Project description:BACKGROUND. Coronavirus disease 2019 (COVID-19) is more benign in children compared with adults for unknown reasons. This contrasts with other respiratory viruses where disease manifestations are often more severe in children. We hypothesize that a more robust early innate immune response to SARS coronavirus 2 (SARS-CoV-2) protects against severe disease. METHODS. Clinical outcomes, SARS-CoV-2 viral copies, and cellular gene expression were compared in nasopharyngeal swabs obtained at the time of presentation to the emergency department from 12 children and 27 adults using bulk RNA sequencing and quantitative reverse-transcription PCR. Total protein, cytokines, and anti–SARS-CoV-2 IgG and IgA were quantified in nasal fluid. We used a subset of 21 samples for RNAseq analysis. RESULTS. SARS-CoV-2 copies, angiotensin-converting enzyme 2 (ACE2), and TMPRSS2 gene expression were similar in children and adults, but children displayed higher expression of genes associated with IFN signaling, NLRP3 inflammasome, and other innate pathways. Higher levels of IFN-α2, IFN-γ, IP-10, IL-8, and IL-1β protein were detected in nasal fluid in children versus adults. Children also expressed higher levels of genes associated with immune cells, whereas expression of those associated with epithelial cells did not differ in children versus adults. Anti–SARS-CoV-2 IgA and IgG were detected at similar levels in nasal fluid from both groups. None of the children required supplemental oxygen, whereas 7 adults did (P = 0.03); 4 adults died. CONCLUSION. These findings provide direct evidence of a more vigorous early mucosal immune response in children compared with adults and suggest that this contributes to favorable clinical outcomes.
Project description:Background: COVID-19 has infected more than 100-million worldwide. Children appear less susceptible to COVID-19 and present with milder symptoms. Cases of children with COVID-19 developing clinical features of Kawasaki-disease have been described. Methods: We utilised SWATH-MS proteomics to determine the plasma proteins expressed in healthy children, children with multisystem inflammatory syndrome (MIS-C) and children with COVID-19 induced ARDS. Pathway analyses were performed to determine the affected pathways. Results: 76 proteins were differentially expressed across the groups, with 85 and 52 proteins specific to MIS-C and COVID-19 ARDS. Complement and coagulation activation were implicated in these clinical phenotypes, however there was contribution of FcGR and BCR activation in MIS-C and scavenging of heme and retinoid metabolism in COVID-19 ARDS. Conclusions: We show proteome differences in MIS-C and COVID-ARDS, although both show complement and coagulation dysregulation. The results may be helpful in developing therapeutic targets that could improve the outcomes for these children.
Project description:Multisystem Inflammatory Syndrome in Children (MIS-C) is a delayed-onset, COVID-19-related hyperinflammatory illness characterized by SARS-CoV-2 antigenemia, cytokine storm, and immune dysregulation. In severe COVID-19, neutrophil activation is central to hyperinflammatory complications, yet the role of neutrophils in MIS-C is undefined. Here, we collect blood from 152 children: 31 cases of MIS-C, 43 cases of acute pediatric COVID-19, and 78 pediatric controls. We find that MIS-C neutrophils display a granulocytic myeloid-derived suppressor cell (G-MDSC) signature with highly altered metabolism, distinct from the neutrophil interferon-stimulated gene (ISG) response we observe in pediatric COVID-19. Moreover, we observe extensive spontaneous neutrophil extracellular trap (NET) formation in MIS-C, and we identify neutrophil activation and degranulation signatures. Mechanistically, we determine that SARS-CoV-2 immune complexes are sufficient to trigger NETosis. Our findings suggest that the hyperinflammatory presentation during MIS-C could be mechanistically linked to persistent SARS-CoV-2 antigenemia, driven by uncontrolled neutrophil activation and NET release in the vasculature.
Project description:Children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) develop less severe coronavirus disease 2019 (COVID-19) than adults. The mechanisms for the age-specific differences and the implications for infection-induced immunity are beginning to be uncovered. We show by longitudinal multimodal analysis that SARS-CoV-2 leaves a small footprint in the circulating T cell compartment in children with mild/asymptomatic COVID-19 compared to adult household contacts with the same disease severity who had more evidence of systemic T cell interferon activation, cytotoxicity and exhaustion. Children harbored diverse polyclonal SARS-CoV-2-specific naive T cells whereas adults harbored clonally expanded SARS-CoV-2-specific memory T cells. More naive interferon-activated CD4+ T cells were recruited into the memory compartment and recovery was associated with the development of robust CD4+ memory T cell responses in adults but not children. These data suggest that rapid clearance of SARS-CoV-2 in children may compromise their cellular immunity and ability to resist reinfection.
