Monocyte-Mediated Thrombosis Linked to Circulating Tissue Factor and Immune Paralysis in COVID-19.

Publication date: Mar 21, 2024

SARS-CoV-2 infections cause COVID-19 and are associated with inflammation, coagulopathy, and high incidence of thrombosis. Myeloid cells help coordinate the initial immune response in COVID-19. Although we appreciate that myeloid cells lie at the nexus of inflammation and thrombosis, the mechanisms that unite the two in COVID-19 remain largely unknown. In this study, we used systems biology approaches including proteomics, transcriptomics, and mass cytometry to define the circulating proteome and circulating immune cell phenotypes in subjects with COVID-19. In a cohort of subjects with COVID-19 (n=35), circulating markers of inflammation (CCL23 and IL [interleukin]-6) and vascular dysfunction (ACE2 [angiotensin-converting enzyme 2] and TF [tissue factor]) were elevated in subjects with severe compared with mild COVID-19. Additionally, although the total white blood cell counts were similar between COVID-19 groups, CD14+ monocytes from subjects with severe COVID-19 expressed more TF. At baseline, transcriptomics demonstrated increased IL-6, CCL3, ACOD1, C5AR1, C5AR2, and TF in subjects with severe COVID-19 compared with controls. Using stress transcriptomics, we found that circulating immune cells from subjects with severe COVID-19 had evidence of profound immune paralysis with greatly reduced transcriptional activation and release of inflammatory markers in response to TLR (Toll-like receptor) activation. Finally, sera from subjects with severe (but not mild) COVID-19 activated human monocytes and induced TF expression. Taken together, these observations further elucidate the pathological mechanisms that underlie immune dysfunction and coagulation abnormalities in COVID-19, contributing to our growing understanding of SARS-CoV-2 infections that could also be leveraged to develop novel diagnostic and therapeutic strategies.

Concepts Keywords
Ccl23 immunity
Covid inflammation
Lie paralysis
Myeloid systems biology
Proteomics thrombosis


Type Source Name
disease MESH Thrombosis
disease MESH COVID-19
disease MESH inflammation
disease IDO immune response
disease IDO cell
drug DRUGBANK Angiotensin II
disease IDO blood
disease VO Toll-like receptor
disease MESH abnormalities
disease MESH Long Covid

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