IMMUNE CELL PHENOTYPE AND FUNCTION IN SEPSIS

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.

Human Leukocyte Antigen-DR Isotype Expression in Monocytes and T Cells Interferon-Gamma Release Assay in Septic Patients and Correlation With Clinical Outcome

Background

Sepsis is a life-threatening dysregulated host response to infection responsible of multiple organs dysfunction (Sepsis-3 International Consensus Definition), during which clinical outcome is a balance between inflammation and immune suppression. Monocytes and lymphocytes may play an important role in immune paralysis, and their impaired functional activity can decrease overall immune system efficiency. We evaluated sepsis-induced changes in monocytes human leukocyte antigen-DR isotype (HLA-DR) expression and T cell capacity of interferon (IFN)-γ production in relation with patient’s clinical outcome.

Methods

Analysis of HLA-DR expression on blood monocytes (mHLA-DR) was performed in 55 patients with high procalcitonin (hPCT, > 0.5 ng/mL,) and suspected/confirmed sepsis, and 20 controls. HLA-DR absolute quantification and IFN-γ release assay were monitored in 16 septic patients for 4 weeks following sepsis confirmation.

Results

Cytofluorimetric analysis revealed a significant decrease of mHLA-DR percentage in septic patients with adverse outcome compared to patients with better clinical outcome (88.4% vs. 98.6% with P < 0.05), in combination with a significant decrease of absolute number of HLA-DR molecules per monocyte (P < 0.05, starting at 1 week of follow-up). Lymphocytes stimulation with phytohemagglutinin (PHA), Staphylococcus aureus (S. aureus) and Candida albicans (C. albicans) showed a severe declining of IFN-γ release related to fatal clinical outcome of patients.

Conclusions

This immunologic anergy of innate and adaptative immunity showed an early immune paralysis during sepsis which appears correlated with the impairment of clinical outcome.

Human neutrophil peptide (HNP) in deteriorate sepsis patients

OBJECTIVE

The objective of this study was analyzed HNP1 and HNP3 level of deteriorating sepsis patients.

METHODS

It was a cross-sectional study that observed HNP and sepsis level, samples size were 40 patients taken by consecutive random sampling. Analysis of HNP serum level use enzyme-linked immunosorbent assay (ELISA), data analyzed used independent T-test and presented in tables with mean, standard deviation, mean difference and probability value.

RESULTS

Results show that when patients become deteriorate or shock sepsis, HNP1 levels increase dramatically, which is 356.2pg/ml higher than sepsis patients and statistically significant (p=0.016, p≤0.05). It is similar to HNP3 level, which is 2.04ng/ml higher than with sepsis patients and statistically significant (p=0.021, p≤0.05).

CONCLUSION

This study reveals that HNP1 and HNP3 level increases dramatically in deteriorate sepsis patients. Level of HNP1 and HNP3 of sepsis patient is higher than nonsepsis patient, shock sepsis patient is higher than sepsis patient and both HNP1 and HNP3 level is higher in die patient compare to alive patient.

Leukocyte Activation Profile Assessed by Raman Spectroscopy Helps Diagnosing Infection and Sepsis

OBJECTIVES

Leukocytes are first responders to infection. Their activation state can reveal information about specific host immune response and identify dysregulation in sepsis. This study aims to use the Raman spectroscopic fingerprints of blood-derived leukocytes to differentiate inflammation, infection, and sepsis in hospitalized patients. Diagnostic sensitivity and specificity shall demonstrate the added value of the direct characterization of leukocyte's phenotype.

DESIGN

Prospective nonrandomized, single-center, observational phase-II study (DRKS00006265).

SETTING

Jena University Hospital, Germany.

PATIENTS

Sixty-one hospitalized patients (19 with sterile inflammation, 23 with infection without organ dysfunction, 18 with sepsis according to Sepsis-3 definition).

INTERVENTIONS

None (blood withdrawal).

MEASUREMENTS AND MAIN RESULTS

Individual peripheral blood leukocytes were characterized by Raman spectroscopy. Reference diagnostics included established clinical scores, blood count, and biomarkers (C-reactive protein, procalcitonin and interleukin-6). Binary classification models using Raman data were able to distinguish patients with infection from patients without infection, as well as sepsis patients from patients without sepsis, with accuracies achieved with established biomarkers. Compared with biomarker information alone, an increase of 10% (to 93%) accuracy for the detection of infection and an increase of 18% (to 92%) for detection of sepsis were reached by adding the Raman information. Leukocytes from sepsis patients showed different Raman spectral features in comparison to the patients with infection that point to the special immune phenotype of sepsis patients.

CONCLUSIONS

Raman spectroscopy can extract information on leukocyte's activation state in a nondestructive, label-free manner to differentiate sterile inflammation, infection, and sepsis.

Circulating mitochondrial N-formyl peptides contribute to secondary nosocomial infection in patients with septic shock

Septic shock commonly leads to multiorgan injury both directly via tissue inflammation and secondarily via hypoperfusion, but both can result in mitochondrial N-formyl peptide (mtFP) release into the circulation. However, no studies have evaluated the role of circulating mtFPs during septic shock. We found that a relatively high plasma nicotinamide adenine dinucleotide dehydrogenase subunit-6 (the most potent human mtFP) level was independently associated with the development of secondary infection in patients with septic shock and that the increased susceptibility to secondary infection is partly attributed to the suppression of polymorphonuclear leukocyte (PMN) chemotaxis by mtFP occupancy of formyl peptide receptor-1. Incorporation of these findings into therapeutic strategies may improve clinical outcomes in septic shock patients by preventing PMN chemotactic anergy.

Secondary infections typically worsen outcomes of patients recovering from septic shock. Neutrophil [polymorphonuclear leukocytes (PMNs)] migration to secondarily inoculated sites may play a key role in inhibiting progression from local bacterial inoculation to secondary infection. Mitochondrial N-formyl peptide (mtFP) occupancy of formyl peptide receptor-1 (FPR1) has been shown to suppress PMN chemotaxis. Therefore, we studied the association between circulating mtFPs and the development of secondary infection in patients with septic shock. We collected clinical data and plasma samples from patients with septic shock admitted to the intensive care unit for longer than 72 h. Impacts of circulating nicotinamide adenine dinucleotide dehydrogenase subunit-6 (ND6) upon clinical outcomes were analyzed. Next, the role of ND6 in PMN chemotaxis was investigated using isolated human PMNs. Studying plasma samples from 97 patients with septic shock, we found that circulating ND6 levels at admission were independently and highly associated with the development of secondary infection (odds ratio = 30.317, 95% CI: 2.904 to 316.407, P = 0.004) and increased 90-d mortality (odds ratio = 1.572, 95% CI: 1.002 to 2.465, P = 0.049). In ex vivo experiments, ND6 pretreatment suppressed FPR1-mediated PMN chemotactic responses to bacterial peptides in the presence of multiple cytokines and chemokines, despite increased nondirectional PMN movements. Circulating mtFPs appear to contribute to the development of secondary infection and increased mortality in patients with septic shock who survive their early hyperinflammatory phase. The increased susceptibility to secondary infection is probably partly mediated by the suppression of FPR1-mediated PMN chemotaxis to secondary infected sites.

PMMA-Based Continuous Hemofiltration Modulated Complement Activation and Renal Dysfunction in LPS-Induced Acute Kidney Injury

Sepsis-induced acute kidney injury (AKI) is a frequent complication in critically ill patients, refractory to conventional treatments. Aberrant activation of innate immune system may affect organ damage with poor prognosis for septic patients. Here, we investigated the efficacy of polymethyl methacrylate membrane (PMMA)-based continuous hemofiltration (CVVH) in modulating systemic and tissue immune activation in a swine model of LPS-induced AKI. After 3 h from LPS infusion, animals underwent to PMMA-CVVH or polysulfone (PS)-CVVH. Renal deposition of terminal complement mediator C5b-9 and of Pentraxin-3 (PTX3) deposits were evaluated on biopsies whereas systemic Complement activation was assessed by ELISA assay. Gene expression profile was performed from isolated peripheral blood mononuclear cells (PBMC) by microarrays and the results validated by Real-time PCR. Endotoxemic pigs presented oliguric AKI with increased tubulo-interstitial infiltrate, extensive collagen deposition, and glomerular thrombi; local PTX-3 and C5b-9 renal deposits and increased serum activation of classical and alternative Complement pathways were found in endotoxemic animals. PMMA-CVVH treatment significantly reduced tissue and systemic Complement activation limiting renal damage and fibrosis. By microarray analysis, we identified 711 and 913 differentially expressed genes with a fold change >2 and a false discovery rate <0.05 in endotoxemic pigs and PMMA-CVVH treated-animals, respectively. The most modulated genes were Granzyme B, Complement Factor B, Complement Component 4 Binding Protein Alpha, IL-12, and SERPINB-1 that were closely related to sepsis-induced immunological process. Our data suggest that PMMA-based CVVH can efficiently modulate immunological dysfunction in LPS-induced AKI.

