Immunodermatology Update: The Immunologically Mediated Vesiculobullous Diseases

Before a specific diagnosis of an immunologically mediated blistering disease can be made, the clinical and histologic features and the results of direct and indirect immunofluorescence studies (with use of multiple substrates in some cases) must be assessed. For both subepidermal and intraepidermal groups of blistering diseases, direct immunofluorescence testing of perilesional tissue is critical for diagnosis. For these conditions, indirect immunofluorescence testing of serum is important for diagnosis and has a role in management of selected diseases. In dermatitis herpetiformis, indirect testing of serum for IgA antiendomysial antibodies is useful for both diagnosis and management. Indirect testing of serum for IgG antibodies to intercellular substance is important for diagnosis and, in conjunction with the clinical findings, can be used as a guide for monitoring disease activity in patients with pemphigus. Immunoelectron microscopy, immunoprecipitation, and immunoblotting studies have identified the sites of immune deposits and the specific antigens in most of the immunologically mediated bullous diseases. From a practical standpoint, however, direct and indirect immunofluorescence testing, in conjunction with clinical and histologic evaluations, is a simple, rapid, and relatively inexpensive tool for diagnosis and management.