Mutations within protein kinase R-binding domain of NS5A protein of hepatitis C virus (HCV) and specificity of HCV antibodies in pretreatment sera of HCV-chronically infected patients and their effect on the result of treatment.

We analyzed protein kinase R (PKR)-binding domain sequences of hepatitis C virus (HCV) NS5A protein and the profile of HCV-specific antibodies from pretreatment sera of HCV-chronically infected patients. Results were compared with clinical data to verify their influence on the course and result of therapy. Of 9 patients enrolled in a 12-month treatment with pegylated interferon alpha (PEG-IFN-alpha) plus ribavirin (RBV), 6 patients responded to therapy, as assessed by the lack of HCV RNA in their sera, and 3 did not. Among 8 HCV-1b-infected patients, those who responded did not have significantly more mutations in the IFN sensitivity determining region (ISDR) compared to non-responders (P = 0.637). Similarly, in the remaining 26-amino acid region of the PKR-binding domain, behind ISDR, the number of mutations did not differ significantly between the two groups (P = 0.796). A correlation was found between the presence of envelope 2 (E2)-specific antibodies and the result of treatment (P = 0.048). This pilot study indicates that mutations in the PKR-binding domain of HCV genotype 1b do not correlate with outcome of PEG-IFN-alpha/RBV therapy. However, the presence of E2-specific antibodies in the pretreatment sera of HCV-chronically infected individuals could serve as a prognostic marker predicting the result of treatment, before its initiation.