Increased number of B-cells in bronchial biopsies in COPD

Recently, it has been shown that the accumulated volume of B-cells in small airways is increased in chronic obstructive pulmonary disease (COPD) Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages 3 and 4. Little is known about the number of B-cells in central airways in COPD. The present authors hypothesised that the number of B-cells in bronchial biopsies of large airways is higher in patients with COPD than in controls without airflow limitation and higher in more severe COPD. Therefore, bronchial biopsies were collected from 114 COPD patients (postbronchodilator forced expiratory volume in one second (FEV1) 63 +/- 9 % predicted value, FEV1/inspiratory vital capacity (IVC) 48 +/- 9%) and 28 controls (postbronchodilator FEV1 108 +/- 12% predicted value, FEV1/IVC 78 +/- 4%). Paraffin sections were stained for B-cells (CD20+) and their number was determined in the subepithelial area (excluding muscle, glands and vessels). B-cell numbers were higher in patients with COPD versus controls (8.5 versus 3.9 cells center dot mm(-2), respectively) and higher in patients with GOLD severity stage 3 (n=11) than stage 2 (n=103; 22.3 versus 7.8 cells center dot mm(-2)). No relationship was found between the number of B-cells and clinical characteristics within the chronic obstructive pulmonary disease group. The authors suggest that these increased B-cell numbers may have an important contribution to the pathogenesis of chronic obstructive pulmonary disease.