Genetic Variation May Raise HIV Risk in African Americans
DARC-negative status -- common in Africans -- protects against malaria; may increase HIV odds
WEDNESDAY, July 23 (HealthDay News) -- A genetic variation that provides protection from Plasmodium vivax malaria appears to increase susceptibility to HIV infection, according to research published in the July 17 issue of Cell Host & Microbe.
Weijing He, M.D., of the South Texas Veterans Health Care System in San Antonio, Texas, and colleagues write that Duffy antigen receptor for chemokines (DARC) is mostly expressed on red blood cells, and can bind to a wide variety of proinflammatory chemokines. DARC on red blood cells also is the receptor for merozoites of P. vivax, so Africans with the DARC -46C/C genotype are at low risk of malaria from this strain, they write.
The investigators found that HIV-1 attaches to red blood cells via DARC, and the DARC -46C/C genotype in African Americans is associated with a 40 percent higher odds of acquiring HIV-1. In sub-Saharan black Africans, this genotype is almost universal, and if DARC -46C/C has a similar effect on HIV acquisition in Africans, it may account for roughly 11 percent of the HIV burden in these individuals.
"In addition to the DARC -46C allele, polymorphisms such as sickle-cell trait can confer infection against malaria, which can be costly by causing genetic disease in the homozygous state. Thus, it should not be surprising then that what might be beneficial in one context (e.g., protection from malaria by DARC -46C/C genotype) can be detrimental in other settings (e.g., association between DARC-46C/C genotype and increased risk of HIV acquisition)," the authors write.