GB virus C during the natural course of HIV-1 infection: viremia at diagnosis does not predict mortality.

OBJECTIVE: To investigate whether GBV-C viremia at diagnosis of HIV-1 infection predicts disease outcome in patients not receiving combination antiretroviral therapy (ART), and whether longitudinal changes in GBV-C viremia are associated with disease progression.
DESIGN: Prospective cohort study.
METHODS: 230 patients with a serum sample available for testing obtained within 2 years of HIV-1 diagnosis were followed until either initiation of ART, death, or their last visit to our clinic (median follow-up 4.3 years). Baseline and follow-up serum samples (available from 163 patients) were tested for GBV-C RNA and antibodies against GBV-C envelope E2 protein (anti-E2; signifying resolved GBV-C viremia).
RESULTS: At inclusion, 62 patients (27%) had GBV-C viremia and 69 (30%) had anti-E2. Baseline GBV-C status was not associated with all-cause mortality (P = 0.12), HIV-related mortality (P = 0.18), or development of AIDS (P = 0.84). However, GBV-C RNA was less prevalent in patients with AIDS at inclusion (P = 0.008). Eleven of 44 patients with baseline GBV-C viremia lost GBV-C RNA during follow-up without showing anti-E2 seroconversion. In comparison with anti-E2-negative patients with either persistent absence, persistent presence, or acquisition of GBV-C viremia, these subjects had significantly increased all-cause mortality (P = 0.018), HIV-related mortality (P = 0.007), and AIDS incidence (P < 0.001).
CONCLUSIONS: GBV-C status at diagnosis did not predict disease outcome in this HIV cohort. GBV-C viremia was rare in patients with AIDS, and tended to disappear without occurrence of anti-E2 in patients with progressive disease. This suggests that the GBV-C status of HIV-1-infected patients could be a phenomenon secondary to HIV progression, rather than an independent prognostic factor.