Changes in hepatitis C virus (HCV) antibody status in patients with chronic hepatitis C after eradication of HCV infection by interferon therapy.

BACKGROUND: Changes in hepatitis C virus (HCV) antibody status were followed for 10 years after the eradication of HCV by interferon (IFN) therapy in 30 patients with chronic hepatitis C who showed a sustained virological response. METHODS: HCV core antibody titer, third-generation HCV recombinant immunoblot assay (RIBA) grade (measuring the presence of antibodies for core, NS3, NS4, and NS5 antigens), and genotype-specific antibodies to the HCV NS4 region were measured annually with commercially available kits for these antibodies. RESULTS: For grade of HCV antibody determined by RIBA, the most significant decrease was observed with anti-NS5 antibody, followed by anti-NS4, anti-NS3, and anti-core antibodies, in that order. Tests for anti-NS5 and anti-NS4 antibodies had negative results in almost 50% of patients 10 years after eradication of HCV. In contrast, the results of tests for anti-core antibody were still markedly positive in most patients. However, anti-core antibody titer decreased continuously during the 10-year follow-up period. Antibodies to the NS4 region specific for HCV genotypes 1 and 2 also decreased during the follow-up period. Differences in the rate at which antibody titers decreased were observed between antibodies for genotypes 1 and 2; as a consequence, the serological type of HCV changed during the follow-up period in some patients. CONCLUSIONS: HCV antibody titer appears to continue to decrease during the 10 years after eradication of HCV by IFN therapy.