Immune suppression is associated with enhanced systemic inflammatory, endothelial and procoagulant responses in critically ill patients

Objective: Patients admitted to the Intensive Care Unit (ICU) oftentimes show immunological signs of immune suppression. Consequently, immune stimulatory agents have been proposed as an adjunctive therapy approach in the ICU. The objective of this study was to determine the relationship between the degree of immune suppression and systemic inflammation in patients shortly after admission to the ICU. Design: An observational study in two ICUs in the Netherlands. Methods: The capacity of blood leukocytes to produce cytokines upon stimulation with lipopolysaccharide (LPS) was measured in 77 patients on the first morning after ICU admission. Patients were divided in four groups based on quartiles of LPS stimulated tumor necrosis factor (TNF)-α release, reflecting increasing extents of immune suppression. 15 host response biomarkers indicative of aberrations in inflammatory pathways implicated in sepsis pathogenesis were measured in plasma. Results: A diminished capacity of blood leukocytes to produce TNF-α upon stimulation with LPS was accompanied by a correspondingly reduced ability to release of IL-1β and IL-6. Concurrently measured plasma concentrations of host response biomarkers demonstrated that the degree of reduction in TNF-α release by blood leukocytes was associated with increasing systemic inflammation, stronger endothelial cell activation, loss of endothelial barrier integrity and enhanced procoagulant responses. Conclusions: In patients admitted to the ICU the strongest immune suppression occurs in those who simultaneously display signs of stronger systemic inflammation. These findings may have relevance for the selection of patients eligible for administration of immune enhancing agents.peer-reviewe

Recommendations for enterovirus diagnostics and characterisation within and beyond Europe.

Enteroviruses (EV) can cause severe neurological and respiratory infections, and occasionally lead to devastating outbreaks as previously demonstrated with EV-A71 and EV-D68 in Europe. However, these infections are still often underdiagnosed and EV typing data is not currently collected at European level. In order to improve EV diagnostics, collate data on severe EV infections and monitor the circulation of EV types, we have established European non-polio enterovirus network (ENPEN). First task of this cross-border network has been to ensure prompt and adequate diagnosis of these infections in Europe, and hence we present recommendations for non-polio EV detection and typing based on the consensus view of this multidisciplinary team including experts from over 20 European countries. We recommend that respiratory and stool samples in addition to cerebrospinal fluid (CSF) and blood samples are submitted for EV testing from patients with suspected neurological infections. This is vital since viruses like EV-D68 are rarely detectable in CSF or stool samples. Furthermore, reverse transcriptase PCR (RT-PCR) targeting the 5'noncoding regions (5'NCR) should be used for diagnosis of EVs due to their sensitivity, specificity and short turnaround time. Sequencing of the VP1 capsid protein gene is recommended for EV typing; EV typing cannot be based on the 5'NCR sequences due to frequent recombination events and should not rely on virus isolation. Effective and standardized laboratory diagnostics and characterisation of circulating virus strains are the first step towards effective and continuous surveillance activities, which in turn will be used to provide better estimation on EV disease burden

Opinions and Management of Hypothermic Sepsis: Results from an Online Survey

Hypothermia is associated with high mortality in sepsis, but it is now recognized that this association may simply reflect its higher prevalence in sicker patients. Furthermore, there is evidence to suggest that hypothermia may not represent a dysfunction in sepsis. In this study, we conducted a survey to assess how this scientific evidence relates to the perceptions of health care professionals regarding septic hypothermia, and how such perceptions drive clinical conduct concerning the use of active rewarming in this population. A survey with questions on opinions and management of spontaneous hypothermia in sepsis was developed and posted online at the European Society of Intensive Care Medicine (ESICM) website from March 24th, 2017 to the June 26th, 2017 and distributed by electronic email. Respondents were asked to fill in the survey from the perspective of their usual or average practice in their intensive care unit. In total, there were 440 survey respondents. Respondents were predominantly from Europe (66%) The majority of respondents were intensivists (78%) and worked in an academic hospital (66%). One percent of respondents were nurses. Most respondents (96%) reported that there was no protocol for the management of hypothermic sepsis. Of the respondents, 62% actively rewarmed patients with hypothermic sepsis. Hypothermia was defined as a temperature below 36°C (44%) and below 35°C (15%). Rewarming practices showed large variation in terms of the temperature, at which respondents initiate rewarming as well as the target temperature to which patients are rewarmed. The most predominant first-line rewarming method was forced-warm air followed by warm IV fluids. Rewarming decisions were mostly physician driven (58%). Most respondents thought rewarming was beneficial (43%), a small proportion thought rewarming to be harmful (9%). In conclusion, policies, procedures, and beliefs about spontaneous hypothermia and active rewarming in patients with sepsis are variable. This must be taken into consideration in designing future trials. We propose a working group to define hypothermic sepsis to improve comparability of research

Granzyme M and K release in human experimental endotoxemia

Granzymes are serine proteases involved in killing of tumor cells and virally infected cells. However, granzymes are also upregulated in blood under inflammatory conditions and contribute to cytokine release and processing. Here, we show that granzyme M (GrM) and to a lesser extent GrK are transiently elevated in the circulation following LPS administration in humans. GrM is released upon stimulation of whole blood with LPS or the gram-negative bacteria Escherichia coli BL21, Pseudomonas aeruginosa, and Neisseria meningitidis. GrK is only released upon stimulation with P. aeruginosa. Thus, GrM and GrK are differentially released in response to LPS and gram-negative bacteria

Reduced Responsiveness of Blood Leukocytes to Lipopolysaccharide Does not Predict Nosocomial Infections in Critically Ill Patients

