Drugs commonly used to prevent rejection after organ transplants may help lower levels of HIV, suggesting a possible new strategy for fighting the virus.

Although anti-viral therapies can suppress HIV to very low levels, they do not eliminate the virus in the immune system. Dr. Steven Deeks, at the University of California, San Francisco, says inflammation in response to the infection may allow the virus to persist.

He and his colleagues noted immunosuppressant therapy given to transplant patients to reduce the risk of organ rejection, also reduces inflammation. They wondered if immunosuppressants could help defeat HIV.

They followed 91 HIV positive kidney recipients for an average of three years. They found HIV remained well-controlled, and the patients who took the drug - sirolimus - had fewer infected cells in their blood.

Based on those findings, the National Institutes of Health is sponsoring a study of sirolimus and HIV.