D3.56 - Investigation of Serum Eosinophilic Granule Proteins Levels in Children with Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is driven predominantly by mast cells; however, eosinophils are recognized as important secondary effector cells. This study aimed to investigate the role of eosinophils in the pathogenesis of pediatric CSU by comparing serum levels of eosinophil granule proteins [Eosinophil Cationic Protein (ECP), Eosinophil Peroxidase (EP), and Eosinophil Major Basic Protein (EMBP)] levels between children with CSU and healthy controls.

Between August 2024 and June 2025, children followed with a diagnosis of CSU at the our pediatric immunology and allergy depertmant and age- and sex-matched healthy controls were enrolled. Clinical, demographic, and laboratory data were recorded, including disease duration, triggers, and Urticaria Activity Score over 7 days (UAS7). Serum levels of ECP, EP, and EMBP were measured from blood samples obtained from patients and controls. 

Seventy-four patients with CSU (age 2–17 years; mean 12.64 ± 3.82; 55.4% female) and 70 healthy controls (age 2–17 years; mean 13.21 ± 3.09; 55.7% female) were included. The primary presenting complaint was urticaria in 63.5% (n=47) and angioedema with urticaria in 36.5% (n=27) of patients. Serum ECP levels were significantly higher in the CSU group than in controls (p<0.001), whereas EP and EMBP levels did not differ significantly between groups. No significant relationships were observed between ECP/EP/EMBP and UAS7 score demographic characteristics, the mean eosinophil counts (p>0.05).

Our study suggests that ECP may play a role in the pathogenesis of CSU in children. These findings may also inform future development of targeted therapeutic strategies.