July 13 (HealthDay News) -- Differences in immune response may explain why HIV infection progresses faster to AIDS in women than in men with similar viral loads, U.S. researchers say.

Their study found that a receptor molecule involved in the recognition of HIV-1 responds to the virus differently in women than in men. This then leads to differences in chronic T-cell activation, a known activator of disease progression, according to the researchers at the Ragon Institute of MGH, MIT and Harvard.

"This study may help to account for reported gender differences in HIV-1 disease progression by demonstrating that women and men differ in the way their immune systems respond to the virus," senior author Dr. Marcus Altfeld, of the Ragon Institute and the MGH Division of Infectious Disease, said in a news release from Massachusetts General Hospital.

"Focusing on immune activation separately from viral replication might give us new therapeutic approaches to limiting HIV-1-induced pathology," he added.

Women tend to have a stronger immune response to HIV than men, the study authors noted.

"While stronger activation of the immune system might be beneficial in the early stages of infection, resulting in lower levels of HIV-1 replication, persistent viral replication and stronger chronic immune activation can lead to the faster progression to AIDS that has been seen in women," Altfeld said.

The study appears online June 12 and in an upcoming print issue of Nature Medicine.

SOURCE: Massachusetts General Hospital, news release, July 13, 2009