Induced sputum eosinophils in the assessment of asthma and chronic cough.
OBJECTIVE
To evaluate induced sputum eosinophils in asthma and chronic cough.


METHODS
This was an analytical, cross-sectional study set in an ambulatory respiratory clinic.


METHODS
Subjects (n=75) referred for evaluation of symptomatic asthma or episodic respiratory symptoms had a clinical assessment, spirometry, hypertonic saline challenge and induced sputum. Two diagnostic groups were identified. The first group comprised subjects with symptomatic asthma and variable airway obstruction (VAO) (n=32). The second group included subjects with episodic respiratory symptoms and no VAO (n=43).


RESULTS
The prevalence of eosinophilic bronchitis (eosinophils >2.75%) was greatest in asthma (n=14, 44%), compared to the episodic respiratory symptoms group (n=9, 21%, P = 0.02). Clinical variables did not predict increased eosinophils (P > 0.05). Sputum eosinophils were highest in asthmatics not using inhaled corticosteroids (6.5% vs 0.5%, P = 0.02). Sputum neutrophils were higher in subjects using inhaled corticosteroid (53% vs 25%, P = 0.04).


CONCLUSIONS
Airway inflammation with eosinophilia was common among patients presenting to a respiratory clinic, especially those with asthma who were not using inhaled corticosteroids. Induced sputum also identified eosinophilic bronchitis in those without asthma. It was not possible to detect the presence or absence of airway eosinophilia by routine clinical assessment. The results in this study imply that the assessment of induced sputum eosinophils may be a useful guide to therapy, especially in the assessment of persistent symptoms in asthmatics on corticosteroids, and in the assessment of non-asthmatic subjects with symptoms.
Wark
P A
PA
Airway Research Centre, Department of Respiratory and Sleep Medicine, John Hunter Hospital, New South Wales, Australia. pwark@mail.newcastle.edu.au
Gibson
P G
PG
Fakes
K
K
D000280:Administration, Inhalation; D001249:Asthma / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology; D001980:Bronchi / Q000473:pathology; D001985:Bronchial Provocation Tests; D002452:Cell Count; D002908:Chronic Disease; D003371:Cough / Q000473:pathology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D004804:Eosinophils; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008407:Mast Cells; D008875:Middle Aged; D009504:Neutrophils; D013147:Spirometry; D013183:Sputum / Q000166:cytology*
D005938:Glucocorticoids