Expression of NK cell and monocyte receptors in critically ill patients--potential biomarkers of sepsis

The Role of the Intravenous IgA and IgM-Enriched Immunoglobulin Preparation in the Treatment of Sepsis and Septic Shock

Polyclonal Intravenous Immunoglobulins (IvIg) are often administered to critically ill patients more as an act of faith than on the basis of relevant clinical studies. This particularly applies to the treatment of sepsis and septic shock because the current guidelines recommend against their use despite many investigations that have demonstrated their beneficial effects in different subsets of patients. The biology, mechanisms of action, and clinical experience related to the administration of IvIg are reviewed, which aim to give a more in-depth understanding of their properties in order to clarify their possible indications in sepsis and septic shock patients.

Predictive value of peripheral lymphocyte subsets for the disease progression in patients with sepsis

OBJECTIVE

To investigate the predictive value of peripheral lymphocyte subsets for sepsis progression.

METHODS

Patients with sepsis were divided into the improved group (n = 46) and severe group (n = 39) according to disease progression. Flow cytometric analysis was performed to enumerate absolute counts of peripheral lymphocyte subsets. Logistic regression analyses were conducted to identify clinical factors linked to sepsis progression.

RESULTS

The absolute counts of peripheral lymphocyte subsets were markedly decreased in septic patients compared with healthy controls. After treatment, the absolute counts of lymphocytes, CD3⁺ T cells, and CD8⁺ T cells were restored in the improved group, and reduced in the severe group. Logistic regression analysis indicated that a low CD8⁺ T cells count was a risk factor for sepsis progression. Receiver operating characteristic curve analysis revealed that CD8⁺ T cells count had the greatest ability to predict sepsis progression.

CONCLUSIONS

The absolute counts of CD3⁺ T cells, CD4⁺ T cells, CD8⁺ T cells, B cells, and natural killer cells were significantly higher in the improved group than the severe group. CD8⁺ T cells count was predictive of sepsis progression. Lymphopenia and CD8⁺ T cells depletion were associated with the clinical outcomes of sepsis, suggesting that CD8⁺ T cells have potential as a predictive biomarker and therapeutic target for patients with sepsis.

INTERLEUKIN-6 AND NKG2D AS PROGNOSTIC FACTORS IN IRAQI FEMALES WITH PITUITARY GAND ADENOMA: A LONGITUDINAL STUDY

OBJECTIVE

The aim: To assess the role of circulating IL-6 & NKG2D in the prognosis of pituitary adenoma.

PATIENTS AND METHODS

Materials and methods: Thirty female with new diagnosis of prolactinoma (pituitary gland adenoma) were enrolled in the study. ELISA test was used to evaluate the level of IL6 and NKG2D. ELISA tests were conducted before the initiation of treatment and six months later.

RESULTS

Results: There are significant differences in mean levels of IL-6 and NKG2D, and the anatomical type (tumor size) (-418.7 & 418.9, p<0.001) of anatomical tumor (-373.72 & -373.920, p=0.001). There is a significant difference between the two immunological markers (IL-6 & NKG2D) (-0.305; p<0.001). The IL-6 markers significantly decreased in means on follow up (-197.8; p-value≤0.0001) while the reverse occur in NKG2D, which increased in levels post-treatment compared with baseline measurement. The high expression of IL-6 positively correlated with the risk of macroadenoma (>10 microns) and poor resonse to treatment and vice versa (p<0.024). High expression of NKG2D significantly (p<0.005) correlated with good prognosis and increased chance for tumor response to medicine and shrinkage in size compared with low concentration.

CONCLUSION

Conclusions: The higher the level of IL-6, the larger the size of adenoma (macroadenoma) and the poorer the response to treatment. The higher the level of NKG2D indidcate a better prognosis, therefore, IL-6 and NKG2D correlate negatively in prolactinoma patients.

Cellular Immuno-Profile in Septic Human Host: A Scoping Review

Simple Summary

Septic shock is a life-threatening disease caused by a dysregulated host response to infection, affecting millions of people every year and killing more than 25% directly despite advances in modern medicine. This pathology is characterized by apoptosis-induced depletion of immune cells and immunodepression. Many alterations in the expression of surface markers of neutrophils and monocytes have been described in septic patients. There is no specific treatment but the early identification and diagnosis of the pathology as well as timely treatment can greatly improve patient outcomes. The aim of this study was to inspect the recently published literature to inform the clinician about the most up-to-date techniques for the study of immune cell phenotypes and on the function of leukocytes of extracorporeal and non-blood purification treatments proposed for sepsis were also analyzed. The most important alteration observed in septic neutrophils is the activation of a survival program capable of resisting apoptotic death. As regards adaptive immunity, sepsis-induced apoptosis leads to lymphopenia in patients with septic shock and this process involves all types of T cells (CD4, CD8 and Natural Killer), except for regulatory T cells, favoring immunosuppression. Several promising therapies that target the host’s immune response to sepsis are currently under evaluation.

