滤泡辅助性T细胞（Tfh）在原发性胆汁性肝硬化疾病中的作用及其相关机制研究

Primary biliary cirrhosis (PBC) is an autoimmune-mediated liver disease.As a novel member of CD4+ T cells, follicular helper T cells (Tfh) have been reported to closely associated with various autoimmune diseases. However,the role of Tfh cells in PBC has not been reported until now. Our preliminary data showed that the frequency of Tfh cells in peripheral blood was significantly higher in PBC patients comparing with healthy control, and positively correlated with PBC specific parameter of ALP and IgM. Further analysis revealed that the frequency of circulating Tfh was positively correlated with plasma cells, but not related with the frequency of B cells;In addition, by cross-sectional study, we found that the frequency of circulating Tfh cells could indirectly indicate the UDCA therapy outcome. Allthe data mentioned above strongly suggest that Tfh cells may play an important role in the occurrence and development of the PBC.The main aim of this project is to clarify the frequency and functional changes of Tfh cell in the PBC patients, and explore how to provide a helper function to B cells by those Tfh cell, involing activation, maturation and antibody-production. By collecting more patient's sample and follow-up study, the relationship between the frequecny changes of Tfh cells and UDCA treatment effecy will be studied. By gene-chip and other molecular methods, the relative signial pathway in Tfh cells will be further analysed.Our result will eventually make a useful supplement in the pathogenesis of PBC, and provide a new target for the treatment of PBC.

原发性胆汁性肝硬化（PBC）是一种自身免疫介导的肝脏疾病。滤泡辅助性T细胞（Tfh）作为一种新型的CD4+T细胞成员，与多种自身免疫性疾病的发生密切相关。然而，至今Tfh细胞在PBC疾病中的作用未见报道。我们的初步研究发现外周血Tfh 细胞的频率在PBC患者中明显升高，且与肝功能指标ALP和IgM呈正相关；进一步分析发现Tfh的频率与浆细胞的频率呈正相关，而与B细胞的频率无关；此外，断面研究发现外周血Tfh细胞的频率可以间接反应熊去氧胆酸（UDCA) 的治疗疗效，强烈提示Tfh细胞在PBC的发生、发展过程中可能发挥重要的作用。本项目的主要目标是明确Tfh细胞在PBC中的频率和功能变化，解析Tfh细胞在辅助B细胞活化、分化和抗体分泌过程中的作用及其与UDCA治疗疗效的相关性，寻找调控Tfh细胞功能的相关信号通路，最终为完善PBC发病的免疫学机制做有益的补充，为PBC的治疗提供新的靶点。

研究背景: .原发性胆汁性胆管炎（PBC）是一种自身免疫介导的肝脏疾病。滤泡辅助性T细胞（Tfh）作为一种新型的CD4+T细胞成员，与多种自身免疫性疾病的发生密切相关。然而，至今Tfh细胞在PBC疾病中的作用未见报道。..主要研究内容:.通过流式细胞染色和免疫组化染色，我们对69例PBC患者外周血和部分肝脏组织内Tfh细胞的数量、表型、分泌细胞因子能力进行了分析；接着，分别纯化Tfh和B 细胞进行共培养，观察了Tfh 细胞对B 细胞数量和功能的调节作用。随后，通过对PBC 患者断面和为期一年的UDCA治疗随访研究，观察UDCA 治疗对Tfh 细胞的影响。最后，通过分离Tfh细胞并进行基因差异分析，寻找调控PBC患者Tfh细胞异常功能的关键分子。..重要结果:.1. 发现与健康对照和AIH患者相比，PBC患者外周血中Tfh细胞频率明显升高；.2. 与健康对照相比，肝脏组织中Tfh细胞的频率同样升高；.3. 与健康对照相比，PBC患者外周血Tfh细胞分泌IL-21、促进B细胞成熟和自身抗体生成的功能增强；.4. 通过断面和长期随访（完成1年的UDCA治疗）研究发现，与UDCA应答差的患者相比，UDCA应答好的患者外周血Tfh细胞频率明显降低。.5. Bcl6、STAT3、Barf 和Acl2基因在健康对照和PBC患者的Tfh 细胞中存在明显的表达差异。但具体相关机制，有待后续的进一步研究。..科学意义:. 这些结果拓宽了我们对Tfh细胞的认识，了解了Tfh细胞在PBC疾病发展中所起到的作用。Tfh细胞可能成为PBC患者UDCA治疗后评估疗效的新指标。