Neutrophilic airway inflammation is a main feature of induced sputum in nonatopic asthmatic children
Article first published online: 14 APR 2009
© 2009 The Authors. Journal compilation © 2009 Blackwell Munksgaard
Volume 64, Issue 11, pages 1597–1601, November 2009
How to Cite
Drews, A. C., Pizzichini, M. M. M., Pizzichini, E., Pereira, M. U., Pitrez, P. M., Jones, M. H., Sly, P. D. and Stein, R. T. (2009), Neutrophilic airway inflammation is a main feature of induced sputum in nonatopic asthmatic children. Allergy, 64: 1597–1601. doi: 10.1111/j.1398-9995.2009.02057.x
- Issue published online: 8 OCT 2009
- Article first published online: 14 APR 2009
- Accepted for publication 28 October 2008
- induced sputum
Background: Asthma phenotypes are well described among children. However, there are few studies comparing airway inflammation in different clinical presentations of pediatric asthma. We tested the hypothesis that nonatopic asthma is associated with a predominant noneosinophilic inflammation in the airways, as assessed by induced sputum. The objective of this study was to evaluate the cytological characteristics of induced sputum (IS) in atopic (AA), nonatopic asthmatics (NAA) and nonatopic nonasthmatic children (NANA).
Methods: Of 90 selected children, 77 met eligibility criteria for performing IS and were classified as: AA, n = 28, NAA, n = 29 and NANA, n = 19. Subjects answered to a set of ISAAC-based questions and were skin-tested for common aeroallergens. A defined series of exclusion criteria was applied.
Results: Induced sputum was obtained from 54 (70.1%) subjects (21 AA, 20 NAA and 13 NANA). Demographic data and mean FEV1 were similar in the three groups. The proportion of eosinophils [median, inter quartile range (IQR)] was significantly higher in the sputum of AA [(6.0.)12)] compared with NAAs [0 (2)] and NANAs [0 (1)], P < 0.001. The proportion of children with sputum eosinophilia (eos > 3%) was also significantly higher in AA (71.4%) when compared with NAA (28.6%); none of the NANA had sputum eosinophilia. Nonatopic asthmatic children had significantly higher proportions and absolute number of neutrophils than AA and controls.
Conclusions: The results suggest that nonatopic children present IS with a cell pattern that is predominantly neutrophilic while eosinophilia is the hallmark of airway inflammation in the majority of atopic wheezing children not treated with inhaled steroids.