Abstract

Innate and adaptive immune system cells play a critical role in the host response to sepsis. Sepsis is a life-threatening disease characterized by apoptosis-induced depletion of immune cells and immunodepression, which contribute to morbidity and mortality. Many alterations in the expression of surface markers of neutrophils and monocytes have been described in septic patients. The aim of this study was to inspect the recently published literature to inform the clinician about the most up-to-date techniques for the study of circulating leukocytes. The impact on cell phenotypes and on the function of leukocytes of extracorporeal and non-blood purification treatments proposed for sepsis were also analyzed. We conducted a systematic review using Pubmed/Medline, Ovid/Willey, the Cochrane Library, the Cochrane Controlled Trials Register, and EMBASE, combining key terms related to immunological function in sepsis and selected the most relevant clinical trials and review articles (excluding case reports) published in the last 50 years. The most important alteration in neutrophils during sepsis is that they activate an anti-apoptotic survival program. In septic monocytes, a reduced characteristic expression of HLA-DR is observed, but their role does not seem to be significantly altered in sepsis. As regards adaptive immunity, sepsis leads to lymphopenia and immunosuppression in patients with septic shock; this process involves all types of T cells (CD4, CD8 and Natural Killer), except for regulatory T cells, which retain their function. Several promising therapies that target the host immune response are currently under evaluation. During the worldwide pandemic caused by SARS-CoV-2, it was useful to study the “cytokine storm” to find additional treatments, such as the oXiris^® filter. This therapy can decrease the concentration of inflammatory markers that affect the severity of the disease.

Construction of an HLA Classifier for Early Diagnosis, Prognosis, and Recognition of Immunosuppression in Sepsis by Multiple Transcriptome Datasets

Background: Sepsis is a clinical syndrome, due to a dysregulated inflammatory response to infection. Accumulating evidence shows that human leukocyte antigen (HLA) genes play a key role in the immune responses to sepsis. Nevertheless, the effects of HLA genes in sepsis have still not been comprehensively understood.

Methods: A systematical search was performed in the Gene Expression Omnibus (GEO) and ArrayExpress databases from inception to 10 September 2021. Random forest (RF) and modified Lasso penalized regression were conducted to identify hub genes in multi-transcriptome data, thus we constructed a prediction model, namely the HLA classifier. ArrayExpress databases, as external validation, were utilized to evaluate its diagnostic, prognostic, and predictive performance. Immune cell infiltration score was calculated via CIBERSORTx tools and single-sample gene set enrichment analysis (ssGSEA). Gene set variation analysis (GSVA) and ssGSEA were conducted to determine the pathways that are significantly enriched in different subgroups. Next, we systematically correlated the HLA classifier with immunological characteristics from multiple perspectives, such as immune-related cell infiltration, pivotal molecular pathways, and cytokine expression. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to validate the expression level of HLA genes in clinical samples.

Results: A total of nine datasets comprising 1,251 patients were included. Based on RF and modified Lasso penalized regression in multi-transcriptome datasets, five HLA genes (B2M, HLA-DQA1, HLA-DPA1, TAP1, and TAP2) were identified as hub genes, which were used to construct an HLA classifier. In the discovery cohort, the HLA classifier exhibited superior diagnostic value (AUC = 0.997) and performed better in predicting mortality (AUC = 0.716) than clinical characteristics or endotypes. Encouragingly, similar results were observed in the ArrayExpress databases. In the E-MTAB-7581 dataset, the use of hydrocortisone in the HLA high-risk subgroup (OR: 2.84, 95% CI 1.07–7.57, p = 0.037) was associated with increased risk of mortality, but not in the HLA low-risk subgroup. Additionally, immune infiltration analysis by CIBERSORTx and ssGSEA revealed that B cells, activated dendritic cells, NK cells, T helper cells, and infiltrating lymphocytes (ILs) were significantly richer in HLA low-risk phenotypes, while Tregs and myeloid-derived suppressor cells (MDSCs) were more abundant in HLA high-risk phenotypes. The HLA classifier was significantly negatively correlated with B cells, activated dendritic cells, NK cells, T helper cells, and ILs, yet was significantly positively correlated with Tregs and MDSCs. Subsequently, molecular pathways analysis uncovered that cytokine-cytokine receptor (CCR) interaction, human leukocyte antigen (HLA), and antigen-presenting cell (APC) co-stimulation were significantly enriched in HLA low-risk endotypes, which was significantly negatively correlated with the HLA classifier in multi-transcriptome data. Finally, the expression levels of several cytokines (IL-10, IFNG, TNF) were significantly different between the HLA subgroups, and the ratio of IL-10/TNF was significantly positively correlated with HLA score in multi-transcriptome data. Results of qRT-PCR validated the higher expression level of B2M as well as lower expression level of HLA-DQA1, HLA-DPA1, TAP1, and TAP2 in sepsis samples compared to control sample.

