Effect of coinfection with GB virus C on survival among patients with HIV infection.

Background: Previous studies have suggested that people with human immunode ficiency virus (HIV) infection who are coinfected with GB virus C (GBV-C, o r hepatitis G virus) have delayed progression of HIV disease. GBV-C is rela ted to hepatitis C virus but does not appear to cause liver disease. Methods: We examined the effect of coinfection with GBV-C on the survival o f patients with HIV infection. We also evaluated cultures of peripheral-blo od mononuclear cells infected with both viruses to determine whether GBV-C infection alters replication in vitro. Results: Of 362 HIV-infected patients, 144 (39.8 percent) had GBV-C viremia in two tests. Forty-one of the patients with GBV-C viremia (28.5 percent) died during the follow-up period, as compared with 123 of the 218 patients who tested negative for GBV-C RNA (56.4 percent; P<0.001). The mean duratio n of follow-up for the entire cohort was 4.1 years. In a Cox regression ana lysis adjusted for HIV treatment, base-line CD4+ T-cell count, age, sex, ra ce, and mode of transmission of HIV, the mortality rate among the 218 HIV-i nfected patients without GBV-C coinfection was significantly higher than th at among the 144 patients with GBV-C coinfection (relative risk, 3.7; 95 pe rcent confidence interval, 2.5 to 5.4). HIV replication, as measured by the detection of p24 antigen in culture supernatants, was reproducibly inhibit ed in cultures of peripheral-blood mononuclear cells by GBV-C coinfection. Coinfection did not alter the surface expression of HIV cellular receptors on peripheral-blood mononuclear cells, as determined by flow cytometry. Conclusions: GBV-C infection is common in people with HIV infection and is associated with significantly improved survival.