Abstract
Airway inflammation is regarded as a central feature of asthma and is mostly sustained by eosinophilic infiltrate. Recent studies have shown that a co-activation of eosinophil- and neutrophil-dependent inflammatory mechanisms might explain why some asthmatics do not respond to conventional asthma therapy. The aim of our study is to determine whether neutrophilic inflammation was involved in 55 allergic children with mild-moderate persistent asthma and the relationship with the response to steroid treatment. Before the sputum analysis, all children underwent spirometry with the reversibility test, and were divided into two groups on the basis of the response (such as >12% of baseline FEV1): group 1 positive and group 2 negative. Eosinophil cationic protein concentrations were measured by radioimmunoassay and neutrophyl myeloperoxidase (MPO) concentrations were measured by an MPO-EIA. Ten healthy children of comparable ages served as control group. Total IgE, FEV1 and FEV/FVC values were similar in both groups. The sputum macrophage count was higher in controls than in allergic asthmatics, but there was no difference between groups 1 and 2 (59.6% vs 18.3% and 17%; p≤ 0.005). Sputum neutrophils were significantly higher in group 2 both vs controls (62% vs 34%; p≤ 0.005) and vs group 1 (62% vs 37%; p≤ 0.005). Our data suggest that neutrophils are involved in airway allergic inflammation in mild-moderate persistent childhood asthma and a high neutrophil count in sputum may be related to a lower responsiveness to inhaled corticosteroids.