Relation of sputum inflammatory markers to symptoms and lung function changes in COPD exacerbations.

BACKGROUND: Although it is presumed that exacerbations of chronic obstructive pulmonary disease (COPD) are associated with increased airway inflammation, there is little information available on inflammatory markers during an exacerbation and the relationship with severity or time course of recovery. A study was undertaken to investigate the sputum cell and cytokine characteristics of COPD when stable and during an exacerbation. METHODS: Induced sputum samples from 57 patients with moderate to severe COPD were analysed (44 samples were taken during a stable period and 37 during an exacerbation). The patients recorded daily symptoms on diary cards. Cell counts and sputum levels of interleukin (IL)-6 and IL-8 were measured. RESULTS: Patients with >/=3 exacerbations/year had higher median stable sputum levels of IL-6 (110 (95% CI 11 to 215) pg/ml) and IL-8 (6694 (95% CI 3120 to 11995) pg/ml) than those with