BIOLOGIC AND IMMUNOLOGIC ASPECTS OF TRANSFUSION MEDICINE

描述(由申请人提供)： 我们的研究集中在输血医学的几个生物学和免疫学方面。有三个项目涉及与血小板生物学有关的问题。具体地说，斯利希特博士的项目试图通过评估最初收集损伤的影响来确定允许延长血小板储存所必须满足的参数，这可能会限制储存持续时间，以及储存溶液在促进延长血小板储存方面的作用。吉利根博士和雷姆斯博士的项目希望找到在培养中培养巨核细胞的最佳方法，目标是制造出功能类似于血小板的血小板，以维持止血。约瑟夫森博士的项目专注于开发泡沫病毒载体作为基因转移系统，将治疗性基因输送到造血干细胞。他将用来作为他的系统模型的目标疾病是先天性无核细胞血小板减少症(CAMT)。另外两个项目侧重于免疫学。纳尔逊博士的项目涉及将三种不同类型的血液产品[标准的(未经修饰的)、去白细胞的或去白细胞的伽马射线]输入到接受心脏直视手术的免疫功能正常的患者体内。将评估三个患者队列中的血清学和细胞免疫反应的差异，以及供者和受者之间共享HLAII类对免疫结果的影响。普雷特博士和汤普森博士的项目致力于解决与预防或逆转获得性或先天性血友病患者抑制抗体形成相关的问题。修改FVIII中T细胞表位可能导致非免疫原性FVIII替代疗法，而新的多肽或重组蛋白可能有助于诱导现有抗体阳性患者的耐受。最后，将使用一个行政核心来维持SCCOR科学家之间的互动环境，并提供行政和统计支助。总而言之，我们利用我们科学家的成熟专业知识来解决输血医学中的几个重要问题。此外，大多数项目涉及一名或多名血液中心科学家的技能，他们在项目内部和项目之间工作，以实现SCCOR计划的目标。(摘要结束) 项目1：扩展血小板存储的策略 (谢里尔·斯利希特) 描述(由申请人提供)： 这些研究的主要目的是确定血小板(Plt)是否可以储存超过目前许可的5天。此外，PLT储存的时间是否取决于所储存的PLT产品的类型(分离PLT、从富含PLT的血浆(PRP)或从闪光涂层(BC)制备的PLT浓缩物、储存前汇集的PRP PLT浓缩物、或病原菌减少的分离法或BC PLTS)以及用于储存的介质，即血浆或储存液。我们的研究中将解决的四个关键问题是：1)使用分离程序采集PLT的方法与从全血中制备PLT浓缩物的方法是否影响PLT的存储持续时间？2)PLT浓缩物的预存储池是否影响PLT的存活率？3)PLT存储溶液是否允许PLT比PLT在血浆中存储的时间更长？以及4)病原体减少的PLT是否可以像非病原体减少的PLT一样延长保存时间？虽然将进行体外测试来记录保存后的PLT计数，以及各种分析来确定保存后的PLT功能、代谢和细胞凋亡，但延长保存的PLT的保存后质量将基于正常志愿者和血小板减少患者的体内测量。具体地说，放射性标记的PLT恢复率和在正常志愿者中延长储存的自体PLT的存活测量将被用来确定所有类型的PLT产品储存在血浆中与储存溶液相比的储存后PLT生存能力。对于储存超过8天和/或储存在储存液中的PLT，将使用血小板减少患者的输血研究，通过测量输血后捐赠者的PLT放射性标记的恢复和存活来评估PLT的生存能力。或者，患者对输血后PLT的反应将通过测量输血后PLT增量、校正计数增量和下一次输血的天数来确定。输注长期储存的供者血小板后的PLT功能(即止血)将通过PLT计数与出血时间的测量以及放射性铬标记的粪便失血研究来监测。在这些研究的结论中，我们应该知道每种类型的PLT在血浆或血浆中可以储存多长时间，每种类型的PLT的相对优点，以及当给予血小板减少症患者时，延长储存的PLT是否既有活性又有功能。(摘要结束)

DESCRIPTION (provided by applicant): Our research focuses on several biologic and immunologic aspects of transfusion medicine. Three projects deal with questions related to platelet biology. Specifically, Dr. Slichter's project seeks to define the parameters that must be met to allow extension of platelet storage by evaluating the effects of an initial collection injury that may limit storage duration and the role of storage solutions in facilitating extended platelet storage. Dr. Gilligan and Reems' project expects to identify the optimal methods of growing megakaryocytes in culture with the goal of producing platelets or "platelet-like fragments" that function similarly to platelets in maintaining hemostasis. Dr. Josephson's project focuses on the development of foamy virus vectors as a gene transfer system to deliver therapeutic genes into hematopoietic stem cells. The target disease that he will use as a model for his system is congenital amegakaryocytic thrombocytopenia (CAMT). Two additional projects have an immunologic emphasis. Dr. Nelson's project involves transfusing three different types of blood products [standard (unmodified), leukoreduced, or leukoreduced gamma-irradiated] into immunocompetent patients undergoing open-heart surgery. The differences in serologic and cellular immune responses in the three patient cohorts as well as the influence of HLA Class II sharing between donors and recipients on immunologic outcomes will be evaluated. Dr. S. Pratt and Thompson's project addresses issues related to the prevention or reversal of inhibitor antibody formation in patients with acquired or congenital hemophilia A. Modification of T-cell epitopes in FVIII may lead to