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1.
Clinical Microbiology and Infection ; 2022.
Article in English | ScienceDirect | ID: covidwho-1814271

ABSTRACT

Objectives The COVID-19 pandemic increases healthcare worker (HCW) absenteeism. The Bacillus Calmette-Guérin (BCG) vaccine may provide non-specific protection against respiratory infections through enhancement of trained immunity. We investigated the impact of BCG vaccination on HCW absenteeism during the COVID-19 pandemic. Methods HCWs exposed to COVID-19 patients in nine Dutch hospitals were randomized to BCG vaccine or placebo in a 1:1 ratio, and followed for one year using a mobile phone application. The primary endpoint was the self-reported number of days of unplanned absenteeism for any reason. Secondary endpoints included documented COVID-19, acute respiratory symptoms or fever. This was an investigator-funded study, registered at ClinicalTrials.gov (NCT03987919). Results In March/April 2020, 1511 HCWs were enrolled. The median duration of follow-up was 357 person-days (IQR, 351 to 361). Unplanned absenteeism for any reason was observed in 2.8% of planned working days in the BCG group and 2.7% in the placebo group (adjusted relative risk 0.94, 95% credible interval (CI) 0.78 to 1.15). Cumulative incidences of documented COVID-19 were 14.2% in the BCG and 15.2% in the placebo group (adjusted hazard ratio (aHR) 0.94, 95%CI: 0.72 to 1.24). First episodes of self-reported acute respiratory symptoms or fever occurred in 490 (66.2%) and 443 (60.2%) participants, respectively (aHR: 1.13, 95% CI 0.99 to 1.28). Thirty-one serious adverse events were reported (13 after BCG, 18 after placebo), none considered related to study medication. Conclusions During the COVID-19 pandemic, BCG-vaccination of HCW exposed to COVID-19 patients did not reduce unplanned absenteeism nor documented COVID-19.

2.
Trends in Molecular Medicine ; 2022.
Article in English | ScienceDirect | ID: covidwho-1799777

ABSTRACT

The innate immune system is able to build memory-like features in response to certain infections or vaccines, resulting in enhanced responsiveness upon (re)challenge with the same or an unrelated pathogen, a phenomenon termed ‘trained immunity’. Compared with antigen-dependent adaptive immune responses triggered by classical vaccines against specific pathogens, trained immunity-related vaccines induce enhanced innate immune responses against unrelated pathogens and provide ‘heterologous protection’. Here, we discuss the heterologous effects of vaccines against infections and detail the latest insights into the cellular and molecular mechanisms mediating trained immunity. Additionally, novel vaccine strategies are suggested for fighting new pandemics in the future by taking advantage of the heterologous memory features of trained immunity.

3.
Cell Rep ; 38(10): 110502, 2022 03 08.
Article in English | MEDLINE | ID: covidwho-1757194

ABSTRACT

Since the vast majority of species solely rely on innate immunity for host defense, it stands to reason that a critical evolutionary trait like immunological memory evolved in this primitive branch of our immune system. There is ample evidence that vaccines such as bacillus Calmette-Guérin (BCG) induce protective innate immune memory responses (trained immunity) against heterologous pathogens. Here we show that while BCG vaccination significantly reduces morbidity and mortality against influenza A virus (IAV), it fails to provide protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). In contrast to IAV, SARS-CoV-2 infection leads to unique pulmonary vasculature damage facilitating viral dissemination to other organs, including the bone marrow (BM), a central site for BCG-mediated trained immunity. Finally, monocytes from BCG-vaccinated individuals mount an efficient cytokine response to IAV infection, while this response is minimal following SARS-CoV-2. Collectively, our data suggest that the protective capacity of BCG vaccination is contingent on viral pathogenesis and tissue tropism.


