Role of IL-17a in the Pathogenesis of Celiac Disease:  A Case–Control Study

Background: Celiac disease (CD) is a chronic inflammation of the intestinal tract, characterized with a lifelong adverse reaction to eating gluten in genetically predisposed individuals. Interleukin 17A (IL-17A) is a multifaceted pro inflammatory cytokine essential for vital functions such as host immunological defense, tissue healing, and the pathogenesis of inflammatory diseases. Aims: This study aimed to characterize the demographic and clinical profiles of CD patients and compare IL-17A levels between CD patients and healthy controls. Subjects and Methods: This case- control study enrolled 80 patients aged 4 -55 years diagnosed with CD from three hospitals: Imam Hassan Al- Mujtaba Hospital, Pediatric Teaching Hospital and Imam Al-Hussein Medical City Hospital, in Karbala, Iraq from September 2024 to (31st) January 2025 and matched with 48 of apparently healthy controls. The ELISA test was applied for determining serum concentrations of anti-tissue transglutaminase (tTG), including IgA and IgG, anti- gliadin antibodies (AGA) including IgA and IgG and IL-17A in both patients and control groups .The data were collected and analyzed using appropriate non-parametric statistical tests to identify significant differences between groups. Results, the study showed that serum IL17A levels were higher in CD patients compared to healthy control, but the difference was non-significant (P= 0.230). Among CD patients, serum IL-17A levels were significantly higher in the anti-tTG IgA-negative group compared to the positive group (P = 0.002). Additionally, IL-17A levels were significantly elevated in patients with a disease duration of more than one year and in those adhering to a gluten-free diet. Conclusion: The results indicate that IL-17A may have a role in the inflammatory mechanisms associated with celiac disease, especially in those with prolonged disease duration. Further investigations should explore the synergistic effects of IL-17 with other inflammatory cytokines considering factors like disease duration and diet.