Deciphering the state of immune silence in fatal COVID-19 patients

Nat Commun. 2021 Mar 5;12(1):1428. doi: 10.1038/s41467-021-21702-6.


Since the beginning of the SARS-CoV-2 pandemic, COVID-19 appeared as a unique disease with unconventional tissue and systemic immune features. Here we show a COVID-19 immune signature associated with severity by integrating single-cell RNA-seq analysis from blood samples and broncho-alveolar lavage fluids with clinical, immunological and functional ex vivo data. This signature is characterized by lung accumulation of naïve lymphoid cells associated with a systemic expansion and activation of myeloid cells. Myeloid-driven immune suppression is a hallmark of COVID-19 evolution, highlighting arginase-1 expression with immune regulatory features of monocytes. Monocyte-dependent and neutrophil-dependent immune suppression loss is associated with fatal clinical outcome in severe patients. Additionally, our analysis shows a lung CXCR6+ effector memory T cell subset is associated with better prognosis in patients with severe COVID-19. In summary, COVID-19-induced myeloid dysregulation and lymphoid impairment establish a condition of 'immune silence' in patients with critical COVID-19.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • CD8-Positive T-Lymphocytes / immunology
  • COVID-19 / blood
  • COVID-19 / immunology*
  • Case-Control Studies
  • Cytokines / immunology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Monocytes / immunology
  • Myeloid Cells / immunology
  • Neutrophils / immunology
  • SARS-CoV-2 / immunology*
  • T-Lymphocytes / immunology


  • Cytokines