing of the procedure is a balance between allowing time for the steroids to work and the risk of toxicity of steroids. In a patient who has low presurgical risk and has either refractory disease or cannot be weaned from high doses of steroids, splenectomy should be done sooner. Splenectomy can be delayed or other therapy tried first in patients who require lower doses of steroids or have medical risk factors for surgery. Most splenectomies are performed via laparoscopy. The small incisions allow for quicker healing, and the laparoscopic approach provides better visualization of the abdomen to find and remove accessory spleens. When splenectomy is performed by experienced surgeons, the mortality rate is low (< 0.5%).¹⁷

The most concerning complication of splenectomy is overwhelming post-splenectomy infection (OPSI).¹⁸ In adults, the spleen appears to play a minimal role in immunity except for protecting against certain encap-sulated organisms. Splenectomized patients infected with an encapsulated organism (eg, Pneumococcus) will develop overwhelming sepsis within hours. These patients will often have disseminated intravascular coagulation and will rapidly progress to purpura fulminans. Approximately 40% to 50% of patients will die of sepsis even when the infection is detected early. The overall lifetime risk of sepsis may be as high as 1:500. The organism that most commonly causes sepsis in splenectomized patients is Streptococcus pneumoniae, reported in over 50% of cases. Neisseria meningitidis and Haemophilus influenzae have also been implicated in many cases.¹⁹ Overwhelming sepsis after dog bites has been reported due to Capnocytophaga canimorsus infections. Patients are also at increased risk of developing severe malaria and severe babesiosis.¹⁸

Patients who have undergone splenectomy need to be warned about the risk of OPSI and instructed to report to the emergency department readily if they develop a fever greater than 101°F (38.3°C) or shaking chills. Once in the emergency department, blood cultures should be obtained rapidly and the patient started on antibiotic coverage with vancomycin and ceftriaxone (or levofloxacin if allergic to beta-lactams).²⁰ For patients in remote areas, some physicians will prescribe prophylactic antibiotics to take while they are traveling to a health care provider or even recommend a “standby” antibiotic dose to take while traveling to health care.⁵ This usually consists of amoxicillin or a macrolide for penicillin-allergic patients.

Patients in whom splenectomy is being planned or considered should be vaccinated for pneumococcal, meningococcal, and influenza infections (Table 2).¹⁸ If there is a plan to treat with rituximab, patients should first be vaccinated since they will not be able to mount an immune response after being treated with rituximab.

Third Line

The therapeutic options for patients who do not respond to either splenectomy or rituximab are much less certain.^5,6 Although intravenous immune globulin is a standard therapy for ITP, response rates are low in warm AIHA.¹⁷ Numerous therapies have been reported in small series, but no clear approach has emerged. Options include azathioprine, cyclophosphamide, mycophenolate, cyclosporine, danazol, and alemtuzumab. Our approach has been to use mycophenolate for patients requiring high doses of steroids or transfusions. Patients who respond to lower doses of steroids may be good candidates for danazol to help wean them off steroids.

Warm AIHA can complicate several diseases. Patients with systemic lupus erythematosus (SLE) can develop warm AIHA as part of their disease complex. The initial treatment approach is the same, but data suggest that splenectomy may not be as effective.^13,17 Also, many SLE patients have complex medical conditions, making surgeries riskier. For SLE patients who are refractory or cannot be weaned from steroids, rituximab may be the better choice. Babesiosis, particularly in asplenic patients, has been associated with the development of AIHA.^21,22

Of the malignances associated with AIHA, chronic lymphocytic leukemia (CLL) has the strongest association.^4,23 Series show that 5% to 10% of patients with CLL will have warm AIHA. AIHA can appear concurrent with CLL or develop during the course of the disease. The introduction of purine analogs such as fludarabine led to a dramatic increase in the incidence of warm AIHA in treated patients.²⁴ It is speculated that these powerful agents reduce the number and effectiveness of T cells that hold in check the autoantibody response, leading to warm AIHA.²⁵ However, when these purine analogs are used in com-bination with agents such as cyclophosphamide or rituximab (with their immunosuppressive effects), the rates of warm AIHA have been lower.²³

The approach to patients with CLL and warm AIHA depends on the state of their CLL.²³ For patients who have low-stage CLL that does not need treatment, the standard approach to warm AIHA should be steroids, splenectomy, and rituximab.²⁴ For patients with higher-stage CLL, the treatment for the leukemia will often provide therapy for the warm AIHA. The combination of rituximab-cyclophosphamide-dexamethasone has been reported to be effective for both the AIHA and CLL components.²⁶ The use of ibrutinib has also been reported to be effective.²⁷

A rare but important variant of warm AIHA is Evans syndrome.^28,29 This is the combination of AIHA and ITP. Approximately 1% to 3% of AIHA cases are the Evans variant. The ITP can precede, be concurrent with, or develop after the AIHA. The diagnosis of Evans syndrome should raise concern for underlying disorders. In young adults, immunodeficiency disorders such as autoimmune lymphoproliferative disease (ALPS) need to be considered. In older patients, Evans syndrome is often associated with T cell lymphomas. The sparse literature on Evans syndrome suggests that it can be more refractory to standard therapy, with response rates to splenectomy in the 50% range.^28,30 In patients with lymphoma, antineoplastic therapy is crucial. There is increasing data showing that mycophenolate or sirolimus may be effective for patients with ALPS in whom splenectomy or rituximab therapy is unsuccessful.³¹

Warm AIHA with IgA or IgM Antibodies

In rare patients with warm AIHA, IgA or IgM is the implicated antibody. The literature suggests that patients with IgA AIHA may have more severe hemolysis.³² Patients with IgM AIHA often have a severe course with a fatal outcome.³³ In such cases, the patient’s plasma may show spontaneous hemolysis and agglutination. The DAT may not be strongly positive or may show C3 reactivity only. The clinical clues are C3 reactivity with no cold agglutinins and severe hemolysis, sometimes with an intravascular component. Treatment is the same as for warm AIHA, including the use of rituximab.³⁴

