Abstract
Background
In asthma the association between airway inflammation, airway remodelling, determined in bronchial biopsies; and lung physiology is unclear.
Methods
Patients with moderate-to-severe persistent asthma and sputum eosinophilia (>2%) underwent endobronchial sampling, spirometry, lung plethysmography and impulse oscillometry. Airway biopsies were examined for airway smooth muscle (ASM) content (ASM%), reticular basement membrane (RBM) thickness and inflammatory cells counts (cells/mm2 of submucosa) for eosinophils, T-lymphocytes, neutrophils and mast cells.
Results
34 patients were recruited. ASM% was negatively correlated with both pre-bronchodilator (rs= -0.446, p=0.008) and post-bronchodilator FEV1/FVC and (rs= -0.445, p=0.008); but no correlation with oscillometry indices or inflammatory cell counts. RBM thickness did not correlate with submucosal inflammatory cell counts or physiological indices. Submucosal eosinophils were positively correlated with CO transfer coefficient (KCO) (rs= 0.381, p=0.026), and R5 (rs= 0.441, p=0.009).
Conclusion
Increased ASM% and submucosal eosinophils were associated with airflow obstruction and resistance respectively. Whether resistance measures are a sensitive measure of response to anti-eosinophilic therapies requires further study.
Acknowledgements: Work funded by Novartis Pharmaceuticals.
- © 2014 ERS