New findings from the Multicenter AIDS Cohort Study (MACS) reveal that a minuscule variation in an immune system gene called RANTES paradoxically both increases susceptibility to HIV infection and slows disease progression in people who have that particular genetic variant (AIDS. 2000;14:2671-2678).
In the study, funded by the National Institute of Allergy and Infectious Diseases (NIAID), researchers examined the RANTES gene of HIV-positive and at-risk HIV-negative participants in the MACS project, a long-term study of HIV-infected people and those at risk of infection. They found that a particular single nucleotide polymorphism (SNP) of the RANTES gene—a difference involving just one DNA base pair—is associated with twice the risk of HIV infection. But they also discovered that people with this SNP who become infected with HIV take about 40% longer to develop AIDS.
Stephenson J. Genes and HIV Infection. JAMA. 2000;284(23):2987. doi:10.1001/jama.284.23.2987