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

P Bost, F De Sanctis, S Canè, S Ugel… - Nature …, 2021 - nature.com
P Bost, F De Sanctis, S Canè, S Ugel, K Donadello, M Castellucci, D Eyal, A Fiore
Nature communications, 2021nature.com
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 …
Abstract
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.
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