Molecular biological aspects of acquired bullous diseases.

Bullous diseases of the oral mucosa and skin were originally classified on the basis of clinical and histological criteria. The discovery of autoantibodies in some of these patients and the introduction of molecular biology have resulted in a new understanding of the pathological mechanisms of many of the bullous lesions. In this article, updated topics of the immune-mediated bullous lesions which involve oral mucosa and skin are reviewed. Pemphigus antigens, which are desmosomal-associated proteins and belong to the cadherin superfamily of cell adhesion proteins, have been isolated, and their genes have been cloned. The antigens which react with autoantibodies from patients with bullous pemphigoid, cicatricial pemphigoid, acquired epidermolysis bullosa, and linear IgA disease are all proteins of the hemidesmosome basement membrane complex. Interestingly, most of the antigens also appear to be the target for mutations seen in patients with the inherited type of epidermolysis bullosa in which bullous lesions are a prominent clinical feature.