IL21-CD8+T细胞途径与核苷类药物治疗慢性乙型肝炎停药转归的关系和机制研究

Induction of sustained off-therapy virological and biochemical response with durable anti-HBe seroconversion in patients with HBeAg-positive chronic hepatitis B (CHB) is a satisfactory end point. Nevertheless the immunologic mechanism of sustained off-therapy response has not been completely clarified. HBV-specific CD8+T cells are the main effector cells responsible for HBV clearance and immunoregulation. Our research group found out that HBeAg seroconversion during telbivudine therapy or spontaneity in HBeAg-positive patients was associated with high serum interleukin-21(IL21) concentrations. The role of IL21-CD8+T cell pathway in the sustained off-therapy virological response on nucleos(t)ide analogues (NAs) therapy and the immunologic mechanism are not elucidated. This research project attempts to clarify whether sustained off-therapy virological response on NAs therapy for CHB is associated with the level of HBV-specific CD8+ T cell response and the level of related immunological factors especially IL21 based on the clinical research involving 126 CHB patients who discontinued the NAs therapy. We further intends to expose the relationship among HBV-specific CD8+ T cells response, IL21/IL21R pathway and HBV replication through the knockout mice experiments and vitro cell tests and finally try to confirm that IL21 plays a role in the immunological controlling for HBV replication by up-regulating the HBV-specific CD8+ T cells response. The research is aimed to provide a theoretical basis and potential immune predictors for sustained virological response after the cessation of NAs therapy, and find a new immunotherapy strategy for patients with CHB at the same time.

核苷类药物治疗HBeAg阳性慢性乙型肝炎(CHB)停药后的持久应答是我们期望的满意治疗终点，但停药后持久应答的免疫学机制尚未充分阐明。HBV特异性CD8+T细胞是机体清除HBV及实现免疫控制的主要效应细胞；既往我室发现IL21 高表达与自然发生和核苷类药物诱导的HBeAg血清学转换均有密切的关联。本项目拟通过我们建立的126例临床停药研究队列，试图阐明核苷类药物抗HBV治疗停药后取得持久应答与HBV特异性CD8+T细胞应答水平以及IL21水平相关；采用基因敲除小鼠动物实验、体外细胞试验等，进一步探讨HBV特异性CD8+T细胞应答、IL21/IL21R途径和HBV复制三者间的关系，试图探讨其介导机制可能是IL21促进HBV特异性CD8+T细胞应答有利于对HBV的免疫学控制。为核苷类药物治疗CHB停药后实现持久应答提供免疫学预测指标和理论依据，以及为CHB免疫学治疗提供新策略。

核苷类药物治疗HBeAg阳性慢性乙型肝炎（CHB）患者停药后持久应答是我们期望的满意治疗终点，但是停药后持久应答的免疫学机制尚未充分阐明。HBV特异性CD8+T细胞是机体清除HBV及实现免疫控制的主要效应细胞；既往本实验室发现IL-21高表达与自然发生和核苷类药物诱导的HBeAg血清学转换均有密切的关联。本研究项目通过我们建立的126例临床停药研究队列，试图阐明核苷类药物抗HBV治疗停药后取得持久应答与HBV特异性CD8+T细胞应答水平以及IL-21水平相关；并通过动物实验、体外细胞实验等进一步探讨HBV特异性CD8+T细胞应答、IL-21/IL-21R途径和HBV复制三者之间的关系，试图探讨其介导机制可能是IL-21促进HBV特异性CD8+T细胞应答有利于对HBV的免疫学控制。为核苷类药物治疗CHB停药后实现持久应答提供免疫学预测指标和理论依据，以及为CHB免疫学治疗提供新策略。.本课题围绕CD8+T细胞途径对慢乙肝核苷类药物治疗后持久应答的机制展开研究。研究期间我们共随访了126名长期核苷类药物治疗停药后的慢乙肝患者，用Cox回归多因素模型分析探索治疗前HBV DNA水平， HBeAg状态、ALT水平、总治疗时间、巩固治疗时间，以及停药基线的年龄、性别、Fibroscan值、ALT水平和HBsAg等因素，发现HBsAg水平和年龄是停药后病毒学复发和临床学复发的预测因素，为核苷类治疗慢乙肝指导停药和停药后的患者管理提供了可靠的证据。虽然前期我们并没有得到IL21-IL21R途径通过调控CD8+T细胞应答影响停药后持久应答的预期结果，但是，我们随后对其可能存在的补偿机制（包括天然免疫和细胞免疫应答）进行了探索。随后我们发现病毒相关颗粒HBsAg可能通过下调TLR7下游干扰素刺激基因Mx1表达影响持久应答。而且，我们还创新性探索了血清标志物Anti-HBc、HBcrAg、HBV pgRNA和CXCL13等与停药后持久应答的关系，为后面探索CD8+T细胞途径对慢乙肝核苷类药物治疗后持久应答机制研究提供了证据与思路。