Conclusion: Based on five HLA genes, a diagnostic and prognostic model, namely the HLA classifier, was established, which is closely correlated with responses to hydrocortisone and immunosuppression status and might facilitate personalized counseling for specific therapy.

Advances in Immune Monitoring Approaches for Sepsis-Induced Immunosuppression

Sepsis represents a life-threatening organ dysfunction due to an aberrant host response. Of note is that majority of patients have experienced a severe immune depression during and after sepsis, which is significantly correlated with the occurrence of nosocomial infection and higher risk of in-hospital death. Nevertheless, the clinical sign of sepsis-induced immune paralysis remains highly indetectable and ambiguous. Given that, specific yet robust biomarkers for monitoring the immune functional status of septic patients are of prominent significance in clinical practice. In turn, the stratification of a subgroup of septic patients with an immunosuppressive state will greatly contribute to the implementation of personalized adjuvant immunotherapy. In this review, we comprehensively summarize the mechanism of sepsis-associated immunosuppression at the cellular level and highlight the recent advances in immune monitoring approaches targeting the functional status of both innate and adaptive immune responses.

Characterization of immune-related genes andimmune infiltration features for early diagnosis, prognosis and recognition of immunosuppression in sepsis

Among the body systems, the immune system plays a fundamental role in the pathophysiology of sepsis. The effects of immunogenomic and immune cell infiltration in sepsis were still not been systematically understood. Based on modified Lasso penalized regression and RF, 8 DEIRGs (ADM, CX3CR1, DEFA4, HLA-DPA1, MAPK14, ORM1, RETN, and SLPI) were combined to construct an IRG classifier. In the discovery cohort, IRG classifier exhibited superior diagnostic efficacy and performed better in predicting mortality than clinical characteristics or MARS/SRS endotypes. Encouragingly, similar results were observed in the ArrayExpress databases. The use of hydrocortisone in IRG high-risk subgroup was associated with increased risk of mortality. In IRG low-risk phenotypes, NK cells, T helper cells, and infiltrating lymphocyte (IL) are significantly richer, while T cells regulatory (Tregs) and myeloid-derived suppressor cells (MDSC) are more abundant in IRG high-risk phenotypes. IRG score were significantly negatively correlated with Cytokine cytokine receptor interaction (CCR) and human leukocyte antigen (HLA). Between the IRG subgroups, the expression levels of several cytokines (IL-10, IFNG, TNF) were significantly different, and IRG score was significantly positively correlated with ratio of IL-10/TNF. Results of qRT-PCR validated that higher expression level of ADM, DEFA4, MAPK14, ORM1, RETN, and SLPI as well as lower expression level of CX3CR1 and HLA-DPA1 in sepsis samples compared to control sample. A diagnostic and prognostic model, namely IRG classifier, was established based on 8 IRGs that is closely correlated with responses to hydrocortisone and immunosuppression status and might facilitate personalized counseling for specific therapy.

Immune Intervention in Sepsis

Sepsis is a host immune disorder induced by infection. It can lead to multiple organ dysfunction syndrome (MODS), which has high morbidity and mortality. There has been great progress in the clinical diagnosis and treatment of sepsis, such as improvements in pathogen detection technology, innovations regarding anti-infection drugs, and the development of organ function support. Abnormal immune responses triggered by pathogens, ranging from excessive inflammation to immunosuppression, are recognized to be an important cause of the high mortality rate. However, no drugs have been approved specifically for treating sepsis. Here, we review the recent research progress on immune responses in sepsis to provide a theoretical basis for the treatment of sepsis. Constructing and optimizing a dynamic immune system treatment regimen based on anti-infection treatment, fluid replacement, organ function support, and timely use of immunomodulatory interventions may improve the prognosis of sepsis patients.