In cold AIHA, the hemolysis is mediated by IgM antibodies directed against red cells.³⁵ As discussed earlier, the term “cold” refers to the fact that the antibody binds maximally at temperatures below 37°C. The most efficient temperature for binding is called the “thermal amplitude,” and, in theory, the higher the thermal amplitude, the more virulent the antibody. An antibody titer can be calculated at each reaction temperature from 4°C to 37°C by serial dilutions of the patient’s serum prior to incubating with reagent red cells. Rarely, the IgM can fix complement rapidly, leading to intravascular hemolysis. In most patients, complement is fixed through C3, and the C3-coated red cells are taken up by macrophages in the mononuclear phagocyte system, primarily in the liver.³

The DAT in patients with cold AIHA will show cells coated with C3. The blood smear will often show ag-glutination of the blood, and if the blood cools before being analyzed, the agglutination will interfere with the analysis. Titers of cold agglutinin can range from 1:1000 to over 1 million. The IgM autoantibodies are most often directed against the I/i antigens on the red blood cell membrane, with 90% against I antigen.³⁵ The I antigen specificity is typical with primary cold agglutinin disease and after Mycoplasma infection. The i antigen specificity is most typical of Epstein-Barr virus and cytomegalovirus infections in children. In young patients, cold AIHA often occurs following an infection, including viral and Mycoplasma infections, and the course is self-limited.^35,36 The hemolysis usually starts 2 to 3 weeks after the illness and will last for 4 to 6 weeks. In older patients, the etiology in over 90% of cases is a B-cell lymphoproliferative disorder, usually with monoclonal kappa B-cells.³⁷ The most common disorders are marginal zone lymphoma, small lymphocytic lymphoma, and lymphoplasmacytic lymphoma.³

Therapeutic Options

It is important to diagnose cold AIHA because the standard therapy for warm AIHA (steroids) is ineffective in cold AIHA. Because C3-coated red cells are taken up primarily in the liver, removing the spleen is also an ineffective therapy. Simple measures to help with cold AIHA should be employed.³⁷ Patients should be kept in a warm environment and should try to avoid the cold. If transfusions are needed, they should be infused via blood warmers to prevent hemolysis. In rare patients with severe hemolysis, therapeutic plasma exchange (TPE) can be considered.³⁸ Given that the culprit antibody is IgM—mostly intravascular—use of TPE may slow the hemolysis to give time for other therapies to take effect.

Treatment of cold AIHA remains difficult (Table 3). Because most patients with primary AIHA have underlying lymphoproliferative diseases, chlorambucil has been used in the past to treat cold AIHA. However, responses were rare and the drug could worsen the anemia.³⁸ Currently, the drug of choice is rituximab. Response is seen in 45% to 75% of patients, but is almost always a partial response and retreatment is often necessary.^17,37,39 As with other autoimmune hematologic diseases, there can be a delay in response that ranges from 2 weeks to 4 months (median time, 1.5 months).³⁷ Given the lack of robust response (complete and durable) with rituximab, the Berentsen group has explored adding bendamustine to rituximab.⁴⁰ In a prospective trial, 71% of patients responded with a 40% complete response rate. Therapy was well tolerated, with only 29% of patients needing dose reduction Although more toxic, this combination can be considered in patients with aggressive disease. A small study of the use of bortezomib showed a good response in one-third of patients.⁴¹ There is increasing use of the C5 complement inhibitor eculizumab to halt the hemolysis, but further study of this agent is also required.^36,42,43 Blockers of C1s complement, which block hemolysis by preventing complement activation, are currently being studied in clinical trials.⁴⁴

Since most patients with cold AIHA are older, a frequent issue that must be considered is cardiac surgery. The concern is that the hypothermia involved with most heart bypass procedures will lead to agglutination and hemolysis. The development of normothermic bypass has expanded treatment options. A recommended approach in patients who have known cold agglutinins is to measure the thermal amplitude of the antibody preoperatively. If the thermal amplitude is above 18°C, normothermic bypass should be done, if feasible.⁴⁵ If not feasible, preoperative TPE should be considered.

Paroxysmal Cold Hemoglobinuria

A unique cold AIHA is paroxysmal cold hemoglobinuria (PCH).^3,46 This cold hemolytic syndrome most often occurs in children following a viral infection, but in the past it complicated any stage of syphilis.⁴⁷ The mediating antibody in PCH is an IgG antibody directed against the P antigen on the red blood cell. This antibody binds best at temperatures below 37°C, fixing complement at cold temperatures, but then activates the complement cascade at body temperature.⁴⁸ Because this antibody can fix complement, hemolysis can be rapid and severe, leading to extreme anemia. The DAT is often weakly positive but can be negative. The diagnostic test for PCH is the Donath–Landsteiner test. This complex test is performed by incubating 3 blood samples, 1 at 0° to 4°C, another at 37°C, and a third at 0° to 4°C and then at 37°C. The diagnosis of PCH is made if only the third tube shows hemolysis.³⁵ PCH can persist for 1 to 3 months but is almost always self-limiting. In severe case, steroids may be of benefit.

Drug-Induced Hemolytic Anemia

AIHA caused by a drug reaction is rare, with a lower incidence than drug-related ITP. The rate of severe drug-related AIHA is estimated at 1:1,000,000, but less severe cases may be missed.¹ Most patients will have a positive DAT without signs of hemolysis, but in rare cases patients will have relentless hemolysis resulting in death.

Mechanisms

Multiple mechanisms for drug-induced immune hemolysis have been proposed, including drug-absorption (hapten-induced) and immune complex mechanisms.^1,49 The hapten mechanism is most often associated with the use of high-dose penicillin.⁵⁰ High doses of penicillin or similar drugs such as piperacillin lead to incorporation of the drug into the red cell membrane by binding to proteins. Patients will manifest a positive DAT with IgG antibody but not complement.⁵¹ The patient’s plasma will be reactive only with penicillin-coated red cells and not with normal cells. As mentioned, very few patients will have hemolysis, and if they have hemolysis, it will resolve in a few days after discontinuation of the offending drug.⁵²

Binding of a drug-antibody complex to the red cell membrane may cause hemolysis via the immune com-plex mechanism.⁵³ Again, most often the patient will have just a positive DAT, but rarely patients will have life-threatening hemolysis upon exposure or reexposure to the drug. The onset of hemolysis is rapid, with signs of acute illness and intravascular hemolysis. The paradigm drug is quinine, but many other drugs have been implicated. Testing shows a positive Coombs test with anti-complement but not anti-IgG.⁵⁰ This pattern is due to the effectiveness of the tertiary complex at fixing complement. The patient’s plasma reacts with red cells only when the drug is added.

