The Effect of IL28B Gene Polymorphism on Treatment Response in Iranian Patients with Hepatitis C Virus Infection

Background: The hepatitis C virus (HCV) is an important human pathogen affecting an estimated 120 - 170 million individuals in the world. Polymorphisms of the IL28B gene are strongly associated with sustained virological response in patients with chronic hepatitis C treated with peginterferon and ribavirin. Objectives: The aims of this study were to compare the allelic and genotypic frequencies of the IL28B rs12979860 polymorphism in sustained virological response in patients who did not respond to the standard of care treatment and to verify whether there is a correlation between the viral load and the IL28B rs12979860 polymorphism. Methods: This cross-sectional study was carried out on 75 HCV-infected patients, including 45 responders to treatment (group 1) and 30 nonresponders (group 2). We compared the allele and genotype frequencies of the IL28B rs12979860 between the two groups using the PCR-RFLP method. Results: The genotype frequencies of rs12979860 polymorphism in group 1 were CC (28.9%), CT (37.8%) and TT (33.3%) and in group 2 were CC (6.7%), CT (43.3%) and TT (50%). There was a significant difference in genotype frequencies of IL28B polymorphism between the two groups (P = 0.03). There was no significant association between the viral load and IL28B rs12979860 genotypes in either group 1 (P = 0.3) or group 2 (P = 0.2). Conclusions: Our findings indicate that patients with the homozygous CC genotype in the IL28B gene had a significantly higher rate of response to treatment than those with the TT or CT genotypes. Nor does the IL28B rs12979860 polymorphism affect the viral load.