J Asthma Allergy Clin Immunol.
2001 Aug;21(4):628-635.
Relationship of airway sensitivity/reactivity with bronchial pathology in asthmatics
- Affiliations
-
- 1Department of Internal Medicine, Catholic University College of Medicine, Seoul, Korea.
Abstract
-
BACKGROUND: Airway hyperresponsiveness is expressed as the provocative dose or concentration of the stimulus required to achieve bronchoconstriction, a 20% fall in FEV1 (PD20 and PC20, respectively). A decrease in PC20 may be due to a steeper dose-response curve (hyperreactivity) or to a shift in the curve to the left (hypersensitivity), or both. It has been suggested that many factors, such as genetic factor, airway inflammation, epithelial damage or airway remodeling, are involved in the airway hyperresponsiveness in asthma.
OBJECTIVE
In this study, we analyzed the relationship of airway sensitivity and reactivity with bronchial inflammation and structural change in asthmatics.
METHOD: The PC20 for methacholine, as the airway sensitivity parameter, and the slope between PC20 and PC40, as the airway reactivity parameter, were measured. Total cell counts and differential cell counts in BAL fluid, percentage of epithelial shedding (ES), basement membrane thickness (BMT) and depth of submucosal collagen deposition (SMC) on bronchial tissue were measured. The patients (n=27) were divided into two groups by median values of ES, BMT, or SMC (32%, 7.3 micrometer, 68 micrometer, respectively).
RESULTS
The PC20 showed a significant correlation with baseline FEV1% (r=0.498, p<0.05), and was significantly lower in patients with over 32% of ES than in those with under 32% of ES (2.89+/-1.05 mg/ml vs 5.70+/-3.70 mg/ml, p<0.05). The slope was significantly steeper in patients with thicker BMT or SMC.
CONCLUSION
These results suggest that airway hypersensitivity is affected by airway caliber, and airway hyperreactivity is affected by bronchial remodeling in asthma.