A form of immune complex hemolysis associated with both disseminated intravascular coagulation (DIC) and brisk hemolysis has been recognized. Patients who receive certain second- and third-generation cephalosporins (especially cefotetan and ceftriaxone.^53,54) have developed this syndrome.^50,55-59 The clinical symptoms start 7 to 10 days after the drug is administered; often the patient has only received the antibiotic for surgical prophylaxis. Immune hemolysis with acute hematocrit drop, hypotension, and DIC ensues. The patients are often believed to have sepsis and are often reexposed to the cephalosporin, resulting in worsening of the clinical status. The outcome is often fatal due to massive hemolysis and thrombosis.^56,60,62

Finally, 8% to 36% of patients taking methyldopa will develop a positive DAT after 6 months of therapy, with less than 1% showing hemolysis.^52,63 The hemolysis in these patients is indistinguishable from warm AIHA, consistent with the notion that methyldopa induces an AIHA. The hemolysis often resolves rapidly after the methyldopa is stopped, but the Coombs test may remain positive for months.⁶³ This type of drug-induced hemolytic anemia has been reported with levodopa, procainamide, and chlorpromazine, but fludarabine is the most common cause currently. This form of AIHA is now being seen with increased use of checkpoint inhibitors.⁶⁴

Diagnosis

In many patients, the first clue to the presence of drug AIHA is the finding of a positive DAT. Rarely, patients will have severe hemolysis, but in many patients the hemolytic process is mild and may be wrongly assumed to be part of the underlying illness. Finding the offending drug can be a challenge, unless a patient has recently started a new drug; in a hospitalized patient on multiple agents, identifying the problem drug is difficult. Patients recently started on “suspect drugs,” especially the most common agents cefotetan, ceftriaxone, and piperacillin, should have these agents stopped (Table 4).^1,49,65 Specialty laboratories such as the Blood Center of Wisconsin or the Los Angeles Red Cross can perform in vitro studies of drug interactions that can confirm the clinical diagnosis of drug-induced AIHA.

Treatment

Therapy for patients with positive DAT without signs of hemolysis is uncertain. If the drug is essential, then the patient can be observed. If the patient has hemolysis, the drug needs to be stopped and the patient observed for signs of end-organ damage. It is doubtful that steroids or other autoimmune-directed therapy is effective. For patients with the DIC-hemolysis syndrome, there are anecdotal reports that TPE may be helpful.¹

Summary

AIHA can range from an abnormal laboratory test (positive DAT and signs of hemolysis) to an acute, life-threatening illness. Treatment is guided by the laboratory work-up and evaluation of the patient’s clinical status. While rituximab is promising for many patients, the lack of robust clinical trials hinders the treatment of patients who fail standard therapies.

The autoimmune hemolytic anemias (AIHA) are rare but important hematologic diseases. They can range in severity from mildly symptomatic illness to a rapidly fatal syndrome. The incidence of AIHA is estimated to be between 0.6 and 3 cases per 100,000 persons.^1,2 AIHA is mediated by antibodies, and in the majority of cases immunoglobulin (Ig) G is the mediating antibody. This type of AIHA is referred to as "warm" AIHA because IgG antibodies bind best at body temperature. "Cold" AIHA is mediated by IgM antibodies, which bind maximally at temperatures below 37°C (Table 1). This article series reviews the most common types of AIHA, with an overview of evaluation and diagnosis presented in this article and management of warm, cold, and drug-induced AIHA reviewed in a separate article.

Pathogenesis

In most cases, the ultimate etiology of AIHA is unknown. In warm AIHA, the target epitopes in most cases are Rh proteins.² What leads the immune system to target these proteins is unidentified, but one theory is that an initial immune response to a foreign antigen starts to cross-react with the Rh proteins and the immune system fails to suppress this autoreactive response, leading to hemolysis. In IgG-mediated (warm) hemolysis, the red cells become coated with IgG molecules, which mark the cells for uptake and destruction by splenic macrophages.³ In "cold" AIHA, IgM molecules fix complement to the surface of red blood cells. Rarely, this can lead to activation of the full complement cascade, resulting in red cell lysis, but more often it is stopped at the C3 stage, leading to C3-coated red cells which are then taken up by hepatic macrophages.⁴

Suspecting the Diagnosis

In many patients, it is the symptoms and signs of anemia that lead to suspicion of hemolysis. Older patients often present earlier in the course of the disease due to lack of tolerance of anemia, especially if there is a sudden drop in the red blood cell count. Dark, cola-colored urine resulting from the presence of free hemoglobin may be noted by some patients. Patients with rapid-onset hemolysis may note lumbar back pain, and those with cold agglutinins often note symptoms related to agglutination of red cells in the peripheral circulation, such as the development of acrocyanosis in cold weather.⁵ In rare cases, patients will have abdominal pain when eating cold food due to ischemia related to agglutination of red cells in the viscera. Some patients with cold agglutinins can have an exacerbation of their hemolysis with cold exposure.

Unlike patients with immune thrombocytopenia, those with AIHA may have mild splenomegaly on exam. The presence of enlarged lymph nodes or massive splenomegaly should raise concern about concomitant lymphoma or chronic lymphocytic leukemia.

Making the Diagnosis

The 2 key steps in diagnosis are (1) demonstrating hemolysis and (2) demonstrating the autoimmune component.

Laboratory Evaluation for Hemolysis

Hemolysis is proven by finding evidence of both red cell breakdown and the compensatory increase in red cell production this stimulates (Table 2). The following sections discuss the laboratory tests that are performed to investigate hemolysis.

