Sputum epithelial cell-derived neutrophil-activating peptide-78 (ENA-78/CXCL5) in asthmatic children: relation to eosinophil activation

Abstract

Background: Epithelial cell-derived neutrophil-activating peptide-78 (ENA-78) is a chemokine that recruits and activates neutrophils, possesses angiogenic properties and promotes connective tissue remodeling. Thus, it could play a pathogenic role in allergic airway inflammation. Eosinophils are the major source for this chemokine in inflamed airways. Objective: To evaluate sputum ENA-78 expression and its relation to acute asthma exacerbations of varying severity, and eosinophil cationic protein (ECP) as a marker of eosinophil activation, as well as eosinophil counts in blood and sputum. Methods: Sputum ENA-78 and serum ECP were measured by ELISA in 21 children during and after acute asthma exacerbation and 21 healthy matched controls. Patients were subdivided according to exacerbation severity into three equal subgroups; mild, moderate and severe. Results: Sputum ENA-78 was significantly higher in asthmatic children during acute exacerbation than controls (310.1±156.9 pg/ml vs 65.9±11.6 pg/ml, p < 0.0001). It was significantly higher in severe than moderate and in moderate than mild exacerbations, and was negatively correlated to the peak expiratory flow rate. Sputum ENA-78 showed significant positive correlations with serum ECP and eosinophil counts in blood and sputum. By follow up of patients with acute asthma exacerbation till remission of symptoms and signs, sputum ENA-78, serum ECP and eosinophil counts in blood and sputum decreased significantly, but their levels remained significantly higher than the control values. Conclusion: Sputum ENA-78 is increased during acute asthma exacerbation and it positively correlates with exacerbation severity and eosinophil activation. Thus, it may play a role in the evolution of acute asthma exacerbation and may be a future target for new asthma therapeutic modalities.

Keywords: Bronchial asthma; chemokines; children; epithelial cell-derived neutrophil-activating peptide-78; eosinophils; eosinophil cationic protein; sputum markers

Egypt J Pediatr Allergy Immunol 2007; 5(2): 55-64