BACKGROUNDChronic obstructive pulmonary disease (COPD) is a progressive disease associated with a cellular inflammatory response mostly concerned with cigarette smoking. Chemokine receptors CCR1/5 play an important role in the inflammatory cells recruitment in the lung of COPD patients. The aim of this study was to determine the impact of cigarette smoking on the expression of CCR1/5 on inflammatory cells in induced sputum, and the relationship between the receptors expression and COPD severity.

METHODSDifferential cells in induced sputum were counted and the optical densities of CCR1 and CCR5 on inflammatory cells in induced sputum from COPD patients (n = 29), healthy smokers (n = 11), and nonsmokers (n = 6) were measured using immunocytochemistry. Concentrations of CCL3, the ligand of CCR1/5, in supernatant of induced sputum were detected by enzyme-linked immunosorbent assay.

RESULTSThe expressions of CCR1 and CCR5 on inflammatory cells in healthy smokers were significantly higher than those in nonsmokers, and the expression of CCR1 in patients with COPD was significantly increased when compared with nonsmokers but not healthy smokers. The expressions of CCR1 and CCR5 on inflammatory cells in severe and very severe COPD patients were higher compared with mild and moderate COPD patients. CCL3 level was positively correlated with the total cell counts in induced sputum and smoking history, and negatively correlated with percentage of predicted FEV(1).

CONCLUSIONSCigarette smoking could increase the expression of CCR1 on the inflammatory cells. Both CCR1 and CCR5 expressions on the inflammatory cells in induced sputum could be associated with COPD severity.