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1.
Cell Rep ; 38(2): 110214, 2022 01 11.
Article in English | MEDLINE | ID: covidwho-1588141

ABSTRACT

T cell immunity is crucial for control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and has been studied widely on a quantitative level. However, the quality of responses, in particular of CD8+ T cells, has only been investigated marginally so far. Here, we isolate T cell receptor (TCR) repertoires specific for immunodominant SARS-CoV-2 epitopes restricted to common human Leukocyte antigen (HLA) class I molecules in convalescent individuals. SARS-CoV-2-specific CD8+ T cells are detected up to 12 months after infection. TCR repertoires are diverse, with heterogeneous functional avidity and cytotoxicity toward virus-infected cells, as demonstrated for TCR-engineered T cells. High TCR functionality correlates with gene signatures that, remarkably, could be retrieved for each epitope:HLA combination analyzed. Overall, our data demonstrate that polyclonal and highly functional CD8+ TCRs-classic features of protective immunity-are recruited upon mild SARS-CoV-2 infection, providing tools to assess the quality of and potentially restore functional CD8+ T cell immunity.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Receptors, Antigen, T-Cell/immunology , SARS-CoV-2/immunology , Adult , Cells, Cultured , Cross Reactions/immunology , Epitopes, T-Lymphocyte/immunology , Female , Humans , Immunodominant Epitopes/immunology , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/virology , Male , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocytes, Cytotoxic/immunology
2.
Eur J Immunol ; 51(12): 2708-3145, 2021 12.
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.


Subject(s)
Autoimmune Diseases/immunology , Flow Cytometry , Infections/immunology , Neoplasms/immunology , Animals , Chronic Disease , Humans , Mice , Practice Guidelines as Topic
3.
Multidiscip Respir Med ; 16(1): 793, 2021 Jan 15.
Article in English | MEDLINE | ID: covidwho-1512830

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) has become a pandemic. Bacterial superinfections seem to be associated with higher mortality in COVID-19 patients in intensive care units (ICUs). However, details on the prevalence and species distribution of secondary infections are limited. Moreover, the increasing use of dexamethasone may pose an additional risk of superinfections. METHODS: We performed a single-center retrospective study of the clinical and microbiological characteristics of 154 COVID-19 patients admitted to the ICU between March 2020 and January 2021, focusing on bacterial infections, use of antimicrobial agents and dexamethasone therapy. RESULTS: The median age was 68 years; 67.5% of the patients were men. Critically ill COVID-19 patients were treated with dexamethasone since July 2020 (second wave), which was not common during the first wave of the pandemic. In the dexamethasone group (n=90, 58.4%), respiratory pathogens were detected more frequently, as were multidrugresistant pathogens. The number of patients with polymicrobial detection of respiratory pathogens was significantly increased (p=0.013). The most frequently detected species were Enterobacterales, Staphylococcus aureus, and Aspergillus fumigatus. The rates of bloodstream infections did not differ between the groups. The use of dexamethasone in ICU COVID-19 patients was associated with higher rates of respiratory infectious complications. CONCLUSIONS: Secondary infections are present in a substantial fraction of critically ill COVID-19 patients. Respiratory pathogens were detectable in the majority of COVID-19 ICU patients. The use of dexamethasone poses a potential risk of secondary pulmonary infections. Infectious complications in patients with dexamethasone therapy could be associated with worse outcomes.

4.
J Clin Med ; 10(22)2021 Nov 12.
Article in English | MEDLINE | ID: covidwho-1512415

ABSTRACT

Deficiencies in smell and taste are common symptoms of COVID-19. Quantitative losses are well surveyed. This study focuses on qualitative changes such as phantosmia (hallucination of smell), parosmia (alteration of smell), and dysgeusia (alteration of taste) and possible connections with the adaptive immune system. Subjective experience of deficiency in taste and smell was assessed by two different questionnaires after a median of 100 and 244 days after first positive RT-PCR test. SARS-CoV-2-specific antibody levels were measured with the iFlash-SARS-CoV-2 assay. After 100 days a psychophysical screening test for olfactory and gustatory dysfunction was administered. 30 of 44 (68.2%) participants reported a chemosensory dysfunction (14 quantitative, 6 qualitative, 10 quantitative, and qualitative) during COVID-19, eleven (25.0%) participants (1 quantitative, 7 qualitative, 3 quantitative, and quantity) after 100 days, and 14 (31.8%) participants (1 quantitative, 10 qualitative, 3 quantitative and qualitative) after 244 days. Four (9.1%) participants, who were symptom-free after 100 days reported now recently arisen qualitative changes. Serological and T-cell analysis showed no correlation with impairment of taste and smell. In conclusion, qualitative changes can persist for several months and occur as late-onset symptoms months after full recovery from COVID-19-induced quantitative losses in taste and smell.

