Pengo V, Biasiolo A, Rampazzo P, Brocco T
Dept of Cardiology, Thrombosis Center, University of Padova School of Medicine, Italy.
Thromb Haemost. 1999 Feb;81(2):256-8.
Anti-beta2-glycoprotein I (beta2-GPI) antibodies behave as classical Lupus Anticoagulants (LA), as they inhibit phospholipid-dependent coagulation reactions and their activity disappears in the presence of excess exogenous phospholipids (PLs). We have recently shown that a certain amount of PLs in the dilute Russell Viper Venom Time (dRVVT) test system is required to express LA activity of anti beta2-GPI antibodies. We have now extended this observation to two other tests, i.e., Kaolin Clotting Time (KCT) in which PLs are not added, and Tissue Thromboplastin Inhibition test (TTI) in which PLs are extremely diluted. In fact, affinity-purified antibody preparations from 5 patients with antiphospholipid syndrome did not express or only weakly expressed anticoagulant activity in both tests; the mean ratios of coagulation times obtained with purified antibodies and that of control buffer were 1.11 and 1.0 for KCT and TTI, respectively. On the contrary, the mean ratios in dRVVT were 1.31 and 1.49 at a PLs dilution of 1:8 and 1:64, respectively. Therefore, the presence of LA activity due to autoantibodies to beta2-GPI is characterized by a positive dRVVT and negative or only weakly positive KCT and TTI.
抗β2糖蛋白I（β2-GPI）抗体表现为典型的狼疮抗凝物（LA），因为它们抑制磷脂依赖性凝血反应，并且在存在过量外源性磷脂（PL）时其活性消失。我们最近发现，在稀释的罗素蝰蛇毒时间（dRVVT）测试系统中需要一定量的PL来表达抗β2-GPI抗体的LA活性。我们现在已将这一观察结果扩展到另外两项测试，即未添加PL的高岭土凝血时间（KCT）和PL被极度稀释的组织凝血活酶抑制试验（TTI）。事实上，来自5例抗磷脂综合征患者的亲和纯化抗体制剂在这两项测试中均未表现出或仅微弱表现出抗凝活性；纯化抗体与对照缓冲液的凝血时间平均比值在KCT和TTI中分别为1.11和1.0。相反，在PL稀释度为1:8和1:64时，dRVVT中的平均比值分别为1.31和1.49。因此，由抗β2-GPI自身抗体引起的LA活性表现为dRVVT阳性，而KCT和TTI阴性或仅弱阳性。
