PB0058 - Contribution of biology to the diagnosis and follow-up of VITT: a French multicentre experience.

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Co-Author(s)

CP

Claire Pouplard

PU PH
University Hospital of Tours
TOURS, Centre, France
CV

Caroline Vayne

Assitant professor
University Hospital of Tours
Tours, Centre, France
EG

Eve Anne Guery

PharmD
Department of hemostasis, University Hospital of Tours, France
Tours, Centre, France
NA

Nadine Ajzenberg

MD, PhD
Laboratoire d'Hématologie, AP-HP, Hôpital Bichat Claude-Bernard, Paris, France.
Paris, Ile-de-France, France
PC

Philippe Cauchie

Professor
University Hopsital of Charleroi
Charleroi, Namur, Belgium
CC

Charlotte Cordonnier

Professor
University Hospital of Lille
Lille, Nord-Pas-de-Calais, France
ED

Emmanuel De Maistre

MD
Hématologie Biologique, CHU, Dijon
Dijon, Bourgogne, France
MD

Magali Donnard

Medical Doctor
University Hospital of Limoges
Limoges, Limousin, France
ND

Nicolas Drillaud

MD
CRC-MHC, CHU Hôtel-Dieu
Nantes, Pays de la Loire, France
HG

Hubert GALINAT

PharmD
Hematology Laboratory, CHU Brest, France
Brest, Bretagne, France
SG

Sylvie Goffard

Medical Doctor
Hospital of Brive
Brive, Aquitaine, France
Isabelle Gouin-Thibault, Sr., PhD

Head of hemostasis department
Department of Hematology/Hemostasis, Pontchaillou University Hospital of Rennes, Univ Rennes, Irset - Inserm UMR_S 1085, Rennes, France.
Rennes, Bretagne, France
RM

Raphael Marlu

Medical Doctor
University Hospital of Grenoble
Grenoble, Auvergne, France
GM

Guillaume Mourey

Medical Doctor
EFS
Besançon, Bourgogne, France
FM

François Mullier

Professor
University Hospital of Namur
Namur, Namur, Belgium
VS

Virginie Siguret, PhD, PharmD

PharmD PhD, Professor in Hematology
INSERM UMR-S-1140, Innovative therapies in Haemostasis, Université Paris Cité, Paris
Paris, Ile-de-France, France
Sophie Susen, MD, PhD

Professor, MD, PhD
CRC-MHC, Lille University Hospital, Lille, France
Lille, Nord-Pas-de-Calais, France
MT

Marie Tuffigo

Biologist
University Hospital of Angers
Angers, Pays de la Loire, France
JR

Jérôme Rollin

Scientist
University Hospital of Tours
Tours, Centre, France

Presenting Author(s)

Yves Gruel, MD

Professor
University Hospital of Tours
Tours, Centre, France

Background: Vaccine-induced immune thrombocytopenia (VITT) is a rare but serious complication of SARS-COV-2 vaccination and its diagnosis is based on both clinical and biological criteria.

Aims: To evaluate the performance of these criteria in a prospective cohort of patients with suspected VITT.

Methods: Among 105 consecutive patients (table 1), 79 had received one (n=71) or two (n=8) injections of adenoviral vector vaccine, and 26 one (n=18) or two (n=8) doses of an mRNA vaccine. Most patients presented thrombosis either isolated (n=40), or associated with thrombocytopenia (T+T=45). Other patients had isolated thrombocytopenia (n=15), or variable clinical manifestations. ELISA (PVS/PF4 HAT45G®) detected anti-PF4 antibodies, and when present VITT diagnosis was confirmed using PF4 serotonin release assay.

Results: VITT was confirmed in 26 patients (both PVS/PF4 ELISA and PF4/SRA were positive) and probable in one case (PVS/PF4 ELISA OD=2.4 but PF4/SRA negative). VITT was excluded in all patients who had received an mRNA vaccine, or in those with isolated thrombocytopenia or thrombosis or with other symptoms. In contrast, the presence of both thrombocytopenia and thrombosis 5 to 30 days after injection was highly suggestive of VITT with a specificity and PPV of 85% and 69%, respectively, these values increasing to 93.6% and 85% if patients had received adenoviral vector vaccine. Importantly, the PPV reached in these cases 100% when OD > 1 in ELISA. (Table)

Conclusion(s):

Conclusion: The occurrence of thrombocytopenia and thromboses, 5 to 30 days after vaccination with an adenoviral vector is highly predictive of VITT. PF4/PVS ELISA allows to rule out VITT when OD is < 0.4 (NPV 100%) and to confirm the diagnosis when OD is > 1 without necessitating a platelet activation test. Moreover, the follow-up of patients with ELISA is mandatory since anti-PF4 antibodies may remain several weeks after VITT.