Estrogen As A Safe Therapeutic Adjunct in Reducing The Inflammatory Storm in Trauma Hemorrhagic Shock Patients

ABSTRACT

Trauma is a major cause of death and disability throughout the world. It is a leading cause of death with or without sepsis in about 50% of patients. Limited therapeutic options are available besides definitive care with a mortality benefit. Pre-clinical studies have demonstrated the mortality benefit of estrogen in trauma hemorrhagic shock(THS). Based on encouraging results from pre-clinical studies, we hypothesised that early administration of estrogen in male THS patients may reduce the inflammatory storm, prevent sepsis associated problems, and subsequently reduce mortality. The authors studied the safety of early administration of estrogen as a therapeutic adjunct in the emergency department (ED) and its effects on the inflammatory storm, prevention of sepsis, and mortality during the intensive care unit (ICU) stay. 40, THS patients were recruited. THS patients were divided into experimental and placebo control groups based on the estrogen administration in the ED. Serum levels of cytokines and immune cells were measured at different time points on days 0, 3, 7, and 14 in both groups of THS patients. The experimental group received intravenous estrogen (25 mg) at a single time point in the ED beside standard of care as per advanced trauma life support (ATLS) guidelines. Patients did not develop any major or minor adverse events and showed favorable clinical outcomes in the experimental group. The levels of T regulatory cells, monocytes, and systemic cytokines significantly reduced and showed a balanced inflammatory response in THS patients who received estrogen.In conclusion, this preliminary study showed that intravenous estrogen therapy is safe and reduced the inflammatory insult due to trauma hemorrhagic shock. It may protect THS patients from sepsis-associated complications. Future clinical trials are required to study the efficacy and mechanistic pathway.

Predictive value of immune cell counts and neutrophil-to-lymphocyte ratio for 28-day mortality in patients with sepsis caused by intra-abdominal infection

Background

The current study aimed to evaluate the value of immune cell counts and neutrophil-to-lymphocyte ratio (NLR) when attempting to predict 28-day mortality.

Methods

We conducted an observational retrospective study that included consecutive septic patients. Severity scores on the first day and peripheral circulating immune cell counts (at day 1, day 3, day 5 and day 7 of admission) were collected during each patient’s emergency intensive care unit stay. We assessed the associations of peripheral circulating immune cell counts and NLR with the severity of illness. The relationships between 28-day mortality and peripheral circulating immune cell counts and NLR with were evaluated using Cox proportional cause-specific hazards models.

Results

A total of 216 patients diagnosed with sepsis caused by IAI were enrolled. The lymphocyte counts (days 1, 3, 5 and 7) and monocyte counts (days 3, 5 and 7) were significantly lower in non-survivors (n = 72) than survivors (n = 144). The NLR values at each time point were significantly higher in non-survivors. The day 1 lymphocyte counts, as well as the monocyte counts, were significantly lower in the highest-scoring group, when stratified by the Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores, than in the other groups (p < 0.05). The day 1 NLR was significantly higher in the highest-scoring group than in the other groups (p < 0.05). The day 5 and day 7 lymphocyte counts, day 3 and day 7 monocyte counts and day 7 NLR were significant predictors of 28-day mortality in the Cox proportional hazards models (day 5 lymphocyte count: hazard ratio, 0.123 (95% CI, 0.055–0.279), p < 0.001; day 7 lymphocyte count: hazard ratio, 0.115 (95% CI, 0.052–0.254), p < 0.001; day 3 monocyte count: hazard ratio, 0.067 (95% CI, 0.005–0.861), p = 0.038; day 7 monocyte count: hazard ratio, 0.015 (95% CI, 0.001–0.158), p < 0.001; day 7 NLR: hazard ratio, 0.773 (95% CI, 0.659–0.905), p = 0.001).

Conclusions

The results showed that circulating lymphocytes and monocytes were dramatically decreased within 7 days in non-survivors following sepsis from an IAI. Lymphocyte counts, monocyte counts and NLR appeared to be associated with the severity of illness, and they may serve as independent predictors of 28-day mortality in septic patients with IAIs.

Th17, rather than Th1 cell proportion, is closely correlated with elevated disease severity, higher inflammation level, and worse prognosis in sepsis patients

Objective

The current study aimed to investigate the prognostic value of T helper (Th) 1 and Th17 proportions in sepsis patients.

Methods

Th1 and Th17 cells in blood CD4⁺ T cells were detected by flow cytometry in 210 sepsis patients and 100 healthy controls (HCs). Besides, serum interferon‐γ (IFN‐γ), tumor necrosis factor‐α (TNF‐α), and interleukin‐17 (IL‐17) levels in the enrolled sepsis patients were determined with enzyme‐linked immunosorbent assay.

Results

Compared with HCs, Th1 and Th17 proportions were elevated in sepsis patients (both p < .001). Meanwhile, Th1 proportion was strongly correlated with IFN‐γ (p < .001, r = .484) but weakly correlated with TNF‐α (p = .024, r = .156) and IL‐17 (p = .002, r = .212), while Th17 proportion showed faint correlation with IFN‐γ (p = .015, r = .168), but strong correlations with TNF‐α (p < .001, r = .602) and IL‐17 (p < .001, r = .498) in sepsis patients. Besides, Th1 proportion was weakly associated with APACHE II score (p = .030, r = .150), but Th17 proportion was closely associated with APACHE II score (p < .001, r = .322) and SOFA score (p < .001, r = .337) in sepsis patients. Regarding their prognostic value, Th1 proportion (p = .042) was slightly, while Th17 proportion (p < .001) was dramatically, increased in septic deaths compared with survivors, and Th17 possessed good predictive value for 28‐day mortality risk (AUC: 0.748, 95% CI: 0.659–0.836).

Conclusion

Th1 and Th17 proportions are elevated in sepsis patients compared with HCs, and Th17 proportion is correlated with increased disease severity, higher inflammation level, and worse prognosis in sepsis patients.

Targeting Lymphocyte Activation Gene 3 to Reverse T-Lymphocyte Dysfunction and Improve Survival in Murine Polymicrobial Sepsis

BACKGROUND

Lymphocyte activation gene 3 (LAG-3) is one of the immune checkpoint molecules, negatively regulating the T-cell reactions. The present study investigated the role of LAG-3 in sepsis-induced T-lymphocyte disability.

METHODS

Mice sepsis was induced by cecal ligation and puncture (CLP). LAG-3 expression on some immune cells were detected 24 hours after CLP. LAG-3 knockout and anti-LAG-3 antibody were applied to investigate the effects on the survival, bacterial clearance. Cytokine levels, T-cell counts, and the presence of apoptosis (in blood, spleen, and thymus) were also determined. In vitro T-cell apoptosis, interferon γ secretion, and proliferation were measured. The expression of interleukin 2 receptor on T cells was also determined after CLP.

RESULTS

LAG-3 was up-regulated on CD4+/CD8+ T, CD19+ B, natural killer, CD4+CD25+ regulatory T cells and dendritic cells. Both LAG-3 knockout and anti-LAG-3 antibody had a positive effect on survival and on blood or peritoneal bacterial clearance in mice undergoing CLP. Cytokine levels and T-cell apoptosis decreased in anti-LAG-3 antibody-treated mice. Induced T-cell apoptosis decreased, whereas interferon γ secretion and proliferation were improved by anti-LAG-3 antibody in vitro. Interleukin 2 receptor was up-regulated on T cells in both wild-type and LAG-3-knockout mice undergoing CLP.

CONCLUSIONS

LAG-3 knockout or anti-LAG-3 antibody blockade protected mice undergoing CLP from sepsis-associated immunodysfunction and may be a new target for the treatment.

Correlation of sPD1 with Procalcitonin and C-Reactive Protein Levels in Patients with Sepsis

Objective

Sepsis results from dysregulated host responses to infection, and it is a major cause of mortality in the world. Co-inhibitory molecules, such as PD-1, play a critical role in this process. Considering the lack of information on the relation between sPD1 and sepsis, the present study aimed to examine the sPD1 level in septic patients and evaluate its correlation with procalcitonin (PCT) and C-reactive protein (CRP) levels.

