Department of Immunohaematology and Transfusion Medicine, "Papa Giovanni XXIII" Hospital, Bergamo, Italy.
Department of Internal Medicine, "Fondazione IRCCCS Policlinico San Matteo", University of Pavia, Italy.
Blood Transfus. 2017 Sep;15(5):413-421. doi: 10.2450/2016.0033-16. Epub 2016 Oct 4.
Patients with thalassaemia may have thromboembolic events and, even without thrombosis, they have a subclinical hypercoagulable state. In this setting, several coagulation laboratory abnormalities have been described, but thus far no studies have explored the contribution of platelet adhesive and procoagulant properties to blood clotting activation. In this study, we dissected the platelet procoagulant effect and influence of blood transfusions on haemostasis and platelet function in thalassaemic patients.
Sixteen subjects with thalassaemia were studied (9 with transfusion-dependent β-thalassaemia, 7 "trait" carriers). Splenectomised and non-splenectomised patients undergoing blood transfusion were compared. All splenectomised patients were then compared to "trait" carriers and to healthy controls (n=9). The following parameters were measured in transfusion-dependent patients before and after monthly transfusions and compared to those of controls: levels of platelet surface activation markers (P-selectin, tissue factor, and fibrinogen), whole blood platelet aggregation, tissue factor or adenosine diphosphate (ADP)-induced platelet thrombin generation (TG) potential, and D-dimer.
Before transfusion, platelets from splenectomised patients showed significantly higher ADP-induced tissue factor expression, ADP- and collagen-induced platelet aggregation and TG potential than those from non-splenectomised patients and controls. Blood transfusion in splenectomised patients reduced platelet activation, aggregation and TG potential.
Splenectomised patients with β-thalassaemia had a prothrombotic state, characterised by enhanced platelet reactivity and function, and high platelet-induced TG potential. One hour after blood transfusions platelet and coagulation parameters improved, supporting the hypothesis that transfusion might have a protective role on platelet haemostatic status.
患有地中海贫血症的患者可能会发生血栓栓塞事件，即使没有血栓形成，他们也存在亚临床高凝状态。在这种情况下，已经描述了几种凝血实验室异常，但迄今为止，尚无研究探讨血小板黏附和促凝特性对血凝块激活的贡献。在这项研究中，我们剖析了血小板促凝作用以及输血对地中海贫血患者止血和血小板功能的影响。
研究了 16 名地中海贫血症患者（9 名依赖输血的β地中海贫血症患者，7 名“特征”携带者）。比较了接受输血的脾切除术和非脾切除术患者。然后，将所有脾切除术患者与“特征”携带者和健康对照者（n=9）进行比较。在每月输血前后测量依赖输血的患者的以下参数，并与对照者进行比较：血小板表面活化标志物（P-选择素、组织因子和纤维蛋白原）水平、全血血小板聚集、组织因子或二磷酸腺苷（ADP）诱导的血小板凝血酶生成（TG）潜能和 D-二聚体。
脾切除术患者的血小板在输血前显示出明显更高的 ADP 诱导的组织因子表达、ADP 和胶原诱导的血小板聚集和 TG 潜能，高于非脾切除术患者和对照者。脾切除术患者的输血减少了血小板活化、聚集和 TG 潜能。
β地中海贫血症的脾切除术患者存在促血栓形成状态，其特征为血小板反应性和功能增强，以及血小板诱导的 TG 潜能升高。输血后 1 小时，血小板和凝血参数得到改善，支持输血可能对血小板止血状态具有保护作用的假说。
