Urinary Eosinophil Protein X in Children with Atopic Asthma

M Nuijsink,P S Hiemstra,J C De Jongste,E J Duiverman,W C J Hop,P J Sterk,P J Sterk

doi:10.1155/2007/49240

Abstract

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. FEV1 and PD20 methacholine were measured. Sputum induction was performed in 49 and FENO levels measured in 24 children. Results. We found an inverse correlation between uEPX/c and FEV1 (r = −.20, P = .01) and a borderline significant correlation between uEPX/c and PD20 methacholine (r = −.15, P = .06). Symptom score, %eosinophils and ECP in induced sputum and FENO 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.

Highlights

Eosinophilic airway inflammation is the pathological substrate of allergic asthma both in adults and in children [1, 2]
We found a significant correlation of urinary eosinophil protein X (uEPX)/c and forced expiratory volume in 1 second (FEV1), and no association between uEPX/c and bronchial responsiveness or symptom scores in a large group of children with moderately severe allergic asthma
Lugosi et al have shown that uEPX levels were increased in symptomatic versus nonsymptomatic children with asthma, treated with inhaled steroids or disodium

Summary

Introduction

Eosinophilic airway inflammation is the pathological substrate of allergic asthma both in adults and in children [1, 2]. The severity of airway inflammation correlates poorly with symptoms and lung function [3]. As asthma treatment with inhaled steroids aims at reducing inflammation, there is a need to monitor the disease with a marker of inflammation [4, 5]. EPX can be measured accurately in urine (uEPX) [9]. UEPX can be regarded as a marker of eosinophil degranulation in vivo [10]. UEPX levels in allergic asthmatic children were found to be significantly higher than in healthy controls [11,12,13,14]. Treatment with inhaled steroids reduced uEPX levels [14].

Objectives

Methods

Results

Conclusion