DIAGNOSTIC-VALUE OF INDIRECT IMMUNOFLUORESCENCE ON SODIUM CHLORIDE-SPLIT SKIN IN DIFFERENTIAL-DIAGNOSIS OF SUBEPIDERMAL AUTOIMMUNE BULLOUS DERMATOSES

Objective: To determine the diagnostic value of indirect immunofluores cence on sodium chloride-split skin (SSS) in differentiating the pemph igoid group of subepidermal autoimmune bullous dermatoses, including b ullous pemphigoid (BP), cicatricial pemphigoid, and pemphigoid gestati onis, from epidermolysis bullosa acquisita (EBA). Design: Serum sample s were tested using immunofluorescence on SSS and immunoblot assay on epidermal and dermal extracts, a recombinant protein corresponding to the C-terminal end of the 230-kd BP antigen, and purified laminin-5. S etting: An immunodermatology laboratory. Patients: One hundred forty-t wo serum samples from patients with BP (n=98), cicatricial pemphigoid (n=23), pemphigoid gestationis (n=10), EBA (n=10), and antitype IV col lagen (n=1). Main Outcome Measures: Binding sires of serum to the epid ermal and/or dermal sides of SSS were correlated with their antigenic specificities. Results: Epidermal staining on SSS was highly specific for pemphigoid. Alternatively, a poor correlation was found for the de rmal-reacting serum samples and the diagnosis of EBA; of the 19 serum samples with dermal staining on SSS, only 10 reacted with the EBA anti gen. The remaining serum samples were from patients with cicatricial p emphigoid having antibodies to the alpha 3 or beta 3 chains of laminin -5 (n=5) or patients with BP having an tibodies to the 180-kd BP antig en (n=2). One sample recognized exclusively a 185-kd dermal antigen co rresponding to type IV collagen. One more BP serum sample with dermal staining did not recognize any dermal or epidermal antigen. Conclusion : In case of immunofluorescent dermal staining, the precise diagnosis should be confirmed by identification of the involved antigen, since i t may reveal antibodies to laminin-5 or type XVII or IV collagen, in a ddition to the EBA antigen.