Abstract
MHC class I polypeptide-related chain A (MICA), mapping to 6p21.33, belongs to the non-classical class I family and its expression is induced by several stress factors including viral infection. A recent genome-wide association study has identified a single nucleotide polymorphism (SNP) of MICA, rs2596542 to be significantly associated with hepatitis C-induced hepatocellular carcinoma (HCC) in a Japanese population. Therefore, this study aims to investigate whether the SNP rs2596542 plays any role in hepatitis B virus (HBV) sero-clearance or in the development of complications associated with chronic HBV such as cirrhosis and/or HCC. TaqMan genotyping assay was used to identify the association of the SNP among 584 normal healthy controls and 777 HBV-infected patients. The patient group was further categorized into inactive carriers (Group I), active carriers (Group II), cirrhosis (Group III) and cirrhosis-HCC (Group IV). Variation at this SNP was found to be significantly more frequent in control subjects than in patients (OR=0.852; 95% C.I.=0.730–0.994; p=0.0415). Also, the SNP was found to have a highly significant association when the inactive carriers were compared to the rest of the patients (OR=1.308; 95% C.I.=1.058–1.617; p=0.0130). The TT genotype was found to occur more frequently among active HBV carriers (groups II, III and IV) when compared to inactive HBV carriers, thus suggesting that the rs2596542-T may be recessively associated with an active HBV infection. However, no significant association was observed in the case of HBV-related cirrhosis or HCC. These findings indicate that the MICA rs2596542 has a significant role in HBV infection.