Abstract Number: PB0437
Meeting: ISTH 2021 Congress
Background: FVIII and von Willebrand factor antigen (vWFAg) levels are similar in healthy subjects and the FVIII/vWF ratio is therefore > 0.7. In acquired haemophilia A (AHA), this ratio decreases during the acute phase and its normalization could predict a favorable outcome.
Aims: The objective of our study was to analyses how evolved the FVIII/vWF ratio during the follow-up of AHA patients according to their clinical evolution.
Methods: We retrospectively included 45 AHA patients. Complete remission (CR) was defined in a patient on corticosteroid therapy (CST) receiving ≤ 15mg/day prednisone without further immunosuppressive therapy (IST) with anti-FVIII < 0.6BU/mL and FVIII >70%. Partial remission (PR) was defined in patients with anti-FVIII <0.6BU/mL and FVIII >70%, but always on IST. Relapse was defined when anti-FVIII titre became >0.6BU/mL after previous remission. Eight patients were excluded from the final analysis due to insufficient biological data.
Results: Of the 37 patients, 24 showed remission, including 16 with CR and 8 who relapsed after a median of 103 days. Thirteen others did not exhibit remission after a median follow-up of 97 days. Among the 13 patients without initial remission, FVIII levels remained below 15%, while vWFAg levels were above 150%, leading to a dramatic decrease in the FVIII/vWF ratio.
Conversely, in the 16 patients with CR, APTT and FVIII levels normalized over time, as did vWFAg levels (between 150 and 300% in the acute phase) and the FVIII/vWF ratio.
For the 8 patients with remission followed by relapse, the FVIII/vWF ratio remained lower during the remission (ratio=0.556 [0.248-0.985]), and then decreased significantly during the relapse (ratio=0.023 [0.002-0.17]; p=0.029).
Conclusions: Our study shows that the evolution of the FVIII/vWF ratio during AHA is highly predictive of the clinical course. A decrease of the ratio could be a sensitive marker of relapse in patients with an apparent remission of AHA.
To cite this abstract in AMA style:Coulongeat M, Baglo T, Faucheux L, Vayne C, Maillot F, Ferreira-Maldent N, Pouplard C. Why Measure von Willebrand Factor Levels for Biological Follow-up of Acquired Haemophilia A Patients? [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/why-measure-von-willebrand-factor-levels-for-biological-follow-up-of-acquired-haemophilia-a-patients/. Accessed November 27, 2021.
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