For a change, infection stymies HIV

Infection with an obscure and apparently harmless virus can stall replication of HIV, the virus that causes AIDS. It may also prolong the lives of people with HIV, according to two studies published in the Sept. 6 New England Journal of Medicine.

The potentially beneficial virus, dubbed GBV-C, is similar to a handful of other viruses that cause the liver disease hepatitis. However, GBV-C doesn’t lead to any known illness.

A few studies had already indicated that GBV-C infection might slow HIV progression, says Jack T. Stapleton of the University of Iowa in Iowa City. So, he and his colleagues looked at stored blood samples from 362 people (mostly male and Caucasian) treated for HIV infection in Iowa City clinics between 1988 and 2000.

Among the 144 with GBV-C in their blood, 41 had died by the time the researchers analyzed the data. In contrast, 123 of 218 without GBV-C had died. After accounting for the severity of illness, the kind of treatment, and a person’s age, the researchers found that people infected with HIV and GBV-C were about four times as likely to have survived.

In test-tube studies, when the Iowa researchers infected immune cells with both viruses, the cells produced 30 to 60 percent less HIV than did immune cells infected only with HIV.

The findings suggest that GBV-C hinders HIV replication, Stapleton says. But, an editorial accompanying the report cautioned that GBV-C infection–which, like HIV, spreads through unprotected sex and intravenous drug use–might be merely a marker for other biological differences making some people more capable of fighting HIV infections than others are.

Most people who died in the Iowa study did so before AIDS therapies containing multiple drugs were available. So few people getting the newer therapies died in the study that the researchers couldn’t determine whether GBV-C infection benefited these patients. A second study suggests it does: A team of German researchers following patients getting multiple-drug therapies showed that 33 people infected with both HIV and GBV-C lived longer before and survived longer after developing AIDS than did 52 people infected with HIV alone.