Immunodiagnosis of pemphigus and mucous membrane pemphigoid

Pemphigus and pemphigoid are two of a group (if bullous diseases affecting oral mucosa and skin. Mucous membrane pemphigoid (MMP) comprises a heteroge neous group of disorders characterized by subepithelial separation and the deposition of immunoglobulins and complement along the basement membrane zo ne (BMZ). The target antigens in the epithelium and BMZ determine the natur e of the condition, and recently there have been considerable improvements in our understanding of the BMZ antigenic composition. Pemphigus vulgaris ( PV) is characterized by autoantibodies of the IgG isotype to the desmosomal glycoprotein desmoglein (Dsg) 3, whereas pemphigus foliaceus targets Dsg1, although at least 50% of PV patients have additional autoantibodies to Dsg 1. The clinical phenotype appears to he determined by the relative amounts of Dsg1 and Dsg3. patients with oral or mucosal PV have predominantly Dsg3 autoantibodies. The most frequently targeted antigen in MMP is bullous pemp higoid antigen 180 (BP180), although bullous pemphigoid antigen 230 (BP230) , laminin 5. and beta I integrin are also involved. Circulating IgG and IgA antibodies may bind to different epitopes, of BP180 - namely the NC16A dom ain or COOH-terminal domain. pure Ocular disease bas been associated with I gA antibodies to a 45-kDa antigen and IgG antibodies to the 205-kDa antigen b4 integrin. The use (if salt-split skin substrate enables differentiation between epidermal and dermal 'binders', Since both the specificity and the antibody titer appear to have direct relationships with the disease severi ty, and it combination of clinical score and antibody titer provides valuab le prognostic data, these investigations should be carried out on a more ro utine basis.