Objective: To investigate Lanzhou area cases of hepatitis C virus (H-CV) infection with a 5'-non coding region (NCR) 2i genotype and core (C), envelope protein (E) and non-structural protein (NS5) 2a genotype and the relationship with therapeutic response to interferon-alpha (IFNa).
Methods: Nine patients who received IFNa-based treatment for HCV between 2007 and 2009 at the Second People's Hospital of Gansu Province were selected for analysis.Restriction enzyme analysis was carried out for the 5'-NCR and sequencing was carried out for the other gene areas.The relationship between genetic variants and IFNaresponse was examined.
Results: Of the total nine HCV cases treated with IFNa-based therapies, five of the patients achieved sustained virological response (SVR), which included two cases with type 2 genotype and three cases with no MboI restriction enzyme point of tangency (i.e.type 1b). The remaining four patients that did not achieve SVR included one case of type 2a, with a 1b and 2a mixed state, and one case with 5'-NCR 2i genotype and C area, NS5 area 2a genotype; the other two cases had 5'-NCR and C area type 1b. Of the five cases with 5'-NCR 2i genotype, all had C 2a genotype and two had C/E 2a and NS5 2a genotypes.The seven patients that showed no response to ordinary IFNa were converted to long-term IFNa plus ribavirin combination antiviral treatment; five (71.4%) of the cases showed response in HCV RNA level and the patients treated with the pegylated form showed greater response.
Conclusion: HCV genotyping can only provide information on the particular region of gene sequence examined, and it is important to sequence all gene regions where mutations related to antiviral drug response are located. Peg-IFNa-2a combined with ribavirin may achieve better therapeutic effect in patients infected with 2i/2a recombinant forms of HCV.