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1.
Eur J Immunol ; 51(12): 2708-3145, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1568038

ABSTRACT

The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer-reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state-of-the-art handbook for basic and clinical researchers.

2.
Eur J Immunol ; 2021 Dec 06.
Article in English | MEDLINE | ID: covidwho-1555185

ABSTRACT

To better understand the mechanisms at the basis of neutrophil functions during SARS-CoV-2 we studied patients with severe COVID-19 pneumonia. They had high blood proportion of degranulated neutrophils and elevated plasma levels of myeloperoxidase (MPO), elastase and MPO-DNA complexes, which are typical markers of neutrophil extracellular traps (NET). Their neutrophils display dysfunctional mitochondria, defective oxidative burst, increased glycolysis, glycogen accumulation in the cytoplasm, and increase glycogenolysis. Hypoxia-inducible factor 1α (ΗΙF-1α) is stabilized in such cells, and it controls the level of glycogen phosphorylase L (PYGL), a key enzyme in glycogenolysis. Inhibiting PYGL abolishes the ability of neutrophils to produce NET. Patients displayed significant increases of plasma levels of molecules involved in the regulation of neutrophils' function, including CCL2, CXCL10, CCL20, IL-18, IL-3, IL-6, G-CSF, GM-CSF, IFN-γ. Our data suggest that metabolic remodelling is vital for the formation of NET and for boosting neutrophil inflammatory response, thus suggesting that modulating ΗΙF-1α or PYGL could represent a novel approach for innovative therapies. This article is protected by copyright. All rights reserved.

5.
Nat Commun ; 12(1): 4677, 2021 07 29.
Article in English | MEDLINE | ID: covidwho-1387356

ABSTRACT

SARS-CoV-2 infection can affect all human beings, including pregnant women. Thus, understanding the immunological changes induced by the virus during pregnancy is nowadays of pivotal importance. Here, using peripheral blood from 14 pregnant women with asymptomatic or mild SARS-CoV-2 infection, we investigate cell proliferation and cytokine production, measure plasma levels of 62 cytokines, and perform a 38-parameter mass cytometry analysis. Our results show an increase in low density neutrophils but no lymphopenia or gross alterations of white blood cells, which display normal levels of differentiation, activation or exhaustion markers and show well preserved functionality. Meanwhile, the plasma levels of anti-inflammatory cytokines such as interleukin (IL)-1RA, IL-10 and IL-19 are increased, those of IL-17, PD-L1 and D-dimer are decreased, but IL-6 and other inflammatory molecules remain unchanged. Our profiling of antiviral immune responses may thus help develop therapeutic strategies to avoid virus-induced damages during pregnancy.


Subject(s)
COVID-19/immunology , Cytokines/blood , Inflammation/immunology , Pregnancy Complications, Infectious/immunology , Pregnancy Complications, Infectious/virology , SARS-CoV-2/immunology , Adolescent , Adult , Asymptomatic Infections , Biomarkers/blood , COVID-19/blood , COVID-19/virology , Case-Control Studies , Cross-Sectional Studies , Cytokines/immunology , Female , Humans , Inflammation/blood , Inflammation/prevention & control , Inflammation/virology , Middle Aged , Pregnancy , Pregnancy Complications, Infectious/blood , SARS-CoV-2/isolation & purification , Young Adult
6.
Cells ; 10(7)2021 06 23.
Article in English | MEDLINE | ID: covidwho-1285369

ABSTRACT

Cell death mechanisms are crucial to maintain an appropriate environment for the functionality of healthy cells. However, during viral infections, dysregulation of these processes can be present and can participate in the pathogenetic mechanisms of the disease. In this review, we describe some features of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and some immunopathogenic mechanisms characterizing the present coronavirus disease (COVID-19). Lymphopenia and monocytopenia are important contributors to COVID-19 immunopathogenesis. The fine mechanisms underlying these phenomena are still unknown, and several hypotheses have been raised, some of which assign a role to cell death as far as the reduction of specific types of immune cells is concerned. Thus, we discuss three major pathways such as apoptosis, necroptosis, and pyroptosis, and suggest that all of them likely occur simultaneously in COVID-19 patients. We describe that SARS-CoV-2 can have both a direct and an indirect role in inducing cell death. Indeed, on the one hand, cell death can be caused by the virus entry into cells, on the other, the excessive concentration of cytokines and chemokines, a process that is known as a COVID-19-related cytokine storm, exerts deleterious effects on circulating immune cells. However, the overall knowledge of these mechanisms is still scarce and further studies are needed to delineate new therapeutic strategies.


