An apparently harmless virus may slow the progression of AIDS, prolonging the lives of some people infected with HIV. Two studies appearing recently in the New England Journal of Medicine show that patients infected with both viruses are often healthier and live longer than other HIV positive individuals.
Researchers have zeroed in on a virus that is part of the hepatitis family, alternately known as Hepatitis G or the GB virus Type C. Hepatitis G is a close relative of hepatitis C, the deadly virus that can cause cirrhosis of the liver and liver cancer. Discovered in 1995, hepatitis G has so far not been found to cause hepatitis or any other disease. So many scientists stopped researching it, and consider the name, hepatitis G, misleading. Instead, researchers refer to this apparently harmless virus by the new name of GB Virus Type C, or GBVC.
"It turned out that healthy blood donors, even 1.8 of the normal population that is healthy, are infected with GBVC," explains researcher Sabina Wunschmann. "So, it seems that you can have the virus without getting sick."
Ms. Wunschmann is part of a research team at the University of Iowa that found there may actually be benefits to GB virus Type C. Investigators expanded on earlier research that suggested that this apparently harmless virus might slow reproduction of the AIDS virus.
As reported in the New England Journal of Medicine, the two part study looked at the effect of the GBC virus on HIV both in humans and in the test tube. Professor Wunschmann explains that when when both viruses were placed together in a lab dish, "the data we got from the lab seems to show that GBVC infection of blood cells seems to reduce replication of HIV in the same culture of human blood cells."
Iowa researchers also looked to see whether GB Virus Type C increased the life span of people infected with the AIDS virus.
Study co-author Daniel Diekema, Internal Medicine Professor, University of Iowa says investigators examined frozen blood samples of 362 patients with HIV taken at a clinic over a 12 year period. Dr. Diekema says tests on the blood samples showed 40 percent of patients were infected with both GBVC and HIV. The remaining 60 percent of patients were infected solely with the AIDS virus. "The patients who were not infected with GBC virus were three to four times more likely to die during follow up than patients who were infected with GB Virus C," he reported. "So it was quite a significant difference in death rate between the two groups."
A second study in the New England Journal followed HIV positive individuals who were also infected with the GBC virus. They lived longer than patients infected with the AIDS virus alone.
In a journal editorial, infectious diseases expert Stephen Wolinsky, Northwestern University, Chicago, suggested there are a number of reasons that might explain why people live longer, other than the GBC virus. "Other factors that we would certainly pay attention to are directly related to the infected person, their genetic make-up, their immune response; also related to their virus, that there may be a virus that is able to cause disease to the extent that we see in other people," he wrote. "Or that there may be other pathogens [disease-causing agents] or other factors that may be involved in this process."
Until more in known about GBV Type C virus, Dr. Wolinsky says it should definitely not be used as a treatment for HIV/AIDS.