Semin Thromb Hemost 2024; 50(02): 275-283
DOI: 10.1055/s-0043-1769939
Review Article

Effects of Recombinant SARS-CoV-2 Spike Protein Variants on Platelet Morphology and Activation

Marco Vettori*
1   Section of Clinical Biochemistry and School of Medicine, University of Verona, Verona, Italy
Giovanni Carpenè*
1   Section of Clinical Biochemistry and School of Medicine, University of Verona, Verona, Italy
Gian Luca Salvagno*
1   Section of Clinical Biochemistry and School of Medicine, University of Verona, Verona, Italy
Matteo Gelati
1   Section of Clinical Biochemistry and School of Medicine, University of Verona, Verona, Italy
Francesco Dima
1   Section of Clinical Biochemistry and School of Medicine, University of Verona, Verona, Italy
Giovanni Celegon
1   Section of Clinical Biochemistry and School of Medicine, University of Verona, Verona, Italy
Emmanuel J. Favaloro
2   Department of Haematology, Sydney Centers for Thrombosis and Haemostasis, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
3   School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, New South Wales, Australia
4   Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
Giuseppe Lippi
1   Section of Clinical Biochemistry and School of Medicine, University of Verona, Verona, Italy
› Author Affiliations


Platelets are central elements of hemostasis and also play a pivotal role in the pathogenesis of thrombosis in coronavirus disease 2019. This study was planned to investigate the effects of different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recombinant spike protein variants on platelet morphology and activation. Citrated whole blood collected from ostensibly healthy subjects was challenged with saline (control sample) and with 2 and 20 ng/mL final concentration of SARS-CoV-2 recombinant spike protein of Ancestral, Alpha, Delta, and Omicron variants. Platelet count was found to be decreased with all SARS-CoV-2 recombinant spike protein variants and concentrations tested, achieving the lowest values with 20 ng/mL Delta recombinant spike protein. The mean platelet volume increased in all samples irrespective of SARS-CoV-2 recombinant spike protein variants and concentrations tested, but especially using Delta and Alpha recombinant spike proteins. The values of both platelet function analyzer-200 collagen-adenosine diphosphate and collagen-epinephrine increased in all samples irrespective of SARS-CoV-2 recombinant spike protein variants and concentrations tested, and thus reflecting platelet exhaustion, and displaying again higher increases with Delta and Alpha recombinant spike proteins. Most samples where SARS-CoV-2 recombinant spike proteins were added were flagged as containing platelet clumps. Morphological analysis revealed the presence of a considerable number of activated platelets, platelet clumps, platelet-monocyte, and platelet-neutrophils aggregates, especially in samples spiked with Alpha and Delta recombinant spike proteins at 20 ng/mL. These results provide support to the evidence that SARS-CoV-2 is capable of activating platelets through its spike protein, though such effect varies depending on different spike protein variants.

* These authors contributed equally to this article.

Publication History

Article published online:
16 June 2023

© 2023. Thieme. All rights reserved.

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