Response to HAART and GB virus type C coinfection in a cohort of antiretroviral-naive HIV-infected individuals

The prognostic role of GB virus type C (GBV-C) viraemia in HIV-infected subjects treated with highly active antiretroviral therapy (HAART) is still undefined, The aim of this analysis is to assess the relationship between GBV-C infection and response to antiretroviral therapy among HIV-infected subjects initiating HAART when antiretroviral-naive. A prospective, observational study of 400 HIV-infected patients with measurements of GBV-C RNA, hepatitis C virus (HCV) antibodies and HCV RNA determined from plasma stored prior to HAART initiation, Time to virological (achieving HIV RNA ≤500 copies/ml) and immunological success (a CD4+ count increase of ≥200cells/μl), and the time to virological relapse (confirmed HIV RNA >500 copies/ml) were assessed by Kaplan-Meier methods and Cox proportional hazard regression model. Of the subjects, 117 (29.3%) were GBV-C positive and, overall, 351 (87.8%) patients achieved virological success, After controlling for a number of confounders including HCV RNA, GBV-C viraemic patients experienced a significantly lower risk of HIV rebound than those who were GBV-C negative [relative hazard (RH)=0.56, 95% CI: 0.34–0.93, P=0.03], Conversely, the probability of achieving initial virological success or CD4+ count response after HAART did not differ between GBV-C-negative and -positive subjects, These results suggest that GBV-C coinfection may play a role in determining the rate of HIV rebound possibly by competing with HIV replication after HIV load has been successfully suppressed by HAART.