Mutations in ISDR of NS5A gene influence interferon efficacy in Chinese patients with chronic hepatitis C virus genotype 1b infection

Abstract

The interferon sensitivity determining region (ISDR) in the non-structural 5A protein (NS5A) gene of hepatitis C virus genotype 1b (HCV-1b) has been demonstrated in Japanese patients; however, contradictory data have been reported from other parts of the world, particularly from Europe and the USA. This study investigated whether mutations in the ISDR of NS5A gene influence interferon efficacy in Chinese patients with chronic HCV-1b infection. Forty-five Chinese patients with chronic HCV infection were enrolled in a retrospective study. Of these patients, 20 with HCV-1b infection completed an interferon monotherapy course and 6-month follow-up. The pretreatment mutations in the nucleic acid sequence of NS5A 2209-2248 (ISDR) of HCV-1b were identified by sequencing RT-PCR products followed by comparison with the prototype sequence (HCV-J). Correlation with the clinical efficacy of interferon alpha therapy was then analyzed retrospectively. The statistical analysis indicated a significant correlation between the mutations in ISDR of HCV-1b and sustained virological response to interferon alpha treatment (P < 0.05), and an association of the mutations in ISDR with the pretreatment serum alanine aminotransferase levels (P < 0.01) in Chinese patients with chronic HCV-1b infection. The results support the concept that the response of HCV-1b infected patients towards interferon therapy is influenced by the mutations within the ISDR of NS5A gene.