Asymptomatic and Mild SARS-CoV-2 Infections Elicit Lower Immune Activation and Higher Specific Neutralizing Antibodies in Children Than in Adults.
Adult
Antibodies, Neutralizing
/ blood
Antibodies, Viral
/ blood
Asymptomatic Infections
B-Lymphocytes, Regulatory
/ immunology
COVID-19
/ pathology
Child
Child, Preschool
Cytokines
/ blood
Female
Humans
Lymphocyte Count
Male
Middle Aged
Pathogen-Associated Molecular Pattern Molecules
/ blood
Prospective Studies
SARS-CoV-2
/ immunology
Severity of Illness Index
T-Lymphocytes, Regulatory
/ immunology
Viral Load
/ immunology
COVID-19 children
Tregs and Bregs
immune activation
neutralizing antibodies (NAbs)
senescence
Journal
Frontiers in immunology
ISSN: 1664-3224
Titre abrégé: Front Immunol
Pays: Switzerland
ID NLM: 101560960
Informations de publication
Date de publication:
2021
2021
Historique:
received:
15
07
2021
accepted:
10
09
2021
entrez:
18
10
2021
pubmed:
19
10
2021
medline:
4
11
2021
Statut:
epublish
Résumé
The immune response plays a pivotal role in dictating the clinical outcome in severe acute respiratory syndrome coronavirus 2 (SARS Of 209 enrolled subjects, 155 patients were confirmed by PCR and/or serology as having coronavirus disease 2019 (COVID-19). Blood samples were obtained at a median of 2.8 (interquartile, 2.1-3.7) and 6.1 (5.3-7.2) months after baseline (symptom onset and/or first positive virus detection). The immune profiles of activation, senescence, exhaustion, and regulatory cells were analyzed by flow cytometry. Neutralizing antibodies (nAbs) were detected by a plaque reduction neutralization test. In available nasopharyngeal swabs at baseline, SARS-CoV-2 levels were quantified by digital droplet PCR (ddPCR). Overall, COVID-19 patients had higher levels of immune activation, exhaustion, and regulatory cells compared to non-COVID-19 subjects. Within the COVID-19 group, activated and senescent cells were higher in adults than in children and inversely correlated with the nAbs levels. Conversely, Tregs and Bregs regulatory cells were higher in COVID-19 children compared to adults and positively correlated with nAbs. Higher immune activation still persisted in adults after 6 months of infection, while children maintained higher levels of regulatory cells. SARS-CoV-2 levels did not differ among age classes. Adults displayed higher immune activation and lower production of anti-SARS-CoV-2 nAbs than children. The different immune response was not related to different viral load. The higher expression of regulatory cells in children may contribute to reduce the immune activation, thus leading to a greater specific response against the virus.
Sections du résumé
Background
The immune response plays a pivotal role in dictating the clinical outcome in severe acute respiratory syndrome coronavirus 2 (SARS
Methods
Of 209 enrolled subjects, 155 patients were confirmed by PCR and/or serology as having coronavirus disease 2019 (COVID-19). Blood samples were obtained at a median of 2.8 (interquartile, 2.1-3.7) and 6.1 (5.3-7.2) months after baseline (symptom onset and/or first positive virus detection). The immune profiles of activation, senescence, exhaustion, and regulatory cells were analyzed by flow cytometry. Neutralizing antibodies (nAbs) were detected by a plaque reduction neutralization test. In available nasopharyngeal swabs at baseline, SARS-CoV-2 levels were quantified by digital droplet PCR (ddPCR).
Results
Overall, COVID-19 patients had higher levels of immune activation, exhaustion, and regulatory cells compared to non-COVID-19 subjects. Within the COVID-19 group, activated and senescent cells were higher in adults than in children and inversely correlated with the nAbs levels. Conversely, Tregs and Bregs regulatory cells were higher in COVID-19 children compared to adults and positively correlated with nAbs. Higher immune activation still persisted in adults after 6 months of infection, while children maintained higher levels of regulatory cells. SARS-CoV-2 levels did not differ among age classes.
Conclusions
Adults displayed higher immune activation and lower production of anti-SARS-CoV-2 nAbs than children. The different immune response was not related to different viral load. The higher expression of regulatory cells in children may contribute to reduce the immune activation, thus leading to a greater specific response against the virus.
Identifiants
pubmed: 34659235
doi: 10.3389/fimmu.2021.741796
pmc: PMC8515185
doi:
Substances chimiques
Antibodies, Neutralizing
0
Antibodies, Viral
0
Cytokines
0
Pathogen-Associated Molecular Pattern Molecules
0
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
741796Informations de copyright
Copyright © 2021 Petrara, Bonfante, Costenaro, Cantarutti, Carmona, Ruffoni, Di Chiara, Zanchetta, Barzon, Donà, Da Dalt, Bortolami, Pagliari, Plebani, Rossi, Cotugno, Palma, Giaquinto and De Rossi.
Déclaration de conflit d'intérêts
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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