Granzymes and Perforin at the Onset of Chronic Obstructive Pulmonary Disease (COPD) Exacerbations

COPD exacerbations are characterized by an excessive accumulation and activation of inflammatory cells in the airways. It is not known whether this phenomenon represents a risk for for lung damage via the release in the extracellular environment of potent cytolitic cellular granular contents such as granzymes and perforin. The investigators assess the intracellular expression of granzymes and perforin in neutrophils and large granular lymphocytes (LGL) at the onset of exacerbations compared to stable disease. The investigators hypothesize that a greater release of intracellular perforin and granzymes from neutrophils and LGL into the extracellular environment occur at exacerbations compared to stable condition and that these changes are more pronounced in COPD patients than in subjects without COPD who undergo respiratory infection.