The theme of this Specialized Center of Research (SCOR) in chronic disease of the airways is the role of hyperreactivity in chronic obstructive pulmonary disease (COPD). It is an interdisciplinary study bringing together basic scientists in immunology and physiology with clinical investigators in allergy and pulmonary medicine. The work proposed is an attempt to understand the connections between allergy, airways hyperreactivity, asthma, and COPD. The fundamental hypothesis on which the proposed work is based is that common to all forms of allergy, airways hyperreactivity, and asthma is the excessive release of chemical mediators from mast cells in a complex inflammatory process. Project I, The Response of the Nasal Mucosa to Hyperventilation with Cold, Dry Air, uses the human nose as a possible model of what is going on in the smaller airways that is responsible for the symptoms of asthma and COPD. Project II, Responses of the Lung Periphery to Dry Air and to Antigen, uses the peripheral airways of the dog to gain insight into what might be occurring in human airways disease. Project III, Relationship Between Mediators of Immediate Hypersensitivity and Cellular Inflammation in the Pathophysiology of Asthma and Obstructive Airways Disease, is concerned with inflammatory cells and mediators obtained from bronchoalveolar lavage in human subjects with and without airways hyperreactivity, asthma, and allergy. Project IV, Mechanism of the Antiasthmatic Action of Glucosteroids, uses antiinflammatory steroids to gain insight into the role of inflammation in allergy, airways hyperreactivity, and asthma. Project V, Human Basophil Activation by IgE-Dependent Factors, is a study of the effect of factors derived from the macrophage that cause mediator release from basophils and mast cells through IgE-dependent mechanisms. Core A, Mediator/Cell Core will characterize the inflammatory cells, and mediators for all of the projects. Core B, Administration, Clinical Physiology, and Data Management, will coordinate administration, data management, and statistical consultation for all of the projects and will recruit and characterize all human subjects used for clinical investigation.