Platelet Function in Viral Immunity and SARS-CoV-2 Infection

Abstract

Platelets, as nonnucleated blood components, are classically recognized for their pivotal role in hemostasis. In recent years, however, accumulating evidence points to a nonhemostatic role for platelets, as active participants in the inflammatory and immune responses to microbial organisms in infectious diseases. This stems from the ability of activated platelets to secrete a plethora of immunomodulatory cytokines and chemokines, as well as directly interplaying with viral receptors. While much attention has been given to the role of the cytokine storm in the severity of the coronavirus disease 2019 (COVID-19), less is known about the contribution of platelets to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we give a brief overview on the platelet contribution to antiviral immunity and response during SARS-CoV-2 infection.

2022 Eberhard F. Mammen Award Announcements: Part I—Most Popular Articles

“…Table 3 lists the top 25 downloaded “free to download” articles from STH (2020 and 2021 inclusive), as eligible for the “Open Access” award. 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Table 4 lists the top 25 downloaded non-open access articles from STH (2020 and 2021 inclusive), as otherwise eligible for the “General category” award. 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51…”

“…This year saw the topic of COVID-19 take prominence, not only worldwide, but also in this journal, including the most downloaded “free to download” papers. 2 3 Indeed, one of these papers was published in 2021, 3 and so is perhaps especially deserving, given its late publication of the 2-year 2020/2021 capture period. I actually predicted that COVID-19-related reviews would likely win the 2022 most popular awards in my previous (2021) editorial.…”

The ongoing enigma of SARS‐CoV‐2 and platelet interaction

“…Indeed, in response to direct infection by dengue and influenza viruses, megakaryocytes upregulate interferon‐α genes. 28 , 29 Similarly, simplex virus‐1 can activate platelet aggregate formation and thrombosis using the previously generated opsonizing antibodies and their interaction with the FcγRIIA. 30 Recently, a key role of platelet‐mediated immunothrombosis in COVID‐19 that signals through FcγRIIA and the C5a–C5a receptor pathway has been identified, revealing the role of platelet hyperactivation in complications associated with SARS‐CoV‐2 infection.…”

“…Platelets are also known to be directly activated by certain viruses. Indeed, in response to direct infection by dengue and influenza viruses, megakaryocytes upregulate interferon‐α genes 28,29 . Similarly, simplex virus‐1 can activate platelet aggregate formation and thrombosis using the previously generated opsonizing antibodies and their interaction with the FcγRIIA 30 .…”

Childhood Immunity and Infections: Time to Consider Endothelial Cells and Platelets

“…In this latter case, SARS-CoV-2 binds to platelets probably via its receptor ACE2, and viral hemagglutinin is cleaved by TMPRSS2 to activate the internalization of the virus. Such cleavage triggers platelet activation and downstream signaling events leading to cytokine overproduction, platelet aggregation, and leukocyte–platelet aggregate formation and, ultimately, to the more severe spectrum of COVID-19 characterized by cellular damage, acute lung injury, and thromboembolism [ 21 ].…”