Lactate Dehydrogenase

When red cells undergo hemolysis, they release their contents, which are mostly comprised of hemoglobin but also include lactate dehydrogenase (LDH), an enzyme found in high concentration in red cells. Most patients with hemolysis will have an elevated LDH level, making this a sensitive test. However, because many other processes, including liver disease and pneumonia, also raise the serum LDH level, this finding is not specific for hemolysis.

Hemoglobin is salvaged by haptoglobin, and the heme moiety is broken down first to bilirubin and then to urobilinogen, which is excreted in the urine.² Bilirubin produced from the breakdown of heme is not conjugated, but rather is delivered to the liver, where it is conjugated and excreted into the bile. In hemolysis, the concentration of unconjugated bilirubin (indirect bilirubin) is increased, while in liver disease the level of conjugated bilirubin (direct bilirubin) is increased. However, if the patient has concomitant liver disease with an increased direct bilirubin level, the serum bilirubin test is not reliable.

Serum Haptoglobin

Haptoglobin binds free serum hemoglobin and is taken up by the liver. Haptoglobin usually falls to very low levels in hemolysis. A confounder is that haptoglobin is an acute phase reactant and can rise with systemic disease or inflammation. However, patients with advanced liver disease will have low haptoglobin levels due to lack of synthesis, and up to 2% of the population may congenitally lack haptoglobin.¹

Serum Hemoglobin

If the hemolysis is very rapid, the amount of free hemoglobin released will overwhelm the binding capacity of haptoglobin and lead to free hemoglobin in the plasma. This can be crudely quantified by examining the plasma color. Even minute amounts of free hemoglobin will turn the plasma pink. In fulminant hemolysis, the plasma will be cola-colored.

Reticulocyte Count

In most patients with hemolysis, the destruction of red cells is accompanied by an increase in the reticulocyte count. Reticulocytes are red cells that still contain RNA and are a marker of red cells that are approximately 24 hours old or less. Traditionally, reticulocytes were measured manually by staining the blood smear with vital blue and counting the percentage of cells that absorb the stain; this percentage needs to be adjusted for the hematocrit. Usually a percentage above 1.5% is considered indicative of an elevated reticulocyte count. Recently, automated complete blood count machines have taken advantage of the fact that reticulocytes will absorb certain stains; these machines can directly measure the reticulocyte count via flow cytometry, which results in an “absolute” reticulocyte count. The reticulocyte count obtained using this method does not have to be corrected for hematocrit, and levels of approximately 90,000/μL are considered raised. However, the reticulocyte count can also be raised in blood loss or in patients who have other causes of anemia (eg, iron deficiency) under treatment. In addition, as many as 25% of patients with AIHA will never have raised counts for various reasons, such as nutritional deficiency, autoimmune destruction of red cell precursors, or lack of erythropoietin.

Blood Smear

The blood smear provides vital information. The hallmark laboratory parameter of AIHA is spherocytes seen on the blood smear. In AIHA, antibodies and/or complement attach to the red cells, and when the antibodies or complement are taken up by macrophages in the spleen some of the red blood cell mem-brane is removed as well, decreasing the surface area of the cell. As the surface area of the red cell decreases with each pass through the spleen, the cell's shape changes from a biconcave disk to a sphere before the cell is destroyed, reflecting the fact that a sphere has the smallest surface area for a given volume. The vast majority of patients with AIHA will have spherocytes on the blood smear. However, spherocytes are not specific to AIHA, as they can be seen in hereditary spherocytosis, Wilson’s disease, clostridial sepsis, and severe burns.

Patients with cold agglutinins will often have red cell agglutination on the blood smear. In addition, patients with AIHA will often have a raised mean corpuscular volume (MCV) for 2 reasons. In patients with brisk reticulocytosis, the MCV will be raised due to the large size of the reticulocyte. In patients with cold agglutinin disease, the MCV may be falsely raised due to clumping of the red blood cells.

Urinary Hemosiderin

When hemoglobin is excreted by the kidney, the iron is deposited in the tubules. When the tubule cells are sloughed off, they appear in the urine. The urine can be stained for iron, and a positive result is another sign of hemolysis. Hemosiderinuria is a later sign of hemolysis, as it takes 1 week for iron-laden tubule cells to be excreted in sufficient quantities to be detected in the urine.

Urinary Hemoglobin

One other sign of hemolysis is the presence of hemoglobin in the urine. A quick way to demonstrate hemoglobinuria is to check the urine with a dipstick followed by a microscopic exam. In hemolysis, the dipstick will detect “blood,” while the microscopic exam will be negative for red cells.

Laboratory Evaluation for Autoimmune Component

The autoimmune component is shown by demonstrating the presence of either IgG molecules or complement on the surface of red blood cells.^4,6 This can be done by performing the direct antiglobulin test (DAT) or Coombs test. IgG bound to red cells will not agglutinate them, but if IgM that is directed against IgG or C3 is added, the red cells will agglutinate, proving that there is IgG and/or C3 on the red cell membrane. The finding of a positive DAT in the setting of a hemolytic anemia is diagnostic of AIHA. Beware of individuals with concomitant weak positive DAT and other causes of hemolysis. The strength of the DAT result and the degree of hemolysis must match in order to conclude that the hemolysis is immune-mediated.

There are several pitfalls to the DAT. One is that a positive DAT is found in 1:1000 patients in the normal population and in up to several percent of ill patients, especially those with elevated gamma globulin, such as patients with liver disease or HIV infection.⁶ Administration of intravenous immunoglobulin (IVIG) can also create a positive DAT. Conversely, patients can have AIHA with a negative DAT.^7-9 For some patients, the number of IgG molecules bound to the red cell is below the detection limit of the DAT reagents. Other patients can have IgA or “warm” IgM as the cause of the AIHA.¹⁰ Specialty laboratories can test for these possibilities. The diagnosis of DAT-negative AIHA should be made with caution, and other causes of hemolysis, such as hereditary spherocytosis or paroxysmal hematuria, should be excluded.

