Dahlbäck B, Nilsson I M, Frohm B
Blood. 1983 Jul;62(1):218-25.
Lupus anticoagulants are spontaneously occurring antibodies with specificity for negatively charged phospholipids. The plasma of a patient with such a polyclonal antibody of IgM type demonstrated low levels of factor VIII coagulant activity (VIII:C) and factors IX, XI and XII when analyzed by biologic clotting assays, whereas in immunochemical assays, normal levels of VIII coagulant antigen and factor IX were obtained. After immunoadsorption of patient plasma with anti-IgM Sepharose, normal biologic activities were demonstrated in clotting assays for VIII:C, factors IX, XI, and XII. The addition of the patient's isolated IgM to normal plasma resulted in grossly abnormal results in these coagulation assays, and a pattern similar to that of the patient's plasma was obtained. The inhibitory effect of the patient's lupus anticoagulant on blood coagulation was demonstrated also in platelet-rich plasma. The results of the clotting assays indicated that the anticoagulant inhibited several of the reactions in the blood coagulation cascade. The availability of purified components made it possible to demonstrate an inhibiting effect on the activation of prothrombin by factor Xa in the presence of isolated platelets, as well as in a system where purified factor V and well defined phospholipid vesicles were substituted for the platelets.
狼疮抗凝物是对带负电荷磷脂具有特异性的自发产生的抗体。当通过生物凝血试验分析时，患有这种IgM型多克隆抗体的患者血浆显示出低水平的凝血因子VIII促凝活性（VIII:C）以及因子IX、XI和XII，而在免疫化学试验中，获得了正常水平的VIII凝血抗原和因子IX。用抗IgM琼脂糖凝胶对患者血浆进行免疫吸附后，在VIII:C、因子IX、XI和XII的凝血试验中显示出正常的生物活性。将患者分离出的IgM添加到正常血浆中，在这些凝血试验中导致了严重异常的结果，并且获得了与患者血浆相似的模式。患者狼疮抗凝物对血液凝固的抑制作用在富含血小板的血浆中也得到了证实。凝血试验的结果表明，该抗凝物抑制了血液凝固级联反应中的几种反应。纯化成分的可得性使得能够证明在存在分离的血小板的情况下，以及在一个用纯化的因子V和明确的磷脂囊泡替代血小板的系统中，对因子Xa激活凝血酶原具有抑制作用。