Project description:Purpose: This study aims to characterize the early innate and adaptive responses induced by SARS-CoV-2 infection in children and adults over time up to 8 weeks post symptoms onset (POS). We report the gene signature of COVID-19 over the course of the disease in both age groups. The kinetic of infection was divided in 5-time intervals according to the calculated days POS: interval 1 (0-5), interval 2 (6-14), interval 3 (15-22), interval 4 (23-35), and interval 5 (36-81). Methods: RNA extraction was performed automatically via the PAXgene Blood miRNA Kit and the QIAcube instrument (Qiagen) following the manufacturer’s protocol. RNA concentration and quality were assessed by using the Qubit instrument (Invitrogen) and the Agilent 2100 Bioanalyzer, respectively. The Stranded Total RNA Ribo-Zero Plus kit from Illumina was used for the library preparation with 100 ng of total RNA as input. Library molarity and quality were assessed with the Qubit and Tapestation using a DNA High sensitivity chip (Agilent Technologies). Libraries were pooled at 2 nM for clustering and sequenced on an Illumina HiSeq 4000 sequencer for a minimum of 30 million single-end 100 reads per sample. Main results: (I) we observed an antiviral-IFN-signature and innate-cell-activation within the first 5 days post symptoms onset (POS), while genes associated with CD4 T-cell responses, plasma cells and immunoglobulin were upregulated in both age groups during the first two weeks POS, indicative of SARS-CoV-2-specific adaptive immune responses; (II) in adults, genes associated with IFN antiviral responses and activated dendritic cells were maintained during the second week of disease, and subsided only after 14 days. By contrast, those transcriptome changes subsided already after 5 days in children.
Project description:Purpose: To understand the single cell transcriptional and epigenetic landscape of immune cells from infants and young children infected with COVID-19
Project description:Post-acute sequelae of COVID-19 (PASC) represent an emerging global crisis. However, quantifiable risk-factors for PASC and their biological associations are poorly resolved. We executed a deep multi-omic, longitudinal investigation of 309 COVID-19 patients from initial diagnosis to convalescence (2-3 months later), integrated with clinical data, and patient-reported symptoms. We resolved four PASC-anticipating risk factors at the time of initial COVID-19 diagnosis: type 2 diabetes, SARS-CoV-2 RNAemia, Epstein-Barr virus viremia, and specific autoantibodies. In patients with gastrointestinal PASC, SARS-CoV-2-specific and CMV-specific CD8+ T cells exhibited unique dynamics during recovery from COVID-19. Analysis of symptom-associated immunological signatures revealed coordinated immunity polarization into four endotypes exhibiting divergent acute severity and PASC. We find that immunological associations between PASC factors diminish over time leading to distinct convalescent immune states. Detectability of most PASC factors at COVID-19 diagnosis emphasizes the importance of early disease measurements for understanding emergent chronic conditions and suggests PASC treatment strategies.
Project description:While SARS-CoV-2 infection results in a mild disease course for most children, severe manifestations including respiratory failure and a Multisystem Inflammatory Syndrome in Children (MIS-C) can develop in rare cases. Here, we present a longitudinal immune profiling study of children who developed SARS-CoV-2-associated MIS-C during acute disease and following recovery, relative to children with more typical clinical manifestations of SARS-CoV-2 infection. We demonstrate distinct immune parameters associated with acute MIS-C including elevated levels of pro-inflammatory cytokines in circulation not observed in children with acute COVID-19 (non-MIS-C), aberrant expression of activation and tissue residency signatures by T cells, and expansion of T cells bearing specific TCR chains. Importantly, markers of tissue-derived T cells correlated with clinical measurements of cardiac damage suggesting key roles for T cells in the disease process. While these T cell alterations and the accompanying systemic inflammation resolved during recovery, children with prior MIS-C generated increased frequencies of functionally robust virus-specific T cells compared to children who recovered from mild disease, while both cohorts generated protective, long-lasting SARS-CoV-2-specific antibodies. Together our results reveal that the T cell response in acute MIS-C contributed to disease pathology, while also generating robust memory responses for future immune protection.