RESUMO
Objective To study the cause of protective immunodeficiency of patients with hepatitis C. Methods An antigen capture ELISA in which HCV synthetic peptides SP42, CP10 and CP9 derived from HCV NS4 and core gene region, respectively, were used as solid-phase antigens was used to detect the differences in light chain isotype expression of anti-HCV antibodies. Results Antibodies in 84 sera of HCV-infected patients against HCV SP42, CP10 and CP9 were characterized by a skewed light chain isotype expression. Eighty-two out of 84 sera of HCV infection (97 62%) showed at least one of the three anti-HCV antibodies skewed from the normal ratio of light chain isotype kappa/lambda. The kappa/lambda ratios of anti-HCV antibodies in all patients with hepatitis C were found to be unique and constant during one year follow-up, and 11 of them received two years follow-up. Conclusions Anti-HCV response was stable and clonally restricted in HCV infection. B-cell clonal dominance may be the cause of human protective immunodeficiency after HCV infection.