CHRONIC OBSTRUCTIVE PULMONARY-DISEASE - ROLE OF BRONCHIOLAR MAST-CELLS AND MACROPHAGES

Chronic obstructive pulmonary disease (COPD) is considered to be cause d in part by smoking-induced inflammation, but it is unknown which inf lammatory cells within the small airways are associated with the obstr uction. We investigated the inflammatory infiltrate in the small airwa ys of 16 current or ex-smokers with COPD (FEV, less than or equal to 7 5% predicted) and 15 without COPD (FEV1 greater than or equal to 85% p redicted) in pneumectomy specimens that were removed for lung cancer, Mast cells, macrophages, neutrophils, eosinophils, T cell, and B cells were identified using immunohistochemistry on formalin-fixed, paraffi n-embedded specimens. These cells were quantified in the epithelium an d the remainder of the airway wall. The number of mast cells and macro phages in the epithelium, but not in the remainder of the airway wall, was significantly increased in patients with COPD, Neutrophil and T c ell numbers did not differ between the groups. Only few B cells and eo sinophils were present in both groups, Smoking history, perioperative steroid usage, tumor localization, or reversibility in the FEV1 to sal butamol could not account for the observed differences. We conclude th at the number of epithelial mast cells and macrophages is increased in the bronchioli in smokers with airflow limitation, suggesting a role in development of COPD.