Elevated Circulating Interleukin-33 in Vitiligo Diagnostic Potential and Clinical Correlates — A Cross-Sectional Study
Abstract Background: Vitiligo is an immune-mediated depigmenting disorder in which oxidative stress, innate immune activation and cytokine dysregulation contribute to melanocyte destruction. As an epithelial alarmin released during cellular stress, interleukin-33 (IL-33) is well positioned to participate in this inflammatory interface, although its circulating profile and diagnostic relevance in vitiligo remain to be established. Aims: To determine serum IL-33 concentrations in patients with vitiligo and to evaluate their diagnostic potential and clinical correlates. Methods: This cross-sectional study included 36 patients with clinically and Wood's lamp-confirmed vitiligo and 36 age- and sex-comparable healthy controls. Serum IL-33 was quantified by sandwich enzyme-linked immunosorbent assay. Lesional activity was graded using the Vitiligo Disease Activity (VIDA) score. Between-group differences, clinical correlations and receiver operating characteristic (ROC) performance were evaluated. Results: Serum IL-33 was significantly higher in patients than controls (median 10.60 [IQR 2.32–22.20] vs 3.03 [2.01–4.44] pg/mL; p=0.005). ROC analysis yielded an area under the curve of 0.691 (95% CI 0.563–0.819). At an optimal cut-off of 9.345 pg/mL, sensitivity was 61.1%, specificity 88.9%, positive predictive value 84.6% and overall accuracy 75.0%, with a positive likelihood ratio of 5.50. Serum IL-33 was not significantly associated with sex, age or VIDA grade and showed no meaningful correlation with VIDA score (ρ=0.088; p=0.611). Conclusion: Circulating IL-33 is elevated in vitiligo and demonstrates moderate discriminatory potential, characterised by relatively high specificity but limited sensitivity. Its lack of association with clinical activity suggests greater value as an exploratory disease-associated biomarker than as a marker of current clinical activity. Keywords: Vitiligo; Interleukin-33; Biomarker; Clinical correlates; ROC curve. |