Subject(s)
COVID-19/pathology , Cell Death/physiology , SARS-CoV-2/pathogenicity , Apoptosis/physiology , COVID-19/immunology , COVID-19/virology , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/pathology , Cytokines/metabolism , Humans , Necroptosis/physiology , Virus Internalization
7.
Sci Rep ; 11(1): 12716, 2021 06 16.
Article in English | MEDLINE | ID: covidwho-1275959

ABSTRACT

Monocyte Distribution Width (MDW), a new cytometric parameter correlating with cytomorphologic changes occurring upon massive monocyte activation, has recently emerged as promising early biomarker of sepsis. Similar to sepsis, monocyte/macrophage subsets are considered key mediators of the life-threatening hyper-inflammatory disorder characterizing severe COVID-19. In this study, we longitudinally analyzed MDW values in a cohort of 87 COVID-19 patients consecutively admitted to our hospital, showing significant correlations between MDW and common inflammatory markers, namely CRP (p < 0.001), fibrinogen (p < 0.001) and ferritin (p < 0.01). Moreover, high MDW values resulted to be prognostically associated with fatal outcome in COVID-19 patients (AUC = 0.76, 95% CI: 0.66-0.87, sensitivity 0.75, specificity 0.70, MDW threshold 26.4; RR = 4.91, 95% CI: 1.73-13.96; OR = 7.14, 95% CI: 2.06-24.71). This pilot study shows that MDW can be useful in the monitoring of COVID-19 patients, as this innovative hematologic biomarker is: (1) easy to obtain, (2) directly related to the activation state of a fundamental inflammatory cell subset (i.e. monocytes, pivotal in both cytokine storm and sepsis immunopathogenesis), (3) well correlated with clinical severity of COVID-19-associated inflammatory disorder, and, in turn, (4) endowed with relevant prognostic significance. Additional studies are needed to define further the clinical impact of MDW testing in the management of COVID-19 patients.


Subject(s)
COVID-19/blood , Cell Size , Monocytes/pathology , SARS-CoV-2 , Severity of Illness Index , Adolescent , Adult , Aged , Aged, 80 and over , Biomarkers/blood , C-Reactive Protein/analysis , COVID-19/epidemiology , COVID-19/virology , Female , Ferritins/blood , Fibrinogen/analysis , Humans , Inflammation/blood , Italy/epidemiology , Longitudinal Studies , Male , Middle Aged , Patient Admission , Pilot Projects , Prognosis , Retrospective Studies , Sensitivity and Specificity , Young Adult
8.
Nat Commun ; 12(1): 2593, 2021 05 10.
Article in English | MEDLINE | ID: covidwho-1223090

