Hematology Department, Faculty of Medical Laboratory Sciences, Port Sudan Ahlia College, Port Sudan, Sudan.
J Med Case Rep. 2021 May 7;15(1):238. doi: 10.1186/s13256-021-02813-6.
The plasma serine protease inhibitor alpha 2-antiplasmin (α-AP, otherwise known as α-plasmin inhibitor) is a rapid-acting plasmin inhibitor recently found in human plasma, which seems to have a significant role in the regulation of in vivo fibrinolysis. Congenital deficiency of α-AP is extremely uncommon.
We report here a case of absolute deficiency of α-AP in an 11-year-old Sudanese boy, who had a lifelong intermittent hemorrhagic tendency (gum bleeding, epistaxis, and exaggerated bleeding after trauma). Coagulation tests including prothrombin time, partial thromboplastin time, thrombin time, bleeding time, platelet count, clot retraction test, antithrombin, and factor VIII levels were within normal limits. Hepatic function tests and complete blood count were also normal. The main interesting finding in this patient was that the whole blood clot lysis was extremely fast, completed within 5-8 hours. The second abnormal finding is that the euglobulin clot lysis time was short. Nevertheless, the concentration of α-AP in the patient's plasma was 0.2 IU/ml (reference range is 0.80-1.20 IU/ml). The addition of pooled plasma (with normal α-AP) to the patient's whole blood corrected the accelerated fibrinolysis.
The study showed that α-AP deficiency resulted in uninhibited fibrinolysis that caused the hemorrhagic tendency in this patient. Thus, this report demonstrates the significant role of α-AP in coagulation.
血浆丝氨酸蛋白酶抑制剂 α2-抗纤溶酶（α-AP，也称为 α-纤溶酶抑制剂）是最近在人血浆中发现的一种快速作用的纤溶酶抑制剂，它似乎在调节体内纤维蛋白溶解中起着重要作用。先天性 α-AP 缺乏极为罕见。
我们在此报告一例 11 岁苏丹男孩的 α-AP 完全缺乏症，他一生都有间歇性出血倾向（牙龈出血、鼻出血和创伤后出血加重）。凝血试验包括凝血酶原时间、部分凝血活酶时间、凝血酶时间、出血时间、血小板计数、凝血块回缩试验、抗凝血酶和因子 VIII 水平均在正常范围内。肝肾功能检查和全血细胞计数也正常。该患者的主要有趣发现是全血凝块溶解非常快，在 5-8 小时内完成。第二个异常发现是优球蛋白溶解时间短。然而，患者血浆中的 α-AP 浓度为 0.2IU/ml（参考范围为 0.80-1.20IU/ml）。将正常的 α-AP 加入患者的全血中可纠正纤溶加速。
研究表明，α-AP 缺乏导致纤溶不受抑制，从而导致该患者的出血倾向。因此，本报告表明 α-AP 在凝血中的重要作用。
