Immunological characterization of compensatory anti-inflammatory response syndrome in patients with severe sepsis: a longitudinal study*

The correlation between serum calcium levels and prognosis in patients with severe acute osteomyelitis

Objective

To explore the relationship between serum calcium levels and the prognosis of severe acute osteomyelitis, and to assess the effectiveness of calcium levels in prognostic evaluation.

Methods

Relevant patient records of individuals diagnosed with severe acute osteomyelitis were obtained for this retrospective study from the Medical Information Mart for Intensive Care (MIMIC-IV). The study aimed to assess the impact of different indicators on prognosis by utilizing COX regression analysis. To enhance prognostic prediction for critically ill patients, a nomogram was developed. The discriminatory capacity of the nomogram was evaluated using the Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve, in addition to the calibration curve.

Result

The study analyzed a total of 1,133 cases of severe acute osteomyelitis, divided into the survivor group (1,025 cases) and the non-survivor group (108 cases). Significant differences were observed between the two groups in terms of age, hypertension, sepsis, renal injury, and various laboratory indicators, including WBC, PLT, Ca2+, CRP, hemoglobin, albumin, and creatinine (P<0.05). However, no significant differences were found in race, gender, marital status, detection of wound microbiota, blood sugar, lactate, and ALP levels. A multivariate COX proportional hazards model was constructed using age, hypertension, sepsis, Ca2+, creatinine, albumin, and hemoglobin as variables. The results revealed that hypertension and sepsis had a significant impact on survival time (HR=0.514, 95% CI 0.339-0.779, P=0.002; HR=1.696, 95% CI 1.056-2.723, P=0.029). Age, hemoglobin, Ca2+, albumin, and creatinine also showed significant effects on survival time (P<0.05). However, no statistically significant impact on survival time was observed for the other variables (P>0.05). To predict the survival time, a nomogram was developed using the aforementioned indicators and achieved an AUC of 0.841. The accuracy of the nomogram was further confirmed by the ROC curve and calibration curve.

Conclusion

According to the findings, this study establishes that a reduction in serum calcium levels serves as a distinct and standalone predictor of mortality among individuals diagnosed with severe acute osteomyelitis during their stay in the Intensive Care Unit (ICU) within a span of two years.

Association between intracellular adenosine triphosphate content of CD4+ T lymphocytes and mortality in sepsis patients: A prospective observational study

OBJECTIVE

This study aimed to link intracellular adenosine triphosphate content in CD4+ T lymphocytes (CD4+ iATP) with sepsis patient mortality, seeking a new predictive biomarker for outcomes and enhanced management.

METHODS

61 sepsis patients admitted to the Intensive Care Unit between October 2021 and November 2022 were enrolled. iATP levels were gauged using whole blood CD4+ T cells stimulated with mitogen PHA-L. Based on CD4+ iATP levels (<132.24 and ≥132.24 ng/mL), patients were categorized into two groups. The primary endpoint was all-cause mortality. To identify factors associated with mortality, both univariate and multivariate Cox proportional hazard analyses were conducted.

RESULTS

Of the patients, 40 had high CD4+ iATP levels (≥132.24 ng/mL) and 21 had low levels (<132.24 ng/mL). In a 28-day follow-up, 21 (34.4%) patients perished. Adjusting for confounders like SOFA score, APACHE II score, lactic acid, and albumin, those with low CD4+ iATP had three- to fivefold higher mortality risk compared to high CD4+ iATP patients (61.9% vs. 20.0%; hazard ratio [95% confidence interval], Model 1: 4.515 [1.276-15.974], p = .019, Model 2: 3.512 [1.197-10.306], p = .022). CD4+ iATP correlated positively with white blood cell and neutrophil counts but not with lymphocytes, CD3, and CD4 counts.

CONCLUSIONS

Low CD4+ iATP levels were associated with a higher risk of mortality in sepsis patients. Measurement of CD4+ iATP may serve as a useful tool for identifying patients at a higher risk of mortality and could potentially provide a basis for clinical treatment. Further research is warranted to fully elucidate the underlying mechanisms of this association.

Diagnostic and prognostic significance of apelin-13, APJ for sepsis in the emergency department: A prospective study

Objectives

This study aimed to assess the diagnostic, risk stratification, and prognostic capabilities of apelin-13 and APJ in comparison to procalcitonin (PCT) for septic patients presenting to the emergency department (ED).

