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

Summary In this study, the association between the risk of chronic hepatitis B virus infection and the polymorphisms within promoter regions of IFN ‐α1 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 IFNA 1 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  =   0.85). By multifactor dimensionality reduction analysis, we found the interaction between IFNA 5 (‐2529) and IFNA 1 (‐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.