Autoimmune aspects of pemphigus vulgaris and mucosal pemphigoid.

Oral mucosal lesions of ulcerative, desquamative, and bullous character are major problems for clinicians and patients alike. Underlying such processes is the autoimmune reaction manifesting as specific subsets of immunopathology. Responsible for the maintenance of mucosal integrity within the oral cavity are numerous adhesion proteins which operate at the cell-to-cell and cell-to-connective-tissue-matrix level. Two of the better-understood conditions characterized by altered or disordered levels of adherence are the pemphigus and the pemphigoid groups of lesions. Autoantibodies in pemphigus vulgaris specifically attack normal proteins within the desmosomal structure. Cellular adhesion is affected by steric interference by antibodies directed against antigens residing within the intercellular space or the desmosome itself. Such alterations ultimately result in cell-to-cell separation, with production of the acantholytic element characteristic of pemphigus vulgaris. Mucous membrane pemphigoid is characterized by a separation at the junction of the epithelium and connective tissue at the level of the basement membrane complex. Histologically, a split occurs in the sub-basilar region, with antibodies directed to the 230-kDa protein component of the hemidesmosome. Minor antigens residing within the basement membrane area include a 180-kDa element as well as other less commonly found proteins near the membrane complex. Manifestations of these illnesses are often severe. Management strategies of pemphigus vulgaris have changed over the recent past, with new modalities supplementing the traditional corticosteroid approach. Both conditions are usually lifelong, with the implications of management a major consideration.