Comparative analysis of BIOCHIP mosaic-based indirect immunofluorescence with direct immunofluorescence in diagnosis of autoimmune bullous diseases: A cross-sectional study

Background: Autoimmune bullous diseases (AIBD) are a heterogeneous group of diseases characterized by autoantibodies against desmosomal proteins in the pemphigus group of disorders and adhesion molecules of the dermal-epidermal junction in pemphigoid group of diseases. Direct immunofluorescence (DIF) establishes the diagnosis of AIBD by demonstrating intercellular deposits of IgG and C3 in case of pemphigus and linear deposits of IgG and C3 along the basement membrane zone (BMZ) in bullous pemphigoid (BP). BIOCHIP mosaic-based indirect immunofluorescence (IIF), a novel diagnostic approach employs detection of characteristic staining pattern and target antigens in a single miniature incubation field. Aim: To compare the BIOCHIP mosaic-based IIF with DIF in the diagnosis of AIBD. Materials and Methods: A total of 40 patients of AIBD in the active phase of the disease were included in the study. Skin biopsy was done in these patients for DIF study and serum was subjected to BIOCHIP mosaic-based IIF assay. The results were then compared. Results: DIF revealed a diagnosis of Pemphigus in 18 patients and BP in 22 patients. BIOCHIP showed a diagnosis of pemphigus in 18 patients, BP in 18 patients and floor pattern staining in four patients, which could be attributed to any of the floor pattern staining subepidermal blistering disease. Limitations: Small sample size, lack of control group and no comparison made with ELISA. Conclusion: This study concludes that the result of BIOCHIP showed a significant correlation with the DIF and can be used as a first line-screening tool in the diagnosis of AIBD.