【摘要】 目的:观察系统性红斑狼疮(SLE)患者B细胞表面功能分子表达的特征及其功能状态,评价以FcγRⅡB1(CD32)为代表的B细胞自身抑制调节机制在SLE发病中的作用。方法:采用Ficoll密度梯度离心法分离出人外周血单个核细胞(PBMC),并以免疫磁珠法(MACS)分离纯化B细胞。采用荧光分光光度法检测B细胞受不同激活物刺激后细胞内钙([Ca2+]i)的反应。用ELISA法检测B细胞与刺激物共同培养后所分泌IgG的量。采用流式细胞术及间接免疫荧光染色法,检测B细胞膜表面CD32、CD19及IgM的表达水平。结果:(1)以羊抗人μ链的F(ab′)2片段及完整IgG分别刺激SLE患者B细胞时,其[Ca2+]i反应的比值显著低于类风湿性关节炎(RA)患者(P<0.05)及正常人对照(P<0.01)。(2)分别用葡萄球菌A蛋白(SPA)单独刺激与SPA和羊抗人μ链的完整IgG抗体共同刺激SLE患者的B细胞所分泌的IgG的比值,明显低于RA患者及正常人对照组(P<0.05)。(3)SLE患者与RA患者及正常对照组B细胞上CD19、CD32及IgM的表达无统计学意义(P>0.05)。结论:SLE患者B细胞上CD32抑制性信号传导的异常,可能是导致B细胞过度活化的重要机制。更多还原

【Abstract】 AIM: To evaluate the effect of FcγRⅡB₁ （CD32） representative self-inhibitory adjustive mechanism of B cells on pathogenesis of systemic lupus erythematosus （SLE） by observing the expression characteristic and functional state of molecules on the surface of B cells from SLE patients. METHODS: The peripheral blood mononuclear cells （PBMC） were prepared by density gradient centrifugation, and the B cells were isolated from PBMC by magnetic activated cell sorting （MACS）. The fluxes of intracytoplasmic calcium （[Ca 2+ ]_i） of B cells activated by different activators were measured by fluorescence spectrophotometric method. The IgG production by B cells cultured with activators was assayed by ELISA. The expression levels of CD32, CD19, and IgM on the surface of B cells were measured by flow cytometry. RESULTS: （1）After B cells were stimulated with goat anti-human μ chain F（ab′）₂ fragments and whole IgG respectively, the ratio of [Ca 2+ ]_i response by F（ab′）₂ fragments to whole IgG was significantly lower in SLE B cells compared to rheumatoid arthritis （RA） （P< 0.05） or normal （P<0.01） B cells. （2）The ratio of total IgG production by B cells cultured with staphylococcal protein A （SPA） to SPA plus IgG anti-μ chain was significantly lower in SLE patients compared to RA patients or normal individuals （P<0.05）. （3）There was no obvious difference in the expression of CD19, CD32, and IgM on the surface of B cells from SLE, RA patients and normal individuals （P>0.05）. CONCLUSION: The inhibitory signaling abnormality of CD32 possibly contributes to the mechanism of hyperactivity of human SLE B cells.更多还原