RESUMO
OBJECTIVE: This study was designed to examine for nitric oxide (NO) metabolites in induced sputum as a marker of airway inflammation in asthmatic children. DESIGN. Prospective interventional SETTING: Pediatric Allergy and Asthma Clinic of a tertiary care referral hospital in Northern India. SUBJECTS: Twenty-one children with asthma who were not receiving corticosteroids for the preceding 3 months and 10 healthy controls were enrolled. METHODS: Hypertonic saline-induced sputum was obtained at study entry in controls, and at study entry and after 6 weeks of inhaled corticosteroid (ICS) therapy in asthmatic children. Fresh expectorated sputum was treated with dithiothreitol and cytospinned for cell count. NO metabolites were measured in the supernatant by the modified Griess reaction. RESULTS: Asthmatic children, compared with controls, had significantly higher concentration of NO metabolites (22.4 +/- 209.69 vs 39.2 +/- 15.9 (moL/L, P <0.01) and a higher percentage of eosinophils (15.3 +/- 12.0 vs 0.8 +/- 1.1%, P <0.01) in induced sputum. Both NO metabolites and eosinophil percentage declined following treatment with ICS for 6 weeks (P <0.01). CONCLUSION: The study confirms that the level of NO metabolites is increased in the tracheobronchial secretions of asthmatic children and decreases following ICS therapy. Measurement of NO metabolites in induced sputum may be useful for monitoring airway inflammation in children with asthma.