The pathogenesis of dipeptidylpeptidase 4 inhibitors associated bullous pemphigoid remains to be determined; alteration in the correct cleavage of BPAg2 (resulting in modification of its antigenicity and function) by dipeptidylpeptidase 4 inhibitors-associated plasmin inhibition has been postulated as a potential mechanism [40]. Here, COL17A1 is linked to bullous pemphigoid.