This study involves a comparison of the inflammatory responses of leukocytes derived from 3 separate subject groups. The aim of the study is to compare the responses of leukocytes from patients with COPD with subjects that smoke and healthy non-smokers. One part of the study will involve isolation of different leukocyte populations from blood from each of the subject groups. In a second part of the study, we will examine the expression of inflammatory mediators in leukocytes derived from bronchoalveolar lavage samples from patients with COPD, smokers without COPD and healthy non-smokers. In subjects that are willing to participate, we will compare blood derived leukocytes and cells derived from those undergoing BAL, although not every subject will provide both blood and BAL samples. The isolated leukocytes (both from blood and BAL) will be used for in vitro experiments to determine the differences in gene expression in inflammatory cells from patients with COPD.