A genetic variation that protected people in sub-Saharan Africa from a now-extinct form of malaria could also have left their ancestors more vulnerable to HIV, according to a new study by US and UK researchers. The variation in a single unit of DNA could account for 11 percent of the HIV infections in Africa, they suggest.Among those who carry this single nucleotide polymorphism (SNP), the surface of red blood cells lack the Duffy antigen receptor that receives a signal from the hormone CCL5, part of the immune system\'s regulatory system.
About 10,000 years ago, it conferred protection to humans against the malarial parasite Plasmodium vivax. More than 90 percent of Africans and about 60 percent of African-Americans lack the receptor.The study involved Air Force members whose HIV infections have been followed for 25 years. African Americans who carried the SNP were 50 percent more likely to acquire HIV than African Americans who did not. However, the disease among carriers progressed more slowly, researchers noted.The finding "would be pretty exciting if it holds up," said David B. Goldstein, a geneticist who studies HIV at Duke University. "If the results are confirmed, it would mean that selection for resistance to malaria has created vulnerability to infection with HIV-1."The exact mechanism promoting HIV infection is not certain, said Dr. Sunil K. Ahuja, director of the Veteran Administration HIV/AIDS Center-San Antonio.
However, CCL5 is known to obstruct HIV\'s proliferation, and the red blood cells act like a sponge for CCL5, which may help prevent HIV infection.The study, "Duffy Antigen Receptor for Chemokines Mediates Trans-Infection of HIV-1 from Red Blood Cells to Target Cells and Affects HIV-AIDS Susceptibility," was published in Cell Host & Microbe.
http://www.hanningfield.com/about/news/
No comments:
Post a Comment