外周免疫调节功能失常在1型糖尿病发生及进展中的作用机制研究

Type 1 diabetes is caused by peripheral immune regulation disorder and with the dysfunction of regulatory T cells（Treg) and cytokine activities to trigger effector T cells (Teff) abnormal activation with high expression of relevant cytokines to mediate the destruction of islet β-cells. In NOD mice, Teff migrated to and infiltrated into the site of target organ and draining lymph nodes accompanied with IFN-γ and Caspase-3 over expression, meanwhile CTLA-4, IL-2, IFN-γ, TH17 high expression displayed effector function in the spleen and second lymph node, similar phenomena was also observed in the recurrent autoimmune attacking of isogeneic islet in transplant model. This project is proposed on the basis of preliminary studies, dynamically to determine cytokine expression intervals and dysfunctional state of peripheral Treg, compared with the type 1 diabetes initialization and pathological progression to investigate the Treg immune state in spleen and the draining lymph nodes and whether its dysfunction depends on the specific costimulatory cytokines, which cytokine has a multiplier effect to accelerate Treg declining on the immunosuppressive function against Teff; as well as to study the precise mechanism that which cytokine paly the role during Teff activation homing and how to migrate to the target organ. These studies will elucidate the fate of Treg during type 1 diabetes occurrence progression, it will guide how to screen the preclinical stage of lesions as well as to develop the implementation of personalized immune intervention in future therapy. Key words: Type I diabetes, autoimmunity, cytokine, regulatory T cells, effector T cells, immune intervention

1型糖尿病系因外周免疫调节功能失常所引发，通过调节T细胞（Treg)和具调节活性细胞因子的表达异常，引发自身效应T细胞(Teff)活化及相关细胞因子的高表达。在NOD小鼠，CTLA-4、IL-2、IFN-γ、TH17的高表达也发生脾脏和胰腺引流淋巴结中以及NOD鼠接受同种胰岛移植后再发自身免疫攻击过程中。本项目拟在前期研究基础上，动态检测细胞因子表达区间和外周调节T细胞的功能失调状态，对照1型糖尿病的病变初始化以及病理进程，研究脾脏及靶器官周围引流淋巴结中Treg的免疫活性状态，以及它的失衡是否需要特定细胞因子的共刺激，哪些细胞因子具有倍增效应而加速Treg失去对Teff的抑制活性；并研究Teff的活化、趋化至靶向器官和组织细胞的过程细胞因子的精细功能，以及它们在介导β细胞的破坏过程中的确切。这些研究将回答1型糖尿病的阶段性演化过程，对早期发现初期病变以及实施个性化的免疫干预具有指导意义。

滤泡辅助T（Tfh）细胞是体液免疫的关键调节剂。 Tfh细胞在帮助B细胞成熟和抗外源抗原产生抗体方面具有重要作用。目前的研究主要关注在自身免疫性疾病中外周Tfh细胞的频率。因而，探究Tfh细胞在1型糖尿病（T1D）患者发病中可能的机制具有重要意义。研究结果表明在T1D患者中循环Tfh细胞的频率增加以及IL-21的增强的表达；T1D患者PBMC中CD4+CXCR5+ICOS5+ T细胞的频率显着高于健康对照。同时确定了循环Tfh细胞频率与血清自身抗体或C肽水平之间的相关性；与自身抗体阴性对象相比，循环Tfh细胞的百分比在ZnT8A和IA2A自身抗体阳性T1D患者中增加。本研究提示Tfh细胞可能参与T1D相关的免疫应答。.T1D不同阶段的体循环中炎症性T细胞的数量及细胞类型与T1D发病关系密切。本研究观察了不同T1D阶段个体的Th17，Th22，Th1，Tc1和Tc17细胞循环的变化。研究表明与对照组相比，在T1D患者中，Th17-Th22和Tc1-Tc17显著升高，Th1细胞没有显着差异。在T1D患者中Th22细胞与Th17细胞呈正相关。然而，我们未发现血清中IL-17和IL-22之间有相关性。胰岛自身抗体在早期T1D患者和病程较长T1D患者之间无显著差异。本研究表明Th22可能参与了T1D的发病机制，促进T1D的进展，阻断Th22细胞可能是T1D患者的临床获益的一种有效手段。