Materials and Methods

This descriptive cross-sectional study consisted of three groups, including septic patients (n=15), suspected of sepsis (n=15), and healthy subjects (n=15). White blood cells (WBCs) and platelet (PLT) counts are evaluated. The serum levels of CRP, PCT, and sPD1 were measured by immunoturbidimetric assay, electro- chemiluminescence technology, and the enzyme-linked immunosorbent assay (ELISA), respectively.

Results

Our study indicated that there was a significant difference in WBC and PLT counts between the septic group compared to suspected and control groups (P<0.001, P<0.01, respectively). The CRP level was significantly higher in septic compared to suspected and control groups (P<0.001). There was also a significant difference between the PCT level in septic and suspected groups in comparison with the controls (P<0.001, P<0.01). The sPD1 level was significantly higher in septic patients compared to suspected and control groups (P<0.001). In septic patients, sPD1 levels were correlated positively with the CRP and PCT levels.

Conclusion

Overall, sPD1 correlation with inflammatory markers, might propose it as a potential biomarker to sepsis diagnosis. However, the clinical application of serum sPD-1 testing in patients with sepsis requires further investigation.

Protective effect of ethyl pyruvate on gut barrier function through regulations of ROS-related NETs formation during sepsis

BACKGROUND

Sepsis impairs the function of the intestinal barrier through neutrophil extracellular traps (NETs). Reactive oxygen species (ROS)-induced activation of mitogen-activated protein kinase (MAPK) is involved in NET formation. Ethyl pyruvate (EP), a potent and effective ROS scavenger, ameliorates sepsis-associated intestinal barrier dysfunction, but the detailed mechanism is unknown. The current study aimed to explore the eff ;ects of EP on sepsis-induced intestinal barrier dysfunction and whether ROS and NETs were involved.

METHODS

A sepsis model was induced in mice by intraperitoneal injection of LPS (10 mg/kg). The mice were divided into 4 groups: (1) sham group; (2) LPS group; (3) DNase-1 + LPS group; and (4) EP + LPS group. EP or DNase-1 was intraperitoneally injected after the LPS model was established. After 24 h, the small intestine and blood were collected for analysis. Human neutrophils were harvested and incubated with phorbol-12-myristate-13-acetate (PMA) or PMA + EP, and ROS and NET generation was measured.

RESULTS

EP significantly decreased proinflammatory cytokines and MPO-DNA in the LPS model. In addition, EP suppressed NET formation in the intestines of endotoxemic mice. The decrease in NETs induced by EP or DNase-1 alleviated histopathological damage, intestinal cell apoptosis and increased tight junction expression. In vitro, the treatment of EP abolished PMA-induced ROS production and NET formation which could be reversed by H₂O₂ treatment. Meanwhile, EP also abolished MAPK ERK1/2 and p38 activation during PMA-induced NET formation.

CONCLUSION

This study was the first to demonstrate that EP alleviated NET formation and sepsis-induced intestinal damage through blockage of ROS mediated MAPK ERK1/2 and p38 activation.

Persistent Systemic Inflammation in Patients With Severe Burn Injury Is Accompanied by Influx of Immature Neutrophils and Shifts in T Cell Subsets and Cytokine Profiles

Severe burn injury causes local and systemic immune responses that can persist up to months, and can lead to systemic inflammatory response syndrome, organ damage and long-term sequalae such as hypertrophic scarring. To prevent these pathological conditions, a better understanding of the underlying mechanisms is essential. In this longitudinal study, we analyzed the temporal peripheral blood immune profile of 20 burn wound patients admitted to the intensive care by flow cytometry and secretome profiling, and compared this to data from 20 healthy subjects. The patient cohort showed signs of systemic inflammation and persistently high levels of pro-inflammatory soluble mediators, such as IL-6, IL-8, MCP-1, MIP-1β, and MIP-3α, were measured. Using both unsupervised and supervised flow cytometry techniques, we observed a continuous release of neutrophils and monocytes into the blood for at least 39 days. Increased numbers of immature neutrophils were present in peripheral blood in the first three weeks after injury (0.1–2.8 × 10⁶/ml after burn vs. 5 × 10³/ml in healthy controls). Total lymphocyte numbers did not increase, but numbers of effector T cells as well as regulatory T cells were increased from the second week onward. Within the CD4⁺ T cell population, elevated numbers of CCR4⁺CCR6^- and CCR4⁺CCR6⁺ cells were found. Altogether, these data reveal that severe burn injury induced a persistent innate inflammatory response, including a release of immature neutrophils, and shifts in the T cell composition toward an overall more pro-inflammatory phenotype, thereby continuing systemic inflammation and increasing the risk of secondary complications.

Correlation of Immunoglobulins and Lymphocytes Levels With the Clinical and Microbiological Response of Septic Patients With Gram-Negative Bacteremia

Background

Immunoglobulins (Igs) and cells of the innate and adaptive immune systems play a critical role in a host's response to sepsis. The aim of this study was to investigate the possible differences in the levels of Igs, white blood cells (WBCs), and T and B lymphocytes cells in relation to the microbiological and clinical responses of patients with sepsis or septic shock from carbapenem non-susceptible Gram-negative bacteria (CnS-GNB).

Methods

This pilot cohort study involved 24 hospitalized patients with sepsis or septic shock due to bacteremia from CnS-GNB. The microbiological and clinical responses of the patients were evaluated in relation to their blood levels of IgA, IgE, IgM and IgG, as well as WBCs and subpopulations of T and B cells upon sepsis diagnosis. A microbiological response was determined as clearance of bacteremia at 14 days of active antibiotic treatment for the isolated bacterial pathogen. Clinical response was defined as the resolution of all clinical and laboratory signs of infection and sepsis at 14 days of active antibiotic treatment for the isolated pathogen.

Results

From the 24 patients included in the study 18 (75%) and six patients (25%) presented and did not present microbiological response respectively, while 16 patients presented clinical response (64%) and eight patients (36%) did not have clinical response. The levels of the Igs did not show statistically significant differences between patients with sepsis from CnS-GNB bacteremia who exhibited microbiological or clinical response. There were also no statistically significant differences in the levels of WBCs and the subpopulations of T and B cells levels for these patients (P > 0.05). According to this pilot study, peripheral blood Igs and lymphocyte subpopulations levels do not affect the clinical and microbiological response of septic patients with bacteremia from CnS-GNB.

Conclusions

In patients with sepsis or septic shock from CnSGNB, there were no differences in the levels of Igs, circulating WBCs and T and B cells subpopulations between those with microbiological or clinical response and non-responders.

The use of fecal microbiota transplant in sepsis

Sepsis is defined as a dysregulated inflammatory response, which ultimately results from a perturbed interaction of both an altered immune system and the biomass and virulence of involved pathogens.  This response has been tied to the intestinal microbiota, as the microbiota and its associated metabolites play an essential role in regulating the host immune response to infection.  In turn, critical illness as well as necessary health care treatments result in a collapse of the intestinal microbiota diversity and a subsequent loss of health-promoting short chain fatty acids, such as butyrate, leading to the development of a maladaptive pathobiome.  These perturbations of the microbiota contribute to the dysregulated immune response and organ failure associated with sepsis.  Several case series have reported the ability of fecal microbiota transplant (FMT) to restore the host immune response and aid in recovery of septic patients.  Additionally, animal studies have revealed the mechanism of FMT rescue in sepsis is likely related to the ability of FMT to restore butyrate producing bacteria and alter the innate immune response aiding in pathogen clearance.  However, several studies have reported lethal complications associated with FMT, including bacteremia.  Therefore, FMT in the treatment of sepsis is and should remain investigational until a more detailed mechanism of how FMT restores the host immune response in sepsis is determined, allowing for the development of more fine-tuned microbiota therapies.

Persistent Activation of Innate Immunity in Patients with Primary Antibody Deficiencies

Primary antibody deficiencies (PAD) represent a heterogeneous group of disorders, with common variable immunodeficiency being the most common with clinical significance. The main phenotypic defect resides in the inability of B cells to produce antibodies, and the cornerstone of therapy is immunoglobulin replacement treatment in order to fight infections. However, the management of the other inflammatory manifestations is inadequate, reinforcing the hypothesis that a complex genetic background affecting additional cell populations, such as polymorphonuclear cells (PMN) and monocytes, influences the expression of the clinical phenotype of the disease. In this study, we investigated by flow cytometry in different conditions (resting state, and after isolation and incubation, with and without stimuli) the expression pattern of several markers on PMN and monocytes, indicative of their maturation, capacity for chemotaxis, adhesion, opsonization, migration, and phagocytosis in 25 PAD patients, 12 healthy blood donors, and 4 septic patients. In this context, we also analyzed patients before and after the initiation of replacement treatment, as well as an untreated patient in different clinical conditions. Interestingly, we observed that PAD patients exhibit a chronic activation status of the innate immunity compartment, along with several differences in the expression of activation, maturation, and adhesion markers, with respect to different clinical conditions. Moreover, immunoglobulin replacement treatment had a favorable effect on PMN, as it was expressed by a more mature and less activated phenotype on basal state cells, and an enhanced activation capacity after LPS exposure. Thus, we conclude that PAD patients display a persistent innate immune cell activation, which is probably associated with the chronic inflammatory stress, usually observed in these disorders.

