Assessment of airways inflammation in chronic bronchitis.

Chronic bronchitis is a clinical syndrome, defined on the basis of sputum production [1, 2]. Investigations have demonstrated that airway inflammation is central to the clinical changes associated with chronic bronchitis. Histological investigations of surgical and autopsy specimens have provided material to determine the site and nature of the airway inflammation. Sampling of the airways via flex ible fibreoptic bronchoscopy has also advanced understanding of the nosology and cell biology of airway inflammation, and promises to provide a means for rational assessment of therapeutic interventions. Histological investigations of resected lungs, and lungs obtained at autopsy, have correlated the presence of airways inflammation with airways obstruction in chronic bronchitis. In studies reported by Costo et al. [3], airway inflammation was found to be a distinguishing characteristic in the airways of smokers with obstruction, compared to smokers without obstruction. More recently, these findings have been confirmed by MUUEN et al. (4], who demonstrated that airway Infl ammation correlated with hypertrophy of mucous glands and best distinguished smokers with chronic bronchitis from smokers without chronic bronchitis. Thus, pathological investigations confirm the central role of airways inflammation in the clinical manifestations of chronic obstructive. pulmonary disease (COPD). However, pathological investigations are obviously limited in their applicability for testing of therapeutic modalities directed towards ·the treatment of airways inflammation. Sputum has been used for assessment of airways inflammation in chronic bronchitis [5]. In particular, sputum cytology has been used to determine the presence or absence of intraluminal neutrophilia, and can, to some degree, assess the intensity of the inflammation. Moreo· ver, mediators of airways inflammation can be assessed in sputum [6, 7]. However, measurements in sputum are limited by several factors. Sputum is not available from normal individuals. The collection of expectorated spu· tum is inevitably associated with contamination by oral contents. Sputum is very heterogeneous. Finally, quanti-