Decreased levels of myeloperoxidase in induced sputum of patients with COPD after treatment with oral glucocorticoids

Background: Inhaled glucocorticoids may decrease exacerbations in some patients with COPD, and oral glucocorticoids may improve FEV1 and shorten hospital stay during exacerbations. The mechanism of these improvements is unknown. This study examines the effect of oral glucocorticoids on markers of neutrophilic airway inflammation. Methods: Eighteen patients with COPD received oral prednisone, 0.5 mg/kg/d for 2 weeks. Clinical status, lung function measurements, and sputum induction were performed before and after treatment with oral prednisone. Levels of the neutrophil chemoattractant (interleukin-8 [IL-8]) and neutrophil activation marker (myeloperoxidase [MPO]) were measured in the supernatant of induced sputum by enzyme-linked immunosorbent assay. Results: Levels of MPO decreased significantly after treatment with prednisone (p = 0.0004): before treatment median, 2.54 mug/mL (range, 1.49 to 12.58 mug/mL); after treatment median, 1.79 mug/mL (range, 1.32 to 3.57 mug/mL). Treatment with prednisone did not influence the levels of IL-8. Conclusions: The treatment of patients with COPD with oral glucocorticoids decreases the activation of neutrophils, which may be partially responsible for clinical improvement in these patients.