Stimulating Thymus Reactivates T-Cell Production

FRIDAY Feb. 22, 2008 -- It's possible to stimulate the thymus gland to produce new immune system T-cells in adults infected with HIV, U.S. researchers say.

HIV infection destroys T-cells, which leads to the collapse of the immune system and severe infection. The thymus gland produces T-cells early in life but gradually loses function and becomes mostly inactive in adulthood. That means it's difficult for HIV-infected adults to produce new T-cells to rebuild their depleted immune systems.

It has long been believed that it wasn't possible to reactivate T-cell production in the thymus. The new study, by researchers at the Gladstone Institute of Virology and Immunology and the University of California, San Francisco (UCSF), is the first to show that therapy can help boost thymus function in adults.

The two-year study of 22 HIV-infected adults found that treatment with growth hormone (GH) increased thymus mass and more than doubled the number of newly made T-cells. The results are published in the March issue of the Journal of Clinical Investigation.

"These results represent new proof-of-principle findings that thymic involution can be reversed in humans," study author Dr. Laura Napolitano, an assistant investigator at Gladstone and an assistant professor of medicine at UCSF, said in a prepared statement.

"Improved T-cell production may be helpful for some medical conditions such as HIV disease or bone marrow transplantation. These findings contribute new information to our understanding of T-cell production and are also an important step to determine whether immune therapies might someday benefit patients who need more T-cells," Napolitano said.

However, much more research is needed to determine whether stimulating production of new T-cells actually provides a health benefit for HIV patients or anyone else, the researchers said.

More information

The U.S. Centers for Disease Control and Prevention has more about HIV/AIDS.

Posted: February 2008


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