African-Americans with HIV Have 'Survival' Genes

A certain gene found mainly in persons of African ancestry slows the HIV to AIDS progression in patients, according to a study published in Blood (2009 Jul 20. Epub ahead of print).

The study, led by Sunil Ahuja, MD, of the Veterans Administration (VA) Research Center for AIDS and HIV-1 Infection, evaluated genetic and clinical data from 1,132 participants. The research team tested for the presence of variation in the Duffy antigen receptor for chemokine (DARC) gene and assessed patients' white blood cell (WBC) counts.

The findings revealed that a low white blood cell count (known as leukopenia) was associated with a faster disease progression from HIV to AIDS. "On average, leukopenic European Americans progressed nearly three times faster than their non-leukopenic African or European counterparts," noted Kemant Kularni, MD, first author of the study. "However, leukopenic African Americans had a slower disease course than leukopenic European Americans, even though twice as many African Americans in the study had leukopenia."

The researchers found that DARC variation, not race, explained the differences in WBC counts in African Americans with HIV. Additionally, the survival advantage became increasingly pronounced in those with progressively lower WBC counts.The study suggest that the interaction between DARC and WBC counts is the primary influence on slowing HIV disease progression in African Americans.

"The results of this collaborative study highlight the importance of accounting for other factors, such as the white blood cell count, to uncover the full effects of genetic variations that may influence HIV disease course," said Capt. Gregory Martin, MD, program director for the Infectious Disease Clinical Research Program.