调节性B细胞在视神经脊髓炎中病生理作用和治疗的意义

A subset of regulatory B cells (Bregs) has been defined functionally in human and mice by their ability to express interleukin (IL)-10. Many studies have found that Breg exhibit reduced frequency and impaired function in autoimmune and inflammatory diseases. But its role in Neuromyelitis Optica(NMO) is still unknown. Our preliminary data showed that Breg in NMO patients exhibited reduced number compared to healthy controls. In addition, the Breg frequencies varied in NMO patients according to differences in responsiveness to rituximab. We will investigate the presence, function and dynamics of Breg in NMO patients compared with healthy subjects. We will seek the correlation between clinical characteristics and the frequency of Breg. Rituximab targets the CD20 antigen and efficiently depletes pre-B cells and mature B cells, all of which express CD20. After B cell depletion, repopulation follows subsequently. Therefore, rituximab therapy provides a unique opportunity to study the kinetics of repopulation of subsets of B cells in NMO. As NMO patients undergo therapy with rituximab, we will study the clinical response to treatment and look for an association with different patterns of Breg populations. We will also search for the optimum factors for Breg proliferation and estimate its therapeautic effect by adoptive transfer of Breg to NMO mice. The results will promote better understanding therapeautic functions of Breg in NMO and the pathogenesis of NMO as well.

近年发现的调节性B细胞（Regulatory B cells, Bregs）为能分泌IL-10的CD1d+CD5+双阳性B细胞，它能抑制多种自身免疫疾病的炎症反应。其在视神经脊髓炎（Neuromyelitis Optica, NMO）中的作用尚无报道。我们课题组前期工作发现NMO患者Breg细胞数减少，且对CD20单抗治疗反应不同的NMO患者其Breg细胞数量截然不同。本研究将检测NMO患者和健康人Breg细胞的数量、频率及分泌IL-10的功能。分析CD20单抗治疗后NMO患者Breg细胞的变化及其与临床之间的联系。探索体外增殖、修复Breg细胞的最佳条件，将Breg细胞分别与NMO患者外周血单个核细胞及水通道蛋白4反应性T细胞共培养，观察其对不同细胞亚群分化及细胞因子分泌的影响。通过给NMO小鼠回输Breg细胞评价其治疗作用，以明确Breg细胞在NMO病生理中的作用及治疗的意义。

背景：近年发现的调节性B细胞（Regulatory B cells, Bregs）为能分泌IL-10的CD1d+CD5+双阳性B细胞，它能抑制多种自身免疫疾病的炎症反应。其在视神经脊髓炎谱系疾病（Neuromyelitis Optica Spectrum Disorders, NMOSD）中的作用尚无报道。研究内容：合并结缔组织病（CTD）与不合并CTD的NMOSD患者在临床特点、实验室检测、头和脊髓MRI存在区别；NMOSD患者Breg细胞的表型、频率及功能研究及与疾病活动性的关系；Breg细胞恢复率在利妥昔单抗治疗不同反应的NMOSD患者中的变化；实验性NMOSD模型小鼠中及对抗鼠CD20单抗删除治疗后Breg细胞变化；外源性IL-21对Breg细胞分泌IL-10的影响；NMOSD患者骨髓间充质干细胞的生物学特性、增殖能力和凋亡情况；IL-36水平在NMOSD患者中的变化及其与年复发率、EDSS评分、脊髓病灶节段的相关性，探索IL-36与NMOSD疾病活动性的相关性；在NMOSD的治疗方面，我们发现抗利妥昔单抗抗体存在于接受利妥昔单抗治疗的NMOSD患者外周血中并影响疗效。重要结果：合并CTD的NMOSD患者血清IgG的水平和γ球蛋白的水平明显高于不合并CTD的NMOSD患者，其脊髓病灶节段更长，在T1加权像上出现低信号的比例更高。NMOSD患者较健康对照组外周血Breg细胞数量减少。Breg细胞数与NMOSD患者疾病严重程度负相关。NMOSD患者外周血Breg细胞的恢复程度与B细胞删除治疗的疗效有关。NMOSD小鼠分泌IL-10的CD1d+CD5+CD19+B细胞减少。用抗鼠CD20单抗治疗NMOSD小鼠，治疗组外周B细胞较对照组分别减少。NMOSD患者的骨髓间充质干细胞增殖能力降低、凋亡增加。IL-36在NMOSD患者中表达升高，且与疾病活动具有相关性。发现小剂量利妥昔单抗治疗NMOSD时，部分患者体内存在抗利妥昔单抗抗体并影响药物疗效。科学意义：明确Breg细胞在NMOSD中的变化及对疾病活动性和治疗的指导意义，为后续研究奠定基础。