Does eosinophil cationic protein in sputum and blood reflect bronchial inflammation and obstruction in allergic asthmatics?

In the assessment of asthma severity and monitoring of asthma drug therapy eosinophils and eosinophil cationic protein (ECP) have been identified in b lood but rarely in sputum. The aim of our study was to determine ii ECP con centrations in blood and sputum reflect bronchial inflammation and obstruct ion in allergic asthmatics and if inhaled steroids influence this relations hip. We carried out a descriptive, cross-sectional study of 42 allergic ast hmatic outpatients from a respiratory medicine department, of whom 22 were on beta(2)-adrenergic agonists only and 20 were treated with low doses of i nhaled steroids. Spirometry and methacholine challenge were performed and e osinophils and ECP values in induced sputum and blood were determined The a ge and FEV1 were similar in both groups. If was found that in patients rece iving inhaled steroids, the methacholine PD20 was higher than in patients o n beta(2)-adrenergic agonists only. However, there were no significant diff erences in serum and sputum ECP between the groups (median 14.5 mu g/l vs. 17.2 mu g/l and 235 mu g/l vs. 301 mu g/l respectively). In patients not re ceiving steroids, sputum ECP correlated positively with eosinophils in sput um (r = 0.61, p <0.01) and inversely with FEV1 (r = -0.43, p <0.05). Serum ECP correlated with blood eosinophils and methacholine PD20. In patients tr eated with inhaled steroids most correlations were no longer significant. W e concluded that ECP in sputum, rather than in blood, seems to reflect both eosinophilic inflammation and bronchial obstruction in asthmatics not rece iving inhaled steroids. Asthmatics on low doses of inhaled steroids had inc reased ECP levels in sputum and serum, indicating persistent eosinophilic i nflammation of the airways.