Abstract: Objective By observing the serum level changes and their correlations of Interleukin-17(IL-17) and C reactive protein(CRP) in patients with chronic obstructive pulmonary disease(COPD) at acute exacerbation phase and stable phase，to investigate the role of IL-17 and CRP in pathogenesy of COPD in order to offer evidence for the judgement of illness state and treatment of COPD.Methods The serum levels of IL-17 and CRP were determined in 100 COPD patients at acute exacerbation phase and stable phase by double antibody enzyme-labeled immunosorbent assay (DA-ELISA) . Pulmonary function of all research subjects were tested and calculated for the percentage of FEV1 in prediction value (FEV1%Pre). Results The serum level of IL-17 and CRP in COPD patients at acute exacerbation phase was significantly higher than that at table phase(P<0．01). The serum levels of IL-17 were in negative correlation with FEV1%Pre in COPD patients at acute exacerbation phase, coefficient of correlation r=-0.437, P<0.05；IL-17 were in positive correlation with CRP at acute exacerbation phase, coefficient of correlation r=0.582, P<0.05；at stable phase，coefficient of correlation r=0.481, P<0.05.Conclusions IL-17 might be associated with pathogenesy of COPD,especially play an role of acute exacerbation.It can substitute CRP to monitor the activity of COPD.

Key words: Chronic obstructive pulmonary disease, Interleukin-17, C reactive protein, FEV1