HLA-DRB1 and autoimmune disease: Interestingly, in another study carried out in Scandinavian patients suffering from primary sclerosing cholangitis, an autoimmune disease, residue 37 (pocket 9) and residue 86 (pocket 1) were found to distinguish predisposing (DRB1*13:01) and protective (DRB1*13:02) alleles [46].