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Researchers believe they have discovered how a commonly administered vaccine protects children from developing acute lymphoblastic leukemia (ALL).
The Haemophilus influenzae Type b (Hib) vaccine is part of the standard vaccination schedule recommended for children by the US Centers for Disease Control and Prevention. The vaccine is routinely given in 4 doses before children reach 15 months of age.
The Hib vaccine prevents ear infections and meningitis caused by the Hib bacterium, but it may also protect against ALL.
This protection has been suggested in previous studies, but it is not well-known among the public at large, and the mechanism underlying this effect has been poorly understood.
Now, researchers have shown that recurrent Hib infections can shift certain genes into overdrive, converting pre-leukemic cells into full-blown cancer. The team described this work in Nature Immunology.
“These experiments help explain why the incidence of leukemia has been dramatically reduced since the advent of regular vaccinations during infancy,” said study author Markus Müschen, MD, PhD, of the University of California San Francisco.
“Hib and other childhood infections can cause recurrent and vehement immune responses, which we have found could lead to leukemia, but infants that have received vaccines are largely protected and acquire long-term immunity through very mild immune reactions.”
For this study, Dr Müschen and his colleagues tested the idea that chronic inflammation caused by recurrent infections might cause additional genetic lesions in blood cells already carrying an oncogene, promoting their transformation to overt disease.
The team conducted experiments in mice and discovered that the enzymes AID and RAG1-RAG2 drive this process. AID and RAG1-RAG2 introduce mutations in DNA that allow immune cells to adapt to infectious challenges, and these enzymes are necessary for a normal and efficient immune response.
The researchers found that, in the presence of chronic infection, AID and RAG1-RAG2 were hyperactivated, randomly cutting and mutating genes.
Additional experiments revealed that AID and RAG1-RAG2 working together is critical to introduce the additional lesions that result in ALL.
Though the researchers focused on a bacterial infection in this study, they believe the same mechanisms may be at work in viral infections.
The team is currently conducting experiments to determine if protection against leukemia is provided by vaccines against viral infections, such as the measles-mumps-rubella vaccine. 
Photo by Petr Kratochvil
Researchers believe they have discovered how a commonly administered vaccine protects children from developing acute lymphoblastic leukemia (ALL).
The Haemophilus influenzae Type b (Hib) vaccine is part of the standard vaccination schedule recommended for children by the US Centers for Disease Control and Prevention. The vaccine is routinely given in 4 doses before children reach 15 months of age.
The Hib vaccine prevents ear infections and meningitis caused by the Hib bacterium, but it may also protect against ALL.
This protection has been suggested in previous studies, but it is not well-known among the public at large, and the mechanism underlying this effect has been poorly understood.
Now, researchers have shown that recurrent Hib infections can shift certain genes into overdrive, converting pre-leukemic cells into full-blown cancer. The team described this work in Nature Immunology.
“These experiments help explain why the incidence of leukemia has been dramatically reduced since the advent of regular vaccinations during infancy,” said study author Markus Müschen, MD, PhD, of the University of California San Francisco.
“Hib and other childhood infections can cause recurrent and vehement immune responses, which we have found could lead to leukemia, but infants that have received vaccines are largely protected and acquire long-term immunity through very mild immune reactions.”
For this study, Dr Müschen and his colleagues tested the idea that chronic inflammation caused by recurrent infections might cause additional genetic lesions in blood cells already carrying an oncogene, promoting their transformation to overt disease.
The team conducted experiments in mice and discovered that the enzymes AID and RAG1-RAG2 drive this process. AID and RAG1-RAG2 introduce mutations in DNA that allow immune cells to adapt to infectious challenges, and these enzymes are necessary for a normal and efficient immune response.
The researchers found that, in the presence of chronic infection, AID and RAG1-RAG2 were hyperactivated, randomly cutting and mutating genes.
Additional experiments revealed that AID and RAG1-RAG2 working together is critical to introduce the additional lesions that result in ALL.
Though the researchers focused on a bacterial infection in this study, they believe the same mechanisms may be at work in viral infections.
The team is currently conducting experiments to determine if protection against leukemia is provided by vaccines against viral infections, such as the measles-mumps-rubella vaccine.
Photo by Petr Kratochvil
Researchers believe they have discovered how a commonly administered vaccine protects children from developing acute lymphoblastic leukemia (ALL).
The Haemophilus influenzae Type b (Hib) vaccine is part of the standard vaccination schedule recommended for children by the US Centers for Disease Control and Prevention. The vaccine is routinely given in 4 doses before children reach 15 months of age.
The Hib vaccine prevents ear infections and meningitis caused by the Hib bacterium, but it may also protect against ALL.
This protection has been suggested in previous studies, but it is not well-known among the public at large, and the mechanism underlying this effect has been poorly understood.
Now, researchers have shown that recurrent Hib infections can shift certain genes into overdrive, converting pre-leukemic cells into full-blown cancer. The team described this work in Nature Immunology.
“These experiments help explain why the incidence of leukemia has been dramatically reduced since the advent of regular vaccinations during infancy,” said study author Markus Müschen, MD, PhD, of the University of California San Francisco.
“Hib and other childhood infections can cause recurrent and vehement immune responses, which we have found could lead to leukemia, but infants that have received vaccines are largely protected and acquire long-term immunity through very mild immune reactions.”
For this study, Dr Müschen and his colleagues tested the idea that chronic inflammation caused by recurrent infections might cause additional genetic lesions in blood cells already carrying an oncogene, promoting their transformation to overt disease.
The team conducted experiments in mice and discovered that the enzymes AID and RAG1-RAG2 drive this process. AID and RAG1-RAG2 introduce mutations in DNA that allow immune cells to adapt to infectious challenges, and these enzymes are necessary for a normal and efficient immune response.
The researchers found that, in the presence of chronic infection, AID and RAG1-RAG2 were hyperactivated, randomly cutting and mutating genes.
Additional experiments revealed that AID and RAG1-RAG2 working together is critical to introduce the additional lesions that result in ALL.
Though the researchers focused on a bacterial infection in this study, they believe the same mechanisms may be at work in viral infections.
The team is currently conducting experiments to determine if protection against leukemia is provided by vaccines against viral infections, such as the measles-mumps-rubella vaccine.