HIV positive patients are progressing to AIDS more slowly as a result of widespread access to antiretroviral therapy (ART), a recent study found.
In a study published in November 2014 in the Proceedings of the National Academy of Sciences, researchers examined more than 2000 women with chronic HIV infections in Botswana and South Africa. Key to this research were human leukocyte antigens (HLAs), 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 ART on HIV virulence. They 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,” lead scientist 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.”