Sepsis-Pathophysiology and Therapeutic Concepts

Sepsis is a life-threatening condition and a global disease burden. Today, the heterogeneous syndrome is defined as severe organ dysfunction caused by a dysregulated host response to infection, with renewed emphasis on immune pathophysiology. Despite all efforts of experimental and clinical research during the last three decades, the ability to positively influence course and outcome of the syndrome remains limited. Evidence-based therapy still consists of basic causal and supportive measures, while adjuvant interventions such as blood purification or targeted immunotherapy largely remain without proof of effectiveness so far. With this review, we aim to provide an overview of sepsis immune pathophysiology, to update the choice of therapeutic approaches targeting different immunological mechanisms in the course of sepsis and septic shock, and to call for a paradigm shift from the pathogen to the host response as a potentially more promising angle.

A Minimal Parameter Set Facilitating Early Decision-making in the Diagnosis of Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune dysregulation syndrome characterized by uncontrolled immune cell activation. Timely diagnosis is important, since early treatment can improve survival rates. However, completing all assessments needed to reach ≥5 positive criteria out of the 8 HLH-2004 criteria can be time consuming and may delay timely initiation of treatment. Hence, we applied a data-driven approach to identify a minimal parameter set for early decision-making towards the initiation of HLH-specific treatment. We retrospectively evaluated 165 patients from five Dutch tertiary hospitals with suspected HLH. Sixteen pHLH (median age 0.5 years) and 70 sHLH patients (median age 8.7 years) were identified using the HLH-2004 criteria. Clustering analysis and multi-receiver operator characteristics were used to identify parameters distinctive of HLH. The presence of either increased ferritin, cytopenia in ≥2 lineages, or splenomegaly distinguished HLH from non-HLH cases with a negative predictive value of 100%. A minimal parameter set consisting of 2 major criteria (phagocytosis and splenomegaly) and 3 minor criteria (cytopenia, increased ferritin, and increased triglycerides/low fibrinogen) predicted HLH with 95% (88-99) sensitivity and 94% (86-98) specificity. This finding was replicated in an independent retrospective validation cohort of 109 US patients (n = 109). By dividing a subset of the HLH-2004 criteria into major and minor criteria, this strategy uses the evaluation of less than 5 criteria to quickly identify patients with HLH. When confirmed in a prospective setting, this approach could be of value for timely diagnosis and treatment of HLH.

Immune Cell Number, Phenotype, and Function in the Elderly with Sepsis

Sepsis is a form of life-threatening organ dysfunction caused by dysregulated host responses to an infection that can be partly attributed to immune dysfunction. Although sepsis affects patients of all ages, elderly individuals display increased susceptibility and mortality. This is partly due to immunosenescence, a decline in normal immune system function associated with physiological aging that affects almost all cell types in the innate and adaptive immune systems. In elderly patients with sepsis, these alterations in immune cells such as endothelial cells, neutrophils, monocytes, macrophages, natural killer cells, dendritic cells, T lymphocytes, and B lymphocytes, are largely responsible for their poor prognosis and increased mortality. Here, we review recent studies investigating the events affecting both innate and adaptive immune cells in elderly mice and patients with sepsis, including alterations in their number, phenotype, and function, to shed light on possible new therapeutic strategies.

Increased percentage of PD-L1+ natural killer cells predicts poor prognosis in sepsis patients: a prospective observational cohort study

Background

Natural killer (NK) cells play a major role in immune tolerance after sepsis, and the programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) system mediates evasion of host immunity. The correlation between PD-L1 levels in NK cells and the prognosis of patients with sepsis, however, has not been elucidated. Thus, it was hypothesized that PD-L1 in NK cells could be a novel biomarker of the mortality for sepsis patients.

Methods

A prospective, observational, cohort study in a general intensive care unit had earlier enrolled patients according to the sepsis-3 criteria, and peripheral blood samples were collected within 24 h post-recruitment. The expression of four co-signaling molecules (PD-1, CD28, PD-L1, and CD86) in NK cells was assayed, and the sequential organ failure assessment (SOFA) scores were recorded on day 1. Patients were followed up until 28 days. Multivariate regression analysis assessed the independent risk factors for 28-day mortality. The association between biomarkers and 28-day mortality was assessed by Cox regression survival analysis. The accuracy of biomarkers for mortality was determined by the area under the receiver operating characteristic (ROC) curve (AUC) analysis.

