D-dimer and CoV-2 spike-immune complexes contribute to the production of PGE2 and proinflammatory cytokines in monocytes

PLoS Pathog. 2022 Apr 6;18(4):e1010468. doi: 10.1371/journal.ppat.1010468. eCollection 2022 Apr.

Abstract

An overreactive inflammatory response and coagulopathy are observed in patients with severe form of COVID-19. Since increased levels of D-dimer (DD) are associated with coagulopathy in COVID-19, we explored whether DD contributes to the aberrant cytokine responses. Here we show that treatment of healthy human monocytes with DD induced a dose dependent increase in production of pyrogenic mediator, Prostaglandin E2 (PGE2) and inflammatory cytokines, IL-6 and IL-8. The DD-induced PGE2 and inflammatory cytokines were enhanced significantly by co-treatment with immune complexes (IC) of SARS CoV-2 recombinant S protein or of pseudovirus containing SARS CoV-2 S protein (PVCoV-2) coated with spike-specific chimeric monoclonal antibody (MAb) containing mouse variable and human Fc regions. The production of PGE2 and cytokines in monocytes activated with DD and ICs was sensitive to the inhibitors of β2 integrin and FcγRIIa, and to the inhibitors of calcium signaling, Mitogen-Activated Protein Kinase (MAPK) pathway, and tyrosine-protein kinase. Importantly, strong increase in PGE2 and in IL-6/IL-8/IL-1β cytokines was observed in monocytes activated with DD in the presence of IC of PVCoV-2 coated with plasma from hospitalized COVID-19 patients but not from healthy donors. The IC of PVCoV-2 with convalescent plasma induced much lower levels of PGE2 and cytokines compared with plasma from hospitalized COVID-19 patients. PGE2 and IL-6/IL-8 cytokines produced in monocytes activated with plasma-containing IC, correlated well with the levels of spike binding antibodies and not with neutralizing antibody titers. Our study suggests that a combination of high levels of DD and high titers of spike-binding antibodies that can form IC with SARS CoV-2 viral particles might accelerate the inflammatory status of lung infiltrating monocytes leading to increased lung pathology in patients with severe form of COVID-19.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigen-Antibody Complex
  • COVID-19 Serotherapy
  • COVID-19* / therapy
  • Cytokines / metabolism
  • Dinoprostone / metabolism
  • Fibrin Fibrinogen Degradation Products
  • Humans
  • Immunization, Passive
  • Immunologic Factors / metabolism
  • Interleukin-6 / metabolism
  • Interleukin-8 / metabolism
  • Mice
  • Monocytes*
  • Spike Glycoprotein, Coronavirus / metabolism

Substances

  • Antigen-Antibody Complex
  • Cytokines
  • Fibrin Fibrinogen Degradation Products
  • Immunologic Factors
  • Interleukin-6
  • Interleukin-8
  • Spike Glycoprotein, Coronavirus
  • fibrin fragment D
  • spike protein, SARS-CoV-2
  • Dinoprostone

Grants and funding

This work was funded by Intramural funding to the lab from the Center for Biologics Evaluation and Research (CBER) at the US Food and Drug Administration (FDA). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.