Pathophysiologically, the underlying intraepithelial blister formation is caused by IgG autoantibodies against the desmosomal adhesion proteins, desmoglein 3 and/or desmoglein 1, on epidermal keratinocytes. ( Amagai .et al .,1991) In PV the antigen is desmoglein 3 which is presented in lower epidermis and is expressed more strongly in buccal mucosa than in the skin ,in contrast to PF which its antigen is desmoglein 1 which is expressed in the skin throughout the epidermis and weakly expressed in the mucous membranes . ( Kneisel and Hertl. .,2011).