Background & aims: Genome-wide association studies (GWAS) recently indicated that polymorphisms in the human leucocyte antigen (HLA)-DP genes were associated with risk of persistent hepatitis B virus (HBV) infection and clearance of HBV, but the effect of HLA-DP gene polymorphisms on the effect of antiviral therapy was unknown. We here investigated whether such polymorphisms were associated with decreases in HBsAg levels and seroclearance in patients who received long-term lamivudine (LAM) treatment.
Methods: Japanese patients (202) who were hepatitis B e antigen positive at baseline, received LAM as first-line treatment, and consented to HLA-DP genotyping (HLA-DPA1 rs3077 and HLA-DPB1 rs9277535) were categorized into two cohorts, viz., a cohort who achieved virological response without rescue therapy (cohort 1) and those who did so with rescue therapy (cohort 2).
Results: Serum HBsAg levels declined significantly between year 3 and 9 from baseline among cohort 1 patients possessing ≥2 A-alleles at rs3077 and rs9277535. The percentages of such patients in cohort 1 patients with decreases in HBsAg ≥0.5 log IU/ml were higher than those with <2 A-alleles (71.8% [28/39] vs. 38.9% [23/59]; P = 0.004). However, there was no significant difference in cumulative HBsAg seroclearance rates between patients with ≥2 and those with <2 A-alleles in cohort 1. In cohort 2, HBsAg seroclearance rates were higher in patients with ≥2 A-alleles than in those with <2 A-alleles (P = 0.003).
Conclusion: We found an association between HLA-DP polymorphisms and decreases in HBsAg levels and seroclearance among HBeAg-positive patients treated with LAM.
Keywords: HLA-DP; hepatitis B surface antigen; lamivudine; nucleot(s)ide analogue.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.