non-immunogenic FVIII replacement therapy while new peptides or recombinant proteins may be useful in tolerance induction for patients with existing antibodies. Finally, an administrative core will be used to maintain an interactive environment among the SCCOR scientists and provide administrative and statistical support. In summary, we have utilized the established expertise of our scientists to address several important questions in Transfusion Medicine. In addition, most projects involve the skills of one or more Blood Center scientists working within and between the projects to accomplish the objectives of this SCCOR Program. (End of Abstract) PROJECT 1: Strategies to Extend Platelet Storage (Slichter, Sherrill) DESCRIPTION (provided by applicant): The primary objective of these studies is to determine whether platelets (plts) can be stored for longer than the currently-licensed 5 days. Furthermore, does the duration of plt storage depend on the type of plt product being stored (apheresis plts, plt concentrates prepared from plt-rich plasma (PRP), or from buffy coats (BC), pre-storage pooled PRP plt concentrates, or pathogen-reduced apheresis or BC plts), and the medium used for storage; i.e., plasma or a storage solution. The four critical questions that will be addressed in our studies are: 1) does the method of plt collection using apheresis procedures versus preparing plt concentrates from whole blood influence storage duration?; 2) does pre-storage pooling of plt concentrates affect plt viability?; 3) do plt storage solutions allow plts to be stored longer than plts stored in plasma?; and 4) can pathogen-reduced plts be stored for extended time periods similar to non-pathogen reduced plts? Although in vitro tests will be performed to document post-storage plt counts as well as a variety of assays to determine post-storage plt function, metabolism and apoptosis, the post-storage quality of the extended stored plts will be based on in vivo measurements in normal volunteers and thrombocytopenic patients. Specifically, radiolabeled plt recovery and survival measurements of extended stored autologous plts in normal volunteers will be used to determine post-storage plt viability for all types of plt products stored in plasma versus a storage solution. For plts that are stored for longer than 8 days and/or are stored in a storage solution, transfusion studies in the thrombocytopenic patients will be used to evaluate plt viability by measuring the radiolabeled recovery and survival of the donors' plts following transfusion. Alternatively, patient responses to transfused donor plts will be determined by measuring post-transfusion plt increments, corrected count increments, and days-to-next transfusion. Plt function (i.e., hemostasis) following the transfusion of extended stored donor plts will be monitored by plt count versus bleeding time measurements and by radiochromium-labeled stool blood loss studies. At the conclusion of these studies, we should know how long each type of plts can be stored in plasma or Plasmalyte, the relative merits of each type of plts, and whether the extended stored plts are both viable and functional when given to thrombocytopenic patients. (End of Abstract)