Methods

Two hundred and thirty-eight patients meeting the Third International Consensus Definition (Sepsis-3) criteria were enrolled from Beijing Chaoyang Hospital's ED, along with a control group of forty healthy individuals. Patients were categorized into two groups based on disease severity: those with sepsis or septic shock. Plasma levels of apelin-13, CD4+ Th cells, and PCT were measured. The expression levels of plasma APJ mRNA were quantified using real-time fluorescence quantitative PCR (RT-qPCR) methodology. The Sequential Organ Failure Assessment (SOFA) score was determined at the time of enrollment. The prognostic values of apelin-13 and APJ was evaluated in comparison to that of PCT and the SOFA score. All patients were followed up for a duration of 28 days.

Results

The plasma concentrations of apelin-13 and APJ exhibited a positive correlation with the severity of sepsis, while the number of CD4+ T cells decreased in septic patients. The areas under the receiver operating characteristic (AUC) curves for apelin-13 and APJ in the diagnosis and prediction of 28-day mortality were greater than that of PCT. In non-survivors at the 28-day follow-up, the plasma levels of apelin-13 and APJ were significantly higher compared to survivors. Furthermore, apelin-13 levels were notably higher in cases of sepsis-induced cardiomyopathy (SICM) than in those without SICM. Apelin-13 and APJ emerged as independent predictors of 28-day mortality among septic patients.

Conclusions

Apelin-13 and APJ demonstrate value in the assessment of risk stratification, early diagnosis, and prognosis of sepsis in the ED. Apelin-13 also proves to be an effective biomarker for assessing the prognosis of SICM in the ED. Sepsis may lead to immune function suppression.

Inflammatory biomarkers to predict the prognosis of acute bacterial and viral infections

Mortality in acute infections is mostly associated with sepsis, defined as 'life-threatening organ dysfunction caused by a dysregulated host response to infection'. It remains challenging to identify the patients with increased mortality risk due to the high heterogeneity in the dysregulated host immune response and disease progression. Biomarkers reflecting different pathways involved in the inflammatory response might improve prediction of mortality risk (prognostic enrichment) among patients with acute infections by reducing heterogeneity of the host response, as well as suggest novel strategies for patient stratification and treatment (predictive enrichment) through precision medicine approaches. The predictive value of inflammatory biomarkers has been extensively investigated in bacterial infections and the recent COVID-19 pandemic caused an increased interest in inflammatory biomarkers in this viral infection. However, limited research investigated whether the prognostic potential of these biomarkers differs between bacterial and viral infections. In this narrative review, we provide an overview of the value of various inflammatory biomarkers for the prediction of mortality in bacterial and viral infections.

Potential role of IgM-enriched immunoglobulin as adjuvant treatment in severe SARS-CoV-2 infection

BACKGROUND

Severe COVID-19 patients are characterized by a dysregulated host response to an infection, with uncontrolled pro- and anti- inflammatory pathway activation. Consistent proportion of patients require admission in intensive care units and are at risk of progression to severe forms of disease. These patients are generally admitted during later stages of the disease, when effective antiviral and monoclonal antibody are not indicated. We aimed to assess the potential role of IgM-enriched intra venous immunoglobulins (IGAM) preparations in this setting.

METHODS

This retrospective, observational case-controlled study was conducted at a single-center University Hospital of Udine in the Friuli Venezia Giulia Region of Italy. Patients referring to the center between March 2020 and April 2021 was included. During the study period, patient who received Pentaglobin® IGAM treatment (N.=56), administered as compassionate use, was compared with a control group (N.=169) to assess, by propensity score analysis, clinical outcome.

RESULTS

Untreated controls required, respect to patient treated with IGAM therapy, longer time to hospitalization with no significant differences in death and orotracheal intubation requirement. Significant differences in the two cohort were in: SOFA was higher in treated, while D-dimer and P/F ratio was better in the treatment cohort. Multivariate logistic regression analysis performed on the "matched sample," obtained by a weighting propensity score approach, identify, as significant protective factor for death outcome, the Pentaglobin® treatment (0.820 [0.698-0.963], P=0.016) and low C-reactive protein (1.001 [1.000-1.002], P=0.031) value while the delay of onset hospitalization is associate with a worst outcome (0.983 [0.967-0.999], P=0.041).

