Immune Pathophysiology of Sickle Cell Disease

项目摘要 慢性炎症状态现在被认为是持续不断的镰状细胞病(SCD)的标志 对潜在血管系统的溶血性侮辱和反复循环的血管闭塞危象(VOC)。输血 仍然是SCD患者的基石治疗，但与其他输血患者不同，更高的 SCD患者中有20%-50%的患者出现同种异体抗体，并有可能危及生命的后遗症。这些 包括鲜为人知的延迟输血反应(DHTR)，其发生以及临床 从轻微到严重的进展是不可预测的。我们研究计划的一个长期兴趣是 了解导致SCD并发症的潜在免疫机制，包括VOC和输血 并发症。我们的研究揭示了循环中的单核细胞和先天的 对溶血的免疫反应是SCD的一个标志，在输血并发症中，包括同种异体免疫和 DHTR。作为R35的一部分，我们计划的研究将集中在先天免疫细胞通路上 放大炎症SCD状态与细胞的血红素保护途径，如血红素解毒 同种异体免疫和DHTRs发展中的关键酶--血红素加氧酶1。我们的实验室也有 发现了一组循环单核细胞的新功能，称为巡逻单核细胞(PMO)，在 它们清除和清除受损的内皮细胞和内皮附着的镰刀状红细胞的能力。这一发现 一种新的PMO在SCD中的作用机制的研究为我们对VOC的理解提供了一个范式的转变，并打开了 增加了PMOS被操纵以防止痛苦的VOC的可能性。拟议研究的目标之一是 R35旨在了解PMO保护SCD血管系统的机制以及它们是如何受到影响的 在血管闭塞事件期间的功能和数值，目的是帮助建立他们在VOC中的角色 病理生理学，以及它们作为VOC治疗靶点的潜力。正如我们过去所做的那样，所有的 拟议的这两个目标的研究将结合使用体内小鼠模型、体外人类模型 系统和患者样本以严格的方式机械地解剖特定的免疫细胞类型 分子途径在SCD异体免疫和VOC中起重要作用。总之，我们相信我们的 实验室将人体研究和实验模型结合起来进行机械解剖的方法 调节SCD并发症的免疫途径可能会产生影响，并在某些领域产生新的发现 对NHLBI科学任务至关重要。

Project Abstract A chronic inflammatory state is now considered a hallmark of sickle cell disease (SCD) resulting from ongoing hemolytic insult to the underlying vasculature and repeated cycles of vaso-occlusion crisis (VOC). Transfusions remain a cornerstone treatment for patients with SCD, but unlike other transfused patient populations, a higher proportion (20-50%) of patients with SCD develop alloantibodies with potentially life-threatening sequalae. These include poorly understood delayed transfusion reactions (DHTRs) whose occurrence, as well as clinical progression from mild to severe, is unpredictable. A long-standing interest of our research program has been to understand the underling immune mechanisms leading to SCD complications including VOC and transfusion complications. Our studies have uncovered an underappreciate role of circulating monocytes and the innate immune response to hemolysis, a hallmark of SCD, in transfusion complications including alloimmunization and DHTRs. Our projected studies as part of this R35 will be focused on innate immune cellular pathways that magnify the inflammatory SCD state versus the cells' heme protective pathways such as the heme detoxifying key enzyme heme oxygenase 1 in alloimmunization and in the development of DHTRs. Our laboratory has also identified a novel function for a subset of circulating monocytes, referred to as patrolling monocytes (PMo), in their ability to scavenge and remove damaged endothelium and endothelial-attached sickle RBCs. The discovery of a novel mechanism of action of PMo in SCD offers a paradigm shift in our understanding of VOC and opens up the possibility that PMos can be manipulated to prevent painful VOC. An objective of the proposed studies in this R35 is to understand the mechanisms by which PMo protect SCD vasculature and how they are affected both functionally and numerically during a vaso-occlusive event with the goal to help establish their role in VOC pathophysiology, and their potential as a therapeutic target for VOC. As we have done in the past, all the proposed studies for both objectives will combine the use of in vivo mouse models, in vitro human model systems, and patient samples to mechanistically dissect in a rigorous manner how specific immune cell types and molecular pathways contribute to SCD alloimmunization and VOC. Altogether, we believe that our laboratory's approach of integrating studies in humans and experimental models to mechanistically dissect immune pathways that regulate SCD complications is likely to be impactful and generate novel findings in areas critical to the NHLBI scientific mission.