Results

A total of 269 patients were recruited, and 114 patients were finally included for final analysis. Of these, 30 (26.3%) patients died during 28 days. The percentage of PD-L1⁺ NK cells (OR 1.022; 95% CI 1.002–1.043) and SOFA scores (OR 1.247; 95% CI 1.092–1.424) were independent risk factors for 28-day mortality. The AUC of the percentage of PD-L1⁺ NK cells, SOFA scores, and their combination model were 0.655 (0.559–0.742), 0.727 (0.635–0.807) and 0.808 (0.723–0.876), respectively. The combination model was the indicator with the best AUC to predict mortality in 28 days (all p < 0.05). Patients with the percentage of PD-L1⁺ NK cells above the cutoff point 5.58% (hazard ratio (HR) 10.128 (1.372–74.772), p = 0.001), and the combination model prediction possibility above 0.1241 (HR 13.730 (3.241–58.158), p < 0.001) were the indexes that had greater discriminative capacity to predict 28 days mortality.

Conclusions

The percentage of PD-L1⁺ NK cells at admission serves as a novel prognostic biomarker for predicting mortality and contributes to improve the predictive capacity of SOFA score in patients with sepsis.

Best-practice IgM- and IgA-enriched immunoglobulin use in patients with sepsis

Background

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Despite treatment being in line with current guidelines, mortality remains high in those with septic shock. Intravenous immunoglobulins represent a promising therapy to modulate both the pro- and anti-inflammatory processes and can contribute to the elimination of pathogens. In this context, there is evidence of the benefits of immunoglobulin M (IgM)- and immunoglobulin A (IgA)-enriched immunoglobulin therapy for sepsis. This manuscript aims to summarize current relevant data to provide expert opinions on best practice for the use of an IgM- and IgA-enriched immunoglobulin (Pentaglobin) in adult patients with sepsis.

Main text

Sepsis patients with hyperinflammation and patients with immunosuppression may benefit most from treatment with IgM- and IgA-enriched immunoglobulin (Pentaglobin). Patients with hyperinflammation present with phenotypes that manifest throughout the body, whilst the clinical characteristics of immunosuppression are less clear. Potential biomarkers for hyperinflammation include elevated procalcitonin, interleukin-6, endotoxin activity and C-reactive protein, although thresholds for these are not well-defined. Convenient biomarkers for identifying patients in a stage of immune-paralysis are still matter of debate, though human leukocyte antigen–antigen D related expression on monocytes, lymphocyte count and viral reactivation have been proposed. The timing of treatment is potentially more critical for treatment efficacy in patients with hyperinflammation compared with patients who are in an immunosuppressed stage. Due to the lack of evidence, definitive dosage recommendations for either population cannot be made, though we suggest that patients with hyperinflammation should receive an initial bolus at a rate of up to 0.6 mL (30 mg)/kg/h for 6 h followed by a continuous maintenance rate of 0.2 mL (10 mg)/kg/hour for ≥ 72 h (total dose ≥ 0.9 g/kg). For immunosuppressed patients, dosage is more conservative (0.2 mL [10 mg]/kg/h) for ≥ 72 h, without an initial bolus (total dose ≥ 0.72 g/kg).

Conclusions

Two distinct populations that may benefit most from Pentaglobin therapy are described in this review. However, further clinical evidence is required to strengthen support for the recommendations given here regarding timing, duration and dosage of treatment.

Use of Intravenous Immunoglobulins in Sepsis Therapy-A Clinical View

Sepsis is a life-threatening organ dysfunction, defined by a dysregulated host immune response to infection. During sepsis, the finely tuned system of immunity, inflammation and anti-inflammation is disturbed in a variety of ways. Both pro-inflammatory and anti-inflammatory pathways are upregulated, activation of the coagulation cascade and complement and sepsis-induced lymphopenia occur. Due to the manifold interactions in this network, the use of IgM-enriched intravenous immunoglobulins seems to be a promising therapeutic approach. Unfortunately, there is still a lack of evidence-based data to answer the important questions of appropriate patient populations, optimal timing and dosage of intravenous immunoglobulins. With this review, we aim to provide an overview of the role of immunoglobulins, with emphasis on IgM-enriched formulations, in the therapy of adult patients with sepsis and septic shock.

