联合阻断PD-1与Tim-3恢复晚期慢加急肝衰竭患者T细胞功能耗竭的免疫治疗策略研究

Immune paresis is a hallmark associated with poor prognosis of patients with late-stage acute-on-chronic liver failure (ACLF). T cell functional exhaustion is a key constitution of immune paresis. Literatures and our previous studies showed immune checkpoint receptors PD-1 and Tim-3 play a critical role in regulating T cell function, however, litter is known about their role in mediating T cell functional exhaustion in late-stage acute-on-chronic liver failure. We first measure the dynamic change of T cell function and the expression of PD-1/Tim-3 as well as their ligands with the progression of ACLF.We then investigate the role of PD-1 and Tim-3 in regulating T cell proliferation, cytokine production and cytotoxicity and their synergistic effect. We also explore the potential of T cell function reconstitution as well as therapeutic effect on ACLF by synergisticly blocking PD-1 and Tim-3 pathway, which would shed light on novel immunotherapy for late-stage ACLF. We also establish ACLF follow-up cohort to examine the potential value of PD-1/Tim-3 as biomarkers to predicting ACLF prognosis.

T细胞功能耗竭是导致晚期慢加急肝衰竭患者免疫麻痹状态的重要因素,而后者与晚期慢加急肝衰竭不良预后密切相关。最近资料及本项目组前期研究均显示免疫检验点受体PD-1和Tim-3在调节T细胞功能中起重要作用，但其在晚期慢加急肝衰竭T细胞功能耗竭中的作用及机制尚不明确。我们拟通过研究不同阶段慢加急肝衰竭患者T细胞功能的动态变化，以及PD-1及Tim-3及其配体的动态表达，明确PD-1及TIM-3通路介导T细胞功能耗竭的可能机制及协同作用，并通过建立晚期慢加急肝衰竭大鼠模型，探索协同阻断PD-1及TIM-3通路恢复晚期慢加急肝衰竭T细胞功能及提高疾病存活率的可能途径，为慢加急肝衰竭晚期的免疫治疗提供新的理论依据。同时建立慢加急肝衰竭随访队列，探讨Tim-3及PD-1作为生物标志物预测慢加急肝衰竭预后的可能性。

乙肝相关慢加急肝衰竭是临床常见的危重症，患者的免疫紊乱与高死亡率密切相关。本课题组研究了乙肝相关慢加急肝衰竭的免疫紊乱机制并探索利用免疫检验点分子抗体恢复患者免疫应答功能的效果。我们发现尽管乙肝相关慢加急肝衰竭患者存在显著的全身炎症反应，但其固有免疫中性粒细胞胞外捕获网形成-吞噬功能存在不平衡，同时适应性免疫应答在转录水平明显下调，淋巴细胞的减少与病情进展和短期死亡密切相关。进一步通过临床研究发现慢加急肝衰竭患者循环的细菌DNA含量显著升高，提示内源性的菌群紊乱，另一方面感染的风险显著升高，且合并感染明显增加了患者的死亡率。最后我们发现重症感染患者的外周CD4、CD8阳性T细胞表面检验点分子Tim-3和PD-1的表达明显升高，而单核细胞表面PD-1的配体PD-L1和PD-L2的表达显著升高，单独使用PD-1或Tim-3的阻断抗体增加了T细胞和单核细胞的炎症因子分泌能力，但联合使用没有进一步增加效果。这些研究结果揭示了乙肝相关慢加急肝衰竭后期免疫功能抑制与继发感染及病情进展的关系，同时提示PD-1或Tim-3抗体可能是纠正免疫低下的潜在治疗方案。