Hip Fracture Leads to Transitory Immune Imprint in Older Patients

Background: Hip fracture (HF) is common in the geriatric population and is associated with a poor vital and functional prognosis which could be impacted by immunological changes. The objective here is to decipher immune changes occurring in the 1st days following HF and determine how phenotype, function, and regulation of innate and adaptive compartments adapt during acute stress event.

Methods: We included HF patients, aged over 75 years. For each patient, blood samples were taken at five different timepoints: four in the perioperative period (day 0 to hospital discharge) and one at long term (6–12 months). Phenotypical and functional analysis were performed longitudinally on fresh blood or cryopreserved PBMCs. Clinical data were prospectively collected.

Results: One-hundred HF patients and 60 age-matched controls were included. Innate compartment exhibits pro-inflammatory phenotypes (hyperleukocytosis, increase of CD14+ CD16+ proportion and CCR2 expression), maintaining its ability to produce pro-inflammatory cytokines. Adaptive compartment extends toward a transitory immunosuppressive profile (leucopenia) associated with an active T-cell proliferation. Furthermore, increases of LAG-3 and PD-1 and a decrease of 2-B4 expression are observed on T-cells, reinforcing their transitory suppressive status. Of note, these immune changes are transitory and sequential but may participate to a regulation loop necessary for homeostatic immune control at long term.

Conclusion: HF is associated with several transitory immunological changes including pro-inflammatory phenotype in innate compartment and immunosuppressive profile in adaptive compartment. A comprehensive assessment of immune mechanisms implicated in the patient's prognosis after HF could pave the way to develop new immune therapeutics strategies.

The role of specific biomarkers, as predictors of post-operative complications following flexible ureterorenoscopy (FURS), for the treatment of kidney stones: a single-centre observational clinical pilot-study in 37 patients

BACKGROUND

The number of patients diagnosed and subsequently treated for kidney stones is increasing, and as such the number of post-operative complications is likely to increase. At present, little is known about the role of specific biomarkers, following flexible ureterorenoscopy (FURS) for the surgical treatment of kidney stones. The main aim of the study was to evaluate the role of kidney and infection biomarkers, in patients undergoing FURS.

METHODS

Included were 37 patients (24 males, 13 females), who underwent elective FURS, for the treatment of kidney stones. Venous blood samples were collected from each patient: pre-operatively, and at 30 min, 2 and 4 h post-operatively. Changes to kidney (NGAL, Cystatin-C) and infection (MPO, PCT) biomarkers was quantified by means of ELISA, Biomerieux mini-vidas and Konelab 20 analysers.

RESULTS

Four patients developed post-operative complications (3 - UTIs with urinary retention, 1 - urosepsis. NGAL concentration increased significantly following FURS (p = 0.034). Although no significant changes were seen in Cystatin C, MPO and PCT (p ≥ 0.05) some key clinical observation were noted. Limiting factors for this study were the small number of patients recruited and restriction in blood sampling beyond 4 h.

CONCLUSIONS

Although not confirmative, changes seen to biomarkers such as Cystatin C, NGAL and MPO in our observational clinical pilot-study may warrant further investigation, involving larger cohorts, to fully understand the role of these biomarkers and their potential association with post-operative complications which can develop following FURS.

Polymicrobial Sepsis Impairs Antigen-Specific Memory CD4 T Cell-Mediated Immunity

Patients who survive sepsis display prolonged immune dysfunction and heightened risk of secondary infection. CD4 T cells support a variety of cells required for protective immunity, and perturbations to the CD4 T cell compartment can decrease overall immune system fitness. Using the cecal ligation and puncture (CLP) mouse model of sepsis, we investigated the impact of sepsis on endogenous Ag-specific memory CD4 T cells generated in C57BL/6 (B6) mice infected with attenuated Listeria monocytogenes (Lm) expressing the I-A^b-restricted 2W1S epitope (Lm-2W). The number of 2W1S-specific memory CD4 T cells was significantly reduced on day 2 after sepsis induction, but recovered by day 14. In contrast to the transient numerical change, the 2W1S-specific memory CD4 T cells displayed prolonged functional impairment after sepsis, evidenced by a reduced recall response (proliferation and effector cytokine production) after restimulation with cognate Ag. To define the extent to which the observed functional impairments in the memory CD4 T cells impacts protection to secondary infection, B6 mice were infected with attenuated Salmonella enterica-2W (Se-2W) 30 days before sham or CLP surgery, and then challenged with virulent Se-2W after surgery. Pathogen burden was significantly higher in the CLP-treated mice compared to shams. Similar reductions in functional capacity and protection were noted for the endogenous OVA₃₂₃-specific memory CD4 T cell population in sepsis survivors upon Lm-OVA challenge. Our data collectively show CLP-induced sepsis alters the number and function of Ag-specific memory CD4 T cells, which contributes (in part) to the characteristic long-lasting immunoparalysis seen after sepsis.

Sepsis in the era of data-driven medicine: personalizing risks, diagnoses, treatments and prognoses

Sepsis is a series of clinical syndromes caused by the immunological response to infection. The clinical evidence for sepsis could typically attribute to bacterial infection or bacterial endotoxins, but infections due to viruses, fungi or parasites could also lead to sepsis. Regardless of the etiology, rapid clinical deterioration, prolonged stay in intensive care units and high risk for mortality correlate with the incidence of sepsis. Despite its prevalence and morbidity, improvement in sepsis outcomes has remained limited. In this comprehensive review, we summarize the current landscape of risk estimation, diagnosis, treatment and prognosis strategies in the setting of sepsis and discuss future challenges. We argue that the advent of modern technologies such as in-depth molecular profiling, biomedical big data and machine intelligence methods will augment the treatment and prevention of sepsis. The volume, variety, veracity and velocity of heterogeneous data generated as part of healthcare delivery and recent advances in biotechnology-driven therapeutics and companion diagnostics may provide a new wave of approaches to identify the most at-risk sepsis patients and reduce the symptom burden in patients within shorter turnaround times. Developing novel therapies by leveraging modern drug discovery strategies including computational drug repositioning, cell and gene-therapy, clustered regularly interspaced short palindromic repeats -based genetic editing systems, immunotherapy, microbiome restoration, nanomaterial-based therapy and phage therapy may help to develop treatments to target sepsis. We also provide empirical evidence for potential new sepsis targets including FER and STARD3NL. Implementing data-driven methods that use real-time collection and analysis of clinical variables to trace, track and treat sepsis-related adverse outcomes will be key. Understanding the root and route of sepsis and its comorbid conditions that complicate treatment outcomes and lead to organ dysfunction may help to facilitate identification of most at-risk patients and prevent further deterioration. To conclude, leveraging the advances in precision medicine, biomedical data science and translational bioinformatics approaches may help to develop better strategies to diagnose and treat sepsis in the next decade.

Phagocytosis-Inflammation Crosstalk in Sepsis: New Avenues for Therapeutic Intervention

Phagocytosis is a complex process by which cells within most organ systems remove pathogens and cell debris. Phagocytosis is usually followed by inflammatory pathway activation, which promotes pathogen elimination and inhibits pathogen growth. Delayed pathogen elimination is the first step in sepsis development and a key factor in sepsis resolution. Phagocytosis thus has an important role during sepsis and likely contributes to all of its clinical stages. However, only a few studies have specifically explored and characterized phagocytic activity during sepsis. Here, we describe the phagocytic processes that occur as part of the immune response preceding sepsis onset and identify the elements of phagocytosis that might constitute a predictive marker of sepsis outcomes. First, we detail the key features of phagocytosis, including the main receptors and signaling hallmarks associated with different phagocytic processes. We then discuss how the initial events of phagosome formation and cytoskeletal remodeling might be associated with known sepsis features, such as a cytokine-driven hyperinflammatory response and immunosuppression. Finally, we highlight the unresolved mechanisms of sepsis development and progression and the need for cross-disciplinary approaches to link the clinical complexity of the disease with basic cellular and molecular mechanisms.

