Association of interferon-alpha gene polymorphisms with chronic hepatitis B virus infection

In this study, the association between the risk of chronic hepatitis B virus infection and the polymorphisms within promoter regions of IFN-1 and five genes was explored. This association study was performed on 180 Thai patients with chronic HBV infection [hepatocellular carcinoma (HCC)=65 and non-HCC=115], 173 individuals with self-limited HBV infection and 140 healthy controls. Our results showed that the A allele of -1823G/A SNP within IFNA1 gene was significantly associated with an increased risk of chronic HBV infection as compared to healthy individuals and self-limited HBV group [OR (95% CI)=2.20 (1.51-3.19), P=0.000014 and OR (95% CI)=1.61 (1.12-2.33), P=0.0073, respectively]. The effect of A allele was similar to autosomal recessive in which the presence of AA genotype when compared to GG and GA conferred the OR of 2.79 (95% CI=1.72-4.52, P=0.0000085). By multifactor dimensionality reduction analysis, we found the interaction between IFNA5 (-2529) and IFNA1 (-1823) genes that gave the risk to chronic HBV infection, with the OR (95% CI) of the high-risk to low-risk group was 2.79 (1.77-4.40), P<0.0001. However, further study in functional significance is required.