Impact of GB virus C viraemia on clinical outcome in HIV-1-infected patients: a 20-year follow-up study

OBJECTIVES: The impact of coexisting GB virus C (GBV-C) infection on the clinical course of HIV infection remains controversial. Early data from HIV-1 infected patients attending the Hannover Medical School in 2001 suggested prognostic benefit in GBV-C viraemic patients. The aim of this study was to evaluate patterns in long-term mortality and morbidity outcomes in this cohort. The impact of the introduction of antiretroviral therapy (ART) on the perceived benefits of GBV-C viraemia was subsequently investigated.

METHODS: A retrospective follow-up analysis of data in this cohort was performed. GBV-C status (GBV-C RNA positive, antibodies against GBV-C envelope protein E2 or no evidence of GBV-C exposure) had been determined at enrolment, with several markers of HIV disease progression (such as viral load and CD4 cell count) being collated from 1993/1994, 2000 and 2012. These eras were chosen to reflect variations in treatment strategies within the cohort. In addition, mortality and HIV-related morbidity data were collated for all patients.

RESULTS: Complete data were available for 156 of 197 patients (79%). In highly active antiretroviral therapy (HAART)-naïve patients, GBV-C RNA positivity conferred significant improvements in the course of HIV infection and mortality as well as lower rates of HIV-related diseases. E2 positivity alone conferred no significant advantage. With the advent of HAART, however, the benefits GBV-C RNA positivity disappeared.

CONCLUSIONS: Although GBV-C coinfection appears to inherently improve morbidity and mortality in HIV-infected patients, modern HAART has eradicated these advantages. Evidence of synergy between GBV-C status and HAART response exists, with further studies examining the role of GBV-C in existing treatment de-escalation strategies being required.