Caspase-1-Dependent Pyroptosis of Peripheral Blood Mononuclear Cells Is Associated with the Severity and Mortality of Septic Patients

Purpose

Pyroptosis has been known to play a vital role in the inflammation process which was induced by infection, injury, or inflammatory disease. The present study was aimed at evaluating the percentage of peripheral blood mononuclear cell (PBMC) pyroptosis in septic patients and assessing the correlation of PBMC pyroptosis with the severity and the mortality of septic patients.

Methods

128 trauma-induced patients with sepsis were enrolled in this prospective cohort study. Blood samples were collected, and PBMC pyroptosis was measured by flow cytometry within 24 hours after sepsis was diagnosed.

Results

Percentage of PBMC pyroptosis was positively correlated with the acute physiology and chronic health evaluation (APACHE) II score and sequential organ failure assessment (SOFA) score (all P < 0.01). The area under the curve (AUC) for the percentage of PBMC pyroptosis on a receiver operating characteristic curve was 0.79 (95% confidence interval (CI), 0.68–0.90). A Cox proportional hazard model identified an association between an increased percentage of PBMC pyroptosis (>14.17%) and increased risk of the 28-day mortality (hazard ratio = 1.234, 95% CI, 1.014–1.502).

Conclusion

The percentage of PBMC pyroptosis increases in septic patients, and the increased percentage of PBMC pyroptosis is associated with the severity of sepsis and the 28-day mortality of patients with sepsis.

Septic Shock Alters Mitochondrial Respiration of Lymphoid Cell-Lines and Human Peripheral Blood Mononuclear Cells: The Role of Plasma

INTRODUCTION

In septic shock patients, postseptic immunosuppression state after the systemic inflammatory response syndrome is responsible for nosocomial infections, with subsequent increased mortality. The aim of the present study was to assess the underlying cellular mechanisms of the postseptic immunosuppression state, by investigating mitochondrial functions of peripheral blood mononuclear cells (PBMCs) from septic shock patients over 7 days.

MATERIALS AND METHODS

Eighteen patients admitted to a French intensive care unit for septic shock were included. At days 1 and 7, PBMCs were isolated by Ficoll density gradient centrifugation. Mitochondrial respiration of intact septic PBMCs was assessed versus control group PBMCs, by measuring O2 consumption in plasma, using high-resolution respirometry. Mitochondrial respiration was then compared between septic plasmas and control plasmas for control PBMCs, septic PBMCs, and lymphoid cell-line (CEM). To investigate the role of plasma, we measured several plasma cytokines, among them High-Mobility Group Box 1 (HMGB1), by enzyme-linked immunosorbent assays.

RESULTS

Basal O2 consumption of septic shock PBMCs was of 8.27 ± 3.39 and 10.48 ± 3.99 pmol/s/10 cells at days 1 and 7, respectively, significantly higher than in control PBMCs (5.37 ± 1.46 pmol/s/10 cells, P < 0.05). Septic patient PBMCs showed a lower response to oligomycin, suggesting a reduced ATP-synthase activity, as well as an increased response to carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) suggesting an increased mitochondrial respiratory capacity. At 6 h, septic plasmas showed a decreased O2 consumption of CEM (4.73 ± 1.46 vs. 6.58 ± 1.53, P < 0.05) as well as in control group PBMCs (1.76 ± 0.36 vs. 2.70 ± 0.42, P < 0.05), and triggered a decreased ATP-synthase activity but an increased response to FCCP. These differences are not explained by different cell survival. High HMGB1 levels were significantly associated with reduced PBMCs mitochondrial respiration.

CONCLUSIONS

Septic plasma impairs mitochondrial respiration in immune cells, with a possible role of the proinflammatory protein HMGB1, leading to a subsequent compensation, probably by enzymatic activation. This compensation result is an improvement of global mitochondrial respiratory capacity, but without restoring ATP-synthase activity.

Increased levels of myeloid-derived suppressor cells in esophageal cancer patients is associated with the complication of sepsis

BACKGROUND

To evaluate whether the level of myeloid-derived suppressor cells is related to the complication of sepsis after esophageal cancer surgery and whether changing the myeloid-derived suppressor cells levels can improve the prognosis of patients cancer-related sepsis.

METHODS

A total of 178 esophageal cancer patients from Harbin Medical University Cancer Hospital were included in this study. Blood samples were taken from the patients for the analysis of the levels of G-MDSCs and M-MDSCs by flow cytometry. The conditions of the patients was recorded. Male C57BL/6 mice were implanted with Lewis lung cancer cells (2 × 10⁶/mice) by subcutaneous injection into the iliac fossa. Three weeks later, we performed CLP in the mice. All-trans-retinoic acid (ATRA) was intraperitoneally injected at 20 mg/kg, and the control group was injected with 0.9 % NS. We observed the mortality of the mice with cancer-related sepsis.

RESULTS

In all, 95 % of the esophageal cancer patients had a high level of G-MDSCs (>50 %). A high level of G-MDSCs (>82.5 %) can lead to high morbidity from sepsis after surgery. The increase in M-MDSCs was suggestive of a poor prognosis in patients with cancer-related sepsis. ATRA can improve the survival of patients with cancer-related sepsis.

CONCLUSIONS

A high level of G-MDSCs can be used to determine the incidence of sepsis in preoperative esophageal cancer patients, M-MDSCs might be effective prognostic indicators for cancer-sepsis patients, and changing the MDSC levels can improve the mortality of patients with cancer-related sepsis.

Flow Cytometric Analysis of Monocytes Polarization and Reprogramming From Inflammatory to Immunosuppressive Phase During Sepsis

Sepsis outcome is determined by a balance between inflammation and immune suppression. We aimed to evaluate monocytes polarization and reprogramming during these processes. We analyzed 93 patients with procalcitonin level >0.5 ng/mL (hPCT) and suspected/confirmed sepsis, and 84 controls by analysis of CD14, CD16 and HLA-DR expression on blood monocytes using fluorescent labeled monoclonal antibodies and BD FACS CANTO II. Complete blood cell count, procalcitonin and other biochemical markers were evaluated. Intermediate monocytes CD14⁺⁺CD16⁺ increased in hPCT patients (including both positive and negative culture) compared to controls (13.6% ± 0.8 vs 6.2% ± 0.3, p<0.001), while classical monocytes CD14⁺⁺CD16^-were significantly reduced (72.5% ± 1.6 vs 82.6% ± 0.7, p<0.001). Among hPCT patients having positive microbial culture, the percentage of intermediate monocytes was significantly higher in septic compared with non-septic/localized-infection patients (17.4% vs 11.5%; p<0.05) whilst the percentage of classical monocytes was lower (68.0% vs 74.5%). Three-four days following the diagnosis of sepsis, HLA-DR expression on monocyte (mHLA-DR) was lower (94.3%) compared to controls (99.4%) (p<0.05). Septic patients with the worst clinical conditions showed higher incidence of secondary infections, longtime hospitalization and lower HLA-DR+ monocytes compared to septic patients with better clinical outcome (88.4% vs 98.6%, p=0.05). The dynamic nature of sepsis correlates with monocytes functional polarization and reprogramming from a pro-inflammatory CD14⁺⁺CD16⁺ phenotype in non-septic hPCT patients to a decrease of HLA-DR surface expression in hPCT patients with confirmed sepsis, making HLA-DR reduction a marker of immune-paralysis and sepsis outcome. Analysis of monocytes plasticity opens to new mechanisms responsible for pro/anti-inflammatory responses during sepsis, and new immunotherapies.