Critically ill patients show signs of immune suppression, which is considered to increase vulnerability to nosocomial infections. Whole-blood stimulation is frequently used to test the function of the innate immune system. We here assessed the association between whole-blood leukocyte responsiveness to lipopolysaccharide (LPS) and subsequent occurrence of nosocomial infections in critically ill patients admitted to the intensive care unit (ICU). All consecutive critically ill patients admitted to the ICU between April 2012 and June 2013 with two or more systemic inflammatory response syndrome criteria and an expected length of ICU stay of more than 24 h were enrolled. Age- and sex-matched healthy individuals were included as controls. Blood was drawn the first morning after ICU admission and stimulated ex vivo with 100 ng/mL ultrapure LPS for 3 h. Tumor necrosis factor-α, interleukin-1β (IL-1β), and IL-6 were measured in supernatants. Seventy-three critically ill patients were included, of whom 10 developed an ICU-acquired infection. Compared with healthy subjects, whole-blood leukocytes of patients were less responsive to ex vivo stimulation with LPS, as reflected by strongly reduced tumor necrosis factor-α, IL-1β, and IL-6 levels in culture supernatants. Results were not different between patients who did and those who did not develop an ICU-acquired infection. The extent of reduced LPS responsiveness of blood leukocytes in critically ill patients on the first day after ICU admission does not relate to the subsequent development of ICU-acquired infections. These results argue against the use of whole-blood stimulation as a functional test applied early after ICU admission to predict nosocomial infectio

Intracellular expression of granzymes A, B, K and M in blood lymphocyte subsets of critically ill patients with or without sepsis

Sepsis is a complex syndrome related to an infection-induced exaggerated inflammatory response, which is associated with a high mortality. Granzymes (Gzm) are proteases mainly found in cytotoxic lymphocytes that not only have a role in target cell death, but also as mediators of infection and inflammation. In this study we sought to analyse the intracellular expression of GzmA, B, M and K by flow cytometry in diverse blood lymphocyte populations from 22 sepsis patients, 12 non-infected intensive care unit (ICU) patients and 32 healthy controls. Additionally, we measured GzmA and B plasma levels. Both groups of patients presented decreased percentage of natural killer (NK) cells expressing GzmA, B and M relative to healthy controls, while sepsis patients showed an increased proportion of CD8+ T cells expressing GzmB compared to controls. Expression of GzmK remained relatively unaltered between groups. Extracellular levels of GzmB were increased in non-infected ICU patients relative to sepsis patients and healthy controls. Our results show differential alterations in intracellular expression of Gzm in sepsis patients and non-infected critically ill patients compared to healthy individuals depending on the lymphocyte population and on the Gzm

Extracellular histone H3 levels are inversely correlated with antithrombin levels and platelet counts and are associated with mortality in sepsis patients

Sepsis is a leading cause of death worldwide. Extracellular histones are cytotoxic compounds mediating death in murine sepsis and circulating nucleosome levels predict mortality in human inflammation and sepsis. Whether or not circulating extracellular histone H3 correlates with other plasma parameters and/or ICU scoring systems has not been completely established, nor if levels of circulating extracellular histones can be used as predictive markers for clinical outcome in sepsis. We measured plasma histone H3 (H3) levels in the plasma of 43 sepsis patients who were admitted to the Intensive Care Unit and determined their correlation with disease severity, organ failure, mortality and coagulation- and tissue homeostasis parameters including LDH levels, thrombin potential (ETP), prothrombin levels, antithrombin levels and platelet counts. Median H3 levels of sepsis patients at the ICU were significantly increased in non-survivors as compared to survivors with levels found being 3.15μg/ml versus 0.57μg/ml respectively, P=0.04. H3 levels are positively correlated with lactate dehydrogenase (LDH) activity (Spearman's rho=0.49, P <0.001), and negatively correlated with antithrombin levels (rho=-0.34, P=0.027) and platelet counts (rho=-0.33, P=0.031). We conclude that circulating H3 levels correlate with mortality in sepsis patients and inversely correlate with antithrombin levels and platelet count

Immune suppression is associated with enhanced systemic inflammatory, endothelial and procoagulant responses in critically ill patients

Objective Patients admitted to the Intensive Care Unit (ICU) oftentimes show immunological signs of immune suppression. Consequently, immune stimulatory agents have been proposed as an adjunctive therapy approach in the ICU. The objective of this study was to determine the relationship between the degree of immune suppression and systemic inflammation in patients shortly after admission to the ICU. Design: An observational study in two ICUs in the Netherlands. Methods The capacity of blood leukocytes to produce cytokines upon stimulation with lipopolysaccharide (LPS) was measured in 77 patients on the first morning after ICU admission. Patients were divided in four groups based on quartiles of LPS stimulated tumor necrosis factor (TNF)-α release, reflecting increasing extents of immune suppression. 15 host response biomarkers indicative of aberrations in inflammatory pathways implicated in sepsis pathogenesis were measured in plasma. Results A diminished capacity of blood leukocytes to produce TNF-α upon stimulation with LPS was accompanied by a correspondingly reduced ability to release of IL-1β and IL-6. Concurrently measured plasma concentrations of host response biomarkers demonstrated that the degree of reduction in TNF-α release by blood leukocytes was associated with increasing systemic inflammation, stronger endothelial cell activation, loss of endothelial barrier integrity and enhanced procoagulant responses. Conclusions In patients admitted to the ICU the strongest immune suppression occurs in those who simultaneously display signs of stronger systemic inflammation. These findings may have relevance for the selection of patients eligible for administration of immune enhancing agents. Trial registration ClinicalTrials.gov identifier NCT01905033