Association Between Fecal GIP Concentrations and Tissue Transglutaminase in Celiac Disease Patients

Introduction. Celiac disease (CD) is an autoimmune disorder triggered by gluten ingestion in genetically predisposed individuals. Gluten immunogenic peptides (GIP) in feces and tissue transglutaminase (tTG) are key biomarkers for monitoring gluten intake and immune response, respectively. Despite the increasing use of GIP for assessing gluten-free diet (GFD) adherence, its correlation with tTG remains unclear.Understanding their relationship could enhance CD monitoring.Aim. To evaluate fecal GIP concentrations in CD patients, examine their correlation with tTG levels, and assess the utility of combining these biomarkers for CD management.Methods. This cross-sectional study included 60 CD patients adhering to a GFD and 10 healthy controls. Fecal and serum GIP levels were quantified using ELISA tests, and tTG concentrations were measured. Statistical analyses included Mann-Whitney U tests for group comparisons and Spearman’s rank correlation for assessing relationships between biomarkers.Results. Median fecal GIP concentration in CD patients was significantly lower (39.0 ng/g) compared to controls (474.2 ng/g; p<0.001), confirming GFD adherence. Similarly, serum GIP was lower in the CD group (p<0.001). No significant correlation was found between GIP and tTG levels (Rho=0.114, p=0.387), indicating they measure distinct aspects of CD activity.Conclusion. This study specifically evaluated fecal GIP concentrations in patients with celiac disease and their correlation with tTG levels. Our findings indicate no significant correlation, demonstrating that these biomarkers assess different aspects of disease activity. This study confirms the sensitive nature of GIP for detecting gluten intake and tTG’s role in reflecting immune response and mucosal damage. Hence, the integrated use of these biomarkers, as suggested by our results, can improve the management and monitoring of celiac disease, providing a more precise assessment of dietary adherence and immune activity.