Impact of hepatitis C virus coinfection on T-cell dynamics in long-term HIV-suppressors under combined antiretroviral therapy

OBJECTIVE: The objective of this study is to evaluate the impact of hepatitis C virus (HCV) serostatus on the evolution of CD8 cells and CD4 : CD8 ratio in HIV-infected patients on combined antiretroviral therapy (cART) who achieve sustained undetectable viral load (HIV-pVL). DESIGN AND METHODS: A longitudinal study performed in an outpatient HIV-unit following 1495 HIV-infected patients. Data of patients on cART achieving undetectable HIV-pVL for at least 3 years were collected retrospectively from our medical e-database NADIS from January 1997 to April 2005, a period defined in order to select patients who were naive of hepatitis treatment. T-cell counts were assessed every 6 months from HIV-suppression over the study period. RESULTS: Two hundred and twenty-six HIV mono-infected (group 1) and 130 HCV-coinfected patients (group 2; genotype prevalence: 42% HCV-G1, 26% HCV-G3, 11% HCV-G4 and 21% HCV-G2) fulfilled the selection criteria. cART regimens were comparable between the groups, as were CD4 and CD8 cell counts at the first undetectable HIV-pVL. After 3 years, both groups displayed similar CD4 cell reconstitution, although CD4 percentage was higher in group 1 (30.3 ± 1.1 vs. 27 ± 1.1%; P < 0.001). HIV suppression led to a significant drop of median CD8 cell counts in group 1 (P = 0.027), but not in group 2, which displayed higher CD8 cell counts all through the follow-up (mean diff. = 135.71 ± 26.89 cells/μl, P < 0.001). Moreover, the fraction of patients reaching CD4 : CD8 ratio ≥ 1 was lower in group 2 (14 vs. 27.7%; P < 0.05). CONCLUSION: Despite sustained HIV suppression under cART, HCV coinfection was found to hamper CD8 downregulation. Further studies will determine the impact of treatment with direct-acting antiviral agents on the CD8 pool, and the advantage of systematic HCV-targeted therapy for HIV/HCV-coinfected patients.