Slower progression of HIV-1 infection in persons with GB virus C co-infection correlates with an intact T-Helper 1 cytokine profile

Background: Progression to AIDS is slower in persons infected with both HIV-1 and GB virus C (GBV-C), also known as hepatitis G virus. Objective: To compare clinical, virologic, and immunologic variables in HIV-1-seropositive patients with and without GBV-C co-infection. Design: Subanalysis of a prospective cohort study. Setting: Institute of Infectious Diseases, University of Catania, Catania, Italy. Patients: go asymptomatic HIV-1-seropositive patients. Measurements: GBV-C RNA level; plasma HIV-1 viral load; CD4(+) cell counts; and serum levels of interleukin (IL)-2, IL-4, IL-10, and IL-12. Results: At the start of the study, plasma GBV-C RNA was detected in 17 patients (21%). During follow-up, IL-2 and IL-12 levels decreased significantly (P = 0.005 and P = 0.01, respectively) and IL-4 and IL-10 levels increased significantly (P = 0.01 and P = 0.004, respectively) in the GBV-C-negative group but did not change substantially in the GBV-C-positive group. Each measured variable differed significantly between GBV-C-positive and GBV-C-negative groups during follow-up (P < 0.001 for IL-12, IL-4, and IL-10; P = 0.002 for IL-2). Conclusion: GB virus C may immunologically interfere with progression of HIV-1 infection to AIDS by maintaining an intact T-helper 1 cytokine profile.