[Control of asthma symptoms and cellular markers of inflammation in induced sputum in children and adolescents with chronic asthma]

Abstract

After the GINA 2006 publication, asthma therapy is based on control of symptoms. However there are suggestions of monitoring of airway inflammation. Aim of the study was to compare clinical criteria of asthma control with cellular markers of lower airway inflammation in induced sputum in a group of young asthmatics. To assess relationship between sputum eosinophilia, asthma severity and spirometry.

Material and methods: A group of 154 young patients with chronic asthma (8-21 years) underwent sputum induction by inhalation of 4,5% saline solution. Sputum induction was effective in 121 patients (78%), and in this group control of clinical symptoms was assessed according to GINA 2006 criteria.

Results: Asthma was controlled in 82 subjects (67.8%) and uncontrolled in 39 (32.2%). Patients with controlled asthma had higher FEV1/FVC (79.8 +/- 7.1% vs 74.2 +/- 9.9%; p = 0.004) and MMEF (80.7 +/- 23.0% vs 65.3 +/- 21.8%; p < 0.001) than those with uncontrolled disease, but the average FEV1 (as percent predicted) did not differ between the two groups. Patients with controlled asthma had lower sputum eosinophil count than those with uncontrolled asthma (3.5 +/- 6.3% vs 7.2 +/- 8.7%; p = 0.01), but difference in neutrophil count was borderline (27.3 +/- 15.5% vs 34.5 +/- 21.0%; p = 0.05). High sputum eosinophil count (> 3%) was observed in 24.4% of patients with controlled asthma and in 61.5% with uncontrolled asthma (p < 0.001). Increased sputum neutrophil count was more frequent in a group of uncontrolled asthma (2.4 vs 15.4%; p = 0.022). Mean sputum eosinophil count was lower in patients with mild astma than in patients with moderate-severe disease (3.1 +/- 5.7% vs 7.1% +/- 8.8; p = 0.006). Patients with high sputum eosinophil count had lower FEV1 (89.4 +/- 14.9% vs 94.9 +/- 13.9%; p = 0.047), FEV1/FVC (74.5 +/- 10.1% vs 79.2 +/- 9.3%; p = 0.01) and MMEF (68.7 +/- 23.3% vs 81.7 +/- 23.1%; p = 0.004).

Conclusions: In this study of young asthmatics, control of asthma symptoms was observed in 67.8% of patients. However, cellular markers of lower airway inflammation were present in 1/4 of patients with controlled asthma and in 3/4 with uncontrolled disease. Sputum eosinophilia was related to asthma severity. FEV1/FVC and MMEF were more important that FEV1 for estimating control of asthma. Improvement of asthma control scoring is needed as well as availability of simple methods of inflammation monitoring.