Abstract Number: PB0226
Meeting: ISTH 2020 Congress
Theme: Coagulation and Natural Anticoagulants » Coagulation Factors and Inhibitors
Background: Anti-factor V antibodies (anti-FVAb) rarely occur and mostly in association with autoimmune diseases, cancer, infections, and surgery. Half patients develop bleeding complications. Therapeutic approaches to remove the inhibitor include immunosuppressants, intravenous immunoglobulins and plasmapheresis.
Aims:
Methods:
Results: A 63-year-old man underwent a liver transplantation for hepatocellular carcinoma. On day 19 coagulation tests were prolonged, with a PT ratio of 4.70 (mix 1.42) and a aPTT ratio of 2.76 (mix 0.95). Factor V activity was < 1% with an anti-FV antibody (Ab) of 0.75 BU. Patient's therapy included tacrolimus which previously showed to induce an anti-FVAb1. Hence, at day 20 tacrolimus was discontinued and prednisone 1 mg/kg/day was started, with a normalization of PT and aPTT ratio and FV activity levels at day 28. During the whole clinical course the patient had no bleeding complications. ELISA assay was used to detect Ig antibodies. Data on FV activity, anti-factor V inhibitor and plasma levels of tacrolimus are reported in figure 1. At variance with previously described1, no reduction of FV activity was detected when tacrolimus alcoholic solutions were added to patient’s plasma (collected when FV levels were normal). Thus, we hypothesized that a structurally different FV was produced by the transplanted liver and that may have induced the development of the anti-FVAb. Genetic analysis of FV gene in the donor and recipient was performed and two discordant single nucleotide variants (SNVs) were observed between donor and recipient DNA. We also observed a slightly reduced inhibitory activity of the anti-FVAb on wild type than on mutated FV (figure 2).
Conclusions: In our patient, the hypothesis of a tacrolimus-dependent acquired inhibitor was ruled out. The genetic variants on FV gene might played a role on the anti-FVAb development.
1 Leroy-Matheron C et al. Transplantation. 1999 Oct 15;68(7):1054-6.
To cite this abstract in AMA style:
Ciavarella A, Artoni A, Capecchi M, Bhoori S, Mazzaferro V, Novembrino C, Cairo A, Clerici M, Valsecchi C, Peyvandi F, Martinelli I. Anti-factor V Inhibitor after Liver Transplantation [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/anti-factor-v-inhibitor-after-liver-transplantation/. Accessed March 21, 2024.« Back to ISTH 2020 Congress
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