The Effects Of BAFF On T Lymphocytes In Chronic Obstructive Pulmonary Disease

Background:Chronic inflammation is one of the main characteristics of chronic obstructive pulmonary disease（COPD）and macrophages and T lymphocytes play an important role in the pathogenesis of COPD.B cell activating factor belonging to the tumor necrosis factor family（BAFF）has been reported to be increased in COPD patients but its role in COPD has not been clearly elucidated.Tremendous studies have indicated that BAFF has effects on T lymphocytes,therefore we investigated the effects of BAFF on T lymphocytes in COPD.Objective:To investigate the levels of BAFF in COPD patients and control,study its impact on the apoptosis and function of T lymphocytes from COPD patients.Methods:42 COPD patients,16 Nonsmokers without COPD and 36 Smokers without COPD were recruited.Clinical information（including lung function and medical history etc）and important basic information（including age,gender and smoking history etc）were recorded and peripheral blood and sputum of subjects were collected.BAFF was assessed in sputum cells and plasma.Peripheral blood monouclear cells（PBMCs）of COPD patients were isolated and treated with rh BAFF or rh BAFF plus BR3-Fc（BAFF antagonist）.Apoptosis of CD4⁺cells and CD8⁺cells was assessed by flow cytometry.CD4⁺cells and CD8⁺cells were respectively isolated from peripheral blood of COPD patients and treated with rh BAFF or rh BAFF plus BR3-Fc.Interferonγ（IFN-γ）and interleukin 4（IL-4）were detected in CD4⁺cells and perforin and granzyme B were detected in CD8⁺cells.Results:Compared with Nonsmokers and Smokers,BAFF of COPD patients was significantly increased in sputum cells and plasma and BAFF in plasma of COPD patients was negatively correlated with the FEV₁ percentage of predicted（FEV₁%pred）.BAFF significantly reduced the apoptosis of CD8⁺cells in COPD patients but did not alter the apoptosis of CD4⁺cells.BAFF significantly increased the expression of IFN-γin CD4⁺cells but had little effect on IL-4,and it increased the expression of perforin and granzyme B in CD8⁺cells of COPD patients.Conclusions:BAFF can reduce the apoptosis of CD8⁺cells of COPD patients.It can increase the expression of IFN-γin CD4⁺cells and perforin and granzyme B in CD8⁺cells in COPD patients.Therefore,BAFF may be involved in the inflammatory response through T lymphocytes and thus plays a role in the pathogenesis of COPD.