Kupffer细胞激活与肝移植免疫耐受

Effect of activated kupffer cells on immune tolerance after liver transplantation

目前，关于Kupffer细胞（KC）在肝移植后免疫调节的确切作用尚不清楚。肝移植后KC通过各种途径被激活，激活的KC通过吞噬凋亡的T细胞、高表达FasL促进Th1细胞凋亡，同时分泌大量的Th2／Th3类细胞因子（白介素10、转化生长因子B等），促进Th2细胞的增生分化，诱导免疫耐受。然而，激活的KC也能通过表达MHC抗原，分泌黏附分子、共刺激分子发挥抗原递呈功能，并分泌促进Th1增生分化的细胞因子，启动和促进肝移植后供体肝脏的排斥反应。KC在肝移植后是诱导免疫耐受减轻排斥反应，还是促进并加重排斥反应，可能与其所受刺激因素的变化进而形成一个复杂的动态的细胞因子调控网络，最终导致Th1／Th2细胞比率变化有关：Th2细胞占优势则诱导免疫耐受，Th1细胞占优势则促进排斥反应。

Until now, the exactly effect of Kupffer cells （KCs） on inducing immune tolerance or aggravating acute rejection is still unknown. Activated by various way after liver transplantation, have the ability of phagocytosis the apoptositic T cells, up-regulated expression of FasL and many Th2/Th3 cytokines, such as interleukin-10 and transforming growth faetor-β. These up-regulated eytokines could induce the apoptosis of Thl cells and enhance the proliferation and differentiation of the Th2 cells, finally induce the immune tolerance. However, the activated KCs also have the ability of expression many cytokine-dependent molecules, such as class II major histocompatibility antigens, adhesion molecule and costimulatory molecules which could enhance the function of the antigen presentation, increase the expression of Thl eytokine and aggravate the acute rejection after liver transplantation. It maybe relate to the ratio of the Th1/Th2 cells determined by the complicated net of the cytokine produced by the activated Kupffer cells ： the predominance of Th2 cells could induce the immune tolerance, on the contrary, the acute rejection proceed.