Subject(s)
COVID-19 , Influenza A virus , BCG Vaccine , COVID-19/prevention & control , Humans , Immunity, Innate , SARS-CoV-2 , Vaccination
4.
Clin Infect Dis ; 2022 Mar 05.
Article in English | MEDLINE | ID: covidwho-1730665

ABSTRACT

BACKGROUND: Older age is associated with increased severity and death from respiratory infections, including coronavirus disease 2019 (Covid-19). The tuberculosis vaccine Bacille Calmette-Guérin (BCG) may provide heterologous protection against non-tuberculous infections, and has been proposed as a potential preventive strategy against Covid-19. METHODS: In this multicenter, placebo-controlled trial, we randomly assigned elderly individuals (60 years or older, n=2014) to intracutaneous vaccination with BCG (n=1008) or placebo (n=1006). The primary endpoint was the cumulative incidence of respiratory tract infections that required medical intervention, during 12 months of follow-up. Secondary endpoints included the incidence of Covid-19, and the effect of BCG vaccination on the cellular and humoral immune responses. RESULTS: The cumulative incidence of respiratory tract infection requiring medical intervention was 0.029 in the BCG-vaccinated group and 0.024 in the control group (subdistribution hazard ratio [SHR], 1.26; 98.2% confidence interval [CI], 0.65 to 2.44). 51 and 48 individuals tested positive for SARS-CoV-2 by PCR in the BCG and placebo group, respectively (SHR, 1.053; 95% CI, 0.71 to 1.56). No difference was observed in the frequency of adverse events. BCG vaccination was associated with enhanced cytokines responses after influenza, and partially also after SARS-CoV-2 stimulation. In patients diagnosed with Covid-19, antibody responses after infection were significantly stronger if the volunteers had previously received BCG. CONCLUSIONS: BCG-vaccination had no effect on the incidence of respiratory tract infections, including SARS-CoV-2 infection, in elderly volunteers. However, BCG vaccination improved cytokine responses stimulated by influenza and SARS-CoV-2, and induced stronger antibody titers after Covid-19 infection.

5.
Cell Reports Medicine ; : 100560, 2022.
Article in English | ScienceDirect | ID: covidwho-1706398

ABSTRACT

Summary Most patients infected with SARS-CoV-2 (COVID-19) experience mild, non-specific symptoms, but several develop severe symptoms associated with an excessive inflammatory response. Elevated plasma concentrations of soluble urokinase plasminogen activator receptor (suPAR) provide early warning of progression to severe respiratory failure (SRF) or death, but access to suPAR testing may be limited. The Severe COvid Prediction Estimate (SCOPE) score, derived from C-reactive protein, D-dimers, interleukin-6, and ferritin circulating concentrations among patients not receiving non-invasive or invasive mechanical ventilation during the SAVE-MORE study, offers comparable predictive accuracy for progression to SRF or death within 14 days as suPAR ≥6 ng/ml (area under receiver operator characteristic curve, 0.81 for both). SCOPE score is validated in two similar independent cohorts. SCOPE score 6 or more is an alternative to suPAR for predicting progression to SRF or death within 14 days of hospital admission for pneumonia, and it can be used to guide treatment decisions.

6.
Am J Hum Genet ; 109(3): 471-485, 2022 Mar 03.
Article in English | MEDLINE | ID: covidwho-1679508

ABSTRACT

Humans exhibit remarkable interindividual and interpopulation immune response variability upon microbial challenges. Cytokines play a vital role in regulating inflammation and immune responses, but dysregulation of cytokine responses has been implicated in different disease states. Host genetic factors were previously shown to significantly impact cytokine response heterogeneity mainly in European-based studies, but it is unclear whether these findings are transferable to non-European individuals. Here, we aimed to identify genetic variants modulating cytokine responses in healthy adults of East African ancestry from Tanzania. We leveraged both cytokine and genetic data and performed genome-wide cytokine quantitative trait loci (cQTLs) mapping. The results were compared with another cohort of healthy adults of Western European ancestry via direct overlap and functional enrichment analyses. We also performed meta-analyses to identify cQTLs with congruent effect direction in both populations. In the Tanzanians, cQTL mapping identified 80 independent suggestive loci and one genome-wide significant locus (TBC1D22A) at chromosome 22; SNP rs12169244 was associated with IL-1b release after Salmonella enteritidis stimulation. Remarkably, the identified cQTLs varied significantly when compared to the European cohort, and there was a very limited percentage of overlap (1.6% to 1.9%). We further observed ancestry-specific pathways regulating induced cytokine responses, and there was significant enrichment of the interferon pathway specifically in the Tanzanians. Furthermore, contrary to the Europeans, genetic variants in the TLR10-TLR1-TLR6 locus showed no effect on cytokine response. Our data reveal both ancestry-specific effects of genetic variants and pathways on cytokine response heterogeneity, hence arguing for the importance of initiatives to include diverse populations into genomics research.

