Someone having their blood tested for HIV in Kampala, Uganda, in December 2022
Nicholas Kajoba/Anadolu Agency/Getty Images
An estimated 13 percent of individuals with African ancestry carry this unique genetic variant. Harriet Groom, a researcher at the University of Cambridge, has found that among those infected with HIV, carriers of this variant have HIV viral loads that are 20 times lower than those without the variant. This translates into slower HIV progression and a diminished risk of virus transmission.
This discovery marks the first significant finding related to HIV in the past three decades and is particularly pertinent given that the majority of HIV cases worldwide are concentrated in Africa. Despite strides in reducing the spread of HIV through advanced treatments, the virus continues to mutate, often circumventing the effects of drugs.
Historically, HIV genetic research has been predominantly focused on individuals of European descent. This has led to the identification of two gene variants, HLA and CCR5, associated with reduced HIV viral loads. These variants account for about 15 percent of the differences in HIV viral loads among individuals of European ancestry.
In a recent study led by Paul McLaren at the National Microbiology Laboratory in Canada, the DNA of 2682 HIV-1 positive men and women of African descent was analyzed. The team found a correlation between the participants’ viral loads and variants on the HLA gene, not the CCR5 gene. They also discovered a significant variant in a different gene, CHD1L, exclusive to individuals of African descent.
In order to validate their findings, researchers looked for the CHD1L variant in an additional 1197 HIV-1 positive individuals of African descent from various countries. Their research confirmed that those with the variant had significantly lower viral loads when infected with HIV-1.
In a bid to comprehend how the variant impacts HIV loads, Andrew Lever, also at the University of Cambridge, and his team switched off the variant in genetically modified human immune cells in the lab and exposed them to HIV-1. They observed that the virus replicated more in macrophages, a type of immune cell, when the variant was switched off, suggesting that macrophages could play a more significant role in HIV replication than previously thought.
Overall, these insights offer a promising avenue for more targeted HIV management and treatment strategies among individuals of African descent, potentially revolutionizing the fight against the HIV/AIDS epidemic in these populations.
