中文摘要：

目的探讨临床常用免疫抑制剂对供者骨髓移植和T淋巴细胞协同刺激信号阻滞联合诱导的混合嵌合体和免疫耐受的影响。方法将BALB／c小鼠的皮肤移植于C57BL／6小鼠背部，术后经尾静脉注射BALB／c小鼠骨髓细胞5×10^7个和AdCTLA4-FasL 5×10^9PFU（标准方案组），部分小鼠在此基础上还接受环孢素A（CsA组）、霉酚酸酯（MMF组）和环孢素A、霉酚酸酯联合（CsA＋MMF组）皮下或腹腔注射，共用药28d，同时设移植后不给任何处理的对照组。观察移植皮肤存活情况，流式细胞仪测定受者外周血Vβ11^＋T淋巴细胞的水平和供者来源细胞的嵌合水平，行单向混合淋巴细胞反应（MLR）了解受者对供者抗原的反应。结果除对照组外，其它几个组在短期内（21d）均诱导了高水平的混合嵌合体（〉30％），但在停药后的140d，仅标准方案组和MMF组仍保持稳定的嵌合水平。对照组移植皮片的存活时间为（9．8±1．2）d，CsA组和CsA＋MMF组皮片存活时间均不超过50d，标准方案组和MMF组皮片存活时间均超过150d，明显长于CsA组和CsA＋MMF组（P〈0．05）。术后150d，标准方案组和MMF组的MLR受到显著抑制，刺激指数均〈1，而CsA组和CsA＋MMF组的MLR未受抑制（刺激指数均〉1）。术后21d时，各组小鼠外周血中Vβ11^＋T淋巴细胞的水平均低于对照组，但标准方案组和MMF组的Vβ11^＋T淋巴细胞较CsA组和CsA＋MMF组更低（P〈0．05），至术后140d时，标准方案组和MMF组的Vβ11^＋T淋巴细胞比例降至更低水平。结论CsA或含CsA的免疫抑制方案对供者骨髓移植和输注CTLA4-FasL联合诱导的混合嵌合体和免疫耐受具有抑制作用，其机理可能与早期外周供者反应性T淋巴细胞删除减少有关。

英文摘要：

Objective To investigate the effects of conventional immunosuppressants on chimerism and tolerance induced by allogeneic bone marrow transplantation in combination with CTLA4- FasL gene transfer mediated by adenovirus. Methods C57BL/6（H-2^b,B6） mice received BALB/c（H- 2d） mice skin transplantation, followed by both adenovirus vector encoding CTLA4-FasL gene and bone marrow cells （BMC） of BALB/c mice injected via tail vein. Cyclosporine A （CsA） or mycophenolate mofetil （MMF） or both was administered daily from day 0 through 28 after donor skin transplantation. Then,the survival of skin grafts was observed, the level of Vβ11^＋T cells and donor chimerism were detected by flow cytometry, and tolerance to donor antigen was evaluated through one-way MLR. Results In non-cytoreductive model using BMT and CTLA4-FasL gene transfer, short-course immunosuppression facilitated early engraftment of donor bone marrow, while the mixed chimerism in peripheral blood of 136 recipients treated with CsA or both CsA and MMF were reduced to very low level on day 140 after skin transplantation. As compared with B6 recipients treated with MMF or no immunosuppressants, the mean survival time （MST） of skin allografts in those mice treated with CsA or both CsA and MMF was significantly reduced, and the levels of Vβ11^＋T cell were significantly increased. Furthermore, 136 recipients treated with CsA or both CsA and MMF showed no tolerance to donor antigen. Conclusion Immunosupressive regime containing CsA could abrogate long-lasting mixed chimerism induction and tolerance development in non-cytoreductive model using BMT and CTLA4-FasL gene transfer, owing to negative effect of CsA on peripheral deletion of donor-specific T cells.