7.
J Clin Invest ; 132(7)2022 Apr 01.
Article in English | MEDLINE | ID: covidwho-1673606

ABSTRACT

Trained immunity refers to the long-lasting memory traits of innate immunity. Recent studies have shown that trained immunity is orchestrated by sustained changes in epigenetic marks and metabolic pathways, leading to an altered transcriptional response to a second challenge. However, the potential heterogeneity of trained-immunity induction in innate immune cells has not been explored. In this study, we demonstrate cellular transcriptional programs in response to 4 different inducers of trained immunity in monocyte populations at single-cell resolution. Specifically, we identified 3 monocyte subpopulations upon the induction of trained immunity, and replicated these findings in an in vivo study. In addition, we found gene signatures consistent with these functional programs in patients with ulcerative colitis, sepsis, and COVID-19, suggesting the impact of trained-immunity programs in immune-mediated diseases.


Subject(s)
COVID-19 , Immune System Diseases , COVID-19/genetics , Humans , Immunity, Innate , Immunologic Memory , Monocytes , Sequence Analysis, RNA
8.
Nat Med ; 28(1): 39-50, 2022 01.
Article in English | MEDLINE | ID: covidwho-1641982

ABSTRACT

Immune dysregulation is an important component of the pathophysiology of COVID-19. A large body of literature has reported the effect of immune-based therapies in patients with COVID-19, with some remarkable successes such as the use of steroids or anti-cytokine therapies. However, challenges in clinical decision-making arise from the complexity of the disease phenotypes and patient heterogeneity, as well as the variable quality of evidence from immunotherapy studies. This Review aims to support clinical decision-making by providing an overview of the evidence generated by major clinical trials of host-directed therapy. We discuss patient stratification and propose an algorithm to guide the use of immunotherapy strategies in the clinic. This will not only help guide treatment decisions, but may also help to design future trials that investigate immunotherapy in other severe infections.


Subject(s)
Anticoagulants/therapeutic use , COVID-19/therapy , Complement Inactivating Agents/therapeutic use , Glucocorticoids/therapeutic use , Immunologic Factors/therapeutic use , Immunomodulation , Protein Kinase Inhibitors/therapeutic use , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal, Humanized/therapeutic use , Antibodies, Neutralizing/therapeutic use , Azetidines/therapeutic use , Bradykinin/analogs & derivatives , Bradykinin/therapeutic use , Bradykinin B2 Receptor Antagonists/therapeutic use , COVID-19/immunology , Dexamethasone/therapeutic use , Drug Combinations , Factor Xa Inhibitors/therapeutic use , Heparin/therapeutic use , Humans , Hydrocortisone/therapeutic use , Imatinib Mesylate/therapeutic use , Immunization, Passive , Interferon beta-1a/therapeutic use , Interferon beta-1b/therapeutic use , Interferon-gamma/therapeutic use , Interleukin 1 Receptor Antagonist Protein/therapeutic use , Kallikrein-Kinin System , Piperidines/therapeutic use , Purines/therapeutic use , Pyrazoles/therapeutic use , Pyrimidines/therapeutic use , SARS-CoV-2 , Sulfonamides/therapeutic use
9.
BMC Infect Dis ; 21(1): 1264, 2021 Dec 20.
Article in English | MEDLINE | ID: covidwho-1634701

