Bajaj S P, Rapaport S I, Fierer D S, Herbst K D, Schwartz D B
Blood. 1983 Apr;61(4):684-92.
Antibodies that bind prothrombin without neutralizing its coagulant activity were demonstrated in the plasma of two patients with the acquired hypoprothrombinemia-lupus anticoagulant syndrome. The first patient's plasma contained less than 1% prothrombin activity and no detectable prothrombin antigen. The second patient's plasma contained about 6% of both prothrombin activity and antigen. Neither patient's plasma neutralized the prothrombin coagulant activity of normal plasma or of purified prothrombin added in vitro. Nevertheless, double immunodiffusion studies and binding experiments utilizing 125I-prothrombin demonstrated the presence of prothrombin antibodies in each patient's plasma. A Scatchard analysis of the binding data obtained with different concentrations of 125I-prothrombin and the first patient's plasma indicated the presence of a high affinity antibody, apparent Kd approximately 10(-10)M, and a lower affinity antibody, apparent Kd approximately 10(-9)M. Studies utilizing purified cleavage products of prothrombin suggested that the antibodies were directed against an epitope or epitopes located on the carboxyl-terminal, latent thrombin segment of the prothrombin molecule. We postulate that the acquired hypoprothrombinemia in these two patients and in other reported patients with the acquired hypoprothrombinemia-lupus anticoagulant syndrome stems from rapid clearance from the circulation of prothrombin antigen-antibody complexes.
在两名获得性低凝血酶原血症-狼疮抗凝物综合征患者的血浆中，发现了能结合凝血酶原但不中和其凝血活性的抗体。第一名患者的血浆中凝血酶原活性低于1%，且检测不到凝血酶原抗原。第二名患者的血浆中凝血酶原活性和抗原均约为6%。两名患者的血浆均未中和正常血浆或体外添加的纯化凝血酶原的凝血活性。然而，双向免疫扩散研究以及利用125I-凝血酶原进行的结合实验表明，每名患者的血浆中均存在凝血酶原抗体。对用不同浓度的125I-凝血酶原与第一名患者的血浆获得的结合数据进行Scatchard分析，结果表明存在一种高亲和力抗体，表观解离常数（Kd）约为10（-10）M，以及一种低亲和力抗体，表观Kd约为10（-9）M。利用凝血酶原的纯化裂解产物进行的研究表明，这些抗体针对的是位于凝血酶原分子羧基末端潜在凝血酶片段上的一个或多个表位。我们推测，这两名患者以及其他报道的获得性低凝血酶原血症-狼疮抗凝物综合征患者的获得性低凝血酶原血症，是由于凝血酶原抗原-抗体复合物从循环中快速清除所致。
