Abstract

Cases with COPD who fulfill the diagnostic criteria of chronic bronchitis have been shown to exhibit lower serum levels of complement complements C3 and C4 than healthy subjects, and this may indicate sustained complement activation as a result of recurrent respiratory tract infections. In this study, we aimed to investigate the possible correlations between serum levels of C3, C4, immunoglobulins and degree of emphysema among the cases with COPD of the bronchitic type. We studied 50 male cases admitted to COPD outpatient clinic who had chronic airway obstruction of the bronchitic type. 40 control cases taken in the study with similar ages and smoking habits. C3, C4, IgG, IgA, IgM, IgE levels were measured in case and control groups. Lung function tests and thorax HRCT investigations performed in case group. Degree of emphysema evaluated with thorax HRCT. Measured C3 and C4 serum levels were 126.92±24.5 and 29.42±6.88 mg/dL respective levels in control subjects 127.4±21.41 and 36.31±11.21 respectively). Significant correlations were observed between levels of C4 and incidence of respiratory tract infections, total emphysema score (TES), level of serum total IgE. There was positive correlation between incidence of infective exacerbations and TES. In conclusion, cases with chronic bronchitis who had lower levels of C4 were experiencing more frequent respiratory infections, tend to have more signs of indicative of emphysema in their thorax HRCT.