Study objectives: We examined the effects of glucocorticoids on airway inflammation and its association with the reversibility of airflow obstruction in response to oral glucocorticoid administration in patients with COPD.
Patients: Twenty-four male patients with smoking-related stable pulmonary emphysema without alpha1-antitrypsin deficiency and nine normal healthy volunteers.
Measurements: We measured the pulmonary function, the inflammatory cells, and the levels of eosinophil cationic protein (ECP), immunoreactive neutrophil elastase-alpha1-protease inhibitor (NE-alpha1-PI) complex, and interleukin (IL)-8 in sputum induced from patients with pulmonary emphysema in its stable phase before and after treatment with 20 mg oral prednisolone per day for 2 weeks.
Results: The eosinophil and neutrophil counts and the concentrations of ECP, NE-alpha1-PI complex, and IL-8 in the sputum were significantly increased at baseline. The eosinophil count at baseline was significantly correlated with the reversibility of airflow obstruction following treatment, and the treatment also significantly reduced the eosinophil numbers and ECP level in the sputum. In contrast, the increased neutrophil number and the concentrations of NE-alpha1-PI complex and IL-8 at baseline did not correlate with the reversibility and were not affected by treatment.
Conclusions: These findings suggest that the eosinophilic inflammation, not neutrophilic inflammation, in the airway is involved in the reversible part of the airflow obstruction in response to glucocorticoids in patients with pulmonary emphysema.