Interleukin 7 (IL-7), a naturally occurring molecule that helps maintain proper functioning of the immune system, could be used alongside existing AIDS drugs to help stem HIV's assault on T cells, according to a study by researchers at the National Institutes of Health (NIH).

In its attack on the immune system, HIV hides inside certain T cells. As the infection progress, these cells commit apoptosis -- "cellular suicide" -- undermining the body's ability to combat infections and certain cancers. Dr. Paolo Lusso and colleagues at NIH's National Institute of Allergy and Infectious Diseases (NIAID) examined the role IL-7 plays in averting T cell death.

The scientists, including NIAID Director Dr. Anthony Fauci and Dr. Lia Vassena, used blood samples from 24 HIV patients. IL-7 was added to the samples; the patients themselves were not treated with the molecule. The researchers then gauged the survival of T cells.

The study found that samples with IL-7 displayed lower levels of T cell death. The benefits differed from sample to sample, based on the patient's level of infection.

Lusso expressed "reasonable optimism" that treatment including IL-7 may benefit people with HIV/AIDS. "I don't think one solution will be applicable to all the patients. It's possible that IL-7 may benefit some patients and do nothing in other cases," he said. "But I think we are moving in the right direction because we are starting to appreciate that antiretroviral therapy alone is not sufficient to bring back a full immune competence, and we are starting to identify at least some strategies that may work."

The next step, said Lusso, will be a study in which monkeys with the simian equivalent of HIV are given IL-7 to determine if it blocks immune system dysfunction and immune cell depletion.

The study, "Interleukin 7 Reduces the Levels of Spontaneous Apoptosis in CD4+ and CD8+ T Cells from HIV-1-Infected Individuals," was published in an early online edition of the Proceedings of the National Academy of Sciences (2007;doi/10.1073.pnas.0610775104).

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