The induced sputum IL-8 level and the PaCO2 were significantly higher, while the induced sputum IL-10 level, the FEV1%pred, the FEV1/FVC and the PaO2 were significantly lower in the three COPD groups compared with those in the control group (all P<0.01). The gene discussed is IL10; the disease is chronic obstructive pulmonary disease.