抗磷脂综合征合并静脉血栓和蛋白C活性异常1例研究报告

Antiphospholipid syndrome associated with venous thrombosis and abnormal protein C activity

目的:探讨抗磷脂综合征(antiphospholipid syndrome,APS)患者静脉血栓形成的原因。方法:对1例APS患者用发色底物法测定蛋白C活性(PC:A)、蛋白S活性(PS:A)和抗凝血酶活性;用ELISA方法测定PC、血浆纤溶酶原、血浆组织型纤溶酶原激活物、血浆纤溶酶原激活抑制物-1、α_2-抗纤溶酶抗原和抗心磷脂抗体(ACA)。活化蛋白C抵抗(APC-R)检测结果以受检者血浆加入APC后的AgTT与未加APC血浆的APTT的比值表示,比值<2.0时为APC-R阳性。狼疮抗凝物质(LA)检测使用以dRVVT为基础的商品化试剂盒。采用PCR扩增和直接测序,检测PC的基因及FV Leiden和凝血酶原G20210A的突变。结果:本例患者LA和APC-R阳性,PC:A降低,PC抗原量增加,其他结果正常。PC基因所有外显子测序结果正常,FV Leiden突变和凝血酶原G20210A突变未检出。结论:LA可能通过抑制PC途径导致患者发生血栓,联合检测ACA、APC-R、抗凝蛋白抗原及活性有利于血栓性疾病的病因学诊断。

Objective To investigate the cause of venous thrombosis associated with antiphospholipid syndrome （APS）. Methods The plasma levels of protein C activity （PC：A）, protein S activity（PS：A） and antithrombin activity （AT：A） were detected using chromogenic assay. Protein C antigen （PC：Ag）, plasminogen antigen （PLG：Ag）, tissue plasminogen activator antigen （t-PA：Ag）. plasminogen activator inhibitor-1 antigen （PAI-I：Ag）, α2-antiplasmin antigen（α2-AP：Ag） and anticardiolipin antibodies（ACA）were measured by an enzyme-linked immunosorbent assay（ELISA）. Resistance to activated protein C （APC-R） was studied by an AFIT-based （clotting） assay and expressed as the ratio between the APTT obtained in the presence and absence of exogenous APC, the ratio lower than 2.0 was regarded as APC-R positive. Lupus anticoagulant （LA） was detected by commercial kits, based on dRVVT. The PC gene, FV Leiden and prothrombin G20210A mutation were amplified by polymerase chain reaction （PCR） and directly sequenced. Results The presence of LA and APC-R was associated with the decreased PC：A level and the augmented PC：Ag level. All exons of PC gene were identified as normal. Neither FV Leiden mutation nor prothrombin G20210A mutation were found in the patient. Conclusions LA may cause thrombosis via interfering the activity of protein C. Combined detection of ACA, APC-R and antigen and activity of antieoagulation proteins may be useful for the etiological diagnosis of thrombotic diseases.