Changes in the broncho-alveolar lavage fluid in smokers and patients with chronic obstructive lung disease.

Direct contact of the cells normally present in the bronchial lumen, such as alveolar macrophages, with air pollutants (e.g. cigarette smoke) can lead to the activation of these cells. This activation is beneficial for the cleaning task these cells have in the bronchial tree, but also leads to the release of chemotactic substances, toxic oxygen radicals, enzymes and mediators responsible for bronchial obstruction. As a first step in these processes, an enhanced chemotactic activity can attract neutrophils to the bronchial lumen, where they help by cleaning the lungs from possible dangerous intruders, but can also cause damage to the normal lung architecture. In the present study concerned with the pathogenesis of chronic obstructive lung disease (COLD), broncho-alveolar lavage (BAL) was performed in 35 individuals, who could be divided on he basis of their history and lung function into normal/nonsmokers, normal/smokers, COLD-patients/nonsmokers and COLD-patients/smokers. Neutrophilic chemotactic activity was assayed using Boyden chambers where the patients' own neutrophils were tested. More neutrophils and more neutrophilic chemotactic activity were found in the BAL-fluid of the smokers and COLD-patients. A correlation was demonstrated between the amount of chemotactic activity released during the incubation of cells obtained by BAL and the airway resistance or the airway conductance. These data suggest an enhanced chemotactic activity as one of the initiating factors in the pathogenesis of chronic obstructive lung disease.