The differential statin effect on cytokine production of monocytes or macrophages is mediated by differential geranylgeranylation-dependent Rac1 activation

Monocytes and macrophages contribute to pathogenesis of various inflammatory diseases, including auto-inflammatory diseases, cancer, sepsis, or atherosclerosis. They do so by production of cytokines, the central regulators of inflammation. Isoprenylation of small G-proteins is involved in regulation of production of some cytokines. Statins possibly affect isoprenylation-dependent cytokine production of monocytes and macrophages differentially. Thus, we compared statin-dependent cytokine production of lipopolysaccharide (LPS)-stimulated freshly isolated human monocytes and macrophages derived from monocytes by overnight differentiation. Stimulated monocytes readily produced tumor necrosis factor-α, interleukin-6, and interleukin-1β. Statins did not alter cytokine production of LPS-stimulated monocytes. In contrast, monocyte-derived macrophages prepared in the absence of statin lost the capacity to produce cytokines, whereas macrophages prepared in the presence of statin still produced cytokines. The cells expressed indistinguishable nuclear factor-kB activity, suggesting involvement of separate, statin-dependent regulation pathways. The presence of statin was necessary during the differentiation phase of the macrophages, indicating that retainment-of-function rather than costimulation was involved. Reconstitution with mevalonic acid, farnesyl pyrophosphate, or geranylgeranyl pyrophosphate blocked the retainment effect, whereas reconstitution of cholesterol synthesis by squalene did not. Inhibition of geranylgeranylation by GGTI-298, but not inhibition of farnesylation or cholesterol synthesis, mimicked the retainment effect of the statin. Inhibition of Rac1 activation by the Rac1/TIAM1-inhibitor NSC23766 or by Rac1-siRNA (small interfering RNA) blocked the retainment effect. Consistent with this finding, macrophages differentiated in the presence of statin expressed enhanced Rac1-GTP-levels. In line with the above hypothesis that monocytes and macrophages are differentially regulated by statins, the CD14/CD16-, merTK-, CX₃CR1-, or CD163-expression (M2-macrophage-related) correlated inversely to the cytokine production. Thus, monocytes and macrophages display differential Rac1-geranylgeranylation-dependent functional capacities, that is, statins sway monocytes and macrophages differentially.

Prognostic value of neutrophil-to-lymphocyte ratio in sepsis: A meta-analysis

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR) has been used to predict the prognosis of patients with sepsis with inconsistent results. This meta-analysis aimed to clarify the prognostic value of NLR in patients with sepsis.

METHODS

A comprehensive literature search for relevant studies, published prior to March 2019, was conducted using PubMed, Web of Science, and the China National Knowledge. Infrastructure database. Standard mean differences (SMDs) with 95% confidence intervals (CI) were used to evaluate the NLR of patients with sepsis retrospectively. Hazard ratios (HRs) with 95% CIs were used to evaluate the prognostic value of NLR in patients with sepsis.

RESULTS

Patients from 14 studies (n = 11,564) were selected for evaluation. Nine studies (1371 patients) analyzed the NLR in these patients. The pooled results showed significantly higher NLR in non-survivors than in survivors (random-effects model: SMD = 1.18, 95% CI; 0.42-1.94). Nine studies (10,685 patients) evaluated the prognostic value of NLR for sepsis; the pooled results showed that higher NLR was associated with poor prognosis in patients with sepsis (fixed-effects model: HR = 1.75, 95% CI; 1.56-1.97). Subgroup analysis revealed that study design, cut-off NLR, or primary outcome did not affect the prognostic value of NLR in patients with sepsis.

CONCLUSION

This meta-analysis indicates that NLR may be a helpful prognostic biomarker of patients with sepsis and that higher NLR values may indicate unfavorable prognoses in these patients.

Dynamic changes in human HLA-DRA gene expression and Th cell subsets in sepsis: Indications of immunosuppression and associated outcomes

BACKGROUND

Sepsis is a life-threatening disease that is an immune disorder response that causes multiple organ dysfunction. In this study, we investigated the dynamic changes in mRNA expression of HLA-DRA gene and the specific transcription factor of helper T cell subsets to explore long-term immunophenotyping and its relationship with prognosis.

METHODS

Seventy-eight sepsis patients and twelve healthy controls were recruited in this study. Blood samples were collected at eight-time points during their septic course and were assayed for the gene expression of HLA-DRA and T helper cell subset-specific transcription factors (T-bet: Th1, GATA3: Th2, Foxp3: Treg, RORC: Th17).

RESULTS

The levels of HLA-DRA in survivors gradually increased but were maintained at lower levels in non-survivors. The specific transcription factor of Th1 and Th2 cells, T-bet and GATA-3 were significantly lower in sepsis patients than in normal controls, and the non-survivors showed significantly lower levels than the survivors (P < .05). RORC and FOXP3, the specific transcription factor of Treg and Th17 were significantly higher in survivors than in non-survivors and normal controls (P < .05). T-bet and GATA-3 had a linear correlation with HLA-DRA expression (P < .01).

CONCLUSIONS

The dynamic changes in HLA-DRA expression in peripheral blood could accurately reflect the immune status of sepsis patients, and the reduction in HLA-DRA may be an important reason for abnormal T cell differentiation. The sustained low levels of the Th cell subsets (Th1 and Th2) suggest the suppression of adaptive immunity, and this persistent immunosuppression may be the leading cause of death in septic patients.

Neutrophil to lymphocyte ratio (NLR) as a prognostic marker for in-hospital mortality of patients with sepsis: A secondary analysis based on a single-center, retrospective, cohort study

Neutrophil-to-lymphocyte ratio (NLR) has been reported to serve as a prognostic marker in inflammatory diseases. The purpose of this study was to evaluate the association of NLR at admission with in-hospital mortality in patients with sepsis presenting to emergency department.This was a secondary analysis based on a single-center, retrospective, cohort study. Patients with sepsis admitted to an academic emergency department between January 2010 and January 2015 were enrolled. NLR of patients was analyzed from the hospital's electronic health record (EHR) system. A total of 174 adult patients, of which 80 (46.0%) died in hospital. The primary outcome was in-hospital mortality. Secondary outcome was 28-day mortality.Contrary to previous studies, a larger NLR was found to have less odds of in-hospital mortality, as well as the presence of bacteremia. Patients who has severe/shock or had a history of chronic heart failure (CHF) had larger odds of death during hospital. Multivariate logistic regression analysis indicated that low NLR was an independent predictor of in-hospital mortality (OR = -0.98; 95% CI -0.96 to -0.99; P = .022). However, no correlation was found between the NLR and 28-day hospital mortality in patients with sepsis (P = .988). As a predictor of in-hospital survival, the area under curve (AUC) of the NLR was 0.622 (95%CI 0.54-0.71; P = .006) and the cut-off value was 9.11 with 0.551 sensitivity and 0.707 specificity.NLR at admission was an independent predictor of in-hospital mortality of sepsis patients.

Mechanisms and treatment of organ failure in sepsis

Sepsis is a dysregulated immune response to an infection that leads to organ dysfunction. Knowledge of the pathophysiology of organ failure in sepsis is crucial for optimizing the management and treatment of patients and for the development of potential new therapies. In clinical practice, six major organ systems - the cardiovascular (including the microcirculation), respiratory, renal, neurological, haematological and hepatic systems - can be assessed and monitored, whereas others, such as the gut, are less accessible. Over the past 2 decades, considerable amounts of new data have helped improve our understanding of sepsis pathophysiology, including the regulation of inflammatory pathways and the role played by immune suppression during sepsis. The effects of impaired cellular function, including mitochondrial dysfunction and altered cell death mechanisms, on the development of organ dysfunction are also being unravelled. Insights have been gained into interactions between key organs (such as the kidneys and the gut) and organ-organ crosstalk during sepsis. The important role of the microcirculation in sepsis is increasingly apparent, and new techniques have been developed that make it possible to visualize the microcirculation at the bedside, although these techniques are only research tools at present.

Application of dynamic pulse pressure and vasopressor tools for predicting outcomes in patients with sepsis in intensive care units

PURPOSE

We aimed to determine whether the combination of dynamic pulse pressure and vasopressor (DPV) use is applicable for mortality risk stratification in patients with severe sepsis. We proposed the use of the DPV tool and compared it with traditional sepsis severity indices.

MATERIALS AND METHODS

All adult patients who met the sepsis criteria of the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) between August 2013 and January 2017 were eligible for the study. Patients who expired within 3 days of admission to the intensive care unit (ICU) were excluded. The primary outcomes were 7-day and 28-day mortality.

RESULTS

The study participants included 757 consecutive adult patients. A subpopulation of 155 patients underwent immune profiling assays on days 1, 3, and 7 of ICU admission. The DPV tool had a better performance for predicting 7-day mortality (area under curve, AUC: 0.70), followed by the Sequential Organ Failure Assessment (SOFA) (AUC: 0.64), the plus pulse pressure (AUC: 0.64). For predicting 28-day mortality, the DPV tool was not inferior to the SOFA (AUC: 0.61), DPV tool (AUC: 0.59).

CONCLUSIONS

The DPV tool can be applied for 7-day and 28-day mortality risk prediction in patients with sepsis.