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 is a continuous challenge worldwide, and there is an urgent need to map the landscape of immunogenic and immunodominant epitopes recognized by CD8+ T cells. Here, we analyze samples from 31 patients with COVID-19 for CD8+ T cell recognition of 500 peptide-HLA class I complexes, restricted by 10 common HLA alleles. We identify 18 CD8+ T cell recognized SARS-CoV-2 epitopes, including an epitope with immunodominant features derived from ORF1ab and restricted by HLA-A*01:01. In-depth characterization of SARS-CoV-2-specific CD8+ T cell responses of patients with acute critical and severe disease reveals high expression of NKG2A, lack of cytokine production and a gene expression profile inhibiting T cell re-activation and migration while sustaining survival. SARS-CoV-2-specific CD8+ T cell responses are detectable up to 5 months after recovery from critical and severe disease, and these responses convert from dysfunctional effector to functional memory CD8+ T cells during convalescence.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Immunodominant Epitopes/immunology , SARS-CoV-2/immunology , Adult , Aged , Aged, 80 and over , Alleles , CD8-Positive T-Lymphocytes/pathology , COVID-19/pathology , Epitopes, T-Lymphocyte/immunology , Female , Histocompatibility Antigens Class I/genetics , Histocompatibility Antigens Class I/immunology , Humans , Immunodominant Epitopes/chemistry , Immunologic Memory , Lymphocyte Activation , Male , Middle Aged , Polyproteins/immunology , Viral Proteins/immunology
9.
EMBO Mol Med ; 12(12): e13001, 2020 12 07.
Article in English | MEDLINE | ID: covidwho-881540

ABSTRACT

In patients infected by SARS-CoV-2 who experience an exaggerated inflammation leading to pneumonia, monocytes likely play a major role but have received poor attention. Thus, we analyzed peripheral blood monocytes from patients with COVID-19 pneumonia and found that these cells show signs of altered bioenergetics and mitochondrial dysfunction, had a reduced basal and maximal respiration, reduced spare respiratory capacity, and decreased proton leak. Basal extracellular acidification rate was also diminished, suggesting reduced capability to perform aerobic glycolysis. Although COVID-19 monocytes had a reduced ability to perform oxidative burst, they were still capable of producing TNF and IFN-γ in vitro. A significantly high amount of monocytes had depolarized mitochondria and abnormal mitochondrial ultrastructure. A redistribution of monocyte subsets, with a significant expansion of intermediate/pro-inflammatory cells, and high amounts of immature monocytes were found, along with a concomitant compression of classical monocytes, and an increased expression of inhibitory checkpoints like PD-1/PD-L1. High plasma levels of several inflammatory cytokines and chemokines, including GM-CSF, IL-18, CCL2, CXCL10, and osteopontin, finally confirm the importance of monocytes in COVID-19 immunopathogenesis.


Subject(s)
COVID-19/pathology , Energy Metabolism/physiology , Mitochondria/metabolism , Monocytes/metabolism , Adult , Aged , Aged, 80 and over , COVID-19/virology , Case-Control Studies , Chemokines/blood , Cytokines/blood , Female , Humans , Male , Middle Aged , Mitochondria/ultrastructure , Monocytes/cytology , Programmed Cell Death 1 Receptor/genetics , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2/isolation & purification
11.
Eur J Immunol ; 50(9): 1283-1294, 2020 09.
Article in English | MEDLINE | ID: covidwho-670172

ABSTRACT

Studies on the interactions between SARS-CoV-2 and humoral immunity are fundamental to elaborate effective therapies including vaccines. We used polychromatic flow cytometry, coupled with unsupervised data analysis and principal component analysis (PCA), to interrogate B cells in untreated patients with COVID-19 pneumonia. COVID-19 patients displayed normal plasma levels of the main immunoglobulin classes, of antibodies against common antigens or against antigens present in common vaccines. However, we found a decreased number of total and naïve B cells, along with decreased percentages and numbers of memory switched and unswitched B cells. On the contrary, IgM+ and IgM- plasmablasts were significantly increased. In vitro cell activation revealed that B lymphocytes showed a normal proliferation index and number of dividing cells per cycle. PCA indicated that B-cell number, naive and memory B cells but not plasmablasts clustered with patients who were discharged, while plasma IgM level, C-reactive protein, D-dimer, and SOFA score with those who died. In patients with pneumonia, the derangement of the B-cell compartment could be one of the causes of the immunological failure to control SARS-Cov2, have a relevant influence on several pathways, organs and systems, and must be considered to develop vaccine strategies.


