HIV Weakening in Ability to Cause AIDS

Study suggests that HIV adaptations are evolving it into a weaker virus.

HIV’s evolving resistance to the human immune system is slowing the virus’s ability to cause AIDS, a new study found.

The study, published in Proceedings of the National Academy of Sciences, examined over 2000 women with chronic HIV infections in Botswana and South Africa. Key to this research were human leukocyte antigens (HLA), proteins that help the immune system to identify pathogens. The research team focused in particular on an HLA protein called HLA-B*57, as HIV-infected patients who express the HLA-B*57 gene are often slower in developing AIDS.

Researchers found that patients in Botswana, where HIV has grown more resistant to HLA-B*57 than in South Africa, had lost much of the protection afforded by the gene. However, researchers also found that this adaption significantly reduces the virus’s ability to replicate, making it less virulent and slower to cause AIDS.

The research team also examined the effect of antiretroviral therapy on HIV virulence. The research team concluded that treating patients with low CD4 counts accelerates the evolution of HIV variants with a reduced ability to replicate.

“This research highlights the fact that HIV adaptation to the most effective immune responses we can make against it comes at a significant cost to its ability to replicate,” the study’s lead scientist, Professor Philip Goulder of the University of Oxford, said in a press release. “Anything we can do to increase the pressure on HIV in this way may allow scientists to reduce the destructive power of HIV over time."