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1.
Nature ; 2021 Dec 22.
Article in English | MEDLINE | ID: covidwho-1585831

ABSTRACT

It is not fully understood why COVID-19 is typically milder in children1-3. To examine differences in response to SARS-CoV-2 infection in children and adults, we analysed paediatric and adult COVID-19 patients and healthy controls (total n=93) using single-cell multi-omic profiling of matched nasal, tracheal, bronchial and blood samples. In healthy paediatric airways, we observed cells already in an interferon-activated state, that upon SARS-CoV-2 infection was further induced especially in airway immune cells. We postulate that higher paediatric innate interferon-responses restrict viral replication and disease progression. The systemic response in children was characterised by increases in naive lymphocytes and a depletion of natural killer cells, while in adults cytotoxic T cells and interferon-stimulated subpopulations were significantly increased. We provide evidence that dendritic cells initiate interferon signaling in early infection, and identify novel epithelial cell states that associate with COVID-19 and age. Our matching nasal and blood data showed a strong interferon response in the airways with the induction of systemic interferon-stimulated populations, which were massively reduced in paediatric patients. Together, we provide several mechanisms that explain the milder clinical syndrome observed in children.

2.
Nat Commun ; 12(1): 7092, 2021 12 07.
Article in English | MEDLINE | ID: covidwho-1561304

ABSTRACT

The nasal epithelium is a plausible entry point for SARS-CoV-2, a site of pathogenesis and transmission, and may initiate the host response to SARS-CoV-2. Antiviral interferon (IFN) responses are critical to outcome of SARS-CoV-2. Yet little is known about the interaction between SARS-CoV-2 and innate immunity in this tissue. Here we apply single-cell RNA sequencing and proteomics to a primary cell model of human nasal epithelium differentiated at air-liquid interface. SARS-CoV-2 demonstrates widespread tropism for nasal epithelial cell types. The host response is dominated by type I and III IFNs and interferon-stimulated gene products. This response is notably delayed in onset relative to viral gene expression and compared to other respiratory viruses. Nevertheless, once established, the paracrine IFN response begins to impact on SARS-CoV-2 replication. When provided prior to infection, recombinant IFNß or IFNλ1 induces an efficient antiviral state that potently restricts SARS-CoV-2 viral replication, preserving epithelial barrier integrity. These data imply that the IFN-I/III response to SARS-CoV-2 initiates in the nasal airway and suggest nasal delivery of recombinant IFNs to be a potential chemoprophylactic strategy.

3.
Immunity ; 54(11): 2650-2669.e14, 2021 11 09.
Article in English | MEDLINE | ID: covidwho-1442406

ABSTRACT

Longitudinal analyses of the innate immune system, including the earliest time points, are essential to understand the immunopathogenesis and clinical course of coronavirus disease (COVID-19). Here, we performed a detailed characterization of natural killer (NK) cells in 205 patients (403 samples; days 2 to 41 after symptom onset) from four independent cohorts using single-cell transcriptomics and proteomics together with functional studies. We found elevated interferon (IFN)-α plasma levels in early severe COVD-19 alongside increased NK cell expression of IFN-stimulated genes (ISGs) and genes involved in IFN-α signaling, while upregulation of tumor necrosis factor (TNF)-induced genes was observed in moderate diseases. NK cells exert anti-SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) activity but are functionally impaired in severe COVID-19. Further, NK cell dysfunction may be relevant for the development of fibrotic lung disease in severe COVID-19, as NK cells exhibited impaired anti-fibrotic activity. Our study indicates preferential IFN-α and TNF responses in severe and moderate COVID-19, respectively, and associates a prolonged IFN-α-induced NK cell response with poorer disease outcome.


