Vesiculobullous mucocutaneous disease: pemphigus vulgaris.

Pemphigus vulgaris is a potentially fatal autoimmune mucocutaneous disease in which oral lesions may be the initial and predominant manifestation. The disease is characterized by acantholysis in the immediately suprabasal layers of the stratified squamous epithelium, giving rise to blisters which readily rupture leaving erosions which show little tendency to heal. Immunogenetic studies indicate a marked genetic susceptibility to the disease, with the immune response-associated HLA-DR4 and DRw6 alleles being especially important. The trigger for autoantibody formation is unknown. The antigen in pemphigus vulgaris is probably a 130-140 kD cell adhesion molecule located in the cell membrane of basal and immediately suprabasal keratinocytes. Antibody binding to this antigen is likely to interfere with normal intercellular adhesion, leading to desmosomal detachment. Propagation of acantholysis and cell damage are attributable to complement activation, with deposition of the membrane attack complex on the keratinocyte cell membrane, and proteolysis due to increased plasminogen activator production. Steroid therapy is the treatment of choice, but significant mortality is still associated with the disease.