Effect of immune-enhancing enteral nutrition formula enriched with plant-derived n-3 fatty acids on natural killer cell activity in rehabilitation patients

BACKGROUND/OBJECTIVES

Enteral nutrition formulas with immune-enhancing nutrients, such as n-3 fatty acids, may manage patients' nutritional status and pathophysiological processes. The aim of our study was to investigate natural killer (NK) cell activity alterations and related cytokine changes resulting from feeding with soybean oil-containing enteral nutrition formula (control group) and plant-derived n-3 fatty acid-enriched enteral nutrition formula.

SUBJECTS/METHODS

Subjects participated for 14 consecutive days and consumed enteral formula containing canola and flaxseed oil (n3EN, test group) in nonsurgical patients hospitalized for rehabilitation. Blood samples were collected on the first day and 14 days after the consumption of each formula daily, and anthropometric parameters were collected. Hematology and biochemical values were analyzed, and NK cell activities and serum cytokine concentration were measured. A total of sixty subjects were included in the analysis, excluding dropouts.

RESULTS

No significant differences were found in biochemical parameters. The n3EN group's NK cell activities at effector:tumor cell ratios of 10:1, 5:1, 2.5:1 and 0.625:1 were significantly higher than those of the control group after two weeks (P < 0.05). However, there were no statistically significant differences in serum cytokine interleukin (IL)-12, interferon-γ, IL-1β, IL-6 and tumor necrosis factor-α values between the two groups.

CONCLUSIONS

In conclusion, this study elucidates the beneficial effects of plant-derived n-3 fatty acid supplementation in enteral formula on NK cell activity.

A shift toward inhibitory receptors and impaired effector functions on NK cells contribute to immunosuppression during sepsis

Most information about the immune status of NK cells during sepsis has been obtained from animal models, athough data from clinical septic patients is limited. In this study, we aimed to decipher NK cell immunity of septic patients in a more comprehensive way. We found that cytotoxicity of NK cells dramatically decreased during sepsis, likely due to the reduction of cluster of differentiation (CD)3^- CD56⁺ NK cells and a shift of phenotypic changes of NK group 2 member (NKG2) receptors, natural cytotoxicity receptors (NCRs) and killer immunoglobulin-like receptors (KIRs) toward inhibitory receptors demonstrated by CD3^- CD56⁺ NK cells in septic patients. Expression of the activation indicator CD69 and cytotoxic associated marker CD107a on CD3^- CD56⁺ NK cells in healthy adults was significantly lower than that of septic patients. Although perforin and granzyme B on CD3^- CD56⁺ NK cells from all groups exhibited equivalently high levels, CD3^- CD56⁺ NK cells from septic patients exhibited a much lower fold increase of CD69 and CD107a compared with healthy adults after coculturing with K562 cells in vitro. Cytokine production of IFN-γ and TNF-α on CD3^- CD56⁺ NK cells in septic patients was also impaired after stimulation by PMA and ionomycin. We found that the proportion of NK cells in lymphocytes was negatively associated with patient 28 d death in septic patients. Phenotypic changes of a shift toward inhibitory receptors and impairment of effector functions of NK cells might be an important mechanism of immunosuppression during sepsis.

Endoscopic retrograde cholangiopancreatography-induced and non-endoscopic retrograde cholangiopancreatography-induced acute pancreatitis: Two distinct clinical and immunological entities?

Acute pancreatitis (AP) is common gastrointestinal disease of varied aetiology. The most common cause of AP is gallstones, followed by alcohol abuse as an independent risk factor. With the increased need for invasive techniques to treat pancreatic and bile duct pathologies such as endoscopic retrograde cholangiopancreatography (ERCP), AP has emerged as the most frequent complication. While severe AP following ERCP is rare (0.5%), if it does develop it has a greater severity index compared to non-ERCP AP. Development of a mild form of AP after ERCP is not considered a clinically relevant condition. Differences in the clinical presentation and prognosis of the mild and severe forms have been found between non-ERCP AP and post-endoscopic pancreatitis (PEP). It has been proposed that AP and PEP may also have different immunological responses to the initial injury. In this review, we summarise the literature on clinical and inflammatory processes in PEP vs non-ERCP AP.

Hyporesponsiveness of natural killer cells and impaired inflammatory responses in critically ill patients

Background

To investigate natural killer (NK) cell activity, circulating cytokine level and peripheral blood mononuclear cell (PBMC) cytokine production status in critically ill patients.

Methods

Blood samples were collected <24 h after admission from 24 intensive care unit (ICU) patients and 24 age-, sex-, and body mass index (BMI)-matched healthy controls. Serum cytokine concentrations and cytokine production by PBMCs and lipopolysaccharide (LPS)-stimulated PBMCs were measured.

