[Role of interleukin-9 in the pathogenesis of chronic obstructive pulmonary disease].

OBJECTIVE: To study the role of interleukin-9 in the airway inflammation from patients with COPD. METHODS: Induced sputum was obtained from 30 COPD patients with stable disease(group A),31 asthmatics patients with stable disease(group B) and 15 healthy individuals(group C). IL-9,IL-5 and IL-8 in sputum supernatants were measured by sandwich enzyme-linked immunosorbent assay(ELISA) and IL-9 positive expression and quantitative analysis were conducted by Streptavidin peroxidase method and image analysis technology. RESULTS: The levels of IL-9 in group A and B were all significantly higher than those in groups C. IL-9 positive expression mainly located in the cytoplasm of macrophages. The positive rates of IL-9 in group A and B were all significantly higher than that of group C (chi(2)=20.821, 19.908, P<0.001 . The percentage of neutrophil and the level of IL-8 in group A was significantly higher than those of groups B and C. The level of IL-9 was positively correlated with the number of macrophages in group A(r=0.407,P=0.039). CONCLUSION: The level of IL-9 from the patients with COPD was significantly higher than that of healthy individuals and correlated with the number of macrophages and the level of IL-8. This suggests that IL-9 may be used as a new diagnostic marker in airway inflammation of COPD.