Abstract Number: PB2295
Meeting: ISTH 2020 Congress
Theme: Venous Thromboembolism and Cardioembolism » VTE Diagnosis
Background: We describe a patient with severe acquired functional deficiency of protein S (PS) and protein C (PC). The patient with a history of inflammatory bowel disease and primary biliary cirrhosis without long term specific treatment suffered from two spontaneous venous thromboembolic events in one year. He was treated with warfarin for twelve months when he developed skin necrosis. Subsequently, very low PS levels, low levels of PC and acquired APC (activated protein C) resistance were found.
Aims: The aim was to elucidate the underlying cause of PS deficiency in our patient.
Methods: We measured PS (activity, free PS, total PS) and PS inhibitor (Bethesda) and anti-PS IgG antibodies (ELISA Zymutest, Hyphen). We also measured PC (activity, antigen). The direct Sanger sequencing of all exons of PROS1 was performed.
Results: The patient had to be treated with long term therapeutic doses of LMWH in order to prevent a new thromboembolic event. Attempts to switch him to DOACs resulted in severe side effects. A thorough laboratory testing and diagnostic imaging revealed no other underlying disease or cause of thrombophilia. Five months later, immunosuppressive treatment with prednisone and azathioprine was initiated by patient’s hepatologist. Beside improving clinical condition, the treatment led to a fast increase of PS activity (Fig. 1). PC activity also increased (0,27 to 0,55 IU/ml). The LMWH dose could be lowered progressively. In light of these results we investigated possible presence of anti-PS antibodies, however it was not confirmed by Bethesda or anti‑PS ELISA. We did not find any mutation in PROS1 gene.
Conclusions: We ruled out inherited PS deficiency and the presence of specific antibodies. However, PS and PC levels increased after immunosuppressive treatment, which suggests the presence of inhibitory antibodies in the APC pathway, that might have a clinical effect on thrombosis in our patient.
[Figure 1: PS levels and anti-Xa activity during the follow-up. Initiation of prednison treatment is highlighted. ]
To cite this abstract in AMA style:
Fenclova T, Geierova V, Zemanova M, Salaj P, Hrachovinova I. Acquired Type II (IIb) Protein S Deficiency, Case Report [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/acquired-type-ii-iib-protein-s-deficiency-case-report/. Accessed April 19, 2024.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/acquired-type-ii-iib-protein-s-deficiency-case-report/