Faecal calprotectin and circulating tight junction protein in children with gastrointestinal food allergy

Recent studies have confirmed that increased intestinal permeability syndrome plays a key role in the pathogenesis of allergic diseases, while peripheral tight junction proteins like ZO-1 may serve as potential biomarkers for assessing gut barrier integrity. The aim of the study. To evaluate serum ZO-1 levels as a marker of epithelial barrier dysfunction in children with gut barrier impairment and food allergy. Materials and methods. The study included 27 children with cow’s milk protein allergy (CMPA, Group I) aged 1 month to 3 years and 20 healthy controls (Group II). Serum ZO-1 and fecal calprotectin (FC) were measured by ELIZA. Statistical analysis used MannWhitney U test, Spearman’s correlation, and ROC analysis. Results. Gastrointestinal symptom severity (GSS) was scored based n crying, regurgitation, stool, etc. Group I showed significantly higher GSS (Ме=13, Q1-Q3:7–18) versus controls (Ме=3, Q1-Q3:1–4,5). Serum ZO-1 levels were significantly lower in CMPA patients (Ме=0,007 ng/mL, Q1-Q3:0–0,031) compared to controls (Ме=0,033 ng/mL, Q1-Q3:0,027–0,135; p<0,05). FC levels also differed significantly: 286 μg/g (Group I) vs 87 μg/g (controls; p<0,001). Inverse correlations were found between ZO-1 and FC (r=-0,675; p<0,01) and between ZO-1 and GSS (r=-0,605; p<0.05). Conclusion. Decreased ZO-1 levels and elevated fecal calprotectin confirm intestinal barrier damage in CMPA patients. ZO-1 serves as a reliable marker of barrier integrity, while its combination with FC enhances diagnostic value for predicting allergy progression and atopic march risk.