The HIV virus has rapidly evolved to develop a resistance to patients' immunity against it, but these changes could also be preventing it from causing AIDs as quickly.
Access to antiretroviral therapy (ART) may also be making HIV "less virulent," the Wellcome Trust reported. Understanding these processes could help researchers come closer to eradicating the gloval HIV epidemic, which affected 35 million people as of 2013.
"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. 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," said lead scientist, Professor Phillip Goulder from the University of Oxford.
The research was conducted in Botswana and South Africa, which have been most dramatically affected by the HIVE epidemic. To make their findings the researchers looked at 2,000 women across those two countries.
The research team looked at blood proteins called human leukocyte antigens (HLA), which allows the immune system to differentiate between the body's own proteins and those of pathogens. People with a gene that expresses the HLA protein HLA-B*57 are believed to benefit from a "protective effect" that causes HIV to progress to AIDS more slowly.
In Botswana HIV has evolved to adapt to HLA-B*57 more so than in other regions, canceling out its protective effect. The cost of this adaptation is the virus does not replicate as easily, making it less virulent. The researchers determined these adaptations are actually contributing to the eradication of HIV. The team also used a mathematical model to look at the impact of ART on HIV virulence and found treatment of people with low CD4 counts will accelerate the evolution of HIV variants the weaken its ability to replicate.
"The widespread use of ART is an important step towards the control of HIV. This research is a good example of how further research into HIV and drug resistance can help scientists to eliminate HIV," said Mike Turner, Head of Infection and Immunobiology at the Wellcome Trust.
The findings were published in a recent edition of the Proceedings of the National Academy of Sciences (PNAS).