ABSTRACT

BACKGROUND: From May 2020 to January 2021, we enrolled 1233 health care workers (HCW) from Danish Hospitals in a randomized trial evaluating whether Bacille Calmette-Guérin (BCG) provides protection against COVID-19. Participants were randomized 1:1 to BCG vs saline and followed for 6 months. From December 2020, Covid-19 vaccines were offered to the HCW. In most cases, BCG vaccination results in a characteristic scar. Reactivation of the BCG scar has been described in children during viral infections and following influenza vaccination, but is mostly associated to Kawasaki's disease, a disease entity with pathogenesis likely similar to the child Covid-19 complication MIS-C: Multi-System Inflammatory Syndrome. Reactivation of scars after neonatal BCG vaccination has recently been described in four women after Covid-19 mRNA vaccination. Two of our trial participants experienced reactivation of their novel BCG scars after receiving mRNA Covid-19 vaccination 6 to 8 months post-BCG. CASE PRESENTATIONS: Two female HCW participants that had been randomly allocated to BCG in the BCG-DENMARK-COVID trial, spontaneously reported itching and secretion at the BCG scar site after having received mRNA Covid-19 vaccination (Moderna and Pfizer-BioNTech) 6 to 8 months following inclusion and BCG vaccination. One participant, who had a larger BCG skin reaction, noticed re-appearing symptoms after both the first and the second COVID-vaccine dose, while the other participant only noted symptoms after the second dose. Both had been BCG vaccinated during childhood, and no reactivation was noted in the older scars. No treatment was needed or provided. CONCLUSIONS: The reactivation of the BCG scar after receiving mRNA vaccine might have been caused by cross-reactivity between BCG and SARS-CoV-2. In both cases, the symptoms were bothersome, but self-limiting and left no sequelae. The risk of reactivation at the scar site is thus not a reason to avoid vaccination with either vaccine.


Subject(s)
BCG Vaccine , COVID-19 , BCG Vaccine/adverse effects , COVID-19/complications , COVID-19 Vaccines , Child , Cicatrix , Female , Humans , Infant, Newborn , RNA, Messenger/genetics , SARS-CoV-2 , Systemic Inflammatory Response Syndrome , Vaccination , Vaccines, Synthetic
10.
Trends Immunol ; 43(2): 106-116, 2022 02.
Article in English | MEDLINE | ID: covidwho-1560364

ABSTRACT

Not all individuals exposed to a pathogen develop illness: some are naturally resistant whereas others develop an asymptomatic infection. Epidemiological studies suggest that there is similar variability in susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. We propose that natural resistance is part of the disease history in some individuals exposed to this new coronavirus. Epidemiological arguments for natural resistance to SARS-CoV-2 are the lower seropositivity of children compared to adults, studies on closed environments of ships with outbreaks, and prevalence studies in some developing countries. Potential mechanisms of natural resistance include host genetic variants, viral interference, cross-protective natural antibodies, T cell immunity, and highly effective innate immune responses. Better understanding of natural resistance can help to advance preventive and therapeutic measures against infections for improved preparedness against potential future pandemics.


Subject(s)
COVID-19 , Humans , Immunity, Innate , Pandemics , SARS-CoV-2 , T-Lymphocytes
11.
J Innate Immun ; : 1-11, 2021 Dec 01.
Article in English | MEDLINE | ID: covidwho-1546612

ABSTRACT

BACKGROUND: Macrophage activation-like syndrome (MALS) and complex immune dysregulation (CID) often underlie acute respiratory distress (ARDS) in COVID-19. We aimed to investigate the effect of personalized immunotherapy on clinical improvement of critical COVID-19. METHODS: In this open-label prospective trial, 102 patients with ARDS by SARS-CoV-2 were screened for MALS (ferritin >4,420 ng/mL) and CID (ferritin ≤4,420 ng/mL and low human leukocyte antigen (HLA)-DR expression on CD14-monocytes). Patients with MALS or CID with increased aminotransferases received intravenous anakinra; those with CID and normal aminotransferases received tocilizumab. The primary outcome was ≥25% decrease in the Sequential Organ Failure Assessment (SOFA) score and/or 50% increase in the respiratory ratio by day 8; 28-day mortality, change of SOFA score by day 28, serum biomarkers, and cytokine production by mononuclear cells were secondary endpoints. RESULTS: The primary study endpoint was met in 58.3% of anakinra-treated patients and in 33.3% of tocilizumab-treated patients (p: 0.01). Most patients in both groups received dexamethasone as standard of care. No differences were found in secondary outcomes, mortality, and SOFA score changes. Ferritin decreased among anakinra-treated patients; interleukin-6, soluble urokinase plasminogen activator receptor, and HLA-DR expression increased among tocilizumab-treated patients. Survivors by day 28 who received anakinra were distributed to lower severity levels of the WHO clinical progression scale. Greater incidence of secondary infections was found with tocilizumab treatment. CONCLUSION: Immune assessment resulted in favorable anakinra responses among critically ill patients with COVID-19 and features of MALS.

