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A donor’s CD8 cell count can affect the outcome of hematopoietic stem cell transplant (HSCT) in older patients, according to a study published in the Journal of Clinical Oncology.
Older patients who received stem cells from unrelated donors with higher CD8 counts had a significantly lower risk of relapse and higher rate of
survival than patients who received grafts with lower CD8 counts, even if those grafts were from matched sibling donors.
This suggests that screening for donor T-cell characteristics could optimize donor selection and ultimately lead to more successful transplants in an older population, study investigators said.
“Developing better tools to identify ideal donors is an exciting prospect and fundamental to improving transplant outcomes,” said Ran Reshef, MD, of the Abramson Cancer Center at the University of Pennsylvania in Philadelphia.
“There may be suitable donors out there who are overlooked because they are considered a poorer match by today’s donor selection algorithms. Refining the screening method could greatly increase the chances of finding the most appropriate donor, one that will induce the most potent graft-vs-tumor response.”
For this study, Dr Reshef and his colleagues retrospectively evaluated associations between a graft’s T-cell dose and outcomes in 200 patients undergoing HSCT to treat acute myeloid leukemia, myelodysplastic syndrome, non-Hodgkin lymphoma, and other hematologic disorders.
The investigators looked specifically at CD4 and CD8 counts and found the number of CD8 cells in the graft had an impact on survival. They also found that high CD8 cell counts were much more common among young donors.
The 4-year overall survival rates were 59% for patients who received grafts from younger (<50 years), unrelated donors with high CD8 counts; 18% for those who received grafts from younger, unrelated donors with low CD8 counts; and 33% for patients who received grafts from older (>50 years), HLA-matched sibling donors.
In multivariable analysis, CD8 count was an independent predictor of relapse (adjusted hazard ratio [aHR]=0.43; P=0.009), relapse-free survival (aHR=0.50; P=0.006), and overall survival (aHR=0.57; P=0.04).
The investigators also assessed the effect of CD8 count on survival using a cutoff of 0.72 x 108 CD8 cells/kg. They found that patients with CD8 doses above this cutoff had significantly better relapse-free survival (P=0.005) and overall survival (P=0.007) rates than patients with CD8 doses below this cutoff.
These results suggest it would be better to use a younger, unrelated donor graft with a high CD8 cell count rather than an older sibling donor, the investigators said. However, this strategy should be tested in a prospective trial.
“This is a method deserving additional investigation,” Dr Reshef said, “which could refine the standardized matching system used by registries, such as Be the Match and others, and ultimately optimize the donor pool for older patients undergoing these transplants.” 
Photo by Chad McNeeley
A donor’s CD8 cell count can affect the outcome of hematopoietic stem cell transplant (HSCT) in older patients, according to a study published in the Journal of Clinical Oncology.
Older patients who received stem cells from unrelated donors with higher CD8 counts had a significantly lower risk of relapse and higher rate of
survival than patients who received grafts with lower CD8 counts, even if those grafts were from matched sibling donors.
This suggests that screening for donor T-cell characteristics could optimize donor selection and ultimately lead to more successful transplants in an older population, study investigators said.
“Developing better tools to identify ideal donors is an exciting prospect and fundamental to improving transplant outcomes,” said Ran Reshef, MD, of the Abramson Cancer Center at the University of Pennsylvania in Philadelphia.
“There may be suitable donors out there who are overlooked because they are considered a poorer match by today’s donor selection algorithms. Refining the screening method could greatly increase the chances of finding the most appropriate donor, one that will induce the most potent graft-vs-tumor response.”
For this study, Dr Reshef and his colleagues retrospectively evaluated associations between a graft’s T-cell dose and outcomes in 200 patients undergoing HSCT to treat acute myeloid leukemia, myelodysplastic syndrome, non-Hodgkin lymphoma, and other hematologic disorders.
