The Plasma Proteome in Community-acquired Pneumonia: Pathophysiology, Outcome and 10-Year Risk.

Rationale: Community-acquired pneumonia (CAP) represents a significant health burden.

Objectives: We aimed to map the plasma proteome in patients with CAP and associate protein abundance with pathophysiology, tissue source, and outcome.

Methods: We measured the plasma proteome of CAP patients upon admission to a general ward using Olink technology (derivation cohort).

Pathogen-specific host response in critically ill patients with blood stream infections: a nested case-control study.

Background: Knowledge of the contribution of the pathogen to the heterogeneity of the host response to infection is limited. We aimed to compare the host response in critically ill patients with a bloodstream infection (BSI).

Methods: RNA profiles were determined in blood obtained between one day before and after a positive blood culture.

The blood transcriptional response in patients developing intensive care unit-acquired pneumonia.

Background: Immune response dysregulation has been implicated in the development of intensive care unit (ICU)-acquired pneumonia. We aimed to determine differences in the longitudinal blood transcriptional response between patients who develop ICU-acquired pneumonia (cases) and those who do not (controls).

Methods: We performed a case-cohort study in mechanically ventilated trauma and surgery patients with ICU stays >2 days, enrolled in 30 hospitals across Europe.

Effect of mesenchymal stem cells on the host response in severe community-acquired pneumonia.

Mesenchymal stem cells (MSC) have immune regulatory properties that may ameliorate pathophysiological processes in sepsis. We determined the effect of allogeneic adipose-derived MSCs (Cx611) on the host response during sepsis due to community-acquired bacterial pneumonia (CABP) by measuring 29 plasma biomarkers and blood transcriptomes at six time points in 82 patients randomised to two intravenous infusions of Cx611 or placebo. Cx611 treatment enhanced several endothelial cell and procoagulant response plasma biomarkers, and led to increased expression of pathways related to innate immunity, haemostasis and apoptosis.

Lymphopenia is associated with broad host response aberrations in community-acquired pneumonia.

Objectives: Lymphopenia at hospital admission occurs in over one-third of patients with community-acquired pneumonia (CAP), yet its clinical relevance and pathophysiological implications remain underexplored. We evaluated outcomes and immune features of patients with lymphopenic CAP (L-CAP), a previously described immunophenotype characterized by admission lymphocyte count <0.724 × 10 cells/L.

The Plasma Lipidomic Landscape in Patients with Sepsis due to Community-acquired Pneumonia.

The plasma lipidome has the potential to reflect many facets of the host status during severe infection. Previous work is limited to specific lipid groups or was focused on lipids as prognosticators. To map the plasma lipidome during sepsis due to community-acquired pneumonia (CAP) and determine the disease specificity and associations with clinical features.

Platelets of COVID-19 patients display mitochondrial dysfunction, oxidative stress, and energy metabolism failure compatible with cell death.

Background: Alterations in platelet function have been implicated in the pathophysiology of COVID-19 since the beginning of the pandemic. While early reports linked hyperactivated platelets to thromboembolic events in COVID-19, subsequent investigations demonstrated hyporeactive platelets with a procoagulant phenotype. Mitochondria are important for energy metabolism and the function of platelets.

High-dimensional phenotyping of the peripheral immune response in community-acquired pneumonia.

Background: Community-acquired pneumonia (CAP) represents a major health burden worldwide. Dysregulation of the immune response plays an important role in adverse outcomes in patients with CAP.

Methods: We analyzed peripheral blood mononuclear cells by 36-color spectral flow cytometry in adult patients hospitalized for CAP (n=40), matched control subjects (n=31), and patients hospitalized for COVID-19 (n=35).

Host Response Changes and Their Association with Mortality in COVID-19 Patients with Lymphopenia.

Lymphopenia in coronavirus disease (COVID-19) is associated with increased mortality. To explore the association between lymphopenia, host response aberrations, and mortality in patients with lymphopenic COVID-19. We determined 43 plasma biomarkers reflective of four pathophysiological domains: endothelial cell and coagulation activation, inflammation and organ damage, cytokine release, and chemokine release.

Thrombocytopenia is associated with a dysregulated host response in severe COVID-19.

Background: Thrombocytopenia is associated with increased mortality in COVID-19 patients.

Objective: To determine the association between thrombocytopenia and alterations in host response pathways implicated in disease pathogenesis in patients with severe COVID-19.

Patients/methods: We studied COVID-19 patients admitted to a general hospital ward included in a national (CovidPredict) cohort derived from 13 hospitals in the Netherlands.

Plasma protein biomarkers reflective of the host response in patients developing Intensive Care Unit-acquired pneumonia.

Background: Immune suppression has been implicated in the occurrence of pneumonia in critically ill patients. We tested the hypothesis that Intensive Care Unit (ICU)-acquired pneumonia is associated with broad host immune aberrations in the trajectory to pneumonia, encompassing inflammatory, endothelial and coagulation responses. We compared plasma protein biomarkers reflecting the systemic host response in critically ill patients who acquire a new pneumonia (cases) with those who do not (controls).

Age-related changes in plasma biomarkers and their association with mortality in COVID-19.

Background: Coronavirus disease 2019 (COVID-19)-induced mortality occurs predominantly in older patients. Several immunomodulating therapies seem less beneficial in these patients. The biological substrate behind these observations is unknown.

