Comparison of BIOCHIP Mosaic Based Indirect Immunofluorescence and Oral Direct Immunofluorescence in Patients with Oral Mucosal Pemphigus.

Background: Oral mucosal lesions in pemphigus vulgaris may precede cutaneous lesions and can cause diagnostic confusion. Diagnosis can be made by histopathology, direct immunofluorescence (DIF), and indirect immunofluorescence (IIF). DIF of the oral mucosa is an invasive procedure and difficult to perform in patients with severe mucosal ulcer, and studies have shown that BIOCHIP-IIF can be used to detect desmoglein 1 and 3 in the serum of patients with pemphigus.

Aim: To compare BIOCHIP mosaic-based IIF and oral DIF in patients with oral mucosal pemphigus.

Materials and methods: All cases of oral mucosal pemphigus which were diagnosed by clinical examination and histopathology were included in the study. Oral DIF and BIOCHIP-IIF samples were collected, and the results were analyzed.

Results: Out of 36 patients, DIF was positive in 30 patients (83.3%) and BIOCHIP-IIF in 28 patients (77.8%). On comparing BIOCHIP-IIF with DIF, sensitivity, specificity, positive predictive value, and negative predictive value of BIOCHIP were 80%, 33.3%, 85.71%, and 25%, respectively. Chi-square test showed no statistically significant difference between oral DIF and BIOCHIP-IIF (P value is 0.5143). Among the 28 patients who had positive BIOCHIP, 27 patients (96.4%) showed desmoglein (Dsg) 3 positivity, and 16 patients (57.1%) showed Dsg 1 positivity. The sensitivity and specificity of Dsg1 were 53.3% and 100%, respectively. The sensitivity and specificity of Dsg3 were 76.6% and 33.3%, respectively.

Conclusion: BIOCHIP-IIF can be used as an alternative to oral DIF in the diagnosis of oral mucosal pemphigus.