Abstract Number: PB1910
Meeting: ISTH 2020 Congress
Background: Dysfunction in the VWF:ADAMTS13 axis plays a critical role in thrombosis, and has been proposed to be dysregulated in antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE) patients. However, possible differences between APS and SLE and associations with thrombotic history remain undefined.
Aims: To establish plasma VWF, ADAMTS13 and ADAMTS13 autoantibodies levels in both disorders and possible differences; and associations with antiphospholipid antibody (aPL) status and thrombotic history in a cross-sectional study.
Methods: Plasma VWF and ADAMTS13 antigen levels were measured by ELISA in 97 APS, 49 SLE (aPL-), 29 thrombotic controls (TC) and 66 healthy controls (HC). Samples with low ADAMTS13 antigen (< 100ng/mL) were tested for IgM anti-ADAMTS13 antibodies and ADAMTS13 activity. Clinical history and aPL status were accessed from medical records.
Results: In this ongoing study, VWF antigen levels were significantly higher in APS (median 1.3 IU/ml; 95% CI 1.1-1.5; p< 0.0001), SLE (1.8 IU/ml; 1.6-2.0; p< 0.0001) and TC (1.4 IU/ml; CI 1.1-1.8;
p< 0.0001) compared to HC (mean: 0.8 IU/ml; 0.7-1.0). SLE patients demonstrated higher VWF levels than APS (p=0.001). ADAMTS13 levels were significantly lower in APS (138.9; 123.7-157.1;
p< 0.0001) and SLE (175.3; 154.2-205.3; p=0.01) patients compared to HC (234.8; 197.7-283.3), and significantly lower in APS compared to SLE patients (p=0.0002). 58% (11/19) of APS patients tested so far were positive for IgM anti-ADAMST13 antibodies. No differences in plasma VWF:Ag and ADAMTS13 antigen levels were observed between aPL+ and aPL- patients. No differences in VWF:Ag levels were observed between APS patients with venous (n=61) and arterial (n=25) thrombosis. Notably, APS patients with venous thromboembolism (VTE) had higher VWF:Ag compared to obstetric morbidity (p=0.01).
Conclusions: The mechanisms underlying VWF:ADAMTS13 dysregulation appear to differ between SLE and APS and in APS with VTE or obstetric morbidity, with these differences possibly explained by differential underlying pathogenic mechanisms.
To cite this abstract in AMA style:Dang MN, Thiagarajan R, Mackie I, Cohen H, Isenberg D, McKinnon T, Efthymiou M. Does the von Willebrand Factor: ADAMTS-13 Axis Differ between Antiphospholipid Syndrome and Systemic Lupus Erythematosus? [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/does-the-von-willebrand-factor-adamts-13-axis-differ-between-antiphospholipid-syndrome-and-systemic-lupus-erythematosus/. Accessed January 28, 2022.
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