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Platelets: "multiple choice" effectors in the immune response and their implication in COVID-19 thromboinflammatory
Roberta Rolla1,2, Chiara Puricelli1,2, Alessandra Bertoni3
1IRCAD & Department of Health Sciences, Amedeo Avogadro University of Eastern Piedmont, Novara, Italy.
International Journal of Laboratory Hematology
|March 22, 2021
Summary
Platelets, beyond blood clotting, actively modulate innate and adaptive immunity by releasing signaling molecules and interacting with immune cells. Their complex role in hemostasis, inflammation, and immunity is crucial, especially in infectious diseases like COVID-19.
Area of Science:
- Immunology
- Hematology
- Infectious Diseases
Background:
- Platelets are traditionally known for hemostasis and blood coagulation.
- Emerging evidence highlights their significant immunomodulatory functions.
Purpose of the Study:
- To review current knowledge on platelet immune functions and interactions with pathogens.
- To focus on the role of platelets in COVID-19 pathogenesis.
Main Methods:
- Narrative review of existing literature.
- Analysis of platelet interactions with innate and adaptive immune responses.
- Examination of platelet involvement in infectious agents, including SARS-CoV-2.
Main Results:
- Platelets express Toll-like receptors (TLRs) and release cytokines, contributing to innate immunity.
- Platelets present costimulatory and MHC molecules, activating T cells for adaptive immunity.
- Platelets release extracellular vesicles that interact with various immune cells.
Conclusions:
- Platelet function extends beyond aggregation, involving a complex interplay between hemostasis, inflammation, and immunity.
- Platelets amplify host defense but can also contribute to pathological processes.
- Platelets may play a determinant role in the dysregulated immune and hemostatic processes observed in COVID-19.
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