HCV-specific CD8+ cell detection at week 12 of chronic hepatitis C treatment with PEG-interferon-α2b/ribavirin correlates with infection resolution

• Correlation between HCV-specific CTL response restoration and SVR in HCV treatment.
• Specific CTL detection during HCV treatment depends on viral load decrease.
• SVR positive predictive value of HCV-specific CTL detection at week 12 of treatment.
• Importance of HCV-specific CTLs in HCV control by PegIFN/RBV treatment.
• Patients with HCV-specific CTL deletion or IFN insensitive will not develop SVR.

Lower than 2-log viral-load (VL) decrease at week 12 (w12) of chronic hepatitis C (CHC) treatment with Peg-interferon/ribavirin has 100% negative predictive value (PV) of sustained virologic response (SVR), and this could be related with absence of HCV-specific cytotoxic T lymphocyte (CTL) response. In this study, percentage of cases with SVR, according to peripheral HCV-specific cytotoxic response at w12, was analysed (Group-1: detection+, Group-2: detection−). SVR was higher in group-1 (93%) than in group-2 (47%) (p = 0.003). An increase on HCV-specific CTL frequency between baseline and w12 and higher specific reactivity were observed in group-1 (p = 0.011 and p = 0.025). HCV-specific CTL detection at w12 correlated with level of VL decrease (p = 0.016, r = 0.389), and among HCV genotype-1 patients with either early or delayed virologic response (EDVR), 100% positive PV of SVR was observed. In summary, HCV-specific CTL detection at w12 of Peg-interferon/ribavirin treatment correlates with SVR and in EDVR genotype-1 cases predicts SVR.