Abstract
Background
Little research has been devoted to the characteristics of bronchial inflammation in patients with stable, well-controlled asthma.
Objective
The aim of this study was to assess the degree and type of airway inflammation and investigate the relationship between inflammation and bronchial hyperresponsiveness in patients with well controlled asthma.
Methods
A cross-sectional study was conducted in 84 adult patients (43 men, mean age 43 years) with documented well-controlled asthma. Induced sputum samples were obtained and cell types determined by differential cell count. Spirometry and methacholine challenge testing were performed. Asthma Control Questionnaire (ACQ) was used to assess symptoms. Patients were included if their ACQ score was < 0.75.
Results
Fifty-nine patients had persistent bronchial inflammation: 28 cases were considered eosinophilic, 28 neutrophilic, and 3 mixed. Median (range) percentage of eosinophils was 4% (0-64) in patients testing positive to methacholine challenge (n=66) and 1% (0-3) in those testing negative (n=18) (p=0.003). A positive correlation was found between eosinophil percentage and the methacholine dose/response ratio (r=0.477, p=0.0001). The geometric mean (95% CI) of the methacholine PC20 was 1.74 mg/mL (1.04-2.93) in patients with eosinophilic inflammation and 4.14 mg/mL (2.5-6.84) in neutrophilic inflammation (p=0.03).
Conclusions
Inflammation and bronchial hyperresponsiveness persist in most patients with well-controlled asthma.
© 2012 Blackwell Publishing Ltd
No comments:
Post a Comment