Eosinophil Cationic Protein in Children With Respiratory Allergies - When Is It Useful?

Background: To assess the differences in serum eosinophilic cationic protein (ECP) concentrations between treated and untreated children with asthma, children with rhinitis, and children with both and possible influence of seasonal exposure to sensitizing allergens on ECP levels. Methods: The study included treated (n=156) and untreated (n=55) children with asthma, children with rhinitis, and children with asthma and rhinitis. Serum ECP was measured in serum collected between 8 am and 12 pm under standardized pre-analytical conditions (regarding the type of blood collection tube, time, and incubation temperature during blood clotting). Results: Untreated children had significantly higher ( P <0.0001) concentrations of ECP (M[IQR]=35.1 [29.5–50.9] μg/L) than treated children (M[IQR]=11.3 [7.1–16.1] μg/L). Eosinophilic cationic protein was significantly higher during the allergen exposure season (M[IQR]=23.9 [17.6–40] μg/L) than out of season (M[IQR]=8.3 [5.4–17.2]) μg/L, P =0.0001. Conclusions: To make ECP measurements useful in clinical practices, it is necessary to meet standardized pre-analytical conditions. * ECP : eosinophilic cationic protein IL-2 : interleukin-2 ARIA : Allergic Rhinitis and its Impact on Asthma GINA : Global Initiative for Asthma IgE : immunoglobulin E FeNO : fraction of exhaled nitric oxide