Molecular Heterogeneity in FVIII Inhibitor Patients

使用FVIII因子(FV11)治疗的重度血友病患者中有30%产生抗FVIII抗体 (抑制剂)。这是血友病A患者治疗中最重要的并发症。 导致发病率和治疗费用的显著增加。针对FVIII的抗体也可以在 以前凝血功能正常导致获得性血友病的患者。这些产生的抗体 可以抑制FVIII的生物活性，有必要使用旁路药物治疗 出血发作。然而，由于不明原因，一些患者对药物的止血反应较差。 旁路治疗。因此，需要改进治疗选择，特别是对严重或危及生命的治疗。 流血事件。已经确定了一些增加抑制剂风险的生物决定因素 发展。然而，血友病基因与终极表位之间的关系却知之甚少。 B细胞反应谱或表位谱如何影响治疗和免疫反应 宽容。我们最近已经证明，C2区域内的表位特异性和抑制物动力学是 获得性血友病血浆和一只小鼠对fV11的反应比抑制物效价更重要 单抗(MAb)系统。该项目的中心假设是抑制物表位 单个患者的频谱可用于预测注射FVIII或不注射FVIII的反应 绕过特工。我们建议使用一个不重叠的大小组进一步定义FVIII上的表位 抗IL-FVIII单抗在多种体外检测中的应用(目标1)。给出了不同的体外培养细胞之间的已知差异 检测和出血表型我们将研究不同表位对小鼠体内出血的重要性 表型和纤维蛋白凝块结构(目标2)。在目标3中，我们将采用我们的新的基于ELISA的表位映射 一种更可靠的基于微球的检测方案，并在横断面研究中研究如何 多克隆患者血浆表位图与体外对FVIII和旁路药物的反应相关。 最终，这些结果可以提供一种简单的临床测试，可以预测对FVIII和旁路的反应 药物用于高滴度获得性血友病和先天性血友病患者。

Thirty percent of patients with severe hemophilia treated with factor fVIII (fVlll) develop anti-fVIII antibodies (inhibitors). This is the most significant complication in the management of patients with hemophilia A leading to significant increases In morbidity as well as cost of treatment. Antibodies to fVIII can also develop in patients with previously normal coagulation leading to acquired hemophilia. These antibodies that develop can inhibit the biological activity of fVIII and necessitate the use of bypassing agents for the treatment of bleeding episodes. However, for unknown reasons, some patients display poor hemostatic response to bypass therapy. Thus, improved treatment options are needed, especially for severe or life-threatening bleeding events. Some biological determinants have been identified that increase the risk of inhibitor development. However, little is known about how hemophilia genotype relates to the ultimate epitope spectrum of the B-cell response or how the epitope spectrum affects the response to treatment and immune tolerance. We have recently shown that epitope specificity and inhibitor kinetics within the C2 domain are more important than inhibitor titer in response to fVlll in acquired hemophilia plasma and a murine monoclonal antibody (MAb) system. The central hypothesis of this project is that the inhibitor epitope spectrum of an individual patient can be used to predict the response to infusions of fVIII with or without bypassing agents. We propose to define further the epitopes on fVIII using a large panel of non-overlapping antl-fVIII MAbs in multiple in vitro assays (Aim 1). Given known discrepancies between the different in vitro assays and bleeding phenotype we will study the importance of different epitopes on murine in vivo bleeding phenotypes and fibrin clot structure (Aim 2). In Aim 3, we will adapt our novel ELISA-based epitope mapping protocol to a more robust microsphere-based assay and investigate in a cross-sectional study how polyclonal patient plasma epitope maps correlate with the response to fVIII and bypassing agents in vitro. Ultimately these results could provide a simple clinical test that may predict response to fVIII and bypassing agents in high titer acquired and congenital hemophilia patients.