Zonulin Antibodies in Iraqi Celiac Disease: A Novel Biomarker Assessment

Background: Celiac disease (CD) is an autoimmune disorder of the small intestine triggered by gluten (wheat, barley, rye), leading to inflammation, malabsorption, and symptoms such as diarrhea, abdominal pain, and weight loss. Zonulin, a regulator of intestinal permeability, may contribute to CD pathogenesis; zonulin antibodies are reportedly elevated in affected patients. Objective: The purpose of this study was to assess the association between zonulin antibodies and CD and evaluate their potential as a diagnostic biomarker. Methodology: In this case–control study, 80 CD patients (aged 4–55 years) diagnosed between September 2024 and January 2025 at Imam Hassan Al-Mujtaba Pediatric Teaching Hospital and Imam Al-Hussein Medical City Hospital (Karbala, Iraq) were enrolled alongside healthy controls. Serum anti-tissue transglutaminase (tTG), anti-gliadin antibodies (AGA), and zonulin antibodies were measured by ELISA. Demographic data and zonulin levels were compared using nonparametric statistical tests. Results: CD patients had significantly higher zonulin antibody levels than controls (P = 0.001). Conclusion: Elevated zonulin antibodies in CD patients support a role for zonulin in disease etiology and highlight zonulin antibodies as a promising biomarker for celiac disease.