Decreased anti-hepatitis C virus titer and associated factors in chronic hepatitis C patients after sustained virological response: A prospective study

Background and Aim: Long-term trends of anti-hepatitis C virus (HCV) antibody titer and their associated factors in patients with sustained virological response (SVR) were investigated. Methods: From May 1999 to July 2005, a total of 166 SVR consecutive patients (M/F: 86/80) were enrolled. Anti-HCV titer, samples to cut-off (S/CO) ratios, were measured with AxSYM HCV version 3.0. Their S/CO ratios were followed every 6months after SVR and the patterns over time were identified by trajectory analyses. Changes of recombinant immunoblot assay (RIBA) pattern before treatment and end of follow-up were compared (n=64). Results: The mean duration of follow-up was 4.7±1.5years (median 4.3; range 3-9years). The rates of S/CO ratios decreased annually (P<0.001). Two of them (1.2%) achieved seroreversion. Trajectory groups included lower pretreatment S/CO ratios (LAB, n=83), rapid decrease (RD, n=62) and slow decrease (SD, n=21) groups. Comparing LAB to RD group, odds ratio (OR) of increased platelet count per 1 unit and interferon regimen was 1.12 (95% confidence interval [CI] 1.04-1.20) and 2.17 (95% CI 1.04-4.52) respectively. Comparing SD to LAB and RD groups, the OR of advanced fibrotic stage, using mild fibrotic stage as a reference, was 4.33 (95% CI 1.49-12.63). Reaction strength of all four RIBA bands decreased significantly at the end of follow-up. Conclusions: Anti-HCV titers decreased annually during long-term follow-up after SVR. Higher pretreatment platelet count, interferon regimen and mild fibrosis were associated with decreased anti-HCV titers. However, only a few cases achieved seroreversion. All RIBA bands decreased significantly after long-term follow-up.