Since the mid-1990s scientists have been puzzling over the function of hepatitis G, an unusual virus frequently found in people infected with HIV or with hepatitis C. Although hepatitis C causes serious liver problems such as cirrhosis and cancer, no disease has been associated with hepatitis G.
The new findings that hepatitis G infection may improve survival in HIV patients raises many provocative questions. But don't jump to hasty conclusions, warn experts contacted by WebMD. Findings from the studies -- published in this week's issue of The New England Journal of Medicine -- are very preliminary, they say.
Even the authors of the studies warn against jumping the gun.
"It is too soon to suggest that HIV can be treated by infecting people with [hepatitis G]," says Jack Stapleton, MD, author of one of the studies. The best treatment for HIV remains powerful drug combinations called HAART, he tells WebMD.
In fact, it is very unlikely that hepatitis G will play any role in HIV treatment in the near future, says AIDS expert Steven Wolinsky, MD, of Northwestern University Medical School in Chicago. It is common for people with HIV to have other coexisting viral infections, he says, making it difficult to sort out if this finding is just a coincidence or real.
Stapleton, a professor of internal medicine at the University of Iowa, says that when he tested 362 HIV-infected patients, about 40% of them were also infected with hepatitis G. Over a period of more than four years, 41 of those infected with hepatitis G died -- a death rate of 28.5%, or about half of the death rate seen in patients who were not coinfected with hepatitis G.
Stapleton says that when otherwise healthy people are infected with hepatitis G, the body's immune system can effectively fight the virus and clear it from cells. But sometimes when HIV and hepatitis G both attack the same cells, HIV can disable the immune system before it can rid the body of hepatitis G. That appears to be a good thing since it looks like hepatitis G infection slows the progress of HIV, he says.
In a second study, a team of German researchers followed 197 HIV-infected patients for seven to eight years and found that people who were coinfected with hepatitis G lived longer than those who weren't.
Lead author Hans L. Tillmann, MD, of Medizinische Hochschule Hannover, tells WebMD that hepatitis G appears to be a "new marker for a better course of disease ... but at the moment it is only a marker."
Tillmann points out that it is not unusual for a person to be coinfected with HIV, hepatitis G, and hepatitis C. Because the treatment for hepatitis C will also wipe out hepatitis G, he says, it may be wise to hold off treating hepatitis C in HIV-infected patients until we know for sure if hepatitis G has a role in fighting HIV. But delaying treatment would only be an option for patients with a very mild infection, he stresses.