Results

The ICU group showed lower NK cell activity than the controls under all conditions and an absence of interferon (IFN)-γ. After adjusting for triglycerides, LDL- and HDL-cholesterol, and glucose, the ICU group exhibited lower serum levels of albumin and interleukin (IL)-12 and higher leukocyte counts and hs-CRP and IL-6 levels than the controls. Non-stimulated PBMCs from ICU patients secreted significantly greater amounts of IL-6 and IL-1β than the controls; however, the production of IL-6, TNF-α and IL-1β in response to LPS stimulation was significantly lower in the ICU group.

Conclusions

Significant reductions in NK cell activity and serum IL-12 level, an absence of serum IFN-γ, and decreased cytokine production from LPS-stimulated PBMCs indicate the hyporesponsiveness of NK cells and an impaired early phase inflammatory response in critically ill patients (ClinicalTrials.gov NCT02565589:). Retrospectively registered; October 1, 2015.

Toll-like receptor 4 deficiency increases resistance in sepsis-induced immune dysfunction

Sepsis constitutes a serious life-threatening syndrome associated with complications of deregulated inflammatory response against endotoxin/lipopolysaccharide (LPS)-mediated severe infection. Toll-like receptor 4 (TLR4) plays a critical role in the activation of innate immunity through recognition of LPS. However, the impact of TLR4 signaling on the development of sepsis-induced immune dysfunction remains unclear. The aim of this study was to investigate the effect of TLR4 on regulatory T cells (Tregs) and its potential mechanism. To simulate sepsis, male C57BL/6 (wild-type) and C57BL/10ScNJNJU (TLR4^-/-) mice were subjected to cecal ligation and puncture (CLP). After 24h, pro- and anti-inflammatory cytokine secretion, neutrophil and macrophage lung and liver infiltration were assessed to evaluate the sepsis-induced inflammatory response. The quantity and apoptotic rate of Tregs were measured. The expression of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and forkhead/winged helix transcription factor p3 (Foxp3) were analyzed. Cytokine (i.e., TNF-α, IL-2, IL-10, and IL-4) secretion by Tregs in the cell suspensions and the suppressive activity on CD4⁺CD25^- T cell proliferation were also determined in vitro. At 24h after the CLP procedure, the wild-type mice exhibited increased Treg levels and expression, and secreted inflammatory factors in the serum were markedly overproduced. However, the TLR4^-/- mice attenuated the increased Treg expression and inflammatory factor overproduction. These results indicate that in a model of post-septic mice, TLR4 deficiency improves immune paralysis by attenuating Treg activity and restoring a pro-inflammatory cytokine balance. Thus, modulation of the TLR4 activity may be useful in preventing immune dysfunction in sepsis.

Monocyte and lymphocyte surface molecules in severe sepsis and non-septic critically ill Patients

The aim of the present study was to investigate whether expression of monocyte and lymphocyte surface molecules differs between patients with severe sepsis and non-septic patients treated in the intensive care unit (ICU). The expression of monocyte CD14, CD40, CD80 and HLA-DR, and lymphocyte CD69 were analyzed using quantitative flow cytometry on three consecutive days in 27 patients with severe sepsis and in 15 non-septic patients. Receiver operating characteristic analyses were performed and each corresponding area under the curve (AUC) was determined. The results showed that the expression levels of CD40 on monocytes and CD69 on CD4+ T cells and on natural killer (NK) cells were highest in patients with severe sepsis (p < 0.05). Monocyte CD40 and NK cell CD69 expression levels were higher in patients with severe sepsis and positive blood culture compared with those with negative blood culture (p < 0.05). The highest values of AUC for severe sepsis detection were 0.836 for CD40, 0.872 for CD69 on NK cells, and 0.795 for CD69 on CD4+ T cells. These findings suggest that monocyte CD40 and CD69 on NK cells and CD4+ T cells could prove useful for new approaches in the identification of severe sepsis in the ICU.

