Graphical Abstract Highlights d Severe COVID-19 patients display immune dysregulation or macrophage activation syndrome d Severe respiratory failure is associated with a major decrease of HLA-DR on CD14 monocytes d CD4 cell and NK cell cytopenias are characteristics of severe COVID-19 d IL-6 blocker Tocilizumab partially rescues SARS-CoV-2associated immune dysregulation

BCG vaccination in children protects against heterologous infections and improves survival independently of tuberculosis prevention. The phase III ACTIVATE trial assessed whether BCG has similar effects in the elderly. In this double-blind, randomized trial, elderly patients (n = 198) received BCG or placebo vaccine at hospital discharge and were followed for 12 months for new infections. At interim analysis, BCG vaccination significantly increased the time to first infection (median 16 weeks compared to 11 weeks after placebo). The incidence of new infections was 42.3% (95% CIs 31.9%–53.4%) after placebo vaccination and 25.0% (95% CIs 16.4%–36.1%) after BCG vaccination; most of the protection was against respiratory tract infections of probable viral origin (hazard ratio 0.21, p = 0.013). No difference in the frequency of adverse effects was found. Data show that BCG vaccination is safe and can protect the elderly against infections. Larger studies are needed to assess protection against respiratory infections, including COVID-19 (ClinicalTrials.gov NCT03296423).

Comparative LDH secretion, Ext_data_figure2.ep a, Assessment of Candida induced cell death of PBMCs after 24 hours Extended Data Fig. 2.Extended Data Fig. 3 Relative C. auris induced ROS production and heatsensitivity of the cell wall components responsible for the C. auris induced cytokine production. Ext_data_figure3.ep sa, Neutrophil ROS release after 1-hour stimulation without (RPMI; negative control) or with heat-killed C. albicans, C. auris strains or zymosan (positive control), depicted in relative light units (RLU) either as time-course (left) or as area under the curve (AUC, right), n=9. b, PBMC ROS release after 1-hour stimulation without (RPMI; negative control) or with heat-killed C. albicans, C. auris strains or zymosan (positive control), depicted in RLU either as time-course (left) or as AUC (right), n=6. c, TNF-α, IL-6, IL-1β, and IL-1Ra levels in the supernatant of PBMCs after stimulation without (RPMI; negative control) or with heat-killed C. albicans and C. auris from all five geographical clades for 24 hours, n=8. d, PBMC production of cytokines IFN-γ (n=10; n=7 for C. auris 10051895), IL-10 (n=6), IL-17 (n=6), and IL-22 (n=14; n=6 for C. auris 10051893; n=11 for C. auris 10051895) after stimulation without (RPMI; negative control) or with heat-killed C. albicans and C. auris for 7 days. Graphs represent mean ± SEM, data are pooled from at least two independent experiments. * p < 0.05, ** p < 0.01, *** p < 0.001, **** p = 0.001, a-b Time curves (left panels) were assessed for statistical differences between C. auris strains and C. albicans by a two-way ANOVA, Area Under curve (AUC) means (right panels) were compared using the two-sided Wilcoxon signed rank test, c-d twosided Wilcoxon matched pairs signed-rank test comparing respective C. auris strains with C. albicans as control or reference species. Data used to make this figure can be found in Source Data Extended Data Fig. 3.Extended Data Fig. 4 Transcriptional changes induced by purified cell wall components and their respective exposure on C. albicans and C. auris Ext_data_figure4.ep s . a, Heatmap displaying the Log 2 Fold change (color scale) of the top 50 DEG of C. albicans live, for both Candida species and their cell wall components, β-glucan and mannan, at 4 hour (left panel) and 24 hours (right panel). b, Flow cytometry plot based on forward scatter component (FSC) and side scatter component (SSC), demonstrating C. surface. auris strains are slightly smaller and of higher complexity than C. albicans. c, Flow cytometry-based comparison of cell wall components of C. albicans and C. auris strains. Mean fluorescent intensity (MFI) of thimerosal-fixed Candida cells stained for Fc-Dectin-1, a marker for β-glucan (left), and ConA, a marker for mannans (right). Graphs represent mean ± SEM of the 3 means, each performed with three replicates in three independent measurements, * p < 0.05, Kruskall Wallis test with two-sided Dunn's multiple comparison test was performed comparing the respective C. auris strains with the two C. albicans refere...

Background:The pneumonia of COVID-19 illness has often a subtle initial presentation making mandatory the use of biomarkers for evaluation of severity and prediction of final patient disposition. We evaluated the use of hydrogen sulfide (H2S) for the outcome of COVID-19 pneumonia. Materials & Methods:We studied 74 patients with COVID-19. Clinical data were collected, and survival predictors were calculated. Blood was collected within 24 hours after admission (day 1) and on day 7. H2S was measured in sera by monobromobimanederivation (MBB) followed by high performance liquid chromatography and correlated to other markers likeprocalcitonin (PCT) and C-reactive protein (CRP). Tumor necrosis factor alpha (TNFα) and interleukin (IL)-6 were also measured in serum. Results:Survivors had significantly higher H2S levels on day 1 and 7 after admission. A cutoff point of 150.44 μM could discriminate survivors from non-survivors with 80% sensitivity, 73.4% specificity and negative predictive value 95.9%. Mortality after 28 days was 32% with admission levels lower or equal to 150.44μΜ and 4.1% with levels above 150.44μΜ (p: 0.0008). Mortality was significantly greater among patients with a decrease of H2S levels from day 1 to day 7 greater or equal to 36% (p: 0.0005). Serum H2S on day 1 was negatively correlated with IL-6 and CRP and positively correlated with the absolute lymphocyte countin peripheral blood. Conclusion: It is concluded that H2S is a potential marker for severity and final outcome of pneumonia by the SARS-CoV-2 coronavirus. Its correlation with IL-6 suggests antiinflammatory properties.

