Adverse Outcome in COVID-19 Is Associated With an Aggravating Hypo-Responsive Platelet Phenotype

Area of Science:

• Hematology
• Immunology
• Infectious Diseases

Background:

• Thromboembolic events are common in Coronavirus disease 2019 (COVID-19).
• COVID-19 is associated with platelet dysregulation, but its impact on disease outcome remains unclear.
• Understanding platelet function in COVID-19 is crucial for predicting disease severity.

Purpose of the Study:

• To investigate platelet activation and reactivity in hospitalized COVID-19 patients.
• To determine the association between platelet function and adverse COVID-19 outcomes.
• To explore the role of plasma components in COVID-19-associated platelet dysfunction.

Main Methods:

• Prospective monitoring of platelet activation and reactivity in 97 hospitalized COVID-19 patients during the first week.
• Measurement of plasma markers for platelet degranulation and inflammation.
• Assessment of platelet aggregation and platelet-leukocyte aggregate formation.

Main Results:

• Adverse COVID-19 outcomes correlated with increased basal platelet activation and reduced platelet responses, worsening over time.
• Diminished GPIIb/IIIa responses indicated impaired platelet aggregation.
• Reduced platelet-leukocyte aggregate formation suggested compromised platelet-mediated immune responses.
• No evidence of platelet exhaustion was found; plasma from severe COVID-19 patients impaired platelet function in healthy donors.

Conclusions:

• Unfavorable COVID-19 outcomes are linked to a progressive hypo-responsive platelet phenotype.
• This platelet dysfunction may impair platelet-mediated immunoregulation.
• Plasma factors in severe COVID-19 contribute to platelet hypo-responsiveness.