CXCR5+CD8+T细胞在重型再生障碍性贫血免疫发病机制中作用的研究

In recent years, the close relations between severe aplastic anemia (SAA) and immune pathogenesis have been proved by amounts of researches. CXCR5+ CD8+ T cells are one of important CD8+ T cell subgroups that are recently discovered to participate in immunoregulation, yet their roles are not so clearly in the immunologic mechanisms of SAA. The proposer has been mainly involved in the study of the pathogenesis of SAA. Our previous researches have revealed that CXCR5+ CD8+ T cells are decreased and dysfunction in patients with SAA, and might play an important role in the pathogenesis of SAA. Based on previous work, we intend to investigate CXCR5+ CD8+ T cells’ roles in SAA immunologic mechanisms. Our research contents are as follows: ①Analyze the amount and function of CXCR5+ CD8+ T cells, and the correlations between CXCR5+ CD8+ T cells and clinical feature and immunological status. ②Analyze CXCR5+ CD8+ T cells’ influence on the immunoregulation in SAA patients in vitro. ③Analyze the effects of altered amount and function of CXCR5+ CD8+ T cells on hematopoietic function and immune status in SAA, by using the technology of cell transfection. This research will provide an experimental basis for improving the immunologic mechanisms of SAA and opening up new cell therapies for SAA.

近年大量研究显示重型再生障碍性贫血（SAA）发病与免疫异常密切相关。CXCR5+CD8+T细胞是新近研究提出的具有免疫调节功能的重要CD8+T细胞亚群，但其在SAA免疫发病过程中所发挥的作用尚不明确。申请人主要从事SAA免疫发病机制的研究，前期研究发现CXCR5+CD8+T细胞在SAA患者中数量减少，且可能在SAA发病中发挥重要作用。本课题拟在前期研究工作的基础上，以SAA患者及SAA小鼠模型为研究对象，对CXCR5+CD8+T细胞在SAA免疫发病过程中的作用进行深入探索。①分析SAA患者及小鼠模型中CXCR5+CD8+T细胞的数量、功能及其与临床及免疫状态的相关性；②细胞模型检测CXCR5+CD8+T细胞对SAA患者的免疫调控作用；③应用细胞转染技术，揭示影响CXCR5+CD8+T细胞对SAA造血功能及免疫状态的影响。此研究将为完善SAA的免疫发病学说、开辟新的细胞治疗提供实验基础。

SAA是典型的免疫功能失衡性疾病，CD8+T淋巴细胞比例升高、功能亢进，是导致骨髓造血细胞损伤的效应细胞，CD8+T细胞是由多种表达不同功能分子的细胞亚群组成，而在SAA中免疫“瀑布”失衡后首先发挥作用的CD8+T细胞亚群尚不清楚。.本研究通过反复实验，证实SAA患者CXCR5+CD8+T细胞表达水平升高，效应分子颗粒酶B及CD25表达水平升高，FoxP3表达下降，IST治疗后CXCR5+CD8+T细胞数量及功能分子均有所下降并与SAA及病情严重程度密切相关；通过体外实验及慢病毒转染技术，证实转染后CXCR5+CD8+T细胞功能分子颗粒酶B表达水平升高，与K562细胞共培养后K562细胞凋亡率明显上升；通过动物实验进一步证实SAA小鼠CXCR5+CD8+T细胞数量及功能分子表达升高。.本实验证实CXCR5+CD8+T细胞在SAA发病机制中发挥细胞毒性T细胞的作用，是导致SAA免疫功能异常的主要效应细胞，有可能成为未来治疗的靶点。