Analysis of induced sputum to examine the effects of inhaled corticosteroid on airway inflammation in children with asthma

Background: Analysis of induced sputum can be performed safely in children with asthma and is useful for both cellular and biochemical markers of infl ammation. Glucocorticosteroid inhalation has become the first line therapy for chronic asthma by suppressing airway inflammation, which produces the d ecrease of bronchial hyperreactivity and reduces the number of eosinophil i n bronchial submucosa. Objective: To determine the characteristics of the inflammatory cells and t heir markers in sputum and to examine the pharmacokinetic effects of glucoc orticoid within 3 hours after inhalation therapy on FEV, and sputum inflamm atory indices in children with clinically defined chronic asthma. Methods: Thirty subjects with asthma included 14 current symptomatic asthma tics and 14 normal controls inhaled 4.5% hypertonic saline for 10 minutes b y nebulizer. The expectorated sputum were collected from all asthmatics bef ore and 3 hours after corticosteroid inhalation for children with asthma an d were reduced by dithiotreitol. Total cell counts and differentials were d etermined. ECP was measured by CAP system. Interleukin-5, GM-CSF and albumi n were measured by double sandwich ELISA. Results: The mean eosinophil percentage and ECP in induced sputum of asthma tics were significantly higher than that of controls. The induced sputum sa mples obtained after glucocorticoid inhalation showed a significant reducti on in mean eosinophil percentage, but FEV1, IL-5, GM-CSF, albumin, and ECP values were not significantly decreased. Conclusion: The present results in induced sputum may be interpreted to ref lect direct steroid action on airways and lack of effect on bone marrow eff ectors at 3 hours after glucocorticoid inhalation.