HLA Class II Allele Polymorphisms and the Clinical Outcomes of HBV Infection

Abstract

In 2016, the global health sector strategy (GHSS) on viral hepatitis called for elimination of hepatitis B as a major public health threat by 2030 (i.e., 90% reduction in incidence and 65% in mortality). But persistence or clearance of hepatitis B virus (HBV) infection mainly depends upon host immune responses. The human leukocyte antigen (HLA) system is the center of host immune responses. HLA genes are located in chromosome 6p21.31 and cover 0.13% of the human genome and show a high degree of polymorphism and extensive patterns of linkage disequilibrium (LD), which differ among populations. The HLA genes include HLA class I, HLA class II, and other non-HLA alleles. HLA class II gene polymorphisms are strongly associated with not only persistent HBV infection but also spontaneous HBV clearance and seroconversion, disease progression, and the development of liver cirrhosis (LC) and HBV-related hepatocellular carcinoma (HCC) in chronic hepatitis B. This chapter summarizes the reported associations of HLA class II gene polymorphisms with the outcomes of HBV infection and their related mechanisms.