Some women resistant to AIDS

New Jersey university releases six-year study of community health

March 03, 2002|By Bob Groves | Bob Groves,KNIGHT RIDDER/TRIBUNE

HACKENSACK, N.J. - Some women have immune cells that seem to protect them from the AIDS virus, despite prolonged unsafe sex with infected men, researchers at the University of Medicine and Dentistry of New Jersey said.

The behavior of these cells, called lymphocytes, could be used to test the effectiveness of new vaccines against the disease, said Joan Skurnick, a co-author of the study and an associate professor of preventive medicine and community health at the University of Medicine and Dentistry of New Jersey Medical School in Newark.

The six-year study, published in the current issue of Journal of Infectious Diseases, followed 18 women, most from the metropolitan area.

All the women had been in a long-term relationship with an infected male partner and remained HIV-negative despite having "very heavy unprotected exposure" to the virus, said Dr. Donald B. Louria, head of preventive medicine at the university and co-author of the study.

The study found that a potentially effective defense appeared to be at work in a majority - 13 - of the women.

Most of these involved one or both of the lymphocytes, known as CD8 "suppressor" immune cells, and CD4 "helper" cells.

Four other women did not become HIV positive, but the immune cells were not involved and researchers do not know why they were not infected, Skurnick said.

In those four women, "we couldn't find any evidence of [lymphocyte] response [to HIV], or they had a small response. But everyone has an immune system that works to some extent," Skurnick said.

One woman became HIV-positive during the study, but the reason why is unclear, Louria said. "She had additional medical problems, and she was undernourished. She did not have the defense mechanisms. It goes to show you can convert [to HIV-positive] very late," he said.

`Luck of the draw'

"That's sort of the luck of the draw. If you don't have the defenses, most time you'll [become infected] in the first couple years," he said.

There are two possible reasons why the 13 women with a demonstrated immune response did not become infected. One is that "they were "genetically primed to react to the virus" defensively, Louria said. Or, their male partners may have had high numbers of lymphocytes, which, in effect, "changed the virus and helped immunize" the women, he said.

These women had strictly a "systemic" immune response, as opposed to a "local" defense of some kind in their mouth or genital area against the infection, Louria said.

Developing a vaccine

Knowing how specific immune cells respond to the AIDS virus will give scientists a test to determine which new vaccines will work best against the disease, he said.

"There are all sorts of vaccines being tested by all sorts of companies. The more defense mechanisms you elicit with a vaccine, the better chance you have" of immunization, Louria said. "We can't stop this [AIDS] epidemic by education or condoms or anything else. The only way we can stop it is by a vaccine, and we think this contributes to figuring out what we need to do to get effective vaccines."

Bob Sawyer, an AIDS research advocate in Newark, said the study sheds more light on how the human immune system works.

"Clearly, some people appear to have an innate resistance to HIV infection," said Sawyer, a virologist and clinical director of the North Jersey Community Research Initiative, a nonprofit organization that provides social services to 4,000 AIDS clients, and has conducted 80 drug trials since 1988.

"If we [know] what protects them, then further on down the line we can figure out how to stimulate normally susceptible people's immune systems to protect them," Sawyer said.

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