Performing transfusions can be very difficult in patients with AIHA.² The presence of the autoantibody can interfere with typing of the blood and almost always interferes with the crossmatch, since this final step consists of mixing the patient’s serum or plasma with donor red cells. In most patients with AIHA, the autoantibodies will react with any donor cells, rendering a negative crossmatch impossible. Without the crossmatch, the concern is that underlying alloantibodies can be missed. Studies indicate that 15% to 32% of patients will have underlying alloantibodies, which can lead to transfusion reactions.² However, there are 2 considerations that may mitigate these concerns.^11,12 First, patients who have never been transfused or pregnant will rarely have alloantibodies. Second, a patient who has been transfused in the remote past may have an anamnestic antibody response but not an immediate hemolytic reaction.

The transfusion service can take several steps to identify alloantibodies. Occasionally, if the autoantibody is weakly reacting when the patient’s serum is tested against a panel of reagent red cells, the alloantibodies can be identified by their stronger reactions as compared with the weakly reactive autoantibody. The most common technique for identifying alloantibodies is the autoadsorption technique.^4,13 This involves incu-bating the patient’s red cells with the patient’s serum to adsorb the autoantibody. After a period of incubation, the cells are pelleted and the serum is collected as the supernatant. The adsorbed serum may be incubated with another sample of the patient’s cells for a second adsorption if the initial agglutination reactions of the patient’s serum with the reagent cells were strong. After 1 to 3 adsorptions, the adsorbed serum is tested with a red cell panel in order to check for “leftover” alloantibodies.

When a patient is first suspected of having AIHA, a generous sample of blood should be given to the transfusion service to allow for adequate testing. Many centers will test the blood not only for blood groups ABO and D but also perform full Rh typing plus check for Kidd, Duffy and Kell status.¹⁴ Increasingly, this is performed by direct genetic sequencing for the appropriate genotypes. This can allow transfusion of phenotypically matched red blood cells to lessen the risk of alloantibody formation.

One difficult issue is timing of transfusion. Clinicians are often hesitant to transfuse patients with AIHA due to fear of reactions, but in patients with severe anemia, especially elderly patients or those with heart disease, transfusion can be lifesaving. Since in some cases it may take hours to screen for alloantibodies, it is often preferable to transfuse patients with severe anemia and observe carefully for reaction.

The autoimmune hemolytic anemias (AIHA) are rare but important hematologic diseases. They can range in severity from mildly symptomatic illness to a rapidly fatal syndrome. The incidence of AIHA is estimated to be between 0.6 and 3 cases per 100,000 persons.^1,2 AIHA is mediated by antibodies, and in the majority of cases immunoglobulin (Ig) G is the mediating antibody. This type of AIHA is referred to as "warm" AIHA because IgG antibodies bind best at body temperature. "Cold" AIHA is mediated by IgM antibodies, which bind maximally at temperatures below 37°C (Table 1). This article series reviews the most common types of AIHA, with an overview of evaluation and diagnosis presented in this article and management of warm, cold, and drug-induced AIHA reviewed in a separate article.

Pathogenesis

In most cases, the ultimate etiology of AIHA is unknown. In warm AIHA, the target epitopes in most cases are Rh proteins.² What leads the immune system to target these proteins is unidentified, but one theory is that an initial immune response to a foreign antigen starts to cross-react with the Rh proteins and the immune system fails to suppress this autoreactive response, leading to hemolysis. In IgG-mediated (warm) hemolysis, the red cells become coated with IgG molecules, which mark the cells for uptake and destruction by splenic macrophages.³ In "cold" AIHA, IgM molecules fix complement to the surface of red blood cells. Rarely, this can lead to activation of the full complement cascade, resulting in red cell lysis, but more often it is stopped at the C3 stage, leading to C3-coated red cells which are then taken up by hepatic macrophages.⁴

Suspecting the Diagnosis

In many patients, it is the symptoms and signs of anemia that lead to suspicion of hemolysis. Older patients often present earlier in the course of the disease due to lack of tolerance of anemia, especially if there is a sudden drop in the red blood cell count. Dark, cola-colored urine resulting from the presence of free hemoglobin may be noted by some patients. Patients with rapid-onset hemolysis may note lumbar back pain, and those with cold agglutinins often note symptoms related to agglutination of red cells in the peripheral circulation, such as the development of acrocyanosis in cold weather.⁵ In rare cases, patients will have abdominal pain when eating cold food due to ischemia related to agglutination of red cells in the viscera. Some patients with cold agglutinins can have an exacerbation of their hemolysis with cold exposure.

Unlike patients with immune thrombocytopenia, those with AIHA may have mild splenomegaly on exam. The presence of enlarged lymph nodes or massive splenomegaly should raise concern about concomitant lymphoma or chronic lymphocytic leukemia.

Making the Diagnosis

The 2 key steps in diagnosis are (1) demonstrating hemolysis and (2) demonstrating the autoimmune component.

Laboratory Evaluation for Hemolysis

Hemolysis is proven by finding evidence of both red cell breakdown and the compensatory increase in red cell production this stimulates (Table 2). The following sections discuss the laboratory tests that are performed to investigate hemolysis.

Lactate Dehydrogenase

When red cells undergo hemolysis, they release their contents, which are mostly comprised of hemoglobin but also include lactate dehydrogenase (LDH), an enzyme found in high concentration in red cells. Most patients with hemolysis will have an elevated LDH level, making this a sensitive test. However, because many other processes, including liver disease and pneumonia, also raise the serum LDH level, this finding is not specific for hemolysis.

Hemoglobin is salvaged by haptoglobin, and the heme moiety is broken down first to bilirubin and then to urobilinogen, which is excreted in the urine.² Bilirubin produced from the breakdown of heme is not conjugated, but rather is delivered to the liver, where it is conjugated and excreted into the bile. In hemolysis, the concentration of unconjugated bilirubin (indirect bilirubin) is increased, while in liver disease the level of conjugated bilirubin (direct bilirubin) is increased. However, if the patient has concomitant liver disease with an increased direct bilirubin level, the serum bilirubin test is not reliable.