Park 7: A Novel Therapeutic Target for Macrophages in Sepsis-Induced Immunosuppression

Sepsis remains a serious and life-threatening condition with high morbidity and mortality due to uncontrolled inflammation together with immunosuppression with few therapeutic options. Macrophages are recognized to play essential roles throughout all phases of sepsis and affect both immune homeostasis and inflammatory processes, and macrophage dysfunction is considered to be one of the major causes for sepsis-induced immunosuppression. Currently, Parkinson disease protein 7 (Park 7) is known to play an important role in regulating the production of reactive oxygen species (ROS) through interaction with p47^phox, a subunit of NADPH oxidase. ROS are key mediators in initiating toll-like receptor (TLR) signaling pathways to activate macrophages. Emerging evidence has strongly implicated Park 7 as an antagonist for sepsis-induced immunosuppression, which suggests that Park 7 may be a novel therapeutic target for reversing immunosuppression compromised by sepsis. Here, we review the main characteristics of sepsis-induced immunosuppression caused by macrophages and provide a detailed mechanism for how Park 7 antagonizes sepsis-induced immunosuppression initiated by the macrophage inflammatory response. Finally, we further discuss the most promising approach to develop innovative drugs that target Park 7 in patients whose initial presentation is at the late stage of sepsis.

Sex differences of inflammation in target organs, induced by intraperitoneal injection of lipopolysaccharide, depend on its dose

Purpose

The aim of our research was to study sex differences and the severity of inflammatory changes in target organs and the peculiarities of immunological disorders when low and high doses of lipopolysaccharide (LPS) were administered to rats.

Methods

Male and female 2- to 3-month-old Wistar rats (200–250 g) were injected intraperitoneally with Escherichia coli LPS in one of two doses: 1.5 or 15 mg/kg. In a day after the LPS injection, we studied endotoxin, corticosterone, sex steroids, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activity levels in the serum; morphological disorders in the lung, liver, thymus, and spleen; ex vivo production of IL-2, IL-4, tumor necrosis factor (TNF), and interferon γ (IFNγ) by splenic cells activated by ConA; and relative amount of T- and B-lymphocytes in the peripheral blood.

Results

After the injection of low-dose LPS, the serum endotoxin level increased only in males and was combined with a more pronounced inflammatory response in the lungs and thymus and an increase in ALT and AST activity levels without any changes in corticosterone level. After the injection of high-dose LPS, the inflammatory and pathological changes in the target organs manifested as severe endotoxemia and sex differences of pathological changes in the lungs and liver were not revealed. The level of production of IL-2, IL-4, IFNγ, and TNF by splenic cells and the number of T-lymphocytes, including cytotoxic cells, in the peripheral blood, decreased in males, which is an evidence of a pronounced suppression of the immune response.

Conclusion

We have shown that the morphofunctional changes in the organs of the immune system in females and males, as well as the intensity of the sex differences of inflammation, depend on the severity of systemic inflammatory response, induced by different doses of LPS.

Immune Functional Assays, From Custom to Standardized Tests for Precision Medicine

The immune response is a dynamic system that maintains the integrity of the body, and more specifically fight against infections. However, an unbalanced host immune response is highlighted in many diseases. Exacerbated responses lead to autoimmune and allergic diseases, whereas, low or inefficient responses favor opportunistic infections and viral reactivations. Conflicting situations may also occur, such as in sepsis where inflammation and compensatory immunosuppression make it difficult to deploy the appropriate drug treatment. Until the current day, assessing the immune profile of patients remains a challenge. This is especially due to the inter-individual variability—a key feature of the immune system—which hinders precise diagnosis, prognosis, and therapeutic stratification. Our incapacity to practically interpret the host response may contribute to a high morbidity and mortality, such as the annual 6 million worldwide deaths in sepsis alone. Therefore, there is a high and increasing demand to assess patient immune function in routine clinical practice, currently met by Immune Functional Assays. Immune Functional Assays (IFA) hold a plethora of potentials that include the precise diagnosis of infections, as well as prediction of secondary and latent infections. Current available products are devoted to indirect pathogen detection such as Mycobacteria tuberculosis interferon gamma release assays (IGRA). In addition, identifying the status and the underlying factors of immune dysfunction (e.g., in septic patients) may guide immune targeted therapies. Tools to monitor and stratify the immune status are currently being studied but they still have many limitations such as technical standardization, biomarkers relevance, systematic interpretation and need to be simplified, in order to set the boundaries of “healthy,” “ill,” and “critically ill” responses. Thus, the design of new tools that give a comprehensive insight into the immune functionality, at the bedside, and in a timely manner represents a leap toward immunoprofiling of patients.

Recent advances in endotoxin tolerance

Endotoxin tolerance is defined as a reduced capacity of a cell to respond endotoxin (lipopolysaccharide, LPS) challenge after an initial encounter with endotoxin in advance. The body becomes tolerant to subsequent challenge with a lethal dose of endotoxin and cytokines release and cell/tissue damage induced by inflammatory reaction are significantly reduced in the state of endotoxin tolerance. The main characteristics of endotoxin tolerance are downregulation of inflammatory mediators such as tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and C-X-C motif chemokine 10 (CXCL10) and upregulation of anti-inflammatory cytokines such as IL-10 and transforming growth factor β (TGF-β). Therefore, endotoxin tolerance is often regarded as the regulatory mechanism of the host against excessive inflammation. Endotoxin tolerance is a complex pathophysiological process and involved in multiple cellular signal pathways, receptor alterations, and biological molecules. However, the exact mechanism remains elusive up to date. To better understand the underlying cellular and molecular mechanisms of endotoxin tolerance, it is crucial to investigate the comprehensive cellular signal pathways, signaling proteins, cell surface molecules, proinflammatory and anti-inflammatory cytokines, and other mediators. Endotoxin tolerance plays an important role in reducing the mortality of sepsis, endotoxin shock, and other endotoxin-related diseases. Recent reports indicated that endotoxin tolerance is also related to other diseases such as cystic fibrosis, acute coronary syndrome, liver ischemia-reperfusion injury, and cancer. The aim of this review is to discuss the recent advances in endotoxin tolerance mainly based on the cellular and molecular mechanisms by outline the current state of the knowledge of the involvement of the toll-like receptor 4 (TLR4) signaling pathways, negative regulate factor, microRNAs, apoptosis, chromatin modification, and gene reprogramming of immune cells in endotoxin tolerance. We hope to provide a new idea and scientific basis for the rational treatment of endotoxin-related diseases such as endotoxemia, sepsis, and endotoxin shock clinically.

Dynamic balance of pro- and anti-inflammatory signals controls disease and limits pathology

Immune responses to pathogens are complex and not well understood in many diseases, and this is especially true for infections by persistent pathogens. One mechanism that allows for long-term control of infection while also preventing an over-zealous inflammatory response from causing extensive tissue damage is for the immune system to balance pro- and anti-inflammatory cells and signals. This balance is dynamic and the immune system responds to cues from both host and pathogen, maintaining a steady state across multiple scales through continuous feedback. Identifying the signals, cells, cytokines, and other immune response factors that mediate this balance over time has been difficult using traditional research strategies. Computational modeling studies based on data from traditional systems can identify how this balance contributes to immunity. Here we provide evidence from both experimental and mathematical/computational studies to support the concept of a dynamic balance operating during persistent and other infection scenarios. We focus mainly on tuberculosis, currently the leading cause of death due to infectious disease in the world, and also provide evidence for other infections. A better understanding of the dynamically balanced immune response can help shape treatment strategies that utilize both drugs and host-directed therapies.

Innate and adaptive immune dysregulation in critically ill ICU patients

This study aimed to evaluate whether ICU patients who developed persistent critical illness displayed an immune profile similar to an aged immune phenotype and any associations with patient outcomes. Twenty two critically ill ICU patients (27–76 years, 15 males), at day 5 of mechanical ventilation, and 22 healthy age-matched controls (27–77 years, 13 males) were recruited. Frequency and phenotype of innate and adaptive immune cells and telomere length in peripheral blood mononuclear cells (PBMCs) were measured. An elevated granulocyte count (p < 0.0001), increased numbers of immature granulocytes (p < 0.0001), increased CD16^++ve monocytes (p = 0.003) and CD14^+ve HLADR^dim/low monocytes (p = 0.004) and lower NK cell numbers (p = 0.007) were observed in ICU patients compared to controls. Critically ill patients also had lower numbers of total T lymphocytes (p = 0.03), naïve CD4 T cells (p = 0.003) and PTK7^+ve recent thymic emigrants (p = 0.002), and increased senescent CD28^−ve CD57^+ve CD4 T cells (p = 0.02), but there was no difference in PBMC telomere length. Regulatory immune cell frequency was affected with reduced circulating CD19^+veCD24^hiCD38^hi regulatory B cells (p = 0.02). However, only a raised neutrophil:lymphocyte ratio and reduced frequency of CD14^+ve HLADR^dim/low monocytes were associated with poor outcomes. We conclude that persistent critical illness results in changes to immune cell phenotype only some of which are similar to that seen in physiological ageing of the immune system.

