An observational study to determine the role of indirect immunofluorescence and ELISA for desmogleins in the diagnosis and monitoring of autoimmune bullous disorders

Background

Autoimmune bullous disorder (AIBD) is a diverse group of blistering dermatoses that affects the skin and mucous membrane, characterized by the formation of autoantibodies against the desmosomal glycoproteins and adhesion molecular components of the basement membrane zone. Various immunoassay techniques for serological diagnosis are Direct Immunofluorescence (DIF), Indirect Immunofluorescence (IIF), Enzyme Linked Immunosorbent Assay (ELISA) and immunoblotting. Quantitative ELISA titer can also be used to monitor the disease activity and response to treatment. The aim of this study was to evaluate the role of IIF in diagnosing various AIBDs and the role of ELISA for desmogleins in monitoring disease activity in the pemphigus group of disorders.

Methods

A total of 45 patients with freshly diagnosed AIBD were included in the study. Skin biopsies were done to establish the diagnosis by histopathology and DIF. BIOCHIP-based IIF assay was performed on the sera of the patient. The sensitivity and specificity of the IIF assay were then calculated based on the established diagnosis by Histopathological examination (HPE) and DIF. Quantitative ELISA titer was performed to measure the antibody (anti desmoglein (Dsg) 1 and 3) titre in serum samples of patients with pemphigus at baseline, 1 and 3 months follow-up after initiation of appropriate treatment therapy and results were then compared with disease activity scoring system.

Results

Sensitivity and specificity of IIF for Dsg 1 for the pemphigus group were derived to be 85.7% and 98.2% respectively, while that for Dsg 3 were 100% and 98.7%, respectively. Sensitivity (90–100%) of IIF for Bullous pemphigoid was higher than specificity (85–96%). The ELISA titers of anti Dsg1 and 3 were also observed to fall sequentially so was the disease activity score during the follow-up visits at 1 and 3 months.

Conclusion

Biochip IIF assay can be used as a screening tool for the serological diagnosis of AIBD and quantitative ELISA for monitoring the disease activity and response to treatment.