CONCLUSIONS

The present study offers a significant insight concerning the use of IgM-enriched immunoglobulin preparations in patients with SARS-CoV-2 severe infection and also could identifying the specific immunological and biochemical profile of the patient who can more benefit from this therapeutic option.

During Sepsis and COVID-19, the Pro-Inflammatory and Anti-Inflammatory Responses Are Concomitant

The most severe forms of COVID-19 share many features with bacterial sepsis and have thus been considered to be a viral sepsis. Innate immunity and inflammation are closely linked. While the immune response aims to get rid of the infectious agent, the pro-inflammatory host response can result in organ injury including acute respiratory distress syndrome. On its side, a compensatory anti-inflammatory response, aimed to dampen the inflammatory reaction, can lead to immunosuppression. Whether these two key events of the host inflammatory response are consecutive or concomitant has been regularly depicted in schemes. Initially proposed from 2001 to 2013 to be two consecutive steps, the concomitant occurrence has been supported since 2013, although it was proposed for the first time in 2001. Despite a consensus was reached, the two consecutive steps were still recently proposed for COVID-19. We discuss why the concomitance view could have been initiated as early as 1995.

Modulation of redox-sensitive transcription factors with polyphenols as pathogenetically grounded approach in therapy of systemic inflammatory response

One of the adverse outcomes of acute inflammatory response is progressing to the chronic stage or transforming into an aggressive process, which can develop rapidly and result in the multiple organ dysfunction syndrome. The leading role in this process is played by the Systemic Inflammatory Response that is accompanied by the production of pro- and anti-inflammatory cytokines, acute phase proteins, and reactive oxygen and nitrogen species. The purpose of this review that highlights both the recent reports and the results of the authors' own research is to encourage scientists to develop new approaches to the differentiated therapy of various SIR manifestations (low- and high-grade systemic inflammatory response phenotypes) by modulating redox-sensitive transcription factors with polyphenols and to evaluate the saturation of the pharmaceutical market with appropriate dosage forms tailored for targeted delivery of these compounds. Redox-sensitive transcription factors such as NFκB, STAT3, AP1 and Nrf2 have a leading role in mechanisms of the formation of low- and high-grade systemic inflammatory phenotypes as variants of SIR. These phenotypic variants underlie the pathogenesis of the most dangerous diseases of internal organs, endocrine and nervous systems, surgical pathologies, and post-traumatic disorders. The use of individual chemical compounds of the class of polyphenols, or their combinations can be an effective technology in the therapy of SIR. Administering natural polyphenols in oral dosage forms is very beneficial in the therapy and management of the number of diseases accompanied with low-grade systemic inflammatory phenotype. The therapy of diseases associated with high-grade systemic inflammatory phenotype requires medicinal phenol preparations manufactured for parenteral administration.

Dynamic changes in human single-cell transcriptional signatures during fatal sepsis

Systemic infections, especially in patients with chronic diseases, may result in sepsis: an explosive, uncoordinated immune response that can lead to multisystem organ failure with a high mortality rate. Patients with similar clinical phenotypes or sepsis biomarker expression upon diagnosis may have different outcomes, suggesting that the dynamics of sepsis is critical in disease progression. A within-subject study of patients with Gram-negative bacterial sepsis with surviving and fatal outcomes was designed and single-cell transcriptomic analyses of peripheral blood mononuclear cells (PBMC) collected during the critical period between sepsis diagnosis and 6 h were performed. The single-cell observations in the study are consistent with trends from public datasets but also identify dynamic effects in individual cell subsets that change within hours. It is shown that platelet and erythroid precursor responses are drivers of fatal sepsis, with transcriptional signatures that are shared with severe COVID-19 disease. It is also shown that hypoxic stress is a driving factor in immune and metabolic dysfunction of monocytes and erythroid precursors. Last, the data support CD52 as a prognostic biomarker and therapeutic target for sepsis as its expression dynamically increases in lymphocytes and correlates with improved sepsis outcomes. In conclusion, this study describes the first single-cell study that analyzed short-term temporal changes in the immune cell populations and their characteristics in surviving or fatal sepsis. Tracking temporal expression changes in specific cell types could lead to more accurate predictions of sepsis outcomes and identify molecular biomarkers and pathways that could be therapeutically controlled to improve the sepsis trajectory toward better outcomes.

