Newsday.com, Thursday, July 17, 2008 — A genetic variant commonly found in people of African descent raises the risk of HIV infection by about 40 percent, but also causes HIV-infected people to live longer.
That's the conclusion of joint American and British research published today in the journal Cell Host & Microbe, which indicates the mutation might help account for the spread of the AIDS virus in Africa.
Researchers say the trait is extremely common because it used to have a beneficial effect; it protected people against a form of malaria that is now fairly rare.
About three-quarters of the 33 million people worldwide infected with HIV, the virus that causes AIDS, live in sub-Saharan Africa, where most people are black. The gene variation may provide a clue as to why the virus has spread so much there, as well as among people with African heritage living elsewhere, said Professor Robin Weiss, a University College London virologist who helped write the study.
The researchers did not use volunteers living in Africa, but analyzed data from a 25-year study of Americans from different ethnic backgrounds with HIV. They calculated that, after taking account of social and economic differences, people with the genetic variation were 40 percent more likely to be susceptible to the illness.
If the gene variant were not present in sub-Saharan Africa, they said, they would expect to see approximately an 11 percent lower burden of HIV there.
"It's the first inherited genetic factor that's African-specific shown to increase the risk of the HIV," Weiss said yesterday.
While blacks account for about 13 percent of the U.S. population, about half of people living with HIV in America in 2005 were black, according to the Centers for Disease Control and Prevention, based in Atlanta.
The study gives researchers a new depth of understanding about HIV's spread through populations and the body, said Catherine Hankins, chief scientific officer for UNAIDS, the United Nations agency that coordinates AIDS prevention and care.
The researchers also stressed genes are just one of many factors involved in the relatively high rates of HIV among Africans and U.S. blacks, with social issues, such as poverty and lack of access to health care, also contributing heavily to risk.
"There has always been this myth that people in sub-Saharan Africa were more likely to get HIV because of differences in their sexual behavior. … This shows it's not that simple, and I think it will be an important message for education programs in these areas," said Dr. Ade Fakoya, from the International HIV/AIDS Alliance.
Copyright © 2008, Newsday Inc.
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