Comparison of Protein Profiles in Sputum between COPD and Acute Exacerbation of COPD

Background and objective: Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation that is associated with an abnormal inflammatory response of the lung to noxious particles or gases. Cigarette smoking is the major risk factor for the development of COPD. This study evaluated the levels of cyclophilin B in sputa from patients with COPD and COPD with acute exacerbation (AECOPD). Materials and Methods: Two-dimensional electrophoresis was used for differential display proteomics. Western blotting was used to identify and quantify cyclophilin B in sputum from subjects with AECOPD and COPD. Results: Forty-nine protein spots differed in relative intensity between the AECOPD (n = 6) and COPD (n = 6) subjects. Twenty proteins showed increased expression in the sputum of AECOPD subjects, and 29 proteins were present at lower levels in AECOPD sputum compared with COPD sputum. One of these proteins was associated with cyclophilin B. Cyclophilin B concentrations were lower in sputum from subjects with COPD (n = 4) versus AECOPD (n = 4). Conclusion: The sputum proteomic analysis suggests that changes in various proteins are associated with the development of AECOPD.