系统性红斑狼疮患者骨髓间质干细胞对B淋巴细胞免疫抑制作用的初步研究

Immunosuppressive effects of bone marrow-derived mesenchymal stem cells on B lymphocytes in systemic lupus erythematosus patients

目的：探讨系统性红斑狼疮（SLE）患者骨髓间质干细胞（MSCs）体外对B淋巴细胞的免疫调节作用是否存在异常。方法：采用直接贴壁法分离培养正常人及SLE患者MSCs。免疫磁珠法分选正常人外周血B淋巴细胞,与MSCs共培养,流式细胞术检测B细胞凋亡及表面标志表达,3H掺入法检测B细胞增殖,酶联免疫吸附法（ELISA）检测培养上清中免疫球蛋白IgG、IgM和IgA水平。结果：①B细胞＋正常MSCs共培养组B细胞增殖（4307±308）cpm较单纯B细胞培养组（7059±346）cpm降低（P〈0.05）;②B细胞＋正常MSCs共培养组B细胞凋亡率（14±7）%低于单纯B细胞培养组（25±8）%（P〈0.05）;③B细胞＋正常MSCs共培养组B细胞表面CD86表达率（53±5）%较单纯B细胞培养组（66±10）%低（P〈0.05）;④与MSCs共培养后,B细胞分泌免疫球蛋白IgG、IgM和IgA较单纯B细胞培养显著减少（P〈0.05）;⑤B细胞＋狼疮MSCs共培养组与B细胞＋正常MSCs共培养组比较,B细胞增殖、凋亡、CD86表达和Ig分泌两组间差异无统计学意义。结论：MSCs在体外对B细胞有抑制作用,SLE患者骨髓MSCs与正常MSCs相比,对B细胞的表面刺激分子表达、增殖、Ig分泌有相似的抑制作用。

Objective To investigate the immunoregulatory effects of bone marrow derived mesenchymal stem cells （MSCs） on B lymphocytes in systemic lupus erythematosus （SLE）. Methods Human bone marrow MSCs were isolated from SLE patients and normal controls and cultured ex vivo. B lymphocytes were purified from normal peripheral blood mononuclear cells by using CD19 microbeads. Purified B cells were cocultured in 96-well flat-bottom plates with MSCs. B cell apoptosis and surface markers were analyzed by flow cytometry. B cell proliferation was assessed by [^3H]-thymidine incorporation. ELISA was used to measure supernatant levels of IgG, IgM and IgA. Results ①B cell proliferation in normal MSCs coculture group （4307± 308） cpm was significantly inhibited compared to simple B cell group （7059±346） cpm （P〈0.05）;②B cell apoptotic percentage in normal MSCs cocuhure group （14±7）% was lower than in B cell group （25±8）% （P〈 0.05）; ③The percentage of CD86 molecule expression on B cells in normal MSCs coculture group （53±5）% was lower than that in simple B cell group （66±10）% （P〈0.05）;④The levels of IgG, IgM and IgA secreted by B cell decreased when cocuhured with MSCs （P〈0.05）; ⑤There were no significant differences of B cell proliferation, apoptosis, CD86 expression and immunoglobulin production regulated by MSCs from lupus patients and normal controls. Conclusion MSCs show an inhibitory effect on B cells. Both MSCs from SLE patients and normal MSCs have similar patterns in B cell proliferation, activation and immunoglobulin production.