Zonulin levels in children with chronic immune thrombocytopenia

Chronic immune thrombocytopenia (cITP) is an autoimmune disease characterized by a persistently low circulating platelet count below 100 × 109/L for more than 1 year. Increased intestinal permeability has been implicated in autoimmune diseases due to microbial translocation and disrupted tight junctions. This study aimed to investigate the potential association between zonulin levels, a biomarker of intestinal permeability, and cITP. This case-controlled study included 41 patients with cITP and 41 healthy subjects recruited from a single center in Turkey. All participants were tested for stool Helicobacter pylori antigen (Hpa), antinuclear antibody (ANA), anti-dsDNA antibody, and immune profiling. Serum zonulin levels were measured using a human zonulin enzyme-linked immunosorbent assay (ELISA) kit (Elabscience, Houston) with a measurement range of 0.78 to 50 ng/mL. The mean age of cITP patients and control group was 9.6 ± 4.4 and 10.2 ± 4.4 years, with 29 (70.7%) and 22 (53.7%) being female, respectively. Platelet counts in the cITP group were highly variable, ranging from 4 to 127 × 109/L. ANA positivity was detected in 8 patients (19.5%), stool Hpa positivity in 3 patients (7.3%), and systemic lupus erythematosus in 1 patient (2.4%). Serum zonulin levels were significantly higher in cITP patients compared to controls (19.4 vs 9.1 ng/mL; P < .001). Patients with cITP exhibited significantly elevated zonulin levels, suggesting a potential link between increased intestinal mucosal permeability and cITP.