Role of T-Cells in Asthma

In the last 10 years it has become generally accepted that asthma is an inflammatory disease of the airways. T lymphocytes play a key role in regulating this inflammatory response, through the elaboration of cytokines such as IL-4, IL-5, and IFN-gamma. IL-5 is of particular interest because it is the major eosinophil survival factor in vivo. Eosinophils are felt to be the major effector cells in asthma, causing damage to various airway structures. The pulmonary late phase response, a worsening of airflow seen 4-8 hours after allergen inhalation, is associated with many of the inflammatory changes seen in chronic asthma. Current studies suggest that during the late phase response peripheral blood T cells traffic to the lungs and express cytokines, specifically IL-4 and IL-5. We propose to investigate this trafficking by determining the frequencies and phenotype of cells capable of producing the above cytokines in the peripheral blood in subjects with mild allergic asthma. These studies should lead to a clearer understanding of the cells and processes that lead to T cell trafficking to the lung and may yield a tool to evaluate the proposed anti-inflammatory therapies for asthma.