Immunopathology and molecular diagnosis of autoimmune bullous diseases

•  Introduction •  Pemphigus diseases ‐  Pemphigus vulgaris ‐  Pemphigus foliaceus•  Pemphigus variants ‐  Pemphigus herpetiformis ‐  Pemphigus erythematosus ‐  Drug‐induced pemphigus ‐  Paraneoplastic pemphigus ‐  IgA pemphigus•  Pemphigoid diseases ‐  Bullous pemphigoid ‐  Pemphigoid gestationis ‐  Linear IgA disease ‐  Mucous membrane pemphigoid•  Anti‐p200 pemphigoid •  Epidermolysis bullosa acquisita •  Dermatitis herpetiformis DuhringAbstract Autoimmune bullous diseases are associated with autoimmunity against structural components maintaining cell–cell and cell matrix adhesion in the skin and mucous membranes. Pemphigus diseases are characterized by autoantibodies against the intercellular junctions and intraepithelial blisters. In pemphigoid diseases and epidermolysis bullosa acquisita, sub‐epidermal blistering is associated with autoantibodies targeting proteins of the hemidesmosomal anchoring complex. The autoantigens in autoimmune blistering diseases have been extensively characterized over the past three decades. In general, the pathogenicity of autoantibodies, already suggested by clinical observations, has been conclusively demonstrated experimentally. Detection of tissue‐bound and circulating serum autoantibodies and characterization of their molecular specificity is mandatory for the diagnosis of autoimmune blistering diseases. For this purpose, various immunofluorescence methods as well as immunoassays, including immunoblotting, enzyme‐linked immunosorbent assay and immunoprecipitation have been developed. This review article describes the immunopathological features of autoimmune bullous diseases and the immunological and molecular tests used for their diagnosis and monitoring.