补体及其介导的药物特异性T细胞在重症药疹肝肾损伤中的作用

Serious liver and kidney damage is one of the main causes of death in patients with severe drug eruption，type IV allergy reaction can not fully explain the mechanisms of serious liver and kidney injury. This research group previous study have suggests that the complement system is involved in the pathogenesis of drug eruption. In the present study, to investigate the relationship between complement activation with liver and kidney damage by testing complement relevant indexes as well as liver and kidney damage in patients with severe drug eruption. Detect the active fragments formed by the complement activation of C3a and/or C5a, drug-specific T cells were co-cultured with L-02 cells and HK-2 cell surface receptor expression, inflammatory cytokines, cell proliferation and apoptosis of T cells with and without the C3aR and/or C5aR antagonist, to explore drug specificity of C3a and C5a and its mediated mechanisms involved in the liver and kidney damage. With and without the MAPK antagonist and/or PI3K antagonist, detect C3a and/or C5a stimulate specific T cell subgroup number, cytokines level, expression of surface C3aR and C5aR, to further explore the mechanism of regulation of C3a and C5a on drug specific T cells differentiation by activated MAPK/ERK and PI3K/AKt signalling pathway. The objective of this research results will further enrich the pathogenesis of severe drug eruption, and provide new ideas for prevention and therapeutics of liver and kidney damage of severe drug eruption.

肝肾严重损伤是重症药疹患者死亡的主要原因之一，仅用Ⅳ型变态反应不能完全解释其病理机制。本研究是在课题组前期研究提示药疹存在补体系统被激活的基础上，通过检测重症药疹患者体内补体和肝肾损伤指标，探讨补体激活与肝肾损伤的关系；用与不用C3aRA或/和C5aRA时，检测与补体激活所形成的活性片段C3a或/和C5a、药物特异性T细胞共培养的L-02细胞和HK-2细胞表面受体表达、炎症因子、细胞增殖和凋亡，探讨C3a和C5a及其介导的药物特异性T细胞参与肝肾损伤机制；用与不用MAPK拮抗剂或/和PI3K拮抗剂时，检测C3a或/和C5a刺激的药物特异性T细胞的亚群数量、分泌的细胞因子水平、表面C3aR和C5aR表达，深入探讨C3a和C5a通过MAPK/ERK和PI3K/Akt信号通路调控药物特异性T细胞分化的机制。本项目的研究成果将进一步丰富重症药疹的病理机制，为重症药疹的肝肾损伤防治提供新思路。

近年来, 药疹的发生率随着药物品种的日益增多以及不规范用药而上升，成为临床用药面临的一大难题。肝肾严重损伤是临床上导致重症药疹患者死亡的主要原因，探讨重症药疹患者严重肝肾损伤机制有着重要意义。作为机体免疫效应系统和效应放大系统的补体，在活化过程中产生的活性片段C3a和C5a，具有过敏毒素作用，除介导局部炎症反应外，还调节CD4等免疫细胞的增殖、分化和功能发挥。本研究通过重症药疹患者病例资料收集和生物样品检测，发现重症药疹患者出现肝肾损伤的同时体内补体系统被激活产生C3a，CD4+T细胞亚群失衡，Th1和Th17细胞增殖分化增多，分泌的细胞因子IFN-γ、IL-17水平上升，而Th2和Treg细胞数量下降，分泌的相关细胞因子IL-4和IL-10减少，而且C3a表达水平与Th1和Th17细胞数量呈明显正相关，表明重症药疹患肝肾损伤与补体激活产物C3a和特异性T细胞有关。通过建立三氯乙烯（TCE）经皮致敏BALB/c小鼠药疹样皮炎实验模型，发现TCE致敏小鼠肝脏损害与补体激活相关；在用与不用C3aR拮抗剂情况下，发现TCE致敏小鼠中补体激活片段C3a调控T细胞亚群数量改变，Th1和Th17数量增多，分泌IFN-γ、IL-17等炎性因子增加介导肝肾损伤。体外研究发现TCE经皮致敏小鼠补体激活后可能通过C3a-C3aR和C5a-C5aR分别启动PI3K/Akt/FoxO1和MAPK信号通路，上调T细胞亚群特异性核转录因子T-bet及ROR-γt，而下调GATA-3及Foxp3，促使CD4+T细胞偏向Th1及Th17增殖分化，并抑制Th2及Treg细胞分化。本项目的研究成果表明重症药疹的发生是体液免疫与获得性免疫相互作用的结果，不仅丰富了重症药疹肝肾损伤的发病机制，而且为重症药疹的临床治疗提供新的思路。