Allergic asthma (AA) is a complex disorder with heterogeneous features of airway hyperresponsiveness, inflammation, and remodeling. The increase of airway smooth muscle (ASM) mass is a fundamental component of bronchial remodeling in AA, yet the pathophysiological mechanisms and clinical outcomes associated with ASM modulation are still elusive. The objective of this study is to compare the expression level of β-dystroglycan (β-DG) in ASM in AA subjects and a healthy control group and to investigate the relationship between eosinophils and β-DG in ASM in patients with AA. Thirteen AA patients and seven control subjects were analyzed for the ASM area and eosinophil cells. Bronchial biopsies were stained by β-DG and eosinophil cationic protein (ECP) using immunohistochemistry. The proportion of ASM with β-DG staining was greater in those with AA than in the healthy control group (mean (95% CI) (28.3% (23.8-32.7%) vs. 16.4% (14.1-18.5%), P < 0.0001). The number of ECP positive cells was higher in patients with AA than in the control group (4056 (3819-4296) vs. 466 (395-537) cells/mm2 P < 0.0001). In AA, the number of ECP positive cells was significantly correlated to the β-DG expression in ASM (r = 0.77, P = 0.002). There is an increased β-DG expression in ASM and a higher number of ECP positive cells in the bronchial biopsy of those with AA than those in the control group. The increased expression of β-DG in ASM in AA subjects correlates with the number of eosinophils, suggesting a role for this cell in airway remodeling in AA.
Keywords: airway smooth muscle; allergic asthma; eosinophil; inflammation; remodeling; β-dystroglycan.