Evolution of platelet phenotype during SARS-CoV-2 infection

Objective Arterial thrombosis is common during SARS-CoV-2 infection suggesting possible role of platelet activation.

To determine platelet activation status and procoagulant platelet microvesicles (MVs) in SARSCoV-2 patients.

Material and Methods A prospective longitudinal study was conducted in six SARS-CoV-2 hospitalized patients (four men and two women, ranging in age from 29 to 90 years). During their hospital stay, two patients required oxygen therapy. At study entry, the NEWS2 and SOFA scores were elevated in 3 patients. The median duration of hospital stay was 12 days. Blood was collected on four occasions (Day (D)1, D7, D14 and D28). Surface markers of platelet activation before and after TRAP 50 µM stimulation, and procoagulant MV combining phosphatidylserine (PS) and fibrin (fib) detection were quantified by flow cytometry.

Results The Glycoproteins (GP) IIb/IIIa (CD41+) and Ib (CD42a+) levels were higher at the acute infection phase (D1 and D7) than in the later stages. After stimulation with TRAP, GPIb levels remained higher at D1 than at D28 (p<0.05). The same tendency was observed for GPIIb/IIIa and CD62P. Platelet activation resulted in significantly less PAC-1 binding during the acute phase compared with the later stages. The PAC1 binding after TRAP6 was negatively correlated with CRP (r=-0.84, p<10-6). but not with GPIIb/IIIa levels. 54 to 91% of plasma PS+MVs expressed CD41 (PS+CD41+). The % of CD41+PS+MVs did not varied throughout the follow up. At D1, 2.6 to 14% of PS+MVs bind fibrin (7.2+/-0.8%). These levels continue to rise at D7 (21+/-4.7%) or D14 (14+/-1.4%). At D28 all the patients recovered the D1 value or below (5.4+/-0.8%). The same profile was observed for CD41+Fib+MVs

Conclusion During clinical infection with SARS -CoV -2, platelets circulate primed to adhesion, aggregation and leucocyte interaction. Increased levels of procoagulant MVs during SARS -CoV - 2 may participate to the increased risk of thrombosis

Publication History

Article published online:
18 June 2021