HAVCR2 and chronic hepatitis B virus infection: During chronic hepatitis B infection, HBV-specific B cells differentiate into an atypical phenotype that has difficulty producing anti-hepatitis B surface antigen (HBsAg) antibodies [43], whereas NK cells upregulate TIM-3 and T-cell immunoreceptor with Ig and ITIM domains (TIGHT) and exhibit reduced killing and cytokine production [44].