同源干细胞移植体液免疫记忆细胞重建预防肾移植抗体介导排斥反应的机制研究

Antibody mediated rejection of sensitized renal transplant recipients is difficulty in transplantation field because of the lack of effective prevent and treatment method. Successful renal transplantation in skin sensitized rats with homologous stem cell transplant treatment post lethal dose irradiation and Fludarabine performed by our research group. We speculate the mechanism is that irradiation and chemical treatment deplete CD27+ memory B cells and long-lived CD138+ plasma cells which maintaining the long-term humoral immunological memory. And humoral immunology was reset after syngeneic hematopoietic stem cell transplantation. Alloantibody decreased and antibody mediated rejection was prevented in this model. In according to prove the above conjecture evaluation of specific humoral immunity through the DSA level in recipients serum and in vitro cell culture system. GFP and Y chromosome will be used as maker of renewed stem cell resources. The mechanism of humoral immune memory cells reset post homologous stem cell transplantation to prevent antibody mediated rejection will be discussed in our research which can provide new ideas and theory basis to prevent AMR for sensitized candidates of transplant.

由于缺乏有效防治手段，目前致敏受者体内预存同种异体抗体介导的排斥反应是困扰肾移植领域的难题。本课题组完成了在皮肤移植致敏大鼠通过Fludarabine诱导致死剂量放射照射后同源干细胞移植成功预防肾移植抗体介导排斥反应的模型。推测其机制为：药物及放疗清除维持长期体液免疫记忆的CD27记忆B细胞及CD138长寿命浆细胞，同源造血干细胞移植后进行体液免疫系统重建后新生CD138长寿命浆细胞，不再产生同种异体抗体使致敏受者脱敏，预防抗体介导排斥反应。故本研究拟利用皮肤移植致敏大鼠模型，通过受体血及体外细胞培养体系中抗供体特异性抗体（DSA）水平评价特异性体液免疫，以GFP及Y染色体基因作为新植干细胞标志评价免疫重建后体液免疫记忆细胞来源，证明以上推测，从而探讨同源干细胞移植体液免疫记忆细胞重建预防肾移植抗体介导排斥反应的机制，为临床预防致敏受者肾移植后抗体介导排斥反应提供新的思路。

由于缺乏有效防治手段，目前致敏受者体内预存同种异体抗体介导的排斥反应是困扰肾移植领域的难题。本课题基于在前期建立的皮肤移植致敏大鼠模型，通过致死剂量放射照射后成同源干细胞移植及联合Fludarabine诱导研究对肾移植抗体介导排斥反应的影响及机制研究。致敏受者经同基因干细胞移植脱敏处理后受体DSA水平显著下降，联合氟达拉滨处理显著延长致敏受体肾移植的存活时间。进一步研究氟达拉滨对致敏受者体液免疫系统的影响，发现同基因骨髓移植联合氟达拉滨，受体大鼠记忆性B细胞及长寿命浆细胞比例明显降低，KLF4的基因水平明显也明显下降。同时还研究了AMD3100联合Velcade在预致敏大鼠肾移植模型的作用效果，AMD3100联合Velcade治疗后致敏受者DSA水平及肾移植后存活时间显著优于单独治疗。本研究为致敏受者抗体介导的排斥反应的防治提供重要的理论依据和治疗策略。