Subject(s)
Antibodies, Viral/blood , B-Lymphocytes/immunology , Betacoronavirus/pathogenicity , Coronavirus Infections/immunology , Immunoglobulin Isotypes/blood , Lung/immunology , Pneumonia, Viral/immunology , Adult , Aged , Aged, 80 and over , Antibodies, Viral/classification , B-Lymphocytes/virology , Betacoronavirus/immunology , C-Reactive Protein/immunology , COVID-19 , Case-Control Studies , Cell Proliferation , Coronavirus Infections/mortality , Coronavirus Infections/pathology , Coronavirus Infections/virology , Cross-Sectional Studies , Cytokines/genetics , Cytokines/immunology , Female , Fibrin Fibrinogen Degradation Products/immunology , Humans , Immunity, Humoral , Immunologic Memory , Lung/pathology , Lung/virology , Lymphocyte Activation , Lymphocyte Count , Male , Middle Aged , Organ Dysfunction Scores , Pandemics , Pneumonia, Viral/mortality , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Primary Cell Culture , SARS-CoV-2 , Severity of Illness Index , Survival Analysis
12.
Nat Commun ; 11(1): 3434, 2020 07 06.
Article in English | MEDLINE | ID: covidwho-631255

ABSTRACT

The immune system of patients infected by SARS-CoV-2 is severely impaired. Detailed investigation of T cells and cytokine production in patients affected by COVID-19 pneumonia are urgently required. Here we show that, compared with healthy controls, COVID-19 patients' T cell compartment displays several alterations involving naïve, central memory, effector memory and terminally differentiated cells, as well as regulatory T cells and PD1+CD57+ exhausted T cells. Significant alterations exist also in several lineage-specifying transcription factors and chemokine receptors. Terminally differentiated T cells from patients proliferate less than those from healthy controls, whereas their mitochondria functionality is similar in CD4+ T cells from both groups. Patients display significant increases of proinflammatory or anti-inflammatory cytokines, including T helper type-1 and type-2 cytokines, chemokines and galectins; their lymphocytes produce more tumor necrosis factor (TNF), interferon-γ, interleukin (IL)-2 and IL-17, with the last observation implying that blocking IL-17 could provide a novel therapeutic strategy for COVID-19.


Subject(s)
Betacoronavirus/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , T-Lymphocyte Subsets/immunology , Adult , Aged , Aged, 80 and over , Biomarkers/metabolism , CD4-Positive T-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/pathology , CD8-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/pathology , COVID-19 , Cellular Senescence , Coronavirus Infections/blood , Coronavirus Infections/pathology , Cytokine Release Syndrome , Cytokines/immunology , Cytokines/metabolism , Female , Humans , Immunologic Memory , Italy/epidemiology , Lymphocyte Activation , Lymphocyte Count , Male , Middle Aged , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/pathology , SARS-CoV-2 , T-Lymphocyte Subsets/metabolism , T-Lymphocyte Subsets/pathology , Th17 Cells/immunology , Th17 Cells/metabolism , Th17 Cells/pathology
13.
Cytometry A ; 97(7): 668-673, 2020 07.
Article in English | MEDLINE | ID: covidwho-47563

ABSTRACT

The pandemic caused by severe acute respiratory syndrome coronavirus 2 heavily involves all those working in a laboratory. Samples from known infected patients or donors who are considered healthy can arrive, and a colleague might be asymptomatic but able to transmit the virus. Working in a clinical laboratory is posing several safety challenges. Few years ago, International Society for Advancement of Cytometry published guidelines to safely analyze and sort human samples that were revised in these days. We describe the procedures that we have been following since the first patient appeared in Italy, which have only slightly modified our standard one, being all human samples associated with risks. © 2020 International Society for Advancement of Cytometry.


Subject(s)
Betacoronavirus , Coronavirus Infections/blood , Medical Laboratory Personnel , Occupational Health , Pneumonia, Viral/blood , Specimen Handling/methods , COVID-19 , Cytokine Release Syndrome/blood , Flow Cytometry/methods , Humans , Italy , Masks , Occupational Exposure/prevention & control , Pandemics , Protective Clothing , SARS-CoV-2
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