Effect of Immune-Enhancing Enteral Nutrition Enriched with or without Beta-Glucan on Immunomodulation in Critically Ill Patients

We investigated whether high-protein enteral nutrition with immune-modulating nutrients (IMHP) enriched with β-glucan stimulates immune function in critically ill patients. In a randomized double-blind placebo-controlled study, 30 patients consumed one of three types of enteral nutrition: a control or IMHP with and without β-glucan. The IMHP with β-glucan group showed increases in natural killer (NK) cell activities relative to the baseline, and greater increases were observed in NK cell activities relative to the control group after adjusting for age and gender. The IMHP groups with and without β-glucan had greater increases in serum prealbumin and decreases in high-sensitivity C-reactive protein (hs-CRP) than the control group. The control group had a greater decrease in peripheral blood mononuclear cell (PBMC) interleukin (IL)-12 production than the IMHP with and without β-glucan groups. In all patients, the change (Δ) in hs-CRP was correlated with Δ prealbumin and Δ PBMC IL-12, which were correlated with ΔNK cell activity and Δ prealbumin. This study showed beneficial effects of a combination treatment of β-glucan and IMHP on NK cell activity. Additionally, strong correlations among changes in NK cell activity, PBMC IL-12, and hs-CRP suggested that β-glucan could be an attractive candidate for stimulating protective immunity without enhanced inflammation (ClinicalTrials.gov: NCT02569203).

Defining immunological dysfunction in sepsis: A requisite tool for precision medicine

OBJECTIVES

Immunological dysregulation is now recognised as a major pathogenic event in sepsis. Stimulation of immune response and immuno-modulation are emerging approaches for the treatment of this disease. Defining the underlying immunological alterations in sepsis is important for the design of future therapies with immuno-modulatory drugs.

METHODS

Clinical studies evaluating the immunological response in adult patients with Sepsis and published in PubMed were reviewed to identify features of immunological dysfunction. For this study we used key words related with innate and adaptive immunity.

RESULTS

Ten major features of immunological dysfunction (FID) were identified involving quantitative and qualitative alterations of [antigen presentation](FID1), [T and B lymphocytes] (FID2), [natural killer cells] (FID3), [relative increase in T regulatory cells] (FID4), [increased expression of PD-1 and PD-ligand1](FID5), [low levels of immunoglobulins](FID6), [low circulating counts of neutrophils and/or increased immature forms in non survivors](FID7), [hyper-cytokinemia] (FID8), [complement consumption] (FID9), [defective bacterial killing by neutrophil extracellular traps](FID10).

CONCLUSIONS

This review article identified ten major features associated with immunosuppression and immunological dysregulation in sepsis. Assessment of these features could help in utilizing precision medicine for the treatment of sepsis with immuno-modulatory drugs.

IMMUNE CELL PHENOTYPE AND FUNCTION IN SEPSIS

Cells of the innate and adaptive immune systems play a critical role in the host response to sepsis. Moreover, their accessibility for sampling and their capacity to respond dynamically to an acute threat increases the possibility that leukocytes might serve as a measure of a systemic state of altered responsiveness in sepsis.The working group of the 14th Acute Dialysis Quality Initiative (ADQI) conference sought to obtain consensus on the characteristic functional and phenotypic changes in cells of the innate and adaptive immune system in the setting of sepsis. Techniques for the study of circulating leukocytes were also reviewed and the impact on cellular phenotypes and leukocyte function of nonextracorporeal treatments and extracorporeal blood purification therapies proposed for sepsis was analyzed.A large number of alterations in the expression of distinct neutrophil and monocyte surface markers have been reported in septic patients. The most consistent alteration seen in septic neutrophils is their activation of a survival program that resists apoptotic death. Reduced expression of HLA-DR is a characteristic finding on septic monocytes, but monocyte antimicrobial function does not appear to be significantly altered in sepsis. Regarding adaptive immunity, sepsis-induced apoptosis leads to lymphopenia in patients with septic shock and it involves all types of T cells (CD4, CD8, and Natural Killer) except T regulatory cells, thus favoring immunosuppression. Finally, numerous promising therapies targeting the host immune response to sepsis are under investigation. These potential treatments can have an effect on the number of immune cells, the proportion of cell subtypes, and the cell function.

Recent developments in severe sepsis research: from bench to bedside and back

Severe sepsis remains a worldwide threat, not only in industrialized countries, due to their aging population, but also in developing countries where there still are numerous cases of neonatal and puerperal sepsis. Tools for early diagnosis, a prerequisite for rapid and appropriate antibiotic therapy, are still required. In this review, we highlight some recent developments in our understanding of the associated systemic inflammatory response that help deciphering pathophysiology (e.g., epigenetic, miRNA, regulatory loops, compartmentalization, apoptosis and synergy) and discuss some of the consequences of sepsis (e.g., immune status, neurological and muscular alterations). We also emphasize the challenge to better define animal models and discuss past failures in clinical investigations in order to define new efficient therapies.