Impact of Interleukin 28B Genotype on the Virological Responses in Chronic Hepatitis C Treatment

BACKGROUND Interleukin (IL) 28B single nucleotide polymorphisms may play a role in the clearance of hepatitis C virus (HCV). We aimed to evaluate the treatment response of chronic HCV infection patients to pegile interferon (pegIFN) and ribavirin treatment with regard to IL28B rs12979860 C/T polymorphism. METHODS A total of 186 patients (mean age, 55.6 ± 10 years; 65.1% female) who underwent pegIFN and ribavirin treatment for chronic HCV infection were studied. We analyzed demographics, HCV genotype, baseline alanine aminotransferase (ALT) levels, histopathological data, viral load before treatment and at 4, 12, 24, 48, and 72 weeks from the treatment start, and IL28B genotype. IL28B polymorphism was genotyped using polymerase chain reaction based restriction fragment length polymorphism (PCR-RFLP) in all the subjects. RESULTS One hundred forty-five (86.8%) patients were infected with viral genotype 1b, and 13.2% were infected with viral genotype 4. The rates of C/C, C/T, and T/T genotypes were 22.6%, 52.7%, and 24.7% respectively. The percentage of patients with a viral load over 400,000 IU/mL was higher in the C/T group (P = 0.020). Of the patients, 44.6% provided sustained virological response (SVR) to pegIFN and ribavirin combination treatment. The frequency of T allele was 41% in patients with SVR, whereas 59% patients provided no response (P < 0.001). SVR was obtained in 66.7%, 42.9%, and 28.3% of CC, CT, and TT groups (P = 0.001). The rates of rapid virological response (RVR), early virological response (EVR), end-of-treatment response (ETR), and SVR were higher in the CC group than other groups (P = 0.216, P < 0.001, P = 0.001, P = 0.001, respectively). The relapse and null response (NR) rates were higher in TT group and partial response rate (PR) was higher in CT group. CONCLUSIONS IL28B rs12979860 C/T gene polymorphism affects the response to antiviral treatment in the patients with chronic HCV genotypes 1b and 4 infections.