Related Experiment Video
Updated: May 30, 2026
Methodology for Sputum Induction and Laboratory Processing
Published on: December 17, 2017
Use of sputum eosinophil counts to guide management in children with severe asthma
Louise Fleming1, Nicola Wilson, Nicolas Regamey
1National Heart and Lung Institute, Respiratory Paediatrics, Imperial College, London, UK. l.fleming@imperial.ac.uk
Insights
Controlling sputum eosinophils in severe pediatric asthma did not significantly reduce exacerbations. While short-term improvements were noted, further research is needed to determine its clinical utility in specific subgroups.
Area of Science:
- Pediatric Pulmonology
- Asthma Management
- Inflammatory Diseases
Background:
- Previous adult studies demonstrated reduced asthma exacerbations by controlling sputum eosinophils.
- The efficacy of this strategy in severe pediatric asthma remained uninvestigated.
Purpose of the Study:
- To evaluate if controlling sputum eosinophils improves outcomes in children with severe asthma.
- To compare inflammation-based versus symptom-based asthma management.
Main Methods:
- A randomized controlled trial involving 55 children (7-17 years) with severe asthma.
- Participants were assigned to either symptom-based or inflammation-based (sputum eosinophil-guided) management.
- Follow-up occurred every 3 months over a 1-year period.
Main Results:
- The inflammation-based group showed non-significant reductions in total and major exacerbations (IRR 0.75 and 0.73, respectively).
- Fewer participants in the inflammation group experienced exacerbations within 28 days of visits.
- No significant differences were observed in asthma control measures or prescribed inhaled corticosteroid doses.
Conclusions:
- Controlling sputum eosinophils did not significantly decrease overall exacerbations or improve asthma control in severe pediatric asthma.
- Short-term exacerbation reduction suggests potential benefits in subgroups, possibly with more frequent monitoring.
- Further investigation into targeted inflammation control in specific pediatric asthma populations is warranted.
Background:
Previous studies in adults with asthma incorporating the control of sputum eosinophils into management strategies have shown significant reductions in exacerbations. A study was undertaken to investigate whether this strategy would be successful in children with severe asthma.
Methods:
55 children (7-17 years) with severe asthma were randomised to either a conventional symptom-based management strategy or to an inflammation-based strategy (principally sputum eosinophils). Children were seen 3-monthly over a 1-year period.
Results:
The annual rate of total and major exacerbations (courses of oral corticosteroids) was non-significantly lower in the inflammatory management group compared with the symptom management group (3.6 vs. 4.8, incident rate ratio (IRR) 0.75, 95% CI 0.54 to 1.04, p=0.082; and 1.9 vs. 2.7 IRR 0.73, 95% CI 0.42 to 1.28, p=0.274 for total and major exacerbations, respectively). Significantly fewer subjects in the inflammatory management group experienced an exacerbation within 28 days of a study visit. There were small non-significant differences in measures of asthma control (symptom-free days and short-acting β agonist use) favouring the inflammatory management group. There was no significant difference in the inhaled corticosteroid dose prescribed over the course of the study.
Conclusion:
Incorporating the control of sputum eosinophils into the management algorithm did not significantly reduce overall exacerbations or improve asthma control. Exacerbations were reduced in the short term, suggesting that more frequent measurements would be needed for a clinically useful effect and that controlling inflammation may have a role to play in subgroups of children with severe asthma.
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