Pemphigus.
The term pemphigus refers to a group of autoimmune intraepidermal blistering diseases of the skin and mucous membranes. Several clinical variants of pemphigus are recognized. The major histologic feature of all variants is acantholysis, the disruption of normal cell-to-cell adhesion, which leads to intraepidermal blister formation. Most patients with pemphigus demonstrate IgG autoantibodies directed against an antigen located on the surface of keratinocytes. Although the stimulus for autoantibody production is unknown, several mechanisms have been proposed to explain the pathogenesis of acantholysis. One popular model proposes that pemphigus antibodies induce acantholysis through local stimulation of the plasminogen-plasmin system. Another model proposes that pemphigus antibodies fix complement and thereby alter cell membrane integrity to produce acantholysis. Prior to the availability of corticosteroids, pemphigus vulgaris was commonly fatal. Treatment with glucocorticosteroids has drastically improved the prognosis. Immunosuppressive agents and plasmapheresis have been used successfully in some patients with severe disease.