Immunological Basis for Mepolizumab Activity in COPD

The investigators will recruit a total of 30 Chronic Obstructive Pulmonary Disease (COPD) participants from the Temple University Hospital Lung Center Clinic. All participants will have moderate to severe COPD and have a history of 2 or more acute exacerbations in the past year, and eosinophil counts of greater than 300 cells/ul. The investigators studies will include an analysis of the status of the systemic and lung inflammatory phenotype of the major leukocyte populations, using multiparameter flow cytometry. The investigators will couple these studies with an analysis of a panel of inflammatory and anti-inflammatory biomarkers in both the blood and bronchoalveolar lavage fluid. Very importantly, the investigators will characterize the functional capacity of T cells, B cells, monocytes, and granulocytes during drug therapy. By using this approach, the investigators believe a more complete understanding of the scope of activity of mepolizumab at the level of immune competence will be developed.