Subject(s)
COVID-19/immunology , Interferon-alpha/immunology , Killer Cells, Natural/immunology , SARS-CoV-2/immunology , Tumor Necrosis Factor-alpha/metabolism , Base Sequence , Humans , Immunity, Innate/immunology , Inflammation/immunology , Interferon-alpha/blood , Pulmonary Fibrosis/pathology , RNA-Seq , Severity of Illness Index , Transcriptome/genetics , United Kingdom , United States
4.
Commun Dis Intell (2018) ; 452021 Jun 15.
Article in English | MEDLINE | ID: covidwho-1278940

ABSTRACT

Abstract: During the first wave of COVID-19 transmission in New Zealand, a review of RT-PCR testing in all symptomatic cases reported in the Auckland Region found 74% of test results to have been positive. Detection rate was superior for nasopharyngeal swabs than for oropharyngeal samples, and highest one week after symptom onset. Certain symptom presentations may associate with these cases returning negative results, with dyspnoea reported by a greater proportion of cases who tested negative.


Subject(s)
COVID-19/diagnosis , COVID-19/epidemiology , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/mortality , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , New Zealand/epidemiology , Young Adult
5.
Clin Exp Immunol ; 205(2): 99-105, 2021 08.
Article in English | MEDLINE | ID: covidwho-1273082

ABSTRACT

Coronavirus 19 (COVID-19) has been associated with both transient and persistent systemic symptoms that do not appear to be a direct consequence of viral infection. The generation of autoantibodies has been proposed as a mechanism to explain these symptoms. To understand the prevalence of autoantibodies associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, we investigated the frequency and specificity of clinically relevant autoantibodies in 84 individuals previously infected with SARS-CoV-2, suffering from COVID-19 of varying severity in both the acute and convalescent setting. These were compared with results from 32 individuals who were on the intensive therapy unit (ITU) for non-COVID reasons. We demonstrate a higher frequency of autoantibodies in the COVID-19 ITU group compared with non-COVID-19 ITU disease control patients and that autoantibodies were also found in the serum 3-5 months post-COVID-19 infection. Non-COVID patients displayed a diverse pattern of autoantibodies; in contrast, the COVID-19 groups had a more restricted panel of autoantibodies including skin, skeletal muscle and cardiac antibodies. Our results demonstrate that respiratory viral infection with SARS-CoV-2 is associated with the detection of a limited profile of tissue-specific autoantibodies, detectable using routine clinical immunology assays. Further studies are required to determine whether these autoantibodies are specific to SARS-CoV-2 or a phenomenon arising from severe viral infections and to determine the clinical significance of these autoantibodies.


Subject(s)
Antibody Specificity , Autoantibodies , COVID-19 , SARS-CoV-2 , Adult , Aged , Autoantibodies/blood , Autoantibodies/immunology , COVID-19/blood , COVID-19/immunology , Female , Humans , Male , Middle Aged , Organ Specificity , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Severity of Illness Index
6.
Nat Med ; 27(5): 904-916, 2021 05.
Article in English | MEDLINE | ID: covidwho-1195620

ABSTRACT

Analysis of human blood immune cells provides insights into the coordinated response to viral infections such as severe acute respiratory syndrome coronavirus 2, which causes coronavirus disease 2019 (COVID-19). We performed single-cell transcriptome, surface proteome and T and B lymphocyte antigen receptor analyses of over 780,000 peripheral blood mononuclear cells from a cross-sectional cohort of 130 patients with varying severities of COVID-19. We identified expansion of nonclassical monocytes expressing complement transcripts (CD16+C1QA/B/C+) that sequester platelets and were predicted to replenish the alveolar macrophage pool in COVID-19. Early, uncommitted CD34+ hematopoietic stem/progenitor cells were primed toward megakaryopoiesis, accompanied by expanded megakaryocyte-committed progenitors and increased platelet activation. Clonally expanded CD8+ T cells and an increased ratio of CD8+ effector T cells to effector memory T cells characterized severe disease, while circulating follicular helper T cells accompanied mild disease. We observed a relative loss of IgA2 in symptomatic disease despite an overall expansion of plasmablasts and plasma cells. Our study highlights the coordinated immune response that contributes to COVID-19 pathogenesis and reveals discrete cellular components that can be targeted for therapy.


Subject(s)
COVID-19/immunology , Proteome , SARS-CoV-2/immunology , Single-Cell Analysis/methods , Transcriptome , Cross-Sectional Studies , Humans , Monocytes/immunology , Receptors, Antigen, B-Cell/immunology , Receptors, Antigen, T-Cell/immunology , T-Lymphocytes/immunology
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