HLA-DRB1 and autoimmune hepatitis: Prior studies have proposed a histidine residue at position 13 of the DRβ-polypeptide to be a critical determinant of disease susceptibility in Japan,[28] in contrast to a lysine residue at position 71 of the DRβ-polypeptide in patients of European descent.[6], [7] In the present study, the incidence of valine-11 (OR = 2.19), histidine-13 (OR = 2.38), and serine-57 (OR = 2.53) encoded by DRB1*04:05 was significantly higher in AIH patients.