12.
Crit Care Med ; 49(12): 2042-2057, 2021 12 01.
Article in English | MEDLINE | ID: covidwho-1522362

ABSTRACT

OBJECTIVE: Coronavirus disease 2019 is a heterogeneous disease most frequently causing respiratory tract infection, which can induce respiratory failure and multiple organ dysfunction syndrome in its severe forms. The prevalence of coronavirus disease 2019-related sepsis is still unclear; we aimed to describe this in a systematic review. DATA SOURCES: MEDLINE (PubMed), Cochrane, and Google Scholar databases were searched based on a prespecified protocol (International Prospective Register for Systematic Reviews: CRD42020202018). STUDY SELECTION: Studies reporting on patients with confirmed coronavirus disease 2019 diagnosed with sepsis according to sepsis-3 or according to the presence of infection-related organ dysfunctions necessitating organ support/replacement were included in the analysis. The primary end point was prevalence of coronavirus disease 2019-related sepsis among adults hospitalized in the ICU and the general ward. Among secondary end points were the need for ICU admission among patients initially hospitalized in the general ward and the prevalence of new onset of organ dysfunction in the ICU. Outcomes were expressed as proportions with respective 95% CI. DATA EXTRACTION: Two reviewers independently screened and reviewed existing literature and assessed study quality with the Newcastle-Ottawa Scale and the Methodological index for nonrandomized studies. DATA SYNTHESIS: Of 3,825 articles, 151 were analyzed, only five of which directly reported sepsis prevalence. Noting the high heterogeneity observed, coronavirus disease 2019-related sepsis prevalence was 77.9% (95% CI, 75.9-79.8; I2 = 91%; 57 studies) in the ICU, and 33.3% (95% CI, 30.3-36.4; I2 = 99%; 86 studies) in the general ward. ICU admission was required for 17.7% (95% CI, 12.9-23.6; I2 = 100%) of ward patients. Acute respiratory distress syndrome was the most common organ dysfunction in the ICU (87.5%; 95% CI, 83.3-90.7; I2 = 98%). CONCLUSIONS: The majority of coronavirus disease 2019 patients hospitalized in the ICU meet Sepsis-3 criteria and present infection-associated organ dysfunction. The medical and scientific community should be aware and systematically report viral sepsis for prognostic and treatment implications.


Subject(s)
COVID-19/complications , Hospitalization/statistics & numerical data , Sepsis/etiology , Sepsis/virology , Humans , Intensive Care Units/statistics & numerical data , Multiple Organ Failure/etiology , Patient Admission/statistics & numerical data , SARS-CoV-2 , Sepsis/mortality , Severity of Illness Index
13.
Int Med Case Rep J ; 14: 573-576, 2021.
Article in English | MEDLINE | ID: covidwho-1504281

ABSTRACT

PURPOSE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection impacted morbidity and mortality during the pandemic of 2020-2021. A number of anti-COVID-19 vaccines have been developed with an unprecedented speed. While these vaccines have good efficacy and are safe, the experience with their use is limited and hence the knowledge of rare side effects. Identifying rare complications is important for future safe use of these vaccines. MATERIALS AND METHODS: Here, we report a case of a 82-year old patient with dementia who was admitted to a nursing home in the Netherlands. After vaccination with COVID-19 vaccination, physical examinations and lab tests were performed. RESULTS: She had a reactivation of hepatitis C infection after vaccination with the mRNA-based Pfizer-BioNTech COVID-19 vaccine. This reactivation manifested with jaundice, loss of consciousness, hepatic coma and death. CONCLUSION: This reactivation of hepatitis C virus after vaccination with the Pfizer-BioNTech COVID­19 vaccine suggests a need for critical consideration of individuals with prior HCV infection and considered for COVID-19 vaccination.

