Breg在抗CD20调控IgG4相关性眼眶病纤维化中的机制研究

The collection to the orbit and the secretion of the cyctokine of the inflammatory cells induce inflammatory fibrosis are the major causes of the IgG4-related orbital disease (IgG4-ROD). Our previous studies shown that B lymphocyte is important in the development of IgG4-ROD: CD20 is 100% expressed in the tissues of IgG4-ROD, whlie normal in peripheral blood; intraorbital injection of anti-CD20 antibody is effective in IgG4-ROD, can induced reduction in inflammatory fibroblasts. But there are some patients still cannot be controled, need multiple dosing, and even donot response to the drug. In the mean while, negative immune adjustment factor——regulatory B cell (Breg) is expressed lower in IgG4-related disease (IgG4-RD) patients than normal person; Breg can be led to remission during anti-CD20 antibody treatment; and long-term clinical remission is associated with a higher ratio of Breg than before treatment. All above indicate that Breg may enhance anti-CD20 antibody therapy to affect the secretion of inflammatory cells and cytokines that induce fibrosis. Our research intends to clarify the machanism of the effect and regulation of fibrosis by Breg during anti-CD20 antibody immunotherapy in IgG4-ROD. Our reaseach will provide new ideas and therapeutic targets to the prevention and treatment of IgG4-ROD.

炎症细胞被募集到眼眶并分泌细胞因子导致纤维化的机制是IgG4相关性眼眶病（IgG4-ROD）发生、发展的关键。前期研究发现B淋巴细胞在IgG4-ROD的发生发展中起重要作用：CD20在IgG4-ROD患者病变组织中阳性表达率达100%，而外周血表达正常；抗CD20单抗局部注射能控制IgG4-ROD，降低患者的炎症纤维化程度。但存在部分患者不能完全控制，需多次给药，甚至无效的问题。同时，研究发现负向免疫调节因子——调节性B细胞（Breg）在IgG4相关性疾病（IgG4-RD）患者中比例较正常人低；抗CD20治疗Breg浓度急剧降低；长期临床缓解者Breg比例较治疗前提高。上述研究基础提示Breg通过抗CD20介导的信号通路调控IgG4-ROD 纤维化的可能存在。本课题拟明确：Breg在抗CD20调控IgG4相关性眼眶病纤维化中的机制。本研究将为IgG4-ROD的防治提供新的思路和治疗靶点。

IgG4相关性眼眶病（IgG4-related orbital disease, IgG4-ROD）是以IgG4+浆细胞浸润和血清IgG4升高为主要特征的纤维炎症性疾病。目前其发病机制目前尚不明确，认为是眼眶内IgG4+浆细胞浸润导致炎症和组织纤维化。调节性B细胞（regulatory B cell, Breg）作为免疫抑制细胞，可能参与IgG4-ROD的发病。本项目研究了外周血Breg的分布和抗CD20单抗调控IgG4-ROD纤维化的体外研究；比较IgG4-ROD和非IgG4相关性眼眶炎症的临床病理特征，分析调节性T细胞（regulatory T cell, Treg）在其中的分布及作用。研究发现，与健康对照组相比， CD19+CD24hiCD38hi、CD19+CD24intCD38int和CD19+CD24+CD38-这三群在IgG4-ROD中均未发生数量改变。我们发现与健康受试者相比，在IgG4-ROD中，CpG联合CD40L诱导IL-10+Breg的效率显著降低，提示IgG4-ROD患者中Breg可能存在功能缺陷。在特发性眼眶炎症（idiopathic orbital inflammation, IOI）患者病变眼眶组织中透明质酸（hyaluronic acid, HA）和胶原显著增加，外周血循环中HA，基质金属蛋白酶抑制剂-1（matrix metalloproteinase-1, TIMP-1），III型胶原氨基端前肽（amino-terminal propeptide of procollagen type III, PIIINP）及相应的ELF评分也显著增加。B细胞和眼眶成纤维细胞体外共培养中加入抗CD20单抗（利妥昔单抗）刺激后，我们发现IL-6表达增加。同时，我们发现IgG4-ROD在特发性眼眶炎症中的比例超过60%，与非IgG4相关性眼眶炎性假瘤相比，IgG4-ROD具有更多的淋巴浆细胞浸润、滤泡增生和更强的增殖能力。另外，外周血和组织中Treg细胞数量显著增加，但其免疫抑制功能缺失，存在可塑性和功能异质性。本研究揭示了调节性细胞在IgG4-ROD发生发展中的可能作用，为其治疗提供了新策略。