Prospective studies on the routine use of a novel multivariant enzyme-linked immunosorbent assay for the diagnosis of autoimmune bullous diseases

Background Serologic diagnosis of autoimmune blistering disease (AIBD) usually follows a sophisticated multistep algorithm. Objective We sought validation of a multivariant enzyme-linked immunosorbent assay (ELISA) in the routine diagnosis of AIBD. Methods The multivariant ELISA comprising 6 recombinant immunodominant forms of major AIBD target antigens, ie, desmoglein 1, desmoglein 3, envoplakin, BP180, BP230, and type VII collagen was applied in: (1) a cohort of well-characterized AIBD (n = 173) and control sera (n = 130), (2) a prospective multicenter study with 204 sera from patients with newly diagnosed AIBD with positive direct immunofluorescence microscopy, and (3) a prospective monocenter study with 292 consecutive sera from patients with clinical suspicion of AIBD in comparison with the conventional multistep diagnostic algorithm. Results Concordant results in the multivariant ELISA compared with direct immunofluorescence microscopy were seen in 94% of patients with pemphigus and 71% of patients with pemphigoid (Cohen κ value, 0.95 and 0.66) and with the conventional multistep diagnostic approach in 91% of patients with pemphigus and 88% of patients with bullous pemphigoid and 93% of autoantibody-negative sera (Cohen κ, 0.95, 0.84, and 0.78). Limitations IgA autoantibodies and less common target antigens were not analyzed. Conclusions The multivariant ELISA is a practical, highly standardized, and widely available novel diagnostic tool for the routine diagnosis of AIBD.