14.
Lancet Rheumatol ; 3(10): e690-e697, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1486375

ABSTRACT

BACKGROUND: Anakinra might improve the prognosis of patients with moderate to severe COVID-19 (ie, patients requiring oxygen supplementation but not yet receiving organ support). We aimed to assess the effect of anakinra treatment on mortality in patients admitted to hospital with COVID-19. METHODS: For this systematic review and individual patient-level meta-analysis, a systematic literature search was done on Dec 28, 2020, in Medline (PubMed), Cochrane, medRxiv, bioRxiv, and the ClinicalTrials.gov databases for randomised trials, comparative studies, and observational studies of patients admitted to hospital with COVID-19, comparing administration of anakinra with standard of care, or placebo, or both. The search was repeated on Jan 22, 2021. Individual patient-level data were requested from investigators and corresponding authors of eligible studies; if individual patient-level data were not available, published data were extracted from the original reports. The primary endpoint was mortality after 28 days and the secondary endpoint was safety (eg, the risk of secondary infections). This study is registered on PROSPERO (CRD42020221491). FINDINGS: 209 articles were identified, of which 178 full-text articles fulfilled screening criteria and were assessed. Aggregate data on 1185 patients from nine studies were analysed, and individual patient-level data on 895 patients were provided from six of these studies. Eight studies were observational and one was a randomised controlled trial. Most studies used historical controls. In the individual patient-level meta-analysis, after adjusting for age, comorbidities, baseline ratio of the arterial partial oxygen pressure divided by the fraction of inspired oxygen (PaO2/FiO2), C-reactive protein (CRP) concentrations, and lymphopenia, mortality was significantly lower in patients treated with anakinra (38 [11%] of 342) than in those receiving standard of care with or without placebo (137 [25%] of 553; adjusted odds ratio [OR] 0·32 [95% CI 0·20-0·51]). The mortality benefit was similar across subgroups regardless of comorbidities (ie, diabetes), ferritin concentrations, or the baseline PaO2/FiO2. In a subgroup analysis, anakinra was more effective in lowering mortality in patients with CRP concentrations higher than 100 mg/L (OR 0·28 [95% CI 0·17-0·47]). Anakinra showed a significant survival benefit when given without dexamethasone (OR 0·23 [95% CI 0·12-0·43]), but not with dexamethasone co-administration (0·72 [95% CI 0·37-1·41]). Anakinra was not associated with a significantly increased risk of secondary infections when compared with standard of care (OR 1·35 [95% CI 0·59-3·10]). INTERPRETATION: Anakinra could be a safe, anti-inflammatory treatment option to reduce the mortality risk in patients admitted to hospital with moderate to severe COVID-19 pneumonia, especially in the presence of signs of hyperinflammation such as CRP concentrations higher than 100 mg/L. FUNDING: Sobi.

15.
PLoS Pathog ; 17(10): e1009928, 2021 10.
Article in English | MEDLINE | ID: covidwho-1484868

ABSTRACT

Non-specific protective effects of certain vaccines have been reported, and long-term boosting of innate immunity, termed trained immunity, has been proposed as one of the mechanisms mediating these effects. Several epidemiological studies suggested cross-protection between influenza vaccination and COVID-19. In a large academic Dutch hospital, we found that SARS-CoV-2 infection was less common among employees who had received a previous influenza vaccination: relative risk reductions of 37% and 49% were observed following influenza vaccination during the first and second COVID-19 waves, respectively. The quadrivalent inactivated influenza vaccine induced a trained immunity program that boosted innate immune responses against various viral stimuli and fine-tuned the anti-SARS-CoV-2 response, which may result in better protection against COVID-19. Influenza vaccination led to transcriptional reprogramming of monocytes and reduced systemic inflammation. These epidemiological and immunological data argue for potential benefits of influenza vaccination against COVID-19, and future randomized trials are warranted to test this possibility.


Subject(s)
COVID-19/immunology , Cross Protection/physiology , Immunity, Innate/physiology , Influenza Vaccines/administration & dosage , COVID-19/epidemiology , COVID-19/prevention & control , Cytokines/immunology , Cytokines/metabolism , Down-Regulation , Imidazoles/immunology , Incidence , Influenza Vaccines/immunology , Netherlands/epidemiology , Personnel, Hospital , Poly I-C/immunology , Proteomics , Risk Factors , Sequence Analysis, RNA
16.
Annu Rev Immunol ; 39: 667-693, 2021 04 26.
Article in English | MEDLINE | ID: covidwho-1457607

