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The use of sputum eosinophils in the evaluation of occupational asthma

Lemière, Catherine

Current Opinion in Allergy and Clinical Immunology: April 2004 - Volume 4 - Issue 2 - p 81-85
Occupational disease

Purpose of review The diagnosis of occupational asthma needs to be made objectively using as many criteria as possible. These include laboratory exposure tests with occupational agent(s), which are only available in specialized centres. Another approach is to monitor peak expiratory flow or methacholine airway responsiveness during periods at work and away from work. However, these measurements are open to misinterpretation when they are not performed optimally. Airway inflammation is one of the main characterisitics of occupational asthma, but is not often assessed during its investigation. The purpose of this work was to review recent studies that have investigated and characterized the changes in sputum cell counts occurring in patients with occupational asthma, in order to evaluate the role of the analysis of sputum cell counts.

Recent findings There is evidence that monitoring sputum eosinophils can help in the management of asthma. In the majority of cases of occupational asthma, the percentage of sputum eosinophils increases after exposure to occupational agents in the laboratory compared with baseline, but an increase in sputum neutrophils has also been observed. The changes in airway inflammation occurring at the workplace have been less investigated, but indicate that there are significant changes in airway inflammation and especially sputum eosinophils when workers are exposed to a sensitizer at their workplace compared with periods away from the workplace.

Summary Induced sputum has successfully been used to manage patients with mild to moderate asthma. Its use is promising in occupational asthma, and its role in the investigation of occupational asthma needs to be better defined.

Department of Chest Medicine, Sacré-Cœur Hospital, University of Montreal, Montreal, Quebec, Canada

Correspondence to Catherine Lemière, MD, MSc, Department of Chest Medicine, Sacré-Coeur Hospital, 5400 West Gouin, Montreal, Quebec, Canada H4J 1C5 Tel: +1 514 338 2796; fax: +1 514 338 3123; e-mail:

© 2004 Lippincott Williams & Wilkins, Inc.