Association between age and the host response in critically ill patients with sepsis.

Background: The association of ageing with increased sepsis mortality is well established. Nonetheless, current investigations on the influence of age on host response aberrations are largely limited to plasma cytokine levels while neglecting other pathophysiological sepsis domains like endothelial cell activation and function, and coagulation activation. The primary objective of this study was to gain insight into the association of ageing with aberrations in key host response pathways and blood transcriptomes in sepsis.

The Azithromycin Pro-Drug CSY5669 Boosts Bacterial Killing While Attenuating Lung Inflammation Associated with Pneumonia Caused by Methicillin-Resistant Staphylococcus aureus.

Antibiotic resistance is a major problem, with methicillin-resistant Staphylococcus aureus (MRSA) being a prototypical example in surgical and community-acquired infections. S. aureus, like many pathogens, is immune evasive and able to multiply within host immune cells.

The Platelet Lipidome Is Altered in Patients with COVID-19 and Correlates with Platelet Reactivity.

Background:  Activated platelets have been implicated in the proinflammatory and prothrombotic phenotype of coronavirus disease 2019 (COVID-19). While it is increasingly recognized that lipids have important structural and signaling roles in platelets, the lipidomic landscape of platelets during infection has remained unexplored.

Objective:  To investigate the platelet lipidome of patients hospitalized for COVID-19.

The host response in different aetiologies of community-acquired pneumonia.

Background: Community-acquired pneumonia (CAP) can be caused by a variety of pathogens, of which Streptococcus pneumoniae, Influenza and currently SARS-CoV-2 are the most common. We sought to identify shared and pathogen-specific host response features by directly comparing different aetiologies of CAP.

Methods: We measured 72 plasma biomarkers in a cohort of 265 patients hospitalized for CAP, all sampled within 48 hours of admission, and 28 age-and sex matched non-infectious controls.

Association between dexamethasone treatment and the host response in COVID-19 patients admitted to the general ward.

Dexamethasone improves clinical outcomes in COVID-19 patients requiring supplementary oxygen. We investigated possible mechanisms of action by comparing sixteen plasma host response biomarkers in general ward patients before and after implementation of dexamethasone as standard of care. 48 patients without and 126 patients with dexamethasone treatment were sampled within 48 h of admission.

Effect of erythromycin on mortality and the host response in critically ill patients with sepsis: a target trial emulation.

Background: Immunomodulatory therapies that improve the outcome of sepsis are not available. We sought to determine whether treatment of critically ill patients with sepsis with low-dose erythromycin-a macrolide antibiotic with broad immunomodulatory effects-decreased mortality and ameliorated underlying disease pathophysiology.

Methods: We conducted a target trial emulation, comparing patients with sepsis admitted to two intensive care units (ICU) in the Netherlands for at least 72 h, who were either exposed or not exposed during this period to treatment with low-dose erythromycin (up to 600 mg per day, administered as a prokinetic agent) but no other macrolides.

The Immune Response to Respiratory Viruses: From Start to Memory.

Biomedical research has long strived to improve our understanding of the immune response to respiratory viral infections, an effort that has become all the more important as we live through the consequences of a pandemic. The disease course of these infections is shaped in large part by the actions of various cells of the innate and adaptive immune systems. While these cells are crucial in clearing viral pathogens and establishing long-term immunity, their effector mechanisms may also escalate into excessive, tissue-destructive inflammation detrimental to the host.

Serologic Surveillance and Phylogenetic Analysis of SARS-CoV-2 Infection Among Hospital Health Care Workers.

Importance: It is unclear when, where, and by whom health care workers (HCWs) working in hospitals are infected with SARS-CoV-2.

Objective: To determine how often and in what manner nosocomial SARS-CoV-2 infection occurs in HCW groups with varying exposure to patients with COVID-19.

Design, Setting, And Participants: This cohort study comprised 4 weekly measurements of SARS-CoV-2-specific antibodies and collection of questionnaires from March 23 to June 25, 2020, combined with phylogenetic and epidemiologic transmission analyses at 2 university hospitals in the Netherlands.

Key elements in selection of pre-dialysis patients for home dialysis.

Background: Most pre-dialysis patients are medically eligible for home dialysis, and home dialysis has several advantages over incentre dialysis. However, accurately selecting patients for home dialysis appears to be difficult, since uptake of home dialysis remains low. The aim of this study was to investigate which medical or psychosocial elements contribute most to the selection of patients eligible for home dialysis.

Pulmonary Procoagulant and Innate Immune Responses in Critically Ill COVID-19 Patients.

Rationale: Systemic activation of procoagulant and inflammatory mechanisms has been implicated in the pathogenesis of COVID-19. Knowledge of activation of these host response pathways in the lung compartment of COVID-19 patients is limited.

Objectives: To evaluate local and systemic activation of coagulation and interconnected inflammatory responses in critically ill COVID-19 patients with persistent acute respiratory distress syndrome.

Sepsis: deriving biological meaning and clinical applications from high-dimensional data.

The pathophysiology of sepsis is multi-facetted and highly complex. As sepsis is a leading cause of global mortality that still lacks targeted therapies, increased understanding of its pathogenesis is vital for improving clinical care and outcomes. An increasing number of investigations seeks to unravel the complexity of sepsis through high-dimensional data analysis, enabled by advances in -omics technologies.