Resveratrol suppresses the reprogramming of macrophages into an endotoxin-tolerant state through the activation of AMP-activated protein kinase

Resveratrol has been reported to have beneficial effects on sepsis by regulating the inflammatory response. However, it remains unclear if resveratrol plays a role in the development of endotoxin tolerance. Treatment with resveratrol in macrophages stimulated with primary lipopolysaccharide (LPS) resulted in the increased production of TNF-α and IL-6 induced by a 2^nd dose of LPS (by 74.5 ± 12.9% and 63.4 ± 12%, respectively, compared to untreated cells, P < 0.05). This effect was inhibited by compound C, an AMPK inhibitor, and STO609, a calcium/calmodulin-dependent protein kinase-kinase (CaMKK) inhibitor. Resveratrol diminished the expression of interleukin-1 receptor-associated kinase M (IRAK-M) and Src homology 2 (SH2) domain-containing inositol-5-phosphatase 1 (SHIP1) by prolonging the exposure of cells to LPS (by 60.8 ± 16.3% and 70.3 ± 18.1%, respectively, compared to LPS only). The effect of resveratrol on the LPS-induced expression of IRAK-M and SHIP1 was inhibited by compound C or STO609. After a 2^nd dose of LPS, resveratrol increased phosphorylation of ERK1/2, p38, and JNK in endotoxin tolerant macrophages. In vivo systemic administration of resveratrol prevented a significant increase in mortality rate by cecal ligation and puncture in LPS-induced endotoxin-tolerant mice. These results indicate that resveratrol induces AMPK activation through the Ca²⁺/CaMKKβ pathway and suppresses the development of endotoxin tolerance by inhibiting LPS-induced expression of IRAK-M and SHIP1.

Prognosis-related classification and dynamic monitoring of immune status in patients with sepsis: A prospective observational study

BACKGROUND

The dynamic monitoring of immune status is crucial to the precise and individualized treatment of sepsis. In this study, we aim to introduce a model to describe and monitor the immune status of sepsis and to explore its prognostic value.

METHODS

A prospective observational study was carried out in Zhongshan Hospital, Fudan University, enrolling septic patients admitted between July 2016 and December 2018. Blood samples were collected at days 1 and 3. Serum cytokine levels (e.g., tumor necrosis factor-α [TNF-α], interleukin-10 [IL-10]) and CD14⁺ monocyte human leukocyte antigen-D-related (HLA-DR) expression were measured to serve as immune markers. Classification of each immune status, namely systemic inflammatory response syndrome (SIRS), compensatory anti-inflammatory response syndrome (CARS), and mixed antagonistic response syndrome (MARS), was defined based on levels of immune markers. Changes of immune status were classified into four groups which were stabilization (SB), deterioration (DT), remission (RM), and non-remission (NR).

RESULTS

A total of 174 septic patients were enrolled including 50 non-survivors. Multivariate analysis discovered that IL-10 and HLA-DR expression levels at day 3 were independent prognostic factors. Patients with MARS had the highest mortality rate. Immune status of 46.1% patients changed from day 1 to day 3. Among four groups of immune status changes, DT had the highest mortality rate, followed by NR, RM, and SB with mortality rates of 64.7%, 42.9%, and 11.2%, respectively.

CONCLUSIONS

Severe immune disorder defined as MARS or deterioration of immune status defined as DT lead to the worst outcomes. The preliminary model of the classification and dynamic monitoring of immune status based on immune markers has prognostic values and is worthy of further investigation.

Monitoring immunomodulation in patients with sepsis

Introduction: This review aims to summarize current progress of the last ten years in the development of biomarkers used for classifying the immune response of the septic host and for monitoring the efficacy of the applied adjunctive immunotherapy.Areas covered: An extensive search of the literature was performed. In this review the authors discuss available biomarkers of host immune response in sepsis toward two directions; immunosuppression and hyperinflammation. Ferritin, sCD163, sIL-2 ra, and IL-18 may help in the diagnosis of macrophage activation syndrome (MAS) complicating sepsis whereas lymphopenia, decreased HLA-DR expression on monocytes, overexpression of Programmed cell death protein-1 (PD-1)/Programmed death-ligand 1 (PD-L1) and IL-10 are indicators of sepsis-induced immunosuppression. Novel approaches in the classification of immune state in sepsis include Myeloid-Derived Suppressor Cells (MDSC) and specific endotypes, defined by gene expression and molecular techniques.