MicroRNAs as Next-Generation Biomarkers in Pemphigus: Diagnostic Value and Association with Disease Severity

Pemphigus is a life-threatening autoimmune blistering disease that presents diagnostic challenges due to its variable clinical manifestations. In this study, we evaluated the potential of miR-338-3p and miR-424-5p as biomarkers in the peripheral blood mononuclear cells (PBMCs) of patients with pemphigus vulgaris and foliaceus. Expression levels were analyzed in 37 active pemphigus patients, 20 in remission, 20 healthy controls, and 10 patients with other bullous dermatoses. Both microRNAs were significantly elevated in active disease (p < 0.0001). After three weeks of systemic glucocorticoid therapy, miR-338-3p expression decreased 1.36-fold (p = 0.0001). miR-338-3p expression strongly correlated with Pemphigus Disease Area Index scores (r = 0.828, p < 0.0001), whereas miR-424-5p expression showed no significant correlation (p = 0.198). ROC analysis demonstrated high diagnostic accuracy (area under the curve [AUC]: 0.9711 for miR-338-3p and 0.9581 for miR-424-5p), with sensitivities and specificities exceeding 90%. These findings indicate that miR-338-3p and miR-424-5p are promising diagnostic and monitoring biomarkers in pemphigus, with miR-338-3p reflecting treatment response.