Pre-activated anti-viral innate immunity in the upper airways controls early SARS-CoV-2 infection in children

Children have reduced SARS-CoV-2 infection rates and a substantially lower risk for developing severe COVID-19 than adults. However, the molecular mechanisms underlying protection in younger age groups remain unknown. Here, we characterize the single-cell transcriptional landscape in the upper airways of SARS-CoV-2-negative (n=18) and age-matched SARS-CoV-2–positive children (n=24) and corresponding samples from adults (n=44), covering an age range of four weeks to 77 years. Children displayed higher basal expression of the relevant pattern recognition receptors (PRR) such as MDA5 (IFIH1) and RIG-I (DDX58) in upper airway epithelial cells, macrophages, and dendritic cells, resulting in stronger innate antiviral responses upon SARS-CoV-2 infection than adults. We further detected distinct immune cell subpopulations including KLRC1 (NKG2A)+ cytotoxic T cells and a CD8+ T cell population with a memory phenotype occurring predominantly in children. Our study provides evidence that the airway immune cells of children are primed for virus sensing, resulting in a stronger early innate antiviral responses to SARS-CoV-2 infection than adults.

Type: Other
Archiver: European Genome-Phenome Archive (EGA)

1 Dataset 1 Publication

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Dataset ID	Description	Technology	Samples
EGAD00001007969	We investigated 10 female and 14 male SARS-CoV-2 positive children (age range: 0.8 to 18 years). Based on the WHO guidelines, 15 patients were classified as having mild COVID-19, while 7 children were classified as moderate COVID-19 cases. Two children were asymptomatic. 8 female and 10 male SARS-CoV-2 negative children were included as controls (age range: 4 to 16). 12 SARS-CoV-2 positive female and 9 male adults were included ( age range: 27 - 76) together with 13 female and 10 male SARS-CoV-2 negative adult controls (age: 24 - 77). 10 adult COVID-19 patients had mild disease, while 12 had moderate COVID-19. We performed single-cell RNA sequencing experiments.	Illumina NovaSeq 6000	86

Publications	Citations
ELF5 is a potential respiratory epithelial cell-specific risk gene for severe COVID-19. Pietzner M, Chua RL, Wheeler E, Jechow K, Willett JDS, Radbruch H, Trump S, Heidecker B, Zeberg H, Heppner FL, Eils R, Mall MA, Richards JB, Sander LE, Lehmann I, Lukassen S, Wareham NJ, Conrad C, Langenberg C. Nat Commun 13: 2022 4484	8