A novel insight into adaptive immunity in chronic obstructive pulmonary disease: B cell activating factor belonging to the tumor necrosis factor family.

Rationale: Chronic obstructive pulmonary disease (COPD) is a disorder characterized by an abnormal inflammatory response that persists even after smoking cessation, yet the underlying mechanisms are not fully understood.Objectives: To investigate the expression of B-cell activating factor of tumor necrosis factor family (BAFF), a crucial mediator in the crosstalk between innate and adaptive immune responses, in patients with COPD and to explore its correlation with disease severity.Methods: Using immunohistochemistry, expression of BAFF was examined in lung specimens from 21 smokers with COPD (FEV1 = 57 ± 5% predicted), 14 control smokers (FEV1 = 99 ± 2% predicted) and 8 nonsmokers (FEV1 = 104 ± 4% predicted). BAFF was quantified in alveolar macrophages and alveolar walls, in bronchiolar and parenchymal lymphoid follicles, and in peripheral airways and pulmonary arterioles.Measurements and Main Results: In alveolar macrophages and parenchymal lymphoid follicles, BAFF expression was increased in smokers wi...