5.
Nat Commun ; 12(1): 4515, 2021 07 26.
Article in English | MEDLINE | ID: covidwho-1327196

ABSTRACT

The in vivo phenotypic profile of T cells reactive to severe acute respiratory syndrome (SARS)-CoV-2 antigens remains poorly understood. Conventional methods to detect antigen-reactive T cells require in vitro antigenic re-stimulation or highly individualized peptide-human leukocyte antigen (pHLA) multimers. Here, we use single-cell RNA sequencing to identify and profile SARS-CoV-2-reactive T cells from Coronavirus Disease 2019 (COVID-19) patients. To do so, we induce transcriptional shifts by antigenic stimulation in vitro and take advantage of natural T cell receptor (TCR) sequences of clonally expanded T cells as barcodes for 'reverse phenotyping'. This allows identification of SARS-CoV-2-reactive TCRs and reveals phenotypic effects introduced by antigen-specific stimulation. We characterize transcriptional signatures of currently and previously activated SARS-CoV-2-reactive T cells, and show correspondence with phenotypes of T cells from the respiratory tract of patients with severe disease in the presence or absence of virus in independent cohorts. Reverse phenotyping is a powerful tool to provide an integrated insight into cellular states of SARS-CoV-2-reactive T cells across tissues and activation states.


Subject(s)
COVID-19/immunology , Gene Expression Profiling/methods , Sequence Analysis, RNA/methods , Single-Cell Analysis/methods , T-Lymphocytes/metabolism , Aged , Aged, 80 and over , CD4-Positive T-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/virology , COVID-19/epidemiology , COVID-19/virology , Cells, Cultured , Cohort Studies , Female , Humans , Male , Middle Aged , Pandemics , Receptors, Antigen, T-Cell/genetics , Receptors, Antigen, T-Cell/immunology , Receptors, Antigen, T-Cell/metabolism , SARS-CoV-2/physiology , T-Lymphocytes/virology
6.
Hemasphere ; 5(7): e603, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1301392

ABSTRACT

The clinical and immunological impact of B-cell depletion in the context of coronavirus disease 2019 (COVID-19) is unclear. We conducted a prospectively planned analysis of COVID-19 in patients who received B-cell depleting anti-CD20 antibodies and chemotherapy for B-cell lymphomas. The control cohort consisted of age- and sex-matched patients without lymphoma who were hospitalized because of COVID-19. We performed detailed clinical analyses, in-depth cellular and molecular immune profiling, and comprehensive virological studies in 12 patients with available biospecimens. B-cell depleted lymphoma patients had more severe and protracted clinical course (median hospitalization 88 versus 17 d). All patients actively receiving immunochemotherapy (n = 5) required ICU support including long-term mechanical ventilation. Neutrophil recovery following granulocyte colony stimulating factor stimulation coincided with hyperinflammation and clinical deterioration in 4 of the 5 patients. Immune cell profiling and gene expression analysis of peripheral blood mononuclear cells revealed early activation of monocytes/macrophages, neutrophils, and the complement system in B-cell depleted lymphoma patients, with subsequent exacerbation of the inflammatory response and dysfunctional interferon signaling at the time of clinical deterioration of COVID-19. Longitudinal immune cell profiling and functional in vitro assays showed SARS-CoV-2-specific CD8+ and CD4+ T-effector cell responses. Finally, we observed long-term detection of SARS-CoV-2 in respiratory specimens (median 84 versus 12 d) and an inability to mount lasting SARS-CoV-2 antibody responses in B-cell depleted lymphoma patients. In summary, we identified clinically relevant particularities of COVID-19 in lymphoma patients receiving B-cell depleting immunochemotherapies.

