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Blood eosinophil counts rarely reflect airway eosinophilia in children with severe asthma

Authors


  • This work was performed at the following Institution: Department of Respiratory Paediatrics, Royal Brompton Hospital London – UK.
  • Edited by: Hans-Uwe Simon

Correspondence

Dr. Sejal Saglani, Clinical Senior Lecturer Respiratory Paediatrics, National Heart & Lung Institute, Imperial College London, 374 Sir Alexander Fleming Building, Exhibition Road, SW7 2AZ London, UK.

Tel.: +44 207 594 3167

Fax: +44 207 594 3119

E-mail: s.saglani@imperial.ac.uk

Abstract

Background

The inflammatory phenotypes of severe asthma in adults may be reflected in peripheral blood. If this were true in children with severe therapy-resistant asthma (STRA), invasive tests could be avoided. At the moment there is no conclusive evidence in children.

Methods

All patients underwent blood tests, exhaled nitric oxide (FeNO), sputum induction, bronchoalveolar lavage (BAL) and endobronchial biopsy (EB).

Results

Sixty-three (71.6%) patients had a normal blood profile and only 1/88 had a combined blood eosinophilia and neutrophilia. 76/88 (86%) had normal blood eosinophils, but of these, 84% had airway eosinophilia in either BAL (n = 43;66%) or EB (n = 41;79%). In children with STRA blood eosinophilia was associated with airway eosinophilia. However, normal blood eosinophil levels did not exclude airway eosinophilic inflammation.

Conclusions

Peripheral blood counts are not reliable in characterising airway inflammation in severe asthmatic children exposed to high dose steroid therapy, therefore bronchoscopy with BAL should be considered.

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