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

Background and AimStudies show that polymorphisms in human leukocyte antigen (HLA)-DP loci and certain -interferon (IFN-) 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- signaling pathway are associated with HBV activities. MethodsWe compared the SNPs in the HLA-DPA1 gene (rs3077) and the IFN- 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>2000IU/mL. ResultsThe 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- receptor-2 gene haplotype block (rs2284553/rs9808753) was not associated with HBV viral activity. ConclusionThere was no significant association between HLA-DP polymorphism (rs3077) and IFN- receptor-2 gene polymorphism (rs2284553) with viral activity in HBeAg-negative CHB patients. Further studies are required to confirm the association between IFN- receptor-2 gene polymorphism (rs9808753) and reduced chance of having undetectable HBV DNA in young CHB patients.