Value of the BIOCHIP mosaic-based indirect immunofluorescent technique in the diagnosis of dermatitis herpetiformis among patients with chronic pruritus

Abstract

Background: The BIOCHIP mosaic-based indirect immunofluorescence technique is a practical, standardized test, and it has been used successfully in the diagnosis of autoimmune bullous dermatosis in recent years. Objectives: The study aimed to examine the diagnostic value of the BIOCHIP to identify dermatitis herpetiformis (DH) in patients with chronic pruritus (CP). Materials and Methods: This single-center case–control study included patients who applied to a dermatology clinic between July 2020 and December 2020. The diagnosis of DH was confirmed by direct immunofluorescence (DIF) test. In cases without DIF positivity, the diagnosis was established with a complete response to a long-term gluten-free diet and/or a swift response to dapsone treatment. All analyses were performed using SPSS version 21 (SPSS Inc., Chicago, IL, USA). The diagnostic performance of the variables was evaluated using receiver operating characteristic (ROC) curve analysis. P values < 0.05 were considered statistically significant. Results: GAF 3X (gliadin analog fusion peptide), as measured by the BIOCHIP method, had an area under the ROC curve of 0.854 (95% confidence interval: 0.688–1.000) for DH diagnosis with sensitivity, specificity, positive predictive, and negative predictive values of 72.73%, 100%, 100%, and 93.62%, respectively, demonstrating an overall accuracy of 94.55%. Conclusion: DH could be determined with nearly excellent accuracy by BIOCHIP GAF 3X analysis among patients with CP. BIOCHIP-based determination of GAF 3X was found to be superior to Enzyme-Linked ImmunoSorbent Assay (ELISA)-based determination of GAF 3X.