HIV Digest	HIV Digest Archive

Why it is that some treatment-naďve HIV-positive people do not progress to AIDS? Some 5 percent of people with HIV who are not taking medicine remain healthy after 10 years, said Dr. Jay Levy, director of the Laboratory of Tumor and AIDS Virus Research at the University of California-San Francisco. Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), however, estimated that only 0.2-0.4 percent of HIV-positive people are long-term non-progressors.

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Some of Levy's patients have had HIV since 1978, confirmed by preserved blood samples drawn in a San Francisco hepatitis B study of 6,704 gay men. Over time, some of Levy's long-term survivors became slow-progressors and died of AIDS. But a dozen have stayed healthy without treatment. In 1986, Levy found that survivors' CD8 cells secreted tiny amounts of an antiviral factor that blocked HIV replication but did not destroy the virus. It remains an elusive factor. When Dr. David Ho, founder of the Aaron Diamond AIDS Research Center, and others reported discovering the factor, Levy told them they were wrong. "After a while they say 'Levy is spending all this time telling us what it isn't. What is it?'" Levy said.

While searching for it, researchers discovered instead three chemokines in the blood of long-term non-progressors. The chemicals inhibit a subset of the virus, "like bouncers at a disco," said Dr. Robert Gallo, director of the Institute of Human Virology and Division of Basic Science at the University of Maryland Biotechnology Institute, who conducted the research with Dr. Paolo Lusso. Of 19 non-progressors in his study, NIAID's Dr. Mark Connors said 95 percent share a gene that encodes molecules allowing the immune system to recognize infected cells, compared to just 10 percent of progressors. In non-progressors, CD4 cells continue to order CD8 cells to kill HIV-infected cells, explained Dr. Eric Rosenberg, an infectious-disease doctor and Harvard professor. In most infected people the CD4 cells stop giving such orders.

Editor's Note: from the New York Times