Association of Genotype and Haplotype of IL-28B Gene with Hepatitis C Infection Outcome in Iran: Spontaneous Clearance Versus Chronic Infection

Background: Spontaneous viral clearance occurs in 10% to 40% of individuals after hepatitis C virus infection. Some polymorphisms in IL-28B gene may influence the outcome of HCV infection. The present study aimed at investigating the genotype and allele frequency of IL-28B rs12979860 and rs8099917 SNPs in HCV infected patients in addition to determining their association with disease outcome. Methods: A total of 302 patients with chronic hepatic C infection and 36 individuals whose infection was spontaneously cleared were included in this case-control study. The presences of chronic or spontaneously cleared infection in participants were determined by serologic and molecular methods. Genomic DNA of the participants was extracted using salting out method. IL-28B/IFN-λ3 gene polymorphisms were conducted using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: The frequency of CC genotype (P = 0.001) and C allele (P = 0.0007) of IL-28B gene at rs12979860 SNP was significantly higher in participants with spontaneously cleared HCV infection compared to that of those who were chronically infected. In the case of rs8099917 SNP of IL-28B, no correlation was found between frequency of genotype (P = 0.17) or allele (P = 0.12) and HCV infection outcome. The results of haplotype analysis showed the association of CT (P = 0.012) and TT (P = 0.013) haplotypes with spontaneous clearance and chronic infection, respectively. Conclusions: The findings implied that individuals with CC or CT genotype at rs12979860 SNP but rs8099917 SNP was not in association with spontaneous clearance of HCV in an Iranian population with HCV infection.