Immunology Laboratory, Department of Rheumatology, University Medical Centre, Ljubljana, Slovenia.
Clin Chem Lab Med. 2011 Jun;49(6):1011-8. doi: 10.1515/CCLM.2011.162. Epub 2011 May 17.
Two approaches for detecting anti-prothrombin antibodies have been described. The first detects antibodies against prothrombin alone and the second, phos-phatidylserine-dependent antiprothrombin antibodies. The latter more often correlate with clinical manifestations of antiphospholipid syndrome and with lupus anticoagulant activity.
In order to increase the capacity of antibody binding, we modified the previously described phosphatidylser-ine-dependent antiprothrombin ELISA and determined their avidity. We examined 203 patients with systemic autoimmune diseases and 222 blood donors.
Our modification resulted in a greater intensity of antibody binding to prothrombin on phosphatidylserine-coated plate surfaces compared to the previously described method. By changing ELISA conditions, we were able to detect with one assay the two, presumably different, populations of antiprothrombin antibodies. Diagnostic specificities of both ELISAs for antiphospholipid syndrome were similar (92.5% vs. 93.1%), while the sensitivity of the modified phosphatidylserine-dependent antiprothrombin ELISA was significantly higher than the anti-prothrombin alone ELISA (59% vs. 25%). Low avidity antiprothrombin antibodies were only detected in the modified phosphatidylserine-dependent antiprothrombin ELISA. Four percent of patients with positive phosphatidylserine-dependent antiprothrombin antibodies, showing clinical manifestations of antiphospholipid syndrome, were negative for all other antiphospholipid antibodies. The risk for antiphospholipid syndrome increased with the number of antiphospholipid antibody positivity.
We conclude that antibodies detected with a modified phosphatidylserine-dependent antiprothrombin ELISA could improve the diagnosis of antiphospholipid syndrome by offering additional information on the risk for thrombosis, especially in patients negative for other antiphospholipid antibodies.
已经描述了两种检测抗凝血酶原抗体的方法。第一种方法仅检测针对凝血酶原的抗体，第二种方法检测磷脂酰丝氨酸依赖性抗凝血酶原抗体。后者与抗磷脂综合征的临床表现和狼疮抗凝物活性的相关性更高。
为了增加抗体结合的能力，我们修改了以前描述的磷脂酰丝氨酸依赖性抗凝血酶原 ELISA，并确定了它们的亲和力。我们检查了 203 例系统性自身免疫性疾病患者和 222 名献血者。
与以前描述的方法相比，我们的改进导致凝血酶原在磷脂酰丝氨酸包被的平板表面上的抗体结合强度增加。通过改变 ELISA 条件，我们能够用一种测定法检测两种可能不同的抗凝血酶原抗体。两种 ELISA 对抗磷脂综合征的诊断特异性相似（92.5%对 93.1%），而改良的磷脂酰丝氨酸依赖性抗凝血酶原 ELISA 的敏感性明显高于单独抗凝血酶原 ELISA（59%对 25%）。只有在改良的磷脂酰丝氨酸依赖性抗凝血酶原 ELISA 中才能检测到低亲和力的抗凝血酶原抗体。4%的磷脂酰丝氨酸依赖性抗凝血酶原抗体阳性且表现出抗磷脂综合征临床表现的患者对所有其他抗磷脂抗体均为阴性。抗磷脂抗体阳性的数量增加了发生抗磷脂综合征的风险。
我们得出结论，用改良的磷脂酰丝氨酸依赖性抗凝血酶原 ELISA 检测到的抗体可以通过提供有关血栓形成风险的更多信息来改善抗磷脂综合征的诊断，特别是在对其他抗磷脂抗体阴性的患者中。
