The Impact of IFN-[gamma] Gene Polymorphisms on Spontaneous Clearance of HCV Infection in Fars Province, Southern of Iran

Background Certain polymorphisms in cytokine genes such as IFN-[gamma] may influence the outcome of hepatitis C virus (HCV) infection. Here the frequency of the genotype, allele, and haplotype of IFN-[gamma] gene at some loci is investigated in HCV-infected patients. Methods Totally 255 patients with chronic HCV infection and 44 spontaneously cleared individuals were included. The chronic or clearance states were confirmed using enzyme-linked immunosorbent assay (ELISA) and two different qualitative reverse transcriptase polymerase chain reaction (RT-PCR) techniques. IFN-[gamma] gene polymorphisms were performed by PCR using sequence-specific primers and PCR-RLFP on extracted genomic DNA. Results The frequency of GG genotype (P = 0.0001, OR: 5.69 and CI: 2.21-14.62) and allele (P = 0.0003, OR: 2.73 and CI: 1.54-4.83) of IFN-[gamma] gene at +2109 locus was significantly higher in cases that spontaneously cleared the infection. Haplotype analysis showed the association of AG haplotype (P = 0.0046, OR = 6.14 and CI = 1.56-25) with spontaneous clearance of the infection. Conclusion Our finding indicated that individuals with GG genotype at +2109 loci of IFN-[gamma] gene and also AG haplotype (A allele at +874 loci and G allele at +2109 loci) may clear HCV infection more frequently than those with AA and AG genotype at +2109 loci and AA, TA, and TG haplotype.