Fetal Tolerance, Chimerism and Sickle Cell Disease ( Translational Study )

子宫内造血干细胞移植(IUHSCTx)是治疗静脉曲张的一种有前途的方法。 血液系统疾病，包括血红蛋白疾病。然而，在缺乏选择性优势的情况下 IUHSCTx的正常细胞、临床和实验努力通常导致有限的或没有检测到 植入，提示在造血竞争中存在着植入的主要障碍 收件人。该项目的长期目标是克服这些障碍，开发临床应用。 将植入增加到治疗水平的策略，以允许IUHSCTx临床扩展到治疗 镰状细胞病(SCD)。我们在基于IUHSCTx的小鼠模型中开发了三种方法 诱导供者特异性耐受以创造高水平的混合造血嵌合体，跨越全部MHC障碍， 不使用骨髓清除术或免疫抑制。在此应用程序中，我们计划利用特定于捐赠者的 容忍创造高水平的嵌合体，使用既定的和新的战略，在众多的模型中！ 并确定治愈SCD所需的嵌合体水平。这样做的具体目的是 建议：1)通过产前联合移植建立IUHSCTx后的高水平混合嵌合体 供者来源的HSC和免疫调节细胞群体。特异性供体细胞 人群将在产前与造血干细胞共同移植，以创造供体细胞的竞争优势。2)至 用策略建立血红蛋白病受者IUHSCTx后的高水平混合免疫 基于产前耐受诱导的非清髓剂促进出生后嵌合体增强 接近了。IUHSCTx在常规SCD中实现的有限混合嵌合体将被转换 出生后通过无毒方案获得高水平或完全供体嵌合体。3)在非去髓系中建立 SCD的小鼠模型，什么水平的混合嵌合体足以防止镰状 与SCD相关的危象和器官损害。创造不同水平的混合嵌合体的能力 小鼠SCD模型结合SCD的表型和功能分析应该允许什么问题 嵌合体水平是完全治疗SCD所必需的。这项建议中的研究包括 旨在测试IUHSCTx治疗SCD后改善植入率的策略，并将指导后续研究 大型动物模型。

In utero hematopoietic stem cell transplantation (IUHSCTx) is a promising approach for the treatment of a varlet)' of hematologic disorders including the hemoglobinopathies. However, in the absence of a selective advantage for normal cells, clinical and experimental efforts at IUHSCTx have generally resulted in limited or no detectable engraftment, suggesting the existence of major barriers to engraftment in the hematopoietically competitive recipient. The long-term objective of this project is to overcome these barriers and develop clinically applicable strategies to increase engraftment to therapeutic levels to allow clinical expansion of IUHSCTx to the treatment of Sickle Cell Disease(SCD). We have developed three approaches in the mouse model based on IUHSCTx induced donor specific tolerance to create high level mixed hematopoietic chimerism, across full MHC barriers, without the use of myeloablation or immunosuppression. In this application we plan to exploit donor specific tolerance to create high level chimerism, using established and new strategies, in mufine models of ! hemoglobinopathy and to determine what levels of chimerism is required to cure SCD. The specific aims of this proposal are: 1) To establish high level mixed chimerism after IUHSCTx by the prenatal cotransplantation of donor derived HSC and immanomodnlatory cell populations. Specific donor cell populations will be cotransplanted with HSC prenatally to create a competitive advantage for donor cells. 2) To establish high level mixed ehimerism after IUHSCTx in the hemoglobinopathy recipient by strategies based on prenatal tolerance induction to facilitate postnatal enhancement of chimerism using nonmyeloablative approaches. Limited mixed chimerismachieved by IUHSCTx in routine SCD will be converted to high level or co,_lplete donor chimerism after birth by non-toxic regimens. 3) To establish in a nonmyeloablated murine model of SCD, what level of mixed chimerism is sufficient to prevent sickling crises and organ d_mage associated with SCD. The ability to create various levels of mixed chimerism in the murine SCD model combined with phenotypic and functional assays of SCD should allow the question of what level of chimerism is necessary to completely treat SCD to be addressed. The studies in this proposal are designed to test strategies to improve engraftment after IUHSCTx for SCD and will direct subsequent studies in a large animal model.