Low extracellular vesicle-associated tissue factor activity in patients with persistent lupus anticoagulant and a history of thrombosis

摘要

Lupus anticoagulants (LA) are a heterogeneous group of antiphospholipid antibodies (aPLAs) that promote thrombosis. Tissue factor (TF)-bearing extracellular vesicles (EVs) might contribute to the prothrombotic state of patients with persistent LA and a history of thrombosis. To investigate if EV-associated TF activity is elevated in a well-defined group of LA-positive patients with a history of thrombosis in comparison to that of healthy controls. Adult patients (n=94, median age 40.1years, interquartile range (IQR) 29.9-53.4; 87% females) positive for LA and a history of thrombosis (78% venous thrombosis, 17% arterial thrombosis, 5% venous thrombosis and arterial thrombosis) and healthy age- and sex-matched controls (n=30, median age 42.9years, IQR 38.6-45.8, 77% females) were included in this study. EV-TF activity was determined with a factor Xa generation assay and anti-2-glycoprotein (anti-2GPI) and anticardiolipin (aCL) antibodies by enzyme-linked immunoassays. EV-TF activity did not differ between 94 LA-positive patients with a history of thrombosis (median 0.05pg/mL, IQR 0.00-0.14) and 30 healthy controls (median 0.06, IQR 0.00-0.11, p=0.7745). No correlation was found between EV-TF activity and lupus-sensitive activated partial thromboplastin time (aPTT-LA) (rho=0.034), Rosner index (rho=-0.056), anti-2GPI IgG (rho=0.05), anti-2GPI IgM (rho=-0.08), aCL IgG (rho=0.12), and aCL IgM (rho=-0.11) in LA-positive patients. We found low EV-TF activity levels in LA-positive patients and a history of thrombosis and no correlation with analyzed aPLAs. Our data indicate that circulating TF-bearing EVs do not contribute to the prothrombotic state of patients with LA.