Pulmonary monocytes and macrophages are believed to function in a wide range of biological roles, including host defense against foreign organisms, maintenance of immunological homeostasis in the lung, presentation of antigen to lymphocytes, and migration to sites of tissue injury and inflammation (1). There is also mounting evidence that recruited blood monocytes and resident alveolar macrophages (AM) in lung disease express an activated phenotype, suggesting that they may play important roles in chronic respiratory diseases, including asthma and interstitial lung diseases (2-6).
