High levels of interleukin-6 in the exhaled breath condensate of patients with COPD

Background: Chronic obstructive pulmonary disease (COPD) is characterised by chronic inflammation of the respiratory tract. Methods: We investigated the presence of interleukin-6 (IL-6: a cytokine secreted by monocytes/macrophages, T cells, B cells, fibroblasts, bone marrow stromal cells, keratinocytes and endothelial cells) in the exhaled breath condensate of 16 ex-smokers with moderate COPD, 12 healthy non-smokers. IL-6 was measured by means of a specific enzyme immunoassay. Results: IL-6 levels were detectable in all of the subjects, but were higher in the COPD patients (8.0+/-0.1 pg/ml; P<0.0001) than in the healthy non-smokers (4.9+/-0.2 pg/ml) with a correlation in this group between age and IL-6 levels (r = 0.597; P < 0.05). Conclusions: The increased IL-6 Levels in exhaled breath condensate may reflect airway inflammation in patients with COPD. (C) 2003 Elsevier Ltd. ALL rights reserved.