Genetic Variations Might Help HIV-Positive People Control Viral Loads, Study Says
Variations in three genes might help people newly diagnosed with HIV control their viral loads, according to a study published Thursday in the online edition of the journal Science, the San Francisco Chronicle reports. For the study, a group of international researchers from the Center for HIV/AIDS Vaccine Immunology, led by David Goldstein of Duke University, pooled information about 486 HIV-positive people from a group of 30,000 to determine if genetic variations are linked to the disease, the Chronicle reports.
The researchers scanned the genes of the participants using gene-reading machines produced by Illumina and Affymetrix to determine if they carried any of the 550,000 gene variants commonly found in the general population. They then analyzed the data to determine if there was an association between the genetic differences and a different ability to control HIV.
The researchers found that two genes, called HLA-B and HLA-C, accounted for 15% of the differences in the participants' viral set-points -- a level at which the concentration of HIV in a person's blood becomes stable. According to the Chronicle, HLA-B helps white blood cells destroy other cells that have been compromised by conditions such as HIV. In previous studies, HLA-B was detected in a few hundred HIV-positive people, known as "elite controllers," who are able to control their viral loads without antiretroviral drugs, the Chronicle reports. HLA-C produces a protein that resides on the surface of white blood cells. Participants with the variant form of the gene seemed to be able to produce more of the protein, which might explain why they had lower viral loads. The researchers also discovered a third variant gene, called ZNRD1, which might inhibit the ability of HIV to replicate (Russell, San Francisco Chronicle, 7/20).
The study's findings might aid in the development of HIV/AIDS vaccines that bolster natural immunity to the disease, according to the Raleigh News & Observer. Researchers plan to confirm that the genes are vital to immune system responses and, if they are, discover how they improve resistance to HIV, according to the News & Observer. Anthony Fauci, director of NIH's National Institute of Allergy and Infectious Diseases, said, "I'm expecting very important things from" this study (Clabby, Raleigh News & Observer, 7/20). "What we are seeing here transcends the study of HIV," Fauci said, adding that these "genome-wide association studies" probably will create insights into how to treat and prevent diseases (San Francisco Chronicle, 7/20). Mark Connors, a scientist at NIH who was not involved in the study, said that even if the three genes do not prove useful for a vaccine, the technique of searching for biological differences in people's DNA might discover genes that could (Raleigh News & Observer, 7/20).
An abstract of the study is available online.