HLA-DRB1 and autoimmune bullous skin disease: Furthermore, human leukocyte antigen (HLA) molecules, including alleles HLA-DQB1*0503 and HLA-DRB1*0402 in pemphigus, as well as HLA-DQB1*0301 in pemphigoid, may represent key predisposing factors for drug-induced AIBDs [124].