ABSTRACT

Traditionally, the innate and adaptive immune systems are differentiated by their specificity and memory capacity. In recent years, however, this paradigm has shifted: Cells of the innate immune system appear to be able to gain memory characteristics after transient stimulation, resulting in an enhanced response upon secondary challenge. This phenomenon has been called trained immunity. Trained immunity is characterized by nonspecific increased responsiveness, mediated via extensive metabolic and epigenetic reprogramming. Trained immunity explains the heterologous effects of vaccines, which result in increased protection against secondary infections. However, in chronic inflammatory conditions, trained immunity can induce maladaptive effects and contribute to hyperinflammation and progression of cardiovascular disease, autoinflammatory syndromes, and neuroinflammation. In this review we summarize the current state of the field of trained immunity, its mechanisms, and its roles in both health and disease.


Subject(s)
Immunologic Memory , Vaccines , Animals , Cell Differentiation , Humans , Immune System , Immunity, Innate
17.
J Clin Invest ; 131(11)2021 06 01.
Article in English | MEDLINE | ID: covidwho-1448082

ABSTRACT

First administered to a human subject as a tuberculosis (TB) vaccine on July 18, 1921, Bacillus Calmette-Guérin (BCG) has a long history of use for the prevention of TB and later the immunotherapy of bladder cancer. For TB prevention, BCG is given to infants born globally across over 180 countries and has been in use since the late 1920s. With about 352 million BCG doses procured annually and tens of billions of doses having been administered over the past century, it is estimated to be the most widely used vaccine in human history. While its roles for TB prevention and bladder cancer immunotherapy are widely appreciated, over the past century, BCG has been also studied for nontraditional purposes, which include (a) prevention of viral infections and nontuberculous mycobacterial infections, (b) cancer immunotherapy aside from bladder cancer, and (c) immunologic diseases, including multiple sclerosis, type 1 diabetes, and atopic diseases. The basis for these heterologous effects lies in the ability of BCG to alter immunologic set points via heterologous T cell immunity, as well as epigenetic and metabolomic changes in innate immune cells, a process called "trained immunity." In this Review, we provide an overview of what is known regarding the trained immunity mechanism of heterologous protection, and we describe the current knowledge base for these nontraditional uses of BCG.


Subject(s)
Diabetes Mellitus, Type 1/therapy , Immunity, Cellular , Multiple Sclerosis/therapy , Mycobacterium bovis/immunology , T-Lymphocytes/immunology , Urinary Bladder Neoplasms/therapy , Virus Diseases/therapy , Animals , Diabetes Mellitus, Type 1/history , Diabetes Mellitus, Type 1/immunology , Diabetes Mellitus, Type 1/pathology , History, 20th Century , History, 21st Century , Humans , Multiple Sclerosis/history , Multiple Sclerosis/immunology , Multiple Sclerosis/pathology , Mycobacterium Infections, Nontuberculous/history , Mycobacterium Infections, Nontuberculous/immunology , Mycobacterium Infections, Nontuberculous/pathology , Mycobacterium Infections, Nontuberculous/prevention & control , Tuberculosis/history , Tuberculosis/immunology , Tuberculosis/prevention & control , Urinary Bladder Neoplasms/history , Urinary Bladder Neoplasms/immunology , Urinary Bladder Neoplasms/pathology , Virus Diseases/history , Virus Diseases/immunology , Virus Diseases/pathology
18.
Med (N Y) ; 2(10): 1163-1170.e2, 2021 10 08.
Article in English | MEDLINE | ID: covidwho-1433668

