The relative importance of the eosinophilia re-mains to be determined, but several eosinophil products maycause inflammatory damage to the airway (eosinophil peroxi-dase, major basic protein, eosinophil cationic protein, metallo-proteinases, platelet activating factor, and cysteinyl leukotrienes)(75) and, together with histamine, can cause bronchospasm

Patients with mild to moderate COPD exacerbations show anincreased number of eosinophils in their bronchial mucosa (72).Although this suggests an “asthmatic profile,” the observed eo-sinophils are not degranulated (as they would be in asthma) andare not associated with increased IL-5 expression (72).