SERPING1 and Venous thrombosis: Patients with primary APS are mainly women (66.7%, n=2): in all cases, patients show both persistent laboratory evidence of lupus anticoagulant (LA single positive) and recurrent venous thrombosis (along with adverse pregnancy outcomes in one woman); all patients are on vitamin K antagonists (VKA) and 2 patients (75%) are on plasma derived C1INH-LTP at the time of the study.