Resistance to HIV-1 may be in the genes.

Scientists have suspected for several decades that an individual's genetic makeup may influence the body's response to various infectious diseases and have known that a percentage of those who are at high risk for acquiring HIV-1 resist the infection. Moreover, some persons infected with HIV-1 live for many years with no immune damage. Does this mean that a person's genetic makeup will prevent invasion by the HIV virus? Can a particular set of genes delay the progression of the disease to AIDS in those already infected?

Research groups around the country have been working feverishly to answer these questions. In one study, scientists at The University of Texas Health Science Center at San Antonio examined mutations in genes for immune molecules called chemokines and chemokine receptors in 1,090 individuals infected with HIV-1. In this group of patients, the researchers found a mutation in a chemokine receptor gene associated with a delay in HIV-1 disease progression in African-Americans and possibly also Hispanics and Native Americans, but not in Caucasians, as well as another mutation associated with an acceleration in the course of the disease.

HIV invades certain immune cells by taking advantage of molecules on the surface of those cells. One group of molecules used by HIV to enter the cell is called chemokine receptors. "Think of these molecules as keys that HIV uses to enter the cell," explains Sunil Ahuja, assistant professor of medicine and microbiology. "The recent discovery that HIV uses co-receptors [chemokine receptors] to enter the cell is a major breakthrough in HIV research. The...