Urinary Eosinophil Protein X in Children with Atopic Asthma

The aim of this study was to investigate the relationship between urinary eosinophil protein X (uEPX) and asthma symptoms, lung function, and other markers of eosinophilic airway inflammation in asthmatic school children. Methods. A cross-sectional study was performed in 180 steroid dependent atopic children with stable moderately severe asthma, who were stable on 200 or 500μg of fluticasone per day. uEPX was measured in a single sample of urine and was normalized for creatinine concentration (uEPX/c). Symptom scores were kept on a diary card. FEV(1) and PD(20) methacholine were measured. Sputum induction was performed in 49 and FE(NO) levels measured in 24 children. Results. We found an inverse correlation between uEPX/c and FEV(1) (r = −.20, P = .01) and a borderline significant correlation between uEPX/c and PD(20) methacholine (r = −.15, P = .06). Symptom score, %eosinophils and ECP in induced sputum and FE(NO) levels did not correlate with uEPX/c. Conclusion. uEPX/c levels did not correlate with established markers of asthma severity and eosinophilic airway inflammation in atopic asthmatic children.