Africa’s HIV epidemic may not be driven by behaviour alone according to a new study suggesting that Kenyan women are more biologically susceptible to the virus.
The study compared CD4 cells [white blood cells that lead the immune system’s response to infections] from cervical cell samples of young women from Kisumu, Kenya with those of young women from San Francisco, California.
Researchers found that the samples from the Kenyan women had a much higher number of “activated” CD4 cells - normally dormant CD4 cells that have reacted to an infection in the body.
Previous studies have shown that a critical mass of these activated CD4 cells may be crucial in allowing the HIV virus to replicate locally before it can spread throughout the body. This is because HIV spreads by infecting CD4 cells which multiply to fight an infection.
The cervical samples from the Kenyan women also had lower levels of the innate proteins that can protect against HIV infection, and higher levels of CD4 cells with the receptors that allow HIV to attach and replicate.
The authors argue that these findings may suggest that biological differences partly explain why African women have much higher HIV prevalence rates than their American counterparts.
The study by researchers from the University of California, San Francisco, and the Kenya Medical Research Institute, was published in a recent edition of the journal, AIDS.
Environmental impact
Understanding the reasons for the differences was beyond the study's scope, but the researchers posit that they may be the result of infections, such as malaria, which are endemic to parts of Africa and cause activated CD4 cells to spike in parts of the body, including the reproductive tract.
Lead researcher Dr Craig Cohen cautioned against generalizing the results of the study to regions outside East Africa, but said if larger studies proved the theory about the role of endemic disease in HIV infection to be correct, it could revolutionize prevention efforts.
"Let's say we found out that other infections, [like intestinal worms], increased people's risk of HIV," he told IRIN/PlusNews. "If that was the case, it would be a matter of rolling out public health measures [in sub-Saharan Africa] that were put in place in countries like the United States a hundred years ago."
Cohen said the findings did not minimize the need to address known HIV risk factors, including multiple concurrent partners, transactional sex and gender inequality, which prevented women from negotiating safer sex.
Cohen and his team have submitted a funding proposal to the US National Institute of Health to conduct a larger follow-up study to determine the effect of endemic infections, such as intestinal parasites and malaria, on activated CD4 cells in the cervix, and their relationship to HIV susceptibility. If their hypothesis about the role of biology in HIV infection is confirmed by larger studies, it could help de-stigmatise HIV.
"I think many people around the world, people who probably affect funding, think of HIV as a problem among 'poor people in Africa', but that it's really 'their fault'," Cohen told IRIN/PlusNews. "I hope that this study gets away from that in saying that part of HIV infection may be the conditions in which people live."
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The study compared CD4 cells [white blood cells that lead the immune system’s response to infections] from cervical cell samples of young women from Kisumu, Kenya with those of young women from San Francisco, California.
Researchers found that the samples from the Kenyan women had a much higher number of “activated” CD4 cells - normally dormant CD4 cells that have reacted to an infection in the body.
Previous studies have shown that a critical mass of these activated CD4 cells may be crucial in allowing the HIV virus to replicate locally before it can spread throughout the body. This is because HIV spreads by infecting CD4 cells which multiply to fight an infection.
The cervical samples from the Kenyan women also had lower levels of the innate proteins that can protect against HIV infection, and higher levels of CD4 cells with the receptors that allow HIV to attach and replicate.
The authors argue that these findings may suggest that biological differences partly explain why African women have much higher HIV prevalence rates than their American counterparts.
The study by researchers from the University of California, San Francisco, and the Kenya Medical Research Institute, was published in a recent edition of the journal, AIDS.
 [If] we found out that other infections increased people's risk of HIV, [then partial prevention] would be a matter of rolling out [basic] public health measures |
Understanding the reasons for the differences was beyond the study's scope, but the researchers posit that they may be the result of infections, such as malaria, which are endemic to parts of Africa and cause activated CD4 cells to spike in parts of the body, including the reproductive tract.
Lead researcher Dr Craig Cohen cautioned against generalizing the results of the study to regions outside East Africa, but said if larger studies proved the theory about the role of endemic disease in HIV infection to be correct, it could revolutionize prevention efforts.
"Let's say we found out that other infections, [like intestinal worms], increased people's risk of HIV," he told IRIN/PlusNews. "If that was the case, it would be a matter of rolling out public health measures [in sub-Saharan Africa] that were put in place in countries like the United States a hundred years ago."
Cohen said the findings did not minimize the need to address known HIV risk factors, including multiple concurrent partners, transactional sex and gender inequality, which prevented women from negotiating safer sex.
Cohen and his team have submitted a funding proposal to the US National Institute of Health to conduct a larger follow-up study to determine the effect of endemic infections, such as intestinal parasites and malaria, on activated CD4 cells in the cervix, and their relationship to HIV susceptibility. If their hypothesis about the role of biology in HIV infection is confirmed by larger studies, it could help de-stigmatise HIV.
"I think many people around the world, people who probably affect funding, think of HIV as a problem among 'poor people in Africa', but that it's really 'their fault'," Cohen told IRIN/PlusNews. "I hope that this study gets away from that in saying that part of HIV infection may be the conditions in which people live."
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