Relationship between HLA-DPA1 mRNA expression and susceptibility to hepatitis B

Chronic hepatitis B virus (HBV) infection is influenced by both viral and host factors. In genome-wide association studies, the human leucocyte antigen HLA-DPA1 and related polymorphism rs3077 were found to be associated with susceptibility to and spontaneous clearance of HBV infection. Here, we evaluated the association between HLA-DPA1 mRNA expression and the risk of HBV infection. HLA-DPA1 and rs3077 polymorphisms were investigated in 169 patients with chronic HBV and 217 healthy controls (HCs) from Sichuan Han blood donors using sequence-based typing and meta-analysis for HLA-DPA1 alleles. HLA-DPA1 mRNA levels were measured by real-time polymerase chain reaction. The results showed that HLA-DPA1 and rs3077 were associated with HBV infection in the Sichuan population. Rs3077T and DPA1*01:03 played protective roles in HBV infection, and rs3077C and DPA1*02:02 increased susceptibility to HBV infection. We found that the HLA-DPA1 mRNA expression was decreased in the CHB group; in particular, the 3077CT, 3077TT, DPA1*01:03 and DPA1*02:01 alleles showed a significant decrease. Our results demonstrated, for the first time, that expression of HLA-DPA1 alleles and rs3077 affected the risk of HBV infection. Genotypes with lower HLA-DPA1 expression had a greater susceptibility to HBV infection. Thus, further independent studies are needed to strengthen the associations of these polymorphisms with susceptibility to and clearance of HBV infection in Chinese populations.