Bronchial provocation testing and collection of sputum with inhaled mannitol in children

Introduction Mannitol is used as an indirect challenge test to assess airway hyperresponsiveness in asthma. Recently, it has been tested in adults as an sputum inducer (Wood, L.G. et al. Clin Exp Allergy 2010; 40:232-41). The aim of this preliminary study was to assess the feasibility and safety of the mannitol challenge test to obtain induced sputum in young children. Methods 17 children (10 healthy and 7 asthmatics) aged 7-13 years were recruited. The mannitol challenge test (Osmohale®; Aldo-Union, Esplugues de Ll., Barcelona, Spain) was performed as previously published and induction sputum was done during the test. Sputum was processed using a slight modification of the method described by Pizzichini et al. (Pizzichini, E. et al. Eur Respir J 1996; 9:1174-80). Sputum eosinophlia was established when the percentage of eosinophils was ≥ 2.5%. Results Mannitol test was positive in 7 children (4 asthmatic and 3 healthy), provoking dose to induce a 15% fall in FEV 1 (PD15) ranged from 75 to 565.38 mg and the response-dose ratio (RDR: % fall in FEV 1 /cumulative dose) ranged from 0.03 to 0.14% fall in FEV 1 /mg. Sputum samples (viability > 50%; squamous cells Conclusions Mannitol can be used to induce good-quality sputum in young children.