Infection with GB
virus C, a "virtually unheard-of" virus related to hepatitis C, can slow
the progression of HIV, according to a study published in the March 4 issue
of the New
England Journal of Medicine, the Pittsburgh
Post-Gazette reports. Dr. Jack Stapleton of the University
of Iowa and colleagues analyzed blood samples from 271 HIV-positive
men who have sex with men who participated in the Multicenter
AIDS Cohort Study, in which blood samples are collected from participants
every six months. The samples were taken prior to 1996, when "highly effective"
antiretroviral treatment first became widely available, according to the
Post-Gazette
(Srikameswaran, Pittsburgh Post-Gazette, 3/4). The researchers discovered
that 85% of the men were infected with both HIV and GBV-C, according to
BBC
News (BBC News, 3/4). Men who remained infected with both
viruses five to six years after first being diagnosed were three times
more likely to be alive than men who cleared the GBV-C infection (Pittsburgh
Post-Gazette, 3/4). After 10 years, 75% of the men who showed both
viruses present at one and five years following HIV infection were alive;
39% of the men who never had GBV-C infection were alive; and 16% of the
men who cleared GBV-C were alive. GBV-C, which like HIV infects CD4+ T
cells, is "harmless" and "common" in the general population, according
to Reuters/Arizona
Daily Star (Reuters/Arizona Daily Star, 3/4).
New Treatments
Despite the evidence that GBV-C
has a protective value against HIV, scientists are hesitant to inject patients
with the virus because of the negative effects that could result if the
virus is cleared (Kaiser
Daily HIV/AIDS Report, 3/4/03). The study found that HIV "seemed
to attack with vigor" after GBC-V was cleared, Reuters/Arizona Daily
Star reports. Stapleton said, "So not only was having a persistent
infection better survival-wise than not having an infection, but the subset
of men who lost their virus did the worst," adding, "It's very unusual
that there would be a good virus." Stapleton and colleagues are designing
a study that would treat HIV-positive individuals with blood from people
infected with GBV-C, according to Reuters/Daily Star (Reuters/Arizona
Daily Star, 3/4). In an accompanying NEJM editorial,
Drs. Roger Pomerantz and Giuseppe Nunnari of Thomas
Jefferson University, suggest that further research into the specific
mechanisms of the interaction is necessary and "may point to therapeutic
approaches to mimicking the clinically protective effects of GBV-C in patients
with HIV infection" (BBC News, 3/4). The study was funded by the
NIH's
National
Institute of Allergy and Infectious Diseases (NIAID release,
3/3).
Also in NEJM
Although advances in antiretroviral
drug treatment have led to increased survival and other benefits for HIV-positive
individuals, such benefits can be "compromised by the development of drug
resistance," Drs. Francois Clavel and Allan Hance of the Institut
National de la Sante et de la Recherche Medicale write in a NEJMreview.
According to Clavel and Hance, up to 50% of patients undergoing antiretroviral
therapy in the United States are resistant to at least one of the available
antiretroviral drugs. Clavel and Hance focus on the "mechanisms underlying
the selection of drug-resistant HIV and on the consequences of viral resistance
with respect to the evolution of HIV infection" (Clavel/Hance, NEJM,
3/4). The complete article is available online.
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