HLA-DRB1 and hepatitis A virus infection: Interestingly, similar contrasting effects have been observed in autoimmune hepatitis in Latin America, where risk is associated with HLA-DRB1*13:01 and protection with DRB1*13:02.15 HLA-DRB1*13:01 has also been associated with a protracted course of hepatitis A virus infection, which has been postulated to be a trigger of autoimmune hepatitis.35 To what extent these parallel observations are relevant for the specificity of the immune response in PSC can currently only be speculated.