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Battling Back AIDS

Study looks at why some immune systems can fight off spread of virus

MONDAY, Oct. 7, 2002 (HealthDayNews) -- The quality, not quantity, of HIV-fighting white blood cells may explain why the immune systems of some people infected with HIV can stem the spread of the virus in their bodies.

That's the claim of a study in today's online issue of Nature Immunology.

The immune systems of most people with HIV can't contain the spread of the HIV virus in the body. However, a rare group of people, called long-term nonprogressors, have immune systems that can limit the spread of the HIV virus.

The reason seems to be that these nonprogressors have better HIV-fighting white blood cells called CD8+ T cells, says the study by scientists at the U.S. National Institute of Allergy and Infectious Diseases (NIAID).

The study examined the immune systems of 40 people infected with HIV. It included a group of about 15 nonprogressors, people who've controlled HIV for as long as 20 years without using antiretroviral therapy.

There was no significant difference in the quantity of CD8+ T cells between the nonprogressors and the other people in the study. However, the researchers found the nonprogressors CD8+ T cells were better able to divide and proliferate when they were needed to defend the body from HIV.

The CD8+ T cells in the nonprogressors also produced higher levels of perforin, a molecule that helps kill off HIV-infected cells.

"Understanding the mechanism by which the immune systems of long-term nonprogressors control HIV is important to our development of effective vaccines. Studies like this one, which reveal basic knowledge about how the immune systems interacts with HIV, form the foundation of our efforts to fight this disease," says NIAID director Anthony S. Fauci.

More information

Learn more about immune deficiency diseases at National Institute of Allergy and Infectious Diseases.

SOURCE: National Institute of Allergy and Infectious Diseases, news release, Oct. 6, 2002
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