T cells and their immunometabolism: A novel way to understanding sepsis immunopathogenesis and future therapeutics

Sepsis has always been considered as a big challenge for pharmaceutical companies in terms of discovering and designing new therapeutics. The pathogenesis of sepsis involves aberrant activation of innate immune cells (i.e. macrophages, neutrophils etc.) at early stages. However, a stage of immunosuppression is also observed during sepsis even in the patients who have recovered from it. This stage of immunosuppression is observed due to the loss of conventional (i.e. CD4⁺, CD8⁺) T cells, Th17 cells and an upregulation of regulatory T cells (Tregs). This process also impacts metabolic processes controlling immune cell metabolism called immunometabolism. The present review is focused on the T cell-mediated immune response, their immunometabolism and targeting T cell immunometabolism during sepsis as future therapeutic approach. The first part of the manuscripts describes an impact of sepsis on conventional T cells, Th17 cells and Tregs along with their impact on sepsis. The subsequent section further describes the immunometabolism of these cells (CD4⁺, CD8⁺, Th17, and Tregs) under normal conditions and during sepsis-induced immunosuppression. The article ends with the therapeutic targeting of T cell immunometabolism (both conventional T cells and Tregs) during sepsis as a future immunomodulatory approach for its management.

The CD40 rs1883832 Polymorphism Affects Sepsis Susceptibility and sCD40L Levels

Sepsis is a severe and progressive disease characterized by systemic inflammatory response syndrome (SIRS). CD40 serves as a vital link between immune response and inflammation. This study was designed to investigate the potential association between a functional single-nucleotide polymorphism (SNP) of CD40 (rs1883832) and susceptibility to sepsis. We first performed a case-control study to explore the relationship between the CD40 rs1883832 polymorphism and sepsis. CD40 mRNA expression and protein expression were determined by real-time PCR and western blotting, respectively, in peripheral blood mononuclear cells (PBMCs) from sepsis patients and healthy controls. The plasma sCD40L levels in the two groups were measured by ELISA. The results showed that the frequencies of the TT genotype and the CD40 rs1883832 T allele were significantly higher in sepsis patients than in healthy controls. Plasma sCD40L levels were also significantly increased in sepsis patients. In addition, TT genotype carriers among sepsis patients displayed the highest CD40 expression at both the mRNA and protein levels, accompanied by the highest plasma sCD40L concentrations. In conclusion, the CD40 rs1883832 T allele acts as a risk factor for increased susceptibility to sepsis and may be involved in the process of sepsis through regulation of CD40 expression and plasma sCD40L levels.

Persistent accumulation of circulating monocytic myeloid-derived suppressor cells contributes to post-infectious immunosuppression in renal transplant recipients with bacterial infection: A pilot study

INTRODUCTION

Post-infectious immunosuppression is disadvantageous to patients' long-term outcomes, especially in transplant recipients receiving large doses of immunosuppressants. A growing body of evidence indicates the immunoregulatory ability of myeloid-derived suppressor cells (MDSCs). We herein investigate the characteristics of monocytic-MDSCs (M-MDSCs) in a cohort of renal transplant recipients with/without infection to clarify the potential involvement in post-infectious immunosuppression.

METHODS

The study prospectively included 28 adult recipients who underwent allogeneic ABO-compatible renal transplant. Blood samples were drawn at day 0, 7, 14, 28, 60 and 90 postoperation. The incidence of infection and treatment strategies were recorded. The frequency and absolute number of peripheral blood M-MDSCs as well as other immune cells were determined by flow cytometry. Immnosuppressive functions of M-MDSCs were analyzed by inhibition of T cells proliferation. mRNA levels of immunosuppressive molecules in sorted M-MDSCs were also examined.

RESULTS

7 recipients were diagnosed with bacterial (n = 5) or viral (n = 2) infection and 3/5 of bacterial-infected recipients suffered from secondary infection during further follow-up. In the non-infected group, M-MDSCs numbers increased transiently during the early postoperative period, however, bacterial but not viral infection led to significant and persistent accumulation of M-MDSCs that remained at high levels after anti-infective treatments. M-MDSCs from infected recipients demonstrated potent ability to suppress T cells proliferation in vitro and negatively correlated with lymphocytes in vivo, yet not in the non-infected group. Inducible nitric oxide synthase (iNOS) mRNA levels were higher in sorted M-MDSCs when compared with monocytes, and suppressive activity was reversed by addition of a NOS inhibitor.

CONCLUSIONS

Circulating M-MDSCs underwent significant and persistent increases after bacterial infection in renal transplant recipients, contributing to post-infectious immunodeficiency. Therefore, special attention should be given to M-MDSCs during the monitoring of immune status and infection management.

Effects of Bioreactor-Oxygenation During Extracorporeal Granulocytes Treatment in Septic Patients

A granulocyte bioreactor for the extracorporeal treatment was developed to enhance the immune cell function in patients with severe sepsis. The influence of oxygenation on the used cells was tested in a prospective clinical study. Ten patients with severe sepsis were treated twice with the granulocyte bioreactor. The used cells were screened for functionality; values of blood gases, glucose and lactate were obtained from the recirculating bioreactor circuit. Five patients were treated with an oxygenator setup (Oxy group), five without oxygenator (Non-Oxy group). The overall in-hospital mortality was 50%. Significantly lower values of oxygen saturation, partial oxygen pressure, lactate, oxyburst and phagocytosis were seen in the Non-Oxy group compared with the Oxy group in the bioreactor circuit. Further studies with this approach are encouraged and should focus on the influence of oxygenation on production of reactive oxygen species and cytokines of used cells.

The Effects of Ex Vivo Administration of Granulocyte-Macrophage Colony-Stimulating Factor and Endotoxin on Cytokine Release of Whole Blood Are Determined by Priming Conditions

Background

Lipopolysaccharide- (LPS-) induced tumour necrosis factor alpha (TNFα) secretion in critically ill patients can be considered as a measure of immune responsiveness. It can be enhanced by granulocyte-macrophage colony stimulating factor (GM-CSF). We investigated the effect of GM-CSF on ex vivo stimulated cytokine production using various preincubation regimens in healthy donors and patients with sepsis.

Results

The maxima for the stimuli occurred 3 hours after stimulation. In donors, there was an increase (p < 0.001) of LPS-induced TNFα levels following incubation with GM-CSF. The simultaneous incubation with GM-CSF and LPS caused an inhibition of TNFα production (p < 0.001). Postincubation with GM-CSF did not yield any difference. In patients, preincubation with GM-CSF yielded an enhanced ex vivo TNFα-response when TNFα levels were low. Patients with increased TNFα concentrations did not show a GM-CSF stimulation effect. The GM-CSF preincubation yielded an increase of IL-8 production in patients and donors.

Conclusions

This study demonstrates the immune-modulating properties of GM-CSF depending on the absence or presence of LPS or systemic TNFα. The timing of GM-CSF administration may be relevant for the modulation of the immune system in sepsis. The lack of stimulation in patients with high TNFα may represent endotoxin tolerance.

Metabolic Inflammatory Complex in Sepsis: Septic Cachexia as a Novel Potential Therapeutic Target

Despite several decades of focused investigation, sepsis remains a major cause of mortality in critically ill patients. Advancements in intensive care have enabled more patients to survive the acute phase of sepsis than previously, but a growing number of them progress to chronic critical illness. The failure of previous randomized clinical trials of anti-inflammatory agents to show any pro-survival benefit in septic patients underscores current thought that simple anti-inflammatory strategies are ineffective because the inhibitory effect of anti-inflammatory agents undermines the immune response to pathogens. New strategies with the dual capability of ameliorating inflammation in organs while stimulating antimicrobial activity are eagerly awaited. On the other hand, the metabolic alterations associated with systemic inflammatory response, including mitochondrial dysfunction and metabolic shift, are closely linked through a nexus of signaling pathways and signaling molecules. Preventing these metabolic derangements may be an alternative way to control excessive inflammation, an intriguing possibility that has not been fully explored. New insight into the molecular pathogenesis of sepsis and sepsis-associated chronic critical illness has led to the recognition of septic cachexia, a life-threatening form of metabolic inflammatory complex associated with multiple organ dysfunction. The potential for septic cachexia to serve as a novel target disease state to improve the clinical outcome of septic patients is discussed in this review.