[A Case of Lupus Anticoagulant-Hypoprothrombinemia Syndrome with Phosphatidylserine-Dependent Anti-Prothrombin Antibody].

Lupus anticoagulant-hypothrombinemia syndrome (LAHS) is a rare disease involving hemorrhagic diathe- sis due to hypothrombinemia with lupus anticoagulant. We report a 28-week-pregnant woman at twenty years of age, who had been hospitalized with jaundice. In laboratory data, AST, ALT, and bilirubin were elevated and the prothrombin time (PT) and activated partial thromboplastin time (APTT) were prolonged. Although the liver failure was improved after she delivered a baby by Caesarean section, postoperative intraperitoneal bleeding persisted. The diagnosis by liver biopsy was autoimmune hepatitis. Although the bleeding was stopped on the seventh postoperative day, the prolongation of PT and APTT remained. LA was positive in the diluted Russell's viper venom time. Anti-cardiolipin and anti-beta-2-glycoprotein anti- bodies were also positive. The prothrombin activity was reduced. A high titer of phosphatidylserine- dependent antiprothrombin antibody (aPS/PT), which causes bleeding, was observed. Based on these data, she was diagnosed with LAHS. The liver dysfunction and prolongation of PT and APTT were normalized following the administration of corticosteroids. In this case, aPS/PT may have contributed to the pathological physiology of LAHS. [Case Report].

Factor Xa inhibitors: new anti-thrombotic agents and their characteristics.

Factor Xa (FXa) is a key enzyme that is positioned at the convergence of the intrinsic and extrinsic pathways in the blood coagulation cascade, and inactivation by a specific FXa inhibitor effectively prevents the generation of thrombin. Various types of low molecular weight (LMW) heparin, which function as semi-selective and indirect FXa inhibitors, are replacing unfractionated heparin (UFH) as agents for the prevention and treatment of venous thromboembolism (VTE), as well as in initial treatment for coronary events. Of those, heparinoid has been shown to be safer and more effective for the prevention of postoperative VTE than UFH, especially for treatment of heparin-induced thrombocytopenia (HIT). Further, synthetic pentasaccharide has been found to offer advantages over current thromboprophylactic regimens in a number of patients undergoing major orthopedic surgery. Other studies have shown that pentasaccharide is more effective for overall VTE in comparison with LMW heparin, though it was also associated with an increased rate of major bleeding. Synthetic, selective, and direct inhibitors to FXa, such as DX-9065a, are highly potent and orally bioavailable antithrombotic agents that have demonstrated an improved side effect profile, probably by allowing sufficient thrombin to remain for platelet activation and normal hemostasis, while preventing pathological thrombus formation. For thrombosis therapy, the most desirable type of antithrombotic agent is an orally active drug that has a broad range of effective doses and no hemorrhagic side effects. Presently, many types of direct inhibitors are in various stages of clinical trials and expected to provide significant benefits as compared to currently utilized therapy strategies.