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Background: The validation of new biomarkers for the diagnosis and risk stratification of patients with sepsis at an early point is essential for successful treatment. Recent publications prompted us to investigate of heparin binding protein (HBP) for the emergency department (ED) admissions. Materials and Methods: In this multicenter, cross-sectional study, HBP and procalcitonin (PCT) were measured within the first hour upon admission to the ED in plasma samples of 371 patients with signs of infection. Patients were classified into non-sepsis and sepsis by the Sepsis-3 definitions and were followed up for outcome. Results: HBP was significantly higher in patients with sepsis and was positively correlated to PCT and C-reactive protein, absolute neutrophil and monocyte counts, creatinine, bilirubin and lactate. Sensitivity, specificity, positive predictive value, and negative predictive value of HBP more than 19.8 ng/mL for the diagnosis of sepsis was 66.3%, 44.9%, 49.3%, and 62.2%, respectively; and for prediction of early death was 100%, 41.0%, 4.5%, and 100%, respectively. Single HBP and PCT could not predict 28-day mortality; this was performed with sensitivity, specificity, positive predictive value, and negative predictive value 44.8%, 81.8%, 17.3%, and 94.6% when used in combination. Conclusion: Admission HBP can be used as a tool for the early diagnosis of sepsis and for the risk of early death in the ED.

Acute respiratory distress syndrome (ARDS) in COVID-19 has been associated with catastrophic inflammation. We present measurements in humans and a new animal model implicating a role in danger-associated molecular patterns. Calprotectin (S100A8/A9) and high-mobility group box 1 (HMGB1) were measured in patients without/with ARDS, and admission calprotectin was associated with soluble urokinase plasminogen activator receptor (suPAR). An animal model was developed by intravenous injection of plasma from healthy or patients with COVID-19 ARDS into C57/BL6 mice once daily for 3 consecutive days. Mice were treated with one anti-S100A8/A9 antibody, the IL-1 receptor antagonist anakinra or vehicle, and Flo1-2a anti-murine anti-IL-1α monoclonal antibody or the specific antihuman IL-1α antibody XB2001 or isotype controls. Cytokines and myeloperoxidase (MPO) were measured in tissues. Calprotectin, but not HMGB1, was elevated in ARDS. Higher suPAR indicated higher calprotectin. Animal challenge with COVID-19 plasma led to inflammatory reactions in murine lung and intestines as evidenced by increased levels of TNFα, IL-6, IFNγ, and MPO. Lung inflammation was attenuated with anti-S100A8/A9 pre-treatment. Anakinra treatment restored these levels. Similar decrease was found in mice treated with Flo1-2a but not with XB2001. Circulating alarmins, specifically calprotectin, of critically ill COVID-19 patients induces tissue-specific inflammatory responses through an IL-1-mediated mechanism. This could be attenuated through inhibition of IL-1 receptor or of IL-1α.

Hydrogen sulfide (H2S) has recently been recognized as a novel gaseous transmitter with several anti-inflammatory properties. The role of host- derived H2S in infections by Pseudomonas aeruginosa was investigated in clinical and mouse models. H2S concentrations and survival was assessed in septic patients with lung infection. Animal experiments using a model of severe systemic multidrug-resistant P. aeruginosa infection were performed using mice with a constitutive knock-out of cystathionine-γ lyase (Cse) gene (Cse-/-) and wild-type mice with a physiological expression (Cse+/+). Experiments were repeated in mice after a) treatment with cyclophosphamide; b) bone marrow transplantation (BMT) from a Cse+/+ donor; c) treatment with H2S synthesis inhibitor aminooxyacetic acid (ΑΟΑΑ) or propargylglycine (PAG) and d) H2S donor sodium thiosulfate (STS) or GYY3147. Bacterial loads and myeloperoxidase activity were measured in tissue samples. The expression of quorum sensing genes (QS) was determined in vivo and in vitro. Cytokine concentration was measured in serum and incubated splenocytes. Patients survivors at day 28 had significantly higher serum H2S compared to non-survivors. A cut- off point of 5.3 μΜ discriminated survivors with sensitivity 92.3%. Mortality after 28 days was 30.9% and 93.7% in patients with H2S higher and less than 5.3 μΜ (p = 7 x 10−6). In mice expression of Cse and application of STS afforded protection against infection with multidrug-resistant P. aeruginosa. Cyclophosphamide pretreatment eliminated the survival benefit of Cse+/+ mice, whereas BMT increased the survival of Cse-/- mice. Cse-/- mice had increased pathogen loads compared to Cse+/+ mice. Phagocytic activity of leukocytes from Cse-/- mice was reduced but was restored after H2S supplementation. An H2S dependent down- regulation of quorum sensing genes of P.aeruginosa could be demonstrated in vivo and in vitro. Endogenous H2S is a potential independent parameter correlating with the outcome of P. aeruginosa. H2S provides resistance to infection by MDR bacterial pathogens.