HLA-DP and γ-interferon receptor-2 gene variants and their association with viral hepatitis activity in chronic hepatitis B infection

Abstract

Background and Aim: Studies show that polymorphisms in human leukocyte antigen (HLA)‐DP loci and certain γ‐interferon (IFN‐γ) signaling pathway genes are related to persistence of hepatitis B virus (HBV) infection and viral load in chronic HBV (CHB) infection respectively. Our study aims to determine whether single‐nucleotide polymorphisms (SNPs) linked to HLA‐DP loci and IFN‐γ signaling pathway are associated with HBV activities.

Methods: We compared the SNPs in the HLA‐DPA1 gene (rs3077) and the IFN‐γ receptor‐2 gene (rs2284553 and rs9808753) of 100 treatment‐naive hepatitis B e antigen (HBeAg)‐negative CHB patients with undetectable HBV DNA with 100 age‐ and sex‐matched controls with HBV DNA > 2000 IU/mL.

Results: The median age of the study group was 47.9 years, and 61% were male patients. The distribution of the three polymorphisms was in Hardy–Weinberg equilibrium. Both rs3077 and rs2284553 polymorphisms were not associated with HBV viral load in terms of allelic frequency, genotypic frequency, dominant/recessive gene action. rs9808753 (G allele) was associated with a reduced chance of “undetectable HBV DNA” for patients below the age of 50 years in allelic frequency analysis (odds ratio 0.562; 95% confidence interval, 0.326–0.967; P value = 0.037). IFN‐γ receptor‐2 gene haplotype block (rs2284553/rs9808753) was not associated with HBV viral activity.

Conclusion: There was no significant association between HLA‐DP polymorphism (rs3077) and IFN‐γ receptor‐2 gene polymorphism (rs2284553) with viral activity in HBeAg‐negative CHB patients. Further studies are required to confirm the association between IFN‐γ receptor‐2 gene polymorphism (rs9808753) and reduced chance of having “undetectable HBV DNA” in young CHB patients.