Induced Sputum Genes Associated With Spirometroc and Radiological Disease Severity in COPD Ex-smokers

Induced sputum is used to sample inflammatory cells, predominantly neutrophils and macrophages, from the airways of COPD patients. Our aim was to identify candidate genes associated with the degree of airflow obstruction and the extent of emphysema by expression profiling, and then to confirm these findings for selected candidates using specific PCR and protein analysis. Two sputum studies were performed in GOLD stage 2 -4 COPD ex-smokers from the ECLIPSE cohort. First, gene array profiling at baseline in 1480 patients was performed. At year 1, samples from a separate population of 176 patients were used for real-time PCR. The gene expression findings for IL-18R were further analysed using immunohistochemistry in lung tissue and induced sputum samples from patients outside the ECLIPSE cohort.