Cell Host Microbe 4, 52–62 (2008)

Credit: H. GELDERBLOM/GETTY IMAGES

A mutation that makes Africans resistant to a form of malaria renders them more vulnerable to HIV infection, researchers have found.

The mutation halts the expression of the protein DARC in red blood cells, where it normally occurs on the surface. Almost all black Africans carry this mutation, which confers resistance to the benign, recurring malaria caused by the parasite Plasmodium vivax.

Sunil Ahuja of the University of Texas Health Science Center in San Antonio and his colleagues analysed blood samples from more than 3,400 African Americans and discovered that the DARC mutation is associated with a 40% increase in the risk of acquiring HIV. However, HIV-infected participants with the DARC mutation also survived an average of two years longer than those without it.

The image (above) shows an immune cell known as a T lymphocyte full of newly manufactured HIV particles (red).