Use of multivariant enzyme-linked immunosorbent assay (ELISA) in the diagnosis of autoimmune bullous disorders in a resource-limited setting: A single-center experience.

Background Autoimmune blistering disorders (AIBD) result from the formation of auto-antibodies against adhesion proteins of the skin/mucosa(e). These auto-antibodies can be detected in the bound form in the tissue using direct immunofluorescence (DIF) or blood circulation using enzyme-linked immunosorbent assay (ELISA) or other methods. Objectives The objective of this study was to evaluate the concordance rate between the results of multivariant ELISA and the diagnosis of AIBD made using DIF and histopathology in an appropriate clinical context. Methods This was a retrospective study (December 2020 to April 2023) in which the multivariant ELISA assay (able to detect antibodies against desmoglein 1, desmoglein 3, BP180, BP230, envoplakin, and collagen VII) data were retrieved from the dermatology laboratory. Corresponding clinical and histopathology data were searched from relevant institutional databases. As per routine practice, the final diagnosis was assigned based on the clinical presentation, histopathology features and corresponding DIF report. Results After screening the records of 338 patients during the study period, 253 patients were included. Of them, 194 had AIBD and 59 had non-AIBD. In the autoimmune blistering disorder group, 122 and 72 patients had pemphigus and pemphigoid, respectively. Overall, a good level of agreement was found between multivariant ELISA results and the final diagnosis (Fleiss kappa = 0.631, p-value < 0.001). The pemphigus vulgaris group exhibited good agreement (kappa = 0.796, p < 0.001), while pemphigus foliaceous, bullous pemphigoid and non-autoimmune blistering disorders demonstrated moderate agreement (kappa = 0.641, 0.651, 0.533, respectively; p < 0.001). The mucous membrane pemphigoid group had a fair agreement (kappa = 0.289; p < 0.001). Limitations The limitations for the study were its retrospective design, fewer number of patients in certain groups like paraneoplastic pemphigus and gold-standard single antigen specific ELISA was not done. Conclusion Considering good agreement between the multivariant ELISA and the gold-standard diagnosis (clinical findings plus histopathology plus DIF), multivariant ELISA can be used for the diagnosis of AIBDs in places where facilities for DIF are unavailable. Multivariant ELISA can improve etiological diagnosis for a set of autoimmune blistering disorders whose target antigens are represented in the multivariant panel.