Objective: To study whether patients with chronic obstructive pulmonary disease (COPD) at the same level of flow limitation but with different clinical phenotypes present different degrees of systemic and/or pulmonary inflammation.
Patients and methods: We studied 15 male smokers without COPD (control group) and 39 males with COPD in stable clinical condition. The COPD patients were assigned to 2 groups based on the ratio of carbon monoxide diffusing capacity (DLCO) to alveolar volume (DLCO/VA) expressed as a percentage as follows: a) mainly emphysema (n = 15) and b) mainly chronic bronchitis (n = 24). Classification was determined by comparing both clinical features and diagnostic images.
Results: Mean (SD) concentrations of interleukin 8 (IL-8) and 8-isoprostane in exhaled breath condensate (EBC) were significantly lower in patients with mainly emphysema (IL-8, 0.34 [0.70] pg/mL; 8-isoprostane, 0.07 [0.26] pg/mL) than in patients with chronic bronchitis (IL-8, 2.32 [3.10] pg/mL; 8-isoprostane, 1.77 [2.98] pg/mL) or in the controls (IL-8, 3.14 [4.59] pg/mL; 8-isoprostane, 1.92 [2.84] pg/mL); P < .05 for IL-8 comparisons and P < .01 for 8-isoprostane. IL-8, leukotriene B4, and 8-isoprostano in EBC correlated significantly with DLCO/VA (% of predicted) (r = 0.30, P < .05; r = 0.29, P < or = .05; and r = 0.46, P < .01, respectively) but not with forced expiratory volume in 1 second. There was a negative correlation between EBC and serum levels of both IL-8 (r = -0.31; P < .05) and 8-isoprostane (r = -0.51; P < .001). The correlation between leukotriene B4 concentrations in EBC and serum was not significant, however. No significant differences were found between smokers' and ex-smokers' serum levels of IL-8, leukotriene B4, 8-isoprostane in serum or EBC.
Conclusions: The results indicate that COPD patients with an emphysematous phenotype have a less intense inflammatory response and less oxidative stress in the lung.