Serum Haptoglobin

Haptoglobin binds free serum hemoglobin and is taken up by the liver. Haptoglobin usually falls to very low levels in hemolysis. A confounder is that haptoglobin is an acute phase reactant and can rise with systemic disease or inflammation. However, patients with advanced liver disease will have low haptoglobin levels due to lack of synthesis, and up to 2% of the population may congenitally lack haptoglobin.¹

Serum Hemoglobin

If the hemolysis is very rapid, the amount of free hemoglobin released will overwhelm the binding capacity of haptoglobin and lead to free hemoglobin in the plasma. This can be crudely quantified by examining the plasma color. Even minute amounts of free hemoglobin will turn the plasma pink. In fulminant hemolysis, the plasma will be cola-colored.

Reticulocyte Count

In most patients with hemolysis, the destruction of red cells is accompanied by an increase in the reticulocyte count. Reticulocytes are red cells that still contain RNA and are a marker of red cells that are approximately 24 hours old or less. Traditionally, reticulocytes were measured manually by staining the blood smear with vital blue and counting the percentage of cells that absorb the stain; this percentage needs to be adjusted for the hematocrit. Usually a percentage above 1.5% is considered indicative of an elevated reticulocyte count. Recently, automated complete blood count machines have taken advantage of the fact that reticulocytes will absorb certain stains; these machines can directly measure the reticulocyte count via flow cytometry, which results in an “absolute” reticulocyte count. The reticulocyte count obtained using this method does not have to be corrected for hematocrit, and levels of approximately 90,000/μL are considered raised. However, the reticulocyte count can also be raised in blood loss or in patients who have other causes of anemia (eg, iron deficiency) under treatment. In addition, as many as 25% of patients with AIHA will never have raised counts for various reasons, such as nutritional deficiency, autoimmune destruction of red cell precursors, or lack of erythropoietin.

Blood Smear

The blood smear provides vital information. The hallmark laboratory parameter of AIHA is spherocytes seen on the blood smear. In AIHA, antibodies and/or complement attach to the red cells, and when the antibodies or complement are taken up by macrophages in the spleen some of the red blood cell mem-brane is removed as well, decreasing the surface area of the cell. As the surface area of the red cell decreases with each pass through the spleen, the cell's shape changes from a biconcave disk to a sphere before the cell is destroyed, reflecting the fact that a sphere has the smallest surface area for a given volume. The vast majority of patients with AIHA will have spherocytes on the blood smear. However, spherocytes are not specific to AIHA, as they can be seen in hereditary spherocytosis, Wilson’s disease, clostridial sepsis, and severe burns.

Patients with cold agglutinins will often have red cell agglutination on the blood smear. In addition, patients with AIHA will often have a raised mean corpuscular volume (MCV) for 2 reasons. In patients with brisk reticulocytosis, the MCV will be raised due to the large size of the reticulocyte. In patients with cold agglutinin disease, the MCV may be falsely raised due to clumping of the red blood cells.

Urinary Hemosiderin

When hemoglobin is excreted by the kidney, the iron is deposited in the tubules. When the tubule cells are sloughed off, they appear in the urine. The urine can be stained for iron, and a positive result is another sign of hemolysis. Hemosiderinuria is a later sign of hemolysis, as it takes 1 week for iron-laden tubule cells to be excreted in sufficient quantities to be detected in the urine.

Urinary Hemoglobin

One other sign of hemolysis is the presence of hemoglobin in the urine. A quick way to demonstrate hemoglobinuria is to check the urine with a dipstick followed by a microscopic exam. In hemolysis, the dipstick will detect “blood,” while the microscopic exam will be negative for red cells.

Laboratory Evaluation for Autoimmune Component

The autoimmune component is shown by demonstrating the presence of either IgG molecules or complement on the surface of red blood cells.^4,6 This can be done by performing the direct antiglobulin test (DAT) or Coombs test. IgG bound to red cells will not agglutinate them, but if IgM that is directed against IgG or C3 is added, the red cells will agglutinate, proving that there is IgG and/or C3 on the red cell membrane. The finding of a positive DAT in the setting of a hemolytic anemia is diagnostic of AIHA. Beware of individuals with concomitant weak positive DAT and other causes of hemolysis. The strength of the DAT result and the degree of hemolysis must match in order to conclude that the hemolysis is immune-mediated.

There are several pitfalls to the DAT. One is that a positive DAT is found in 1:1000 patients in the normal population and in up to several percent of ill patients, especially those with elevated gamma globulin, such as patients with liver disease or HIV infection.⁶ Administration of intravenous immunoglobulin (IVIG) can also create a positive DAT. Conversely, patients can have AIHA with a negative DAT.^7-9 For some patients, the number of IgG molecules bound to the red cell is below the detection limit of the DAT reagents. Other patients can have IgA or “warm” IgM as the cause of the AIHA.¹⁰ Specialty laboratories can test for these possibilities. The diagnosis of DAT-negative AIHA should be made with caution, and other causes of hemolysis, such as hereditary spherocytosis or paroxysmal hematuria, should be excluded.

Performing transfusions can be very difficult in patients with AIHA.² The presence of the autoantibody can interfere with typing of the blood and almost always interferes with the crossmatch, since this final step consists of mixing the patient’s serum or plasma with donor red cells. In most patients with AIHA, the autoantibodies will react with any donor cells, rendering a negative crossmatch impossible. Without the crossmatch, the concern is that underlying alloantibodies can be missed. Studies indicate that 15% to 32% of patients will have underlying alloantibodies, which can lead to transfusion reactions.² However, there are 2 considerations that may mitigate these concerns.^11,12 First, patients who have never been transfused or pregnant will rarely have alloantibodies. Second, a patient who has been transfused in the remote past may have an anamnestic antibody response but not an immediate hemolytic reaction.

The transfusion service can take several steps to identify alloantibodies. Occasionally, if the autoantibody is weakly reacting when the patient’s serum is tested against a panel of reagent red cells, the alloantibodies can be identified by their stronger reactions as compared with the weakly reactive autoantibody. The most common technique for identifying alloantibodies is the autoadsorption technique.^4,13 This involves incu-bating the patient’s red cells with the patient’s serum to adsorb the autoantibody. After a period of incubation, the cells are pelleted and the serum is collected as the supernatant. The adsorbed serum may be incubated with another sample of the patient’s cells for a second adsorption if the initial agglutination reactions of the patient’s serum with the reagent cells were strong. After 1 to 3 adsorptions, the adsorbed serum is tested with a red cell panel in order to check for “leftover” alloantibodies.

