We identified two susceptible haplotypes (DPA1*02∶02-DPB1*05∶01 and DPA1*02∶01-DPB1*09∶01) and three protective haplotypes (DPA1*01∶03-DPB1*04∶01, DPA1*01∶03-DPB1*04∶02, and HLA-DPA1*01∶03-DPB1*02∶01) to chronic hepatitis B infection, which may result in different binding affinities between HLA-DP subtypes and extracellular antigens. The gene discussed is HLA-DPA1; the disease is chronic hepatitis B virus infection.