Investigation of the Association Between Chronic Hepatitis B and C Infection and Interleukin 2 (-330) Gene Polymorphism

Abstract

Objective: Cytokines has an important role in the immunopathogenesis of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. Interleukin-2 (IL-2) secreted by Th1 cells which plays an important role in regulating both in activation of the immune system and homeostasis, is a cytokine having a wide spectrum of effects on the immune system. Although there are many studies investigating the relationship between IL-2-330 gene polymorphism and diseases, a few studied was found to investigate the role in the immunopathogenesis of HBV and HCV infections of this cytokine polymorphisms. This study was aimed to determine the relationship between IL-2-330 gene polymorphisms and chronic hepatitis B and C infections. Methods: A total of 139 patients with chronic hepatitis B, 101 patients with hepatitis C and 87 healthy subjects as control groups were included into this study. Approximately 2 ml of blood from patients and control groups were taken into tubes containing EDTA, and genomic DNA was isolated using DNA isolation kit. Single nucleotide polypmorphsim from the obtained DNAs was investigated using the polymerase chain reaction-confronting two-pair primers (PCR-CTPP) methods. Results: The genotype frequencies of IL-2-330 TT, GT, GG were detected as 23.7%, 53.2%, 23% in patients with chronic hepatitis B and 27.6%, 50.6%, 21.8% in control groups, respectively (p>0.05). The frequencies of TT, GT, GG genotypes were found to be 34.7%, 56.4%, 8.9% in patients with chronic hepatitis C and 27.6%, 50.6%, 21.8% in control group, respectively. GG genotype frequency was significantly lower in patient groups with hepatitis C compared with the control group (p<0.05). The frequency of T allele was 50.4% in patients with chronic hepatitis B and 52.9% in control groups. The frequency of G allele in patients with chronic hepatitis B was 49.6% and 47.1% in control groups ((p>0.05). The frequencies of T and G alleles were found to be 69.4%, 30.6% in patients with chronic hepatitis C and 52.9%, 47.1% in control groups, respectively (p<0.05). Conclusion: In our study while there was no statistically significant relationship between chronic hepatitis B and IL-2-330 gene polymorphisms, significant association was found between GG genotype and chronic hepatitis C. According to our findings the GG genotype in the-330 position of IL-2 gene may be preventive effect in chronicy of hepatitis C in Turkish population, however, further research can contribute to clarify the issue.