ISTH Congress Abstracts

Official abstracts site for the ISTH Congress

MENU 
  • Home
  • Congress Archive
    • ISTH 2022 Congress
    • ISTH 2021 Congress
    • ISTH 2020 Congress
  • Resources
  • Search

Variable Serotonin Release Assay Pattern and Characteristics of PF4-specific Antibodies in Heparin-Induced Thrombocytopenia, and Clinical Impact

N. Charuel1,2, J. Rollin1,3, Y. Gruel1,3, E.-A. Guéry3, M.-A. May4,5, C. Pouplard1,3, C. Vayne1,3

1EA 7501 GICC, University of Tours, Tours, France, 2Diagnostica Stago, Asnières-Sur-Seine, France, 3Department of Haemostasis, University Hospital of Tours, Tours, France, 4Department of Cardiovascular Surgery, University Hospital of Tours, Tours, France, 5Department of Anesthesiology, University Hospital of Tours, Tours, France

Abstract Number: PB0854

Meeting: ISTH 2021 Congress

Theme: Platelet Disorders, von Willebrand Disease and Thrombotic Microangiopathies » HIT

Background: The diagnosis of Heparin-induced thrombocytopenia (HIT) often necessitates functional assays to demonstrate in vitro that antibodies to platelet factor 4 (PF4) are activating platelets, typically only in the presence of therapeutic heparin (H) concentrations (“classical” pattern). More rarely, HIT samples activate platelets even without heparin (“atypical” pattern). However, the clinical significance of such a profile is unclear.

Aims: We aimed to analyze the clinical and biological course of HIT patients according to their platelet activation pattern in serotonin release assay (SRA) and the main characteristics of PF4-specific antibodies.

Methods: We enrolled 74 patients with definite HIT under heparin treatment, and exhibiting in SRA either a “classical” (n=62), or “atypical” pattern (n=12). Titers of IgG to PF4/H complexes and PF4 alone were measured by ELISA in 41 selected patients, and results were analyzed according to the SRA pattern, and bioclinical features.

Results: Higher anti-PF4/H IgG titers were measured in patients with an “atypical” SRA (median OD 2.52 vs. 1.94 in those with a “classical” pattern, p< 0.001). Patients of both groups had similar platelet count (PC) nadir and time to recovery, but those with an “atypical” SRA developed more thrombotic events (66.7 vs. 33.9%, p= 0.05). Significant levels of anti-PF4 IgG (OD > 0.4) were detected in both groups (38% and 58%, respectively). But whatever the SRA pattern, a lower PC nadir (median: 30 vs. 54 G/L, p= 0.007) and a longer PC recovery time (median: 6 vs. 3 days, p= 0.01) were evidenced in patients with anti-PF4 antibodies, compared to those with anti-PF4/H IgG only.

Conclusions: An atypical SRA pattern with elevated anti-PF4/H IgG titers appears to be associated with an increased risk of thrombosis in HIT. IgG antibodies to PF4 alone may contribute to more severe and persistent thrombocytopenia, and their detection could be useful in clinical practice.

To cite this abstract in AMA style:

Charuel N, Rollin J, Gruel Y, Guéry E-, May M-, Pouplard C, Vayne C. Variable Serotonin Release Assay Pattern and Characteristics of PF4-specific Antibodies in Heparin-Induced Thrombocytopenia, and Clinical Impact [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/variable-serotonin-release-assay-pattern-and-characteristics-of-pf4-specific-antibodies-in-heparin-induced-thrombocytopenia-and-clinical-impact/. Accessed June 25, 2022.

« Back to ISTH 2021 Congress

ISTH Congress Abstracts - https://abstracts.isth.org/abstract/variable-serotonin-release-assay-pattern-and-characteristics-of-pf4-specific-antibodies-in-heparin-induced-thrombocytopenia-and-clinical-impact/

Simple Search

Supported By:

Takeda logo

ISTH 2022 Congress site

Visit the official web site for the ISTH 2022 Virtual Congress »

  • Help & Support
  • About Us
  • Cookies & Privacy
  • Wiley Job Network
  • Terms & Conditions
  • Advertisers & Agents
Copyright © 2022 John Wiley & Sons, Inc. All Rights Reserved.
Wiley