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Sci Signal ; 14(673)2021 03 09.
Article in English | MEDLINE | ID: covidwho-1127536


IL-1ß is a key mediator of the cytokine storm linked to high morbidity and mortality from COVID-19, and IL-1ß blockade with anakinra and canakinumab during COVID-19 infection has entered clinical trials. Using mass cytometry of human peripheral blood mononuclear cells, we identified effector memory CD4+ T cells and CD4-CD8low/-CD161+ T cells, specifically those positive for the chemokine receptor CCR6, as the circulating immune subtypes with the greatest response to IL-1ß. This response manifested as increased phosphorylation and, thus, activation of the proinflammatory transcription factor NF-κB and was also seen in other subsets, including CD11c+ myeloid dendritic cells, classical monocytes, two subsets of natural killer cells (CD16-CD56brightCD161- and CD16-CD56dimCD161+), and lineage- (Lin-) cells expressing CD161 and CD25. IL-1ß also induced a rapid but less robust increase in the phosphorylation of the kinase p38 as compared to that of NF-κB in most of these immune cell subsets. Prolonged IL-1ß stimulation increased the phosphorylation of the transcription factor STAT3 and to a lesser extent that of STAT1 and STAT5 across various immune cell types. IL-1ß-induced production of IL-6 likely led to the activation of STAT1 and STAT3 at later time points. Interindividual heterogeneity and inhibition of STAT activation by anakinra raise the possibility that assays measuring NF-κB phosphorylation in response to IL-1ß in CCR6+ T cell subtypes could identify those patients at higher risk of cytokine storm and most likely to benefit from IL-1ß-neutralizing therapies.

COVID-19/immunology , Interleukin-1beta/blood , T-Lymphocyte Subsets/immunology , COVID-19/blood , COVID-19/complications , Cytokine Release Syndrome/blood , Cytokine Release Syndrome/etiology , Cytokine Release Syndrome/immunology , Dendritic Cells/immunology , Dendritic Cells/metabolism , Flow Cytometry , Humans , Interleukin-1beta/pharmacology , Killer Cells, Natural/immunology , Killer Cells, Natural/metabolism , Monocytes/classification , Monocytes/immunology , Monocytes/metabolism , NF-kappa B/blood , Pandemics , Phosphorylation , Receptors, CCR6/blood , SARS-CoV-2 , STAT Transcription Factors/blood , STAT Transcription Factors/immunology , Signal Transduction/immunology , T-Lymphocyte Subsets/metabolism , p38 Mitogen-Activated Protein Kinases/blood
Int Arch Allergy Immunol ; 182(5): 417-424, 2021.
Article in English | MEDLINE | ID: covidwho-1097047


BACKGROUND: Detailed understanding of the immune response to severe acute respiratory syndrome coronavirus (SARS-CoV)-2, the cause of coronavirus disease 2019 (CO-VID-19) has been hampered by a lack of quantitative antibody assays. OBJECTIVE: The objective was to develop a quantitative assay for IgG to SARS-CoV-2 proteins that could be implemented in clinical and research laboratories. METHODS: The biotin-streptavidin technique was used to conjugate SARS-CoV-2 spike receptor-binding domain (RBD) or nucleocapsid protein to the solid phase of the ImmunoCAP. Plasma and serum samples from patients hospitalized with COVID-19 (n = 60) and samples from donors banked before the emergence of COVID-19 (n = 109) were used in the assay. SARS-CoV-2 IgG levels were followed longitudinally in a subset of samples and were related to total IgG and IgG to reference antigens using an ImmunoCAP 250 platform. RESULTS: At a cutoff of 2.5 µg/mL, the assay demonstrated sensitivity and specificity exceeding 95% for IgG to both SARS-CoV-2 proteins. Among 36 patients evaluated in a post-hospital follow-up clinic, median levels of IgG to spike-RBD and nucleocapsid were 34.7 µg/mL (IQR 18-52) and 24.5 µg/mL (IQR 9-59), respectively. Among 17 patients with longitudinal samples, there was a wide variation in the magnitude of IgG responses, but generally the response to spike-RBD and to nucleocapsid occurred in parallel, with peak levels approaching 100 µg/mL, or 1% of total IgG. CONCLUSIONS: We have described a quantitative assay to measure IgG to SARS-CoV-2 that could be used in clinical and research laboratories and implemented at scale. The assay can easily be adapted to measure IgG to mutated COVID-19 proteins, has good performance characteristics, and has a readout in standardized units.

Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , COVID-19/immunology , Immunoglobulin G/blood , SARS-CoV-2/immunology , Biomarkers/blood , COVID-19/virology , Humans , Longitudinal Studies , Sensitivity and Specificity