调节性T细胞（Treg）数量和功能异常是脓毒症免疫抑制的重要原因。GRAIL是新近发现的泛素E3连接酶，负性调节免疫功能，对Treg发挥其免疫抑制功能具有重要作用。我们预实验发现，脓毒症小鼠外周血Treg细胞GRAIL mRNA表达显著增加，Treg/CD4+T细胞比例升高，提示GRAIL可能参与了脓毒症时Treg数量和功能异常。为此，我们首先检测脓毒症患者外周血Treg细胞中GRAIL表达水平的动态变化，并分析其与Treg/CD4+T细胞比例、Treg功能及患者病情严重程度的相关性；进而体外细胞水平研究GRAIL不同表达水平对脓毒症时Treg数量和功能的影响，并探索GRAIL发挥作用的基本机制；最后在体动物实验研究调控GRAIL表达对Treg的影响及脓毒症小鼠的治疗价值。通过本课题的研究，以期进一步揭示GRAIL在脓毒症免疫抑制中的作用，为寻找脓毒症治疗的新靶点提供一定的理论和实验依据。

Regulatory T cell (Treg) abnormality plays an important role in sepsis-induced immunosuppression. Gene related to anergy in lymphocytes (GRAIL), a novel E3 ubiquitin ligase, negatively regulates the immune system and is crucial to the funtion of Treg. Our preliminary study suggested that both GRAIL mRNA expression in Treg and the ratio of Treg and CD4+T cells in the peripheral blood were significantly increased in septic mice, indicating that GRAIL may be invovled in the Treg abnormality in sepsis. The present project was designed to investigate the role of GRAIL in Treg dysfunction in sepsis-induced immunosuppresion from bench to bedside, including septic patients, in vitro Treg study and C57BL/6 mice. First, we will detect the dynamic changes of GRAIL expression in Treg in the peripheral blood in septic patients and investigate the correlation of GRAIL expression, the ratio of Treg and CD4+T cells, Treg function and sepsis severity. Then from the cell level we will in vitro investigate the effect of different levels of GRAIL expression on the number and function of Treg in sepsis, followed by exploring the possible mechanism of GRAIL. Finally, from the animal level we will in vivo investigate the effect of GRAIL on Treg and the therapeutic role of GRAIL in septic mice. Through the present project, we attemp to further reveal the role of GRAIL in sepsis-induced immunosuppression and provide theoretical and experimental basis of seeking potential drugs targeted at sepsis-induced immunosuppression.