7.
Viruses ; 13(2)2021 02 03.
Article in English | MEDLINE | ID: covidwho-1060774

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), comprises mild courses of disease as well as progression to severe disease, characterised by lung and other organ failure. The immune system is considered to play a crucial role for the pathogenesis of COVID-19, although especially the contribution of innate-like T cells remains poorly understood. Here, we analysed the phenotype and function of mucosal-associated invariant T (MAIT) cells, innate-like T cells with potent antimicrobial effector function, in patients with mild and severe COVID-19 by multicolour flow cytometry. Our data indicate that MAIT cells are highly activated in patients with COVID-19, irrespective of the course of disease, and express high levels of proinflammatory cytokines such as IL-17A and TNFα ex vivo. Of note, expression of the activation marker HLA-DR positively correlated with SAPS II score, a measure of disease severity. Upon MAIT cell-specific in vitro stimulation, MAIT cells however failed to upregulate expression of the cytokines IL-17A and TNFα, as well as cytolytic proteins, that is, granzyme B and perforin. Thus, our data point towards an altered cytokine expression profile alongside an impaired antibacterial and antiviral function of MAIT cells in COVID-19 and thereby contribute to the understanding of COVID-19 immunopathogenesis.


Subject(s)
COVID-19/immunology , Lymphocyte Activation , Mucosal-Associated Invariant T Cells/immunology , Adaptive Immunity , COVID-19/physiopathology , Cytokines/metabolism , Female , Granzymes/metabolism , HLA-DR Antigens , Humans , Interleukin-17/metabolism , Killer Cells, Natural/immunology , Male , Mucosal-Associated Invariant T Cells/metabolism , Severity of Illness Index , T-Lymphocyte Subsets/immunology , Tumor Necrosis Factor-alpha/metabolism
8.
Eur J Clin Microbiol Infect Dis ; 40(4): 859-869, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-898040

ABSTRACT

The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide. Bacterial co-infections are associated with unfavourable outcomes in respiratory viral infections; however, microbiological and antibiotic data related to COVID-19 are sparse. Adequate use of antibiotics in line with antibiotic stewardship (ABS) principles is warranted during the pandemic. We performed a retrospective study of clinical and microbiological characteristics of 140 COVID-19 patients admitted between February and April 2020 to a German University hospital, with a focus on bacterial co-infections and antimicrobial therapy. The final date of follow-up was 6 May 2020. Clinical data of 140 COVID-19 patients were recorded: The median age was 63.5 (range 17-99) years; 64% were males. According to the implemented local ABS guidelines, the most commonly used antibiotic regimen was ampicillin/sulbactam (41.5%) with a median duration of 6 (range 1-13) days. Urinary antigen tests for Legionella pneumophila and Streptococcus peumoniae were negative in all cases. In critically ill patients admitted to intensive care units (n = 50), co-infections with Enterobacterales (34.0%) and Aspergillus fumigatus (18.0%) were detected. Blood cultures collected at admission showed a diagnostic yield of 4.2%. Bacterial and fungal co-infections are rare in COVID-19 patients and are mainly prevalent in critically ill patients. Further studies are needed to assess the impact of antimicrobial therapy on therapeutic outcome in COVID-19 patients to prevent antimicrobial overuse. ABS guidelines could help in optimising the management of COVID-19. Investigation of microbial patterns of infectious complications in critically ill COVID-19 patients is also required.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Antimicrobial Stewardship , Bacterial Infections/epidemiology , COVID-19/epidemiology , Practice Patterns, Physicians'/statistics & numerical data , Adolescent , Adult , Aged , Aged, 80 and over , Ampicillin/therapeutic use , Antifungal Agents/therapeutic use , Aspergillosis/drug therapy , Aspergillosis/epidemiology , Azithromycin/therapeutic use , Bacterial Infections/drug therapy , Cohort Studies , Coinfection/epidemiology , Enterobacteriaceae Infections/drug therapy , Enterobacteriaceae Infections/epidemiology , Escherichia coli Infections/drug therapy , Escherichia coli Infections/epidemiology , Female , Germany/epidemiology , Humans , Klebsiella Infections/drug therapy , Klebsiella Infections/epidemiology , Linezolid/therapeutic use , Male , Meropenem/therapeutic use , Middle Aged , Piperacillin, Tazobactam Drug Combination/therapeutic use , Retrospective Studies , SARS-CoV-2 , Staphylococcal Infections/drug therapy , Staphylococcal Infections/epidemiology , Streptococcal Infections/drug therapy , Streptococcal Infections/epidemiology , Sulbactam/therapeutic use , Vancomycin/therapeutic use , Young Adult
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