Intraluminal Airway Inflammation in Chronic Bronchitis: Characterization and Correlation with Clinical Parameters

Abstract

In order to characterize intraluminal airway inflammation in subjects with chronic bronchitis, bronchoscopy and bronchoalveolar lavage were performed in 28 subjects with chronic bronchitis with fixed airway obstruction and, for comparison, 15 asymptomatic smokers and 25 normal nonsmoking volunteers. The chronic bronchitics had a cough productive of sputum on most days of the month for 6 months in the preceding 2 yr, had at least one exacerbation requiring medical intervention in each of the previous 2 yr, and had an FEV1 less than 76% of predicted without response to bronchodilator. During bronchoscopy the airways were assessed for visual evidence of inflammation by assigning them a score, the bronchitis index, that graded the airways according to the apparent severity of airway edema, erythema, friability, and secretions. Bronchoalveolar lavage was performed by sequentially instilling and retrieving with gentle suction five 20-ml aliquots of sterile normal saline into each of three separate lobes. The first aliquots, the "bronchial" sample, were pooled and processed separately from the final four aliquots, the "distal" sample. Cell counts, cell differentials, and albumin were determined for both the bronchial and distal samples. In order to correlate inflammation with clinical parameters, sputum was collected for 24 h prior to bronchoscopy; spirometry was performed just prior to bronchoscopy, and smoking histories were obtained. Visual inspection of the airways, as quantified by the bronchitis index, demonstrated significantly more evidence for inflammation in the chronic bronchitics than in either the asymptomatic smokers or the normal subjects. The bronchial sample lavage fluids from the chronic bronchitics tended to contain more cells (6.1 +/- 2.2 x 10(6) cells) than the bronchial sample fluids from the asymptomatic smokers (3.6 +/- 0.6 x 10(6) cells) or normal subjects (3.7 +/- 0.5 x 10(6) cells). Furthermore, the chronic bronchitics had a higher percentage of neutrophils in their bronchial lavage fluid (35.8 +/- 5.6%) than did either the asymptomatic smokers (20.7 +/- 2.6%, p = 0.0001) or the normal subjects (10.3 +/- 5.6%). The distal sample lavage fluid also recovered more neutrophils from both the chronic bronchitics (15.0 +/- 4.2%, p = 0.0012) and asymptomatic smokers (5.7 +/- 1.3%, p = 0.002) than from the normal subjects (2.8 +/- 0.4%). The chronic bronchitics were divided into two groups: those with low (less than 20%) and those with high (greater than 20%) bronchial sample neutrophils. Those with higher bronchial sample neutrophils had significantly more sputum production and lower FEV1, FEV1/FVC, and FEF25-75 than did the subjects with lower bronchial sample neutrophils.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of 1-year smoking cessation on airway inflammation in COPD and asymptomatic smokers

“…Sputum volume, total cells, percentage of sputum neutrophils and sputum IL-8 levels in COPD were significantly higher than in asymptomatic smokers. This is in line with previous studies that have shown that neutrophils and IL-8 levels in BAL and induced sputum are higher in smokers with COPD than without COPD [34][35][36]. In bronchial biopsies, the number of macrophages, neutrophils and CD8-positive cells are increased in smokers with COPD compared with smokers without COPD, especially in more severe COPD patients [37,38].…”

Subepithelial immunopathology of the large airways in smokers with and without chronic obstructive pulmonary disease

“…The discordance of these results with those showing an increase in numbers of neutrophils and markers of neutrophil activation in bronchoalveolar lavage [10,11,13,14,25], induced sputum [26±28] and airway epithelium [29] remains to be explained.…”

The Importance of Chronic Bronchitis in Chronic Obstructive Pulmonary Disease

“…Consistently, research has highlighted the importance of the neutrophil in the pathogenesis of COPD and chronic bronchitis. Patients with chronic bronchitis and COPD have increased numbers of neutrophils in proximal airway secretions (78,79) and broncheoalveolar lavage fluid (BALF) (80) compared with asymptomatic smokers, and numbers increase with increasing disease (81,82). Airway neutrophil numbers are also raised in patients with chronic bronchitis without COPD, although less so than when airflow obstruction is present (83).…”