ABSTRACT

BACKGROUND: Prolonged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shedding has been described in immunocompromised coronavirus disease 2019 (COVID-19) patients, resulting in protracted disease and poor outcome. Specific therapy to improve viral clearance and outcome for this group of patients is currently unavailable. METHODS: Five critically ill COVID-19 patients with severe defects in cellular immune responses, high SARS-CoV-2 viral RNA loads, and no respiratory improvement were treated with interferon gamma, 100 µg subcutaneously, thrice weekly. Bronchial secretion was collected every 48 h for routine diagnostic SARS-CoV-2 RT-PCR and viral culture. FINDINGS: Interferon gamma administration was followed by a rapid decline in SARS-CoV-2 load and a positive-to-negative viral culture conversion. Four patients recovered, and no signs of hyperinflammation were observed. CONCLUSIONS: Interferon gamma may be considered as adjuvant immunotherapy in a subset of immunocompromised COVID-19 patients. FUNDING: A.v.L. and R.v.C. are supported by National Institutes of Health (R01AI145781). G.J.O. and R.P.v.R. are supported by a VICI grant (016.VICI.170.090) from the Dutch Research Council (NWO). W.F.A. is supported by a clinical fellowship grant (9071561) of Netherlands Organization for Health Research and Development. M.G.N. is supported by an ERC advanced grant (833247) and a Spinoza grant of the Netherlands Organization for Scientific Research.


Subject(s)
COVID-19 , Critical Illness/therapy , Humans , Immunity, Cellular , Immunotherapy , Interferon-gamma , Research , SARS-CoV-2 , United States
19.
Cell ; 181(5): 969-977, 2020 05 28.
Article in English | MEDLINE | ID: covidwho-1385208

ABSTRACT

SARS-CoV-2 infection is mild in the majority of individuals but progresses into severe pneumonia in a small proportion of patients. The increased susceptibility to severe disease in the elderly and individuals with co-morbidities argues for an initial defect in anti-viral host defense mechanisms. Long-term boosting of innate immune responses, also termed "trained immunity," by certain live vaccines (BCG, oral polio vaccine, measles) induces heterologous protection against infections through epigenetic, transcriptional, and functional reprogramming of innate immune cells. We propose that induction of trained immunity by whole-microorganism vaccines may represent an important tool for reducing susceptibility to and severity of SARS-CoV-2.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/immunology , Immunity, Innate , Immunomodulation , Pneumonia, Viral/immunology , SARS Virus/physiology , Animals , BCG Vaccine/immunology , COVID-19 , Clinical Trials as Topic , Coronavirus Infections/pathology , Coronavirus Infections/physiopathology , Coronavirus Infections/transmission , Humans , Immunity, Innate/drug effects , Lung/immunology , Lung/pathology , Lymphopenia/pathology , Middle East Respiratory Syndrome Coronavirus/physiology , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/physiopathology , Pneumonia, Viral/transmission , SARS-CoV-2 , Severe Acute Respiratory Syndrome/immunology , Severe Acute Respiratory Syndrome/pathology , Virus Replication
20.
Front Immunol ; 12: 720090, 2021.
Article in English | MEDLINE | ID: covidwho-1374235

ABSTRACT

Male sex and old age are risk factors for COVID-19 severity, but the underlying causes are unknown. A possible explanation for this might be the differences in immunological profiles in males and the elderly before the infection. With this in mind, we analyzed the abundance of circulating proteins and immune populations associated with severe COVID-19 in 2 healthy cohorts. Besides, given the seasonal profile of COVID-19, the seasonal response against SARS-CoV-2 could also be different in the elderly and males. Therefore, PBMCs of female, male, young, and old subjects in different seasons of the year were stimulated with heat-inactivated SARS-CoV-2 to investigate the season-dependent anti-SARS-CoV-2 immune response. We found that several T cell subsets, which are known to be depleted in severe COVID-19 patients, were intrinsically less abundant in men and older individuals. Plasma proteins increasing with disease severity, including HGF, IL-8, and MCP-1, were more abundant in the elderly and males. Upon in vitro SARS-CoV-2 stimulation, the elderly produced significantly more IL-1RA and had a dysregulated IFNγ response with lower production in the fall compared with young individuals. Our results suggest that the immune characteristics of severe COVID-19, described by a differential abundance of immune cells and circulating inflammatory proteins, are intrinsically present in healthy men and the elderly. This might explain the susceptibility of men and the elderly to SARS-CoV-2 infection.


Subject(s)
COVID-19/immunology , Adolescent , Adult , Age Factors , Aged , Aging/immunology , Blood Proteins/immunology , COVID-19/physiopathology , Cohort Studies , Disease Susceptibility , Female , Humans , Immunity, Cellular , Immunologic Factors , Male , Middle Aged , Patient Acuity , Risk Assessment , Seasons , Sex Factors , T-Lymphocyte Subsets/immunology , Young Adult
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