Bullous pemphigoid (BP) and cicatricial pemphigoid (CP) are subepidermal bullous autoimmune diseases which have distinct clinical features but identical immunological status. In order to determine whether these diseases could be dissociated on the basis of qualitative differences in serum antibodies to basement membrane zone (BMZ) antigens, the reactivity of sera from 7 CP and 29 BP patients with proteins extracted from normal human epidermal sheets (containing most of the lamina lucida components) was analysed using immunoblotting and compared to that of 10 normal sera.20 out of the 29 BP sera contained antibodies recognizing one or several protein(s) of 240, 200, 180 and 165kD molecular weight (MW). Antibodies in 4 out 7CP sera specifically reacted with one or two polypeptides of 240 and 120kDMW. These data confirm the heterogeneity of BP antigens and show the presence in CP of a novel 120kDMW polypeptide which is found only in CP but not in BP.Taken together these findings demonstrate that in BP and CP, autoantibodies are directed to both common and specific BMZ antgiens, their physiopathological significance need to be understood.