Inflammatory cells and mediators in bronchial lavage of patients with chronic obstructive pulmonary disease

Abstract

Cigarette smoking is the most important cause of chronic obstructive pulmonary disease (COPD). Although the precise sequence of events that leads a smoker to experience airway obstruction is not completely clear, airway inflammation is a relevant factor. To investigate airway inflammation, 12 nonatopic smoking COPD patients with a forced expiratory volume in one second (FEV1) < or = 75% predicted and 10 normal nonsmoking subjects (NS) were studied with bronchoscopy and bronchial lavage (BL). Serum immunoglobulin (Ig)E levels of COPD patients correlated with the smoking history (r=0.7, p=0.008). In BL of COPD patients there was an increase of neutrophils (median, range) (COPD 62.6x10(3), 1.2-323, NS 1.35, 0-19.2, p=0.001), eosinophils (COPD 1.6, 0-6.9, NS 0.15, 0-3.7, p=0.035), the levels of interleukin (IL)-8 (COPD 1079 pg x mL(-1), 121-2,500, NS 20.4, 7.2-59, p=0.001), myeloperoxidase (MPO) (COPD 752 microg x L(-1), 11-5,500, NS 22.1, 8-70, p=0.001) and eosinophil cationic protein (ECP) (COPD 21.5 microg x L(-1), 1.8-161, NS 2, 1.8-4.9, p=0.001). Significant correlations were found in BL of COPD patients between IL-8 and neutrophils (p=0.02), MPO and neutrophils (p=0.02), IL-8 and MPO (p=0.0001) and ECP and eosinophils (p=0.02). In addition, the ratios between the BL levels of MPO and the number of neutrophils and between ECP levels and eosinophils were higher in COPD patients than in NS (p=0.03 and 0.01, respectively). These data suggest that cigarette smoke is associated with increased amounts of airway interleukin-8, a chemotactic factor for neutrophils and eosinophils. Recruited neutrophils and eosinophils are activated and they release increased amounts of inflammatory mediators capable of damaging the bronchial tissue.