Abstract：
BACKGROUND: Glanzmann thrombasthenia (GT) is caused by an inherited defect of platelet αIIbβ3 integrin. Concizumab,a monoclonal antibody specific for Tissue Factor Pathway Inhibitor (TFPI), abolishes its anticoagulant effect.
OBJECTIVE: To evaluate the in vitro ability of concizumab to improve haemostasis in GT.
METHODS: The effects of concizumab were evaluated in whole blood or platelet-rich plasma (PRP) from GT patients (n=5-9) using a thrombin generation assay (TGA), rotational thromboelastometry (ROTEM), a global fibrinolytic capacity assay and a flow-chamber assay (T-TAS). Washed platelets (WP) and 20 nM recombinant activated factor VIIa (rFVIIa) were included for comparison.
RESULTS: The lag time in the TGA was significantly longer (+85%, p<0.0001) in GT patients than in controls. WP, rFVIIa and concizumab each significantly improved thrombin generation profiles. The ROTEM clotting time was significantly longer in GT patients than in controls (677 s vs 523 s; p=0.03). However, CT improved after adding WP, rFVIIa or concizumab. Under flow, occlusive thrombi were present in all healthy controls after 10 min, whereas platelet-fibrin depositions were not seen in GT patients. Sub-occlusive or occlusive thrombi formed when GT blood was mixed with WP, rFVIIa or concizumab. Clots in GT PRP were more susceptible to fibrinolysis and were improved by WP, rFVIIa or concizumab.
CONCLUSIONS: Concizumab enhanced thrombin generation, decreased the ROTEM CT, improved thrombus formation under flow and reduced clot lysis. Our results demonstrate the potential of concizumab for subcutaneous prophylaxis in GT patients.
OBJECTIVE: To evaluate the in vitro ability of concizumab to improve haemostasis in GT.
METHODS: The effects of concizumab were evaluated in whole blood or platelet-rich plasma (PRP) from GT patients (n=5-9) using a thrombin generation assay (TGA), rotational thromboelastometry (ROTEM), a global fibrinolytic capacity assay and a flow-chamber assay (T-TAS). Washed platelets (WP) and 20 nM recombinant activated factor VIIa (rFVIIa) were included for comparison.
RESULTS: The lag time in the TGA was significantly longer (+85%, p<0.0001) in GT patients than in controls. WP, rFVIIa and concizumab each significantly improved thrombin generation profiles. The ROTEM clotting time was significantly longer in GT patients than in controls (677 s vs 523 s; p=0.03). However, CT improved after adding WP, rFVIIa or concizumab. Under flow, occlusive thrombi were present in all healthy controls after 10 min, whereas platelet-fibrin depositions were not seen in GT patients. Sub-occlusive or occlusive thrombi formed when GT blood was mixed with WP, rFVIIa or concizumab. Clots in GT PRP were more susceptible to fibrinolysis and were improved by WP, rFVIIa or concizumab.
CONCLUSIONS: Concizumab enhanced thrombin generation, decreased the ROTEM CT, improved thrombus formation under flow and reduced clot lysis. Our results demonstrate the potential of concizumab for subcutaneous prophylaxis in GT patients.
摘要：
背景：Glanzmann血栓减少症（GT）是由血小板αIIbβ3整合素的遗传性缺陷引起的。康西单抗，一种特异于组织因子途径抑制剂（TFPI）的单克隆抗体，消除其抗凝血作用。
目的：评价康西单抗改善GT止血的体外能力。
方法：使用凝血酶生成测定法（TGA），在GT患者（n=5-9）的全血或富含血小板的血浆（PRP）中评估了康西单抗的作用，旋转血栓弹性测定法（ROTEM），全局纤溶能力测定和流室测定(T-TAS)。包括洗涤的血小板(WP)和20nM重组活化因子VIIa(rFVIIa)用于比较。
结果：TGA的滞后时间明显更长（+85%，GT患者的p<0.0001）高于对照组。WP,rFVIIa和cencizumab均显著改善凝血酶生成谱。GT患者的ROTEM凝血时间明显长于对照组（677svs523s；p=0.03）。然而,CT在添加WP后得到改善，rFVIIa或康西珠单抗。在流动下，10分钟后，所有健康对照组均存在闭塞性血栓，而GT患者未见血小板-纤维蛋白沉积。当GT血液与WP混合时形成亚闭塞性或闭塞性血栓，rFVIIa或康西珠单抗。GTPRP中的凝块更容易发生纤维蛋白溶解，并被WP改善，rFVIIa或康西珠单抗。
结论：康西单抗增强凝血酶生成，降低了ROTEM的CT，改善流动下的血栓形成并减少凝块溶解。我们的结果证明了康西单抗用于GT患者的皮下预防的潜力。
目的：评价康西单抗改善GT止血的体外能力。
方法：使用凝血酶生成测定法（TGA），在GT患者（n=5-9）的全血或富含血小板的血浆（PRP）中评估了康西单抗的作用，旋转血栓弹性测定法（ROTEM），全局纤溶能力测定和流室测定(T-TAS)。包括洗涤的血小板(WP)和20nM重组活化因子VIIa(rFVIIa)用于比较。
结果：TGA的滞后时间明显更长（+85%，GT患者的p<0.0001）高于对照组。WP,rFVIIa和cencizumab均显著改善凝血酶生成谱。GT患者的ROTEM凝血时间明显长于对照组（677svs523s；p=0.03）。然而,CT在添加WP后得到改善，rFVIIa或康西珠单抗。在流动下，10分钟后，所有健康对照组均存在闭塞性血栓，而GT患者未见血小板-纤维蛋白沉积。当GT血液与WP混合时形成亚闭塞性或闭塞性血栓，rFVIIa或康西珠单抗。GTPRP中的凝块更容易发生纤维蛋白溶解，并被WP改善，rFVIIa或康西珠单抗。
结论：康西单抗增强凝血酶生成，降低了ROTEM的CT，改善流动下的血栓形成并减少凝块溶解。我们的结果证明了康西单抗用于GT患者的皮下预防的潜力。
