Identification of Cicatricial Pemphigoid Antigens

The nature of skin antigens defined by antibodies in patients with cicatricial pemphigoid was studied with use of the 1 mol/L of sodium chloride split skin technique and Western immunoblot analysis. Antibodies in the serum samples of three of seven patients with cicatricial pemphigoid reacted to the epidermal side of 1 mol/L of sodium chloride split skin, and antibodies in the serum sample of one patient reacted to the dermal side. With Western immunoblot analysis, three patients had antibodies to antigens in the epidermal extracts of skin. The antibodies reacted in all patients to a 160-kd antigen and in one patient to an additional 230-kd antigen. These two antigens are similar in molecular weight to the 230-kd major bullous pemphigoid antigen and to the 160-kd minor bullous pemphigoid antigen. However, while the basement membrane zone antibodies present in cicatricial pemphigoid were most often directed to the 160-kd antigen, those present in 38 patients with bullous pemphigoid reacted most often (in 34 patients [89%]) to the 230-kd antigen. None of the serum samples reacted to antigens in dermal extracts that contained the epidermolysis bullosa acquisita antigen. These results indicate that the basement zone membrane antibodies present in cicatricial pemphigoid are directed in part to epidermal antigens that are similar in molecular weight to bullous pemphigoid antigens. However, the frequency of reactions to different basement membrane zone antigens differs in the two diseases, which may account for the clinical differences between the two conditions.