The investigators looked specifically at CD4 and CD8 counts and found the number of CD8 cells in the graft had an impact on survival. They also found that high CD8 cell counts were much more common among young donors.
The 4-year overall survival rates were 59% for patients who received grafts from younger (<50 years), unrelated donors with high CD8 counts; 18% for those who received grafts from younger, unrelated donors with low CD8 counts; and 33% for patients who received grafts from older (>50 years), HLA-matched sibling donors.
In multivariable analysis, CD8 count was an independent predictor of relapse (adjusted hazard ratio [aHR]=0.43; P=0.009), relapse-free survival (aHR=0.50; P=0.006), and overall survival (aHR=0.57; P=0.04).
The investigators also assessed the effect of CD8 count on survival using a cutoff of 0.72 x 108 CD8 cells/kg. They found that patients with CD8 doses above this cutoff had significantly better relapse-free survival (P=0.005) and overall survival (P=0.007) rates than patients with CD8 doses below this cutoff.
These results suggest it would be better to use a younger, unrelated donor graft with a high CD8 cell count rather than an older sibling donor, the investigators said. However, this strategy should be tested in a prospective trial.
“This is a method deserving additional investigation,” Dr Reshef said, “which could refine the standardized matching system used by registries, such as Be the Match and others, and ultimately optimize the donor pool for older patients undergoing these transplants.”
Photo by Chad McNeeley
A donor’s CD8 cell count can affect the outcome of hematopoietic stem cell transplant (HSCT) in older patients, according to a study published in the Journal of Clinical Oncology.
Older patients who received stem cells from unrelated donors with higher CD8 counts had a significantly lower risk of relapse and higher rate of
survival than patients who received grafts with lower CD8 counts, even if those grafts were from matched sibling donors.
This suggests that screening for donor T-cell characteristics could optimize donor selection and ultimately lead to more successful transplants in an older population, study investigators said.
“Developing better tools to identify ideal donors is an exciting prospect and fundamental to improving transplant outcomes,” said Ran Reshef, MD, of the Abramson Cancer Center at the University of Pennsylvania in Philadelphia.
“There may be suitable donors out there who are overlooked because they are considered a poorer match by today’s donor selection algorithms. Refining the screening method could greatly increase the chances of finding the most appropriate donor, one that will induce the most potent graft-vs-tumor response.”
For this study, Dr Reshef and his colleagues retrospectively evaluated associations between a graft’s T-cell dose and outcomes in 200 patients undergoing HSCT to treat acute myeloid leukemia, myelodysplastic syndrome, non-Hodgkin lymphoma, and other hematologic disorders.
The investigators looked specifically at CD4 and CD8 counts and found the number of CD8 cells in the graft had an impact on survival. They also found that high CD8 cell counts were much more common among young donors.
The 4-year overall survival rates were 59% for patients who received grafts from younger (<50 years), unrelated donors with high CD8 counts; 18% for those who received grafts from younger, unrelated donors with low CD8 counts; and 33% for patients who received grafts from older (>50 years), HLA-matched sibling donors.
In multivariable analysis, CD8 count was an independent predictor of relapse (adjusted hazard ratio [aHR]=0.43; P=0.009), relapse-free survival (aHR=0.50; P=0.006), and overall survival (aHR=0.57; P=0.04).
The investigators also assessed the effect of CD8 count on survival using a cutoff of 0.72 x 108 CD8 cells/kg. They found that patients with CD8 doses above this cutoff had significantly better relapse-free survival (P=0.005) and overall survival (P=0.007) rates than patients with CD8 doses below this cutoff.
These results suggest it would be better to use a younger, unrelated donor graft with a high CD8 cell count rather than an older sibling donor, the investigators said. However, this strategy should be tested in a prospective trial.
“This is a method deserving additional investigation,” Dr Reshef said, “which could refine the standardized matching system used by registries, such as Be the Match and others, and ultimately optimize the donor pool for older patients undergoing these transplants.”