带血供的供者骨髓移植联合受者调节性T细胞扩增后回输诱导同种异体复合组织移植免疫耐受的研究

After vascularized composite tissue allotransplantation(VCA), recipients need to take immunosuppressive agents all their lives, so they tend to have a variety kinds of complications. And that’s the reason why this new treatment is not widely used clinically at the present. Introduction of donor-specific tolerance is the hot topic in VCA. Donor bone marrow transplantation(BMT) and expanded recipient regulatory T cell transfusion are among the most popular ways of tolerance introduction. Vascularized bone marrow transplantation(VBMT) is a new promising way of BMT. In animal experiments, despite the satisfactory short-term result, the vascularize bone marrow always went fibrosis in the long term. We successfully modified the VBMT model, which prevented the fibrosis of the graft and gained satisfactory long term result. Regulatory T cell has been successfully used to suppress the rejection after solid organ transplantation, and they have been demonstrated to be important for the success of BMT. Our hypothesis is: the combination of modified VBMT model and regulatory T cell have synergistic effect on suppressing the rejection after VCA, thus, lower the dosage of immunosuppressive agents needed after the VCA. The experiment presented here will test the immunomodulatory effect of the combination mentioned above, and compare it with the other immunomodulatory methods, trying to find out the better way of tolerance introduction.

同种异体复合组织移植术后，患者需长期服用免疫抑制剂，因而易发生各种并发症，阻碍了此类手术的进一步开展。因此，诱导移植免疫耐受是该领域的研究重点。供者骨髓移植和受者调节性T细胞扩增后回输是诱导免疫耐受研究中的两大热点。带血供的供者骨髓移植是近来的研究热点，在动物实验中获得良好的近期效果，但远期骨髓逐渐发生纤维化。申请人改进了带血供骨髓移植模型，有效地防止纤维化发生，获得理想效果。另有研究表明调节性T细胞能减轻异体器官移植后的免疫排斥反应，并有助于骨髓移植后受者接纳供者的骨髓细胞。因此我们提出假设：带血供的供者骨髓移植联合应用受者调节性T细胞移植，能产生协同效应，降低移植后的免疫排斥反应，减少免疫抑制剂用量。本研究将此种联合方法应用到同种异体复合组织移植中，观察移植的骨髓细胞和回输的调节性T细胞的迁移和定植规律，检测其免疫调节作用，并同其它已存方法相对比，探索更高效的移植免疫耐受诱导方案。

同种异体复合组织移植术后长期应用免疫抑制剂而发生的各种并发症，阻碍了此类手术的进一步开展，因此诱导移植免疫耐受是该领域的研究重点，也是本项目的研究目标。供者骨髓移植和受者调节性T细胞扩增后回输是诱导免疫耐受研究中的两大热点，基于此，我们提出“带血供的供者骨髓移植联合应用受者调节性T细胞移植，能产生协同效应，降低移植后的免疫排斥反应，减少免疫抑制剂用量”的假说。在本项目中，项目承担人首先建立了单纯前臂移植模型和带血供的供者骨髓移植，来观察其是否诱导移植免疫耐受。其次，将体外扩增的受者的CD4+CD25+Treg 细胞回，或/和输联合带血供的股骨移植，来观察是否诱导或增强移植免疫耐受。结果显示：1.带血供的骨髓移植（即股骨移植）诱导前臂移植免疫耐受；2.单克隆CD4+CD25+Treg 细胞诱导前臂移植受者的移植免疫耐受；3.单克隆CD4+CD25+Treg 细胞回输联合带血供的骨髓移植增强受者的移植免疫耐受。该项目所涉及的无论是大鼠前臂移植模型，还是改良的带血供的股骨移植模型国内外均无其他相关报道，单克隆CD4+CD25+Treg 虽在其他实质性器官移植中有实验报道，但尚未在同种异体移植领域开展应用。将两者的联合应用，体现了本课题具有一定的创新性和先进性，为该技术的临床应用提供更多的理论依据和技术支持。