Eurasian Journal of Pulmonology, vol.26, no.1, pp.20-27, 2024 (ESCI)
BACKGROUND AND AIM: Chronic Obstructive Pulmonary Disease (COPD) is a respira - tory condition characterized by a chronic inflammatory response and is a common cause of mortality. Recent studies have begun to elucidate the role of the complement system in the pathogenesis of COPD. The primary goal of COPD treatment has been symptom control, but the importance of phenotypic assessments and classifications in COPD management is re-emerging. In this study, we investigate the association between the phenotypic charac - teristics and course of COPD and the complement system, focusing on serum Complement Component 3 (C3) levels. METHODS: The study included 81 patients. To measure complement C3 levels, a single tube of blood was collected from each participant. Body Mass Index (BMI), COPD Assessment Test (CAT), and modified Medical Research Council (mMRC) dyspnea scale were calculated. He- mograms, pulmonary function tests, and lung tomography scans were retrospectively reviewed. RESULTS: An increase in neutrophil predominance in serum was observed in advanced grades of COPD during stable periods. Lymphocyte counts and percentages were lower in advanced grades (p=0.041, p=0.016, p=0.032). Higher C3 levels were found in the group with a higher neutrophil count (p=0.032). The mean C3 level was higher in the high BMI group (p=0.049). Tomography scans were available for 55 patients. A lower mean C3 level was ob - served in the group with increased emphysema percentage, though the difference was not significant. The COPD grade, Forced Expiratory Volume in 1 second (FEV1) value, CAT-mMRC score, smoking status, exacerbation frequency, and inhaled steroid use did not show a signif- icant correlation with C3 levels.