When a patient is first suspected of having AIHA, a generous sample of blood should be given to the transfusion service to allow for adequate testing. Many centers will test the blood not only for blood groups ABO and D but also perform full Rh typing plus check for Kidd, Duffy and Kell status.¹⁴ Increasingly, this is performed by direct genetic sequencing for the appropriate genotypes. This can allow transfusion of phenotypically matched red blood cells to lessen the risk of alloantibody formation.

One difficult issue is timing of transfusion. Clinicians are often hesitant to transfuse patients with AIHA due to fear of reactions, but in patients with severe anemia, especially elderly patients or those with heart disease, transfusion can be lifesaving. Since in some cases it may take hours to screen for alloantibodies, it is often preferable to transfuse patients with severe anemia and observe carefully for reaction.

The autoimmune hemolytic anemias (AIHA) are rare but important hematologic diseases. They can range in severity from mildly symptomatic illness to a rapidly fatal syndrome. The incidence of AIHA is estimated to be between 0.6 and 3 cases per 100,000 persons.^1,2 AIHA is mediated by antibodies, and in the majority of cases immunoglobulin (Ig) G is the mediating antibody. This type of AIHA is referred to as "warm" AIHA because IgG antibodies bind best at body temperature. "Cold" AIHA is mediated by IgM antibodies, which bind maximally at temperatures below 37°C (Table 1). This article series reviews the most common types of AIHA, with an overview of evaluation and diagnosis presented in this article and management of warm, cold, and drug-induced AIHA reviewed in a separate article.

Pathogenesis

In most cases, the ultimate etiology of AIHA is unknown. In warm AIHA, the target epitopes in most cases are Rh proteins.² What leads the immune system to target these proteins is unidentified, but one theory is that an initial immune response to a foreign antigen starts to cross-react with the Rh proteins and the immune system fails to suppress this autoreactive response, leading to hemolysis. In IgG-mediated (warm) hemolysis, the red cells become coated with IgG molecules, which mark the cells for uptake and destruction by splenic macrophages.³ In "cold" AIHA, IgM molecules fix complement to the surface of red blood cells. Rarely, this can lead to activation of the full complement cascade, resulting in red cell lysis, but more often it is stopped at the C3 stage, leading to C3-coated red cells which are then taken up by hepatic macrophages.⁴

Suspecting the Diagnosis

In many patients, it is the symptoms and signs of anemia that lead to suspicion of hemolysis. Older patients often present earlier in the course of the disease due to lack of tolerance of anemia, especially if there is a sudden drop in the red blood cell count. Dark, cola-colored urine resulting from the presence of free hemoglobin may be noted by some patients. Patients with rapid-onset hemolysis may note lumbar back pain, and those with cold agglutinins often note symptoms related to agglutination of red cells in the peripheral circulation, such as the development of acrocyanosis in cold weather.⁵ In rare cases, patients will have abdominal pain when eating cold food due to ischemia related to agglutination of red cells in the viscera. Some patients with cold agglutinins can have an exacerbation of their hemolysis with cold exposure.

Unlike patients with immune thrombocytopenia, those with AIHA may have mild splenomegaly on exam. The presence of enlarged lymph nodes or massive splenomegaly should raise concern about concomitant lymphoma or chronic lymphocytic leukemia.

Making the Diagnosis

The 2 key steps in diagnosis are (1) demonstrating hemolysis and (2) demonstrating the autoimmune component.

Laboratory Evaluation for Hemolysis

Hemolysis is proven by finding evidence of both red cell breakdown and the compensatory increase in red cell production this stimulates (Table 2). The following sections discuss the laboratory tests that are performed to investigate hemolysis.

Lactate Dehydrogenase

When red cells undergo hemolysis, they release their contents, which are mostly comprised of hemoglobin but also include lactate dehydrogenase (LDH), an enzyme found in high concentration in red cells. Most patients with hemolysis will have an elevated LDH level, making this a sensitive test. However, because many other processes, including liver disease and pneumonia, also raise the serum LDH level, this finding is not specific for hemolysis.

Hemoglobin is salvaged by haptoglobin, and the heme moiety is broken down first to bilirubin and then to urobilinogen, which is excreted in the urine.² Bilirubin produced from the breakdown of heme is not conjugated, but rather is delivered to the liver, where it is conjugated and excreted into the bile. In hemolysis, the concentration of unconjugated bilirubin (indirect bilirubin) is increased, while in liver disease the level of conjugated bilirubin (direct bilirubin) is increased. However, if the patient has concomitant liver disease with an increased direct bilirubin level, the serum bilirubin test is not reliable.

Serum Haptoglobin

Haptoglobin binds free serum hemoglobin and is taken up by the liver. Haptoglobin usually falls to very low levels in hemolysis. A confounder is that haptoglobin is an acute phase reactant and can rise with systemic disease or inflammation. However, patients with advanced liver disease will have low haptoglobin levels due to lack of synthesis, and up to 2% of the population may congenitally lack haptoglobin.¹

Serum Hemoglobin

If the hemolysis is very rapid, the amount of free hemoglobin released will overwhelm the binding capacity of haptoglobin and lead to free hemoglobin in the plasma. This can be crudely quantified by examining the plasma color. Even minute amounts of free hemoglobin will turn the plasma pink. In fulminant hemolysis, the plasma will be cola-colored.

Reticulocyte Count

In most patients with hemolysis, the destruction of red cells is accompanied by an increase in the reticulocyte count. Reticulocytes are red cells that still contain RNA and are a marker of red cells that are approximately 24 hours old or less. Traditionally, reticulocytes were measured manually by staining the blood smear with vital blue and counting the percentage of cells that absorb the stain; this percentage needs to be adjusted for the hematocrit. Usually a percentage above 1.5% is considered indicative of an elevated reticulocyte count. Recently, automated complete blood count machines have taken advantage of the fact that reticulocytes will absorb certain stains; these machines can directly measure the reticulocyte count via flow cytometry, which results in an “absolute” reticulocyte count. The reticulocyte count obtained using this method does not have to be corrected for hematocrit, and levels of approximately 90,000/μL are considered raised. However, the reticulocyte count can also be raised in blood loss or in patients who have other causes of anemia (eg, iron deficiency) under treatment. In addition, as many as 25% of patients with AIHA will never have raised counts for various reasons, such as nutritional deficiency, autoimmune destruction of red cell precursors, or lack of erythropoietin.

Blood Smear

The blood smear provides vital information. The hallmark laboratory parameter of AIHA is spherocytes seen on the blood smear. In AIHA, antibodies and/or complement attach to the red cells, and when the antibodies or complement are taken up by macrophages in the spleen some of the red blood cell mem-brane is removed as well, decreasing the surface area of the cell. As the surface area of the red cell decreases with each pass through the spleen, the cell's shape changes from a biconcave disk to a sphere before the cell is destroyed, reflecting the fact that a sphere has the smallest surface area for a given volume. The vast majority of patients with AIHA will have spherocytes on the blood smear. However, spherocytes are not specific to AIHA, as they can be seen in hereditary spherocytosis, Wilson’s disease, clostridial sepsis, and severe burns.

Patients with cold agglutinins will often have red cell agglutination on the blood smear. In addition, patients with AIHA will often have a raised mean corpuscular volume (MCV) for 2 reasons. In patients with brisk reticulocytosis, the MCV will be raised due to the large size of the reticulocyte. In patients with cold agglutinin disease, the MCV may be falsely raised due to clumping of the red blood cells.

Urinary Hemosiderin

When hemoglobin is excreted by the kidney, the iron is deposited in the tubules. When the tubule cells are sloughed off, they appear in the urine. The urine can be stained for iron, and a positive result is another sign of hemolysis. Hemosiderinuria is a later sign of hemolysis, as it takes 1 week for iron-laden tubule cells to be excreted in sufficient quantities to be detected in the urine.

Urinary Hemoglobin

One other sign of hemolysis is the presence of hemoglobin in the urine. A quick way to demonstrate hemoglobinuria is to check the urine with a dipstick followed by a microscopic exam. In hemolysis, the dipstick will detect “blood,” while the microscopic exam will be negative for red cells.

Laboratory Evaluation for Autoimmune Component

The autoimmune component is shown by demonstrating the presence of either IgG molecules or complement on the surface of red blood cells.^4,6 This can be done by performing the direct antiglobulin test (DAT) or Coombs test. IgG bound to red cells will not agglutinate them, but if IgM that is directed against IgG or C3 is added, the red cells will agglutinate, proving that there is IgG and/or C3 on the red cell membrane. The finding of a positive DAT in the setting of a hemolytic anemia is diagnostic of AIHA. Beware of individuals with concomitant weak positive DAT and other causes of hemolysis. The strength of the DAT result and the degree of hemolysis must match in order to conclude that the hemolysis is immune-mediated.

There are several pitfalls to the DAT. One is that a positive DAT is found in 1:1000 patients in the normal population and in up to several percent of ill patients, especially those with elevated gamma globulin, such as patients with liver disease or HIV infection.⁶ Administration of intravenous immunoglobulin (IVIG) can also create a positive DAT. Conversely, patients can have AIHA with a negative DAT.^7-9 For some patients, the number of IgG molecules bound to the red cell is below the detection limit of the DAT reagents. Other patients can have IgA or “warm” IgM as the cause of the AIHA.¹⁰ Specialty laboratories can test for these possibilities. The diagnosis of DAT-negative AIHA should be made with caution, and other causes of hemolysis, such as hereditary spherocytosis or paroxysmal hematuria, should be excluded.

Performing transfusions can be very difficult in patients with AIHA.² The presence of the autoantibody can interfere with typing of the blood and almost always interferes with the crossmatch, since this final step consists of mixing the patient’s serum or plasma with donor red cells. In most patients with AIHA, the autoantibodies will react with any donor cells, rendering a negative crossmatch impossible. Without the crossmatch, the concern is that underlying alloantibodies can be missed. Studies indicate that 15% to 32% of patients will have underlying alloantibodies, which can lead to transfusion reactions.² However, there are 2 considerations that may mitigate these concerns.^11,12 First, patients who have never been transfused or pregnant will rarely have alloantibodies. Second, a patient who has been transfused in the remote past may have an anamnestic antibody response but not an immediate hemolytic reaction.

The transfusion service can take several steps to identify alloantibodies. Occasionally, if the autoantibody is weakly reacting when the patient’s serum is tested against a panel of reagent red cells, the alloantibodies can be identified by their stronger reactions as compared with the weakly reactive autoantibody. The most common technique for identifying alloantibodies is the autoadsorption technique.^4,13 This involves incu-bating the patient’s red cells with the patient’s serum to adsorb the autoantibody. After a period of incubation, the cells are pelleted and the serum is collected as the supernatant. The adsorbed serum may be incubated with another sample of the patient’s cells for a second adsorption if the initial agglutination reactions of the patient’s serum with the reagent cells were strong. After 1 to 3 adsorptions, the adsorbed serum is tested with a red cell panel in order to check for “leftover” alloantibodies.

When a patient is first suspected of having AIHA, a generous sample of blood should be given to the transfusion service to allow for adequate testing. Many centers will test the blood not only for blood groups ABO and D but also perform full Rh typing plus check for Kidd, Duffy and Kell status.¹⁴ Increasingly, this is performed by direct genetic sequencing for the appropriate genotypes. This can allow transfusion of phenotypically matched red blood cells to lessen the risk of alloantibody formation.

One difficult issue is timing of transfusion. Clinicians are often hesitant to transfuse patients with AIHA due to fear of reactions, but in patients with severe anemia, especially elderly patients or those with heart disease, transfusion can be lifesaving. Since in some cases it may take hours to screen for alloantibodies, it is often preferable to transfuse patients with severe anemia and observe carefully for reaction.