Introduction: Airway inflammation and remodeling are well recognized features of asthma. Remodeling is usually regarded as a consequence of chronic inflammation, however there are also data suggesting that remodeling is a relatively independent process in asthma. Neither inflammation nor remodeling is a uniform process. Thus the precise relationship between markers of inflammation and different patterns of remodeling are still matter of investigations. The aim of the study was to assess the relationship between total and differential cell count in induced sputum (IS) and BALF, and thickness of the basement membrane (BM) in patients with stable asthma.
Material and methods: 18 patients with asthma (M/F 9/9, mean age 36 +/- 15 yrs). Duration of symptoms amounted to 12.7 +/- 11.5 years. Patients who have not been treated with steroids for at least 3 months were enrolled to the study. All patients underwent sputum induction and fiberoptic bronchoscopy with BAL and bronchial biopsies. Total and differential cell counts were measured in induced sputum and BALF. Light-microscopic measurements of BM thickness were performed in hematoxylin-eosin stained slides of bronchial wall specimens with semi-automatic software analysis.
Results: Mean BM thickness was 12.9 +/- 2.8 microm (range: 8.5-20.7 microm). Total sputum cell count was 3.4 +/- 2.7 x 106 cells/ml, whereas in BALF 9.7 +/- 10.2 x 106 cells/ml. There was no correlation between differential cell count in induced sputum and BALF. No significant correlations between BM thickness and total and differential cell count in IS and BALF were observed. There also was no correlation between BM thickness and length of asthma duration or degree of the disease.
Conclusions: There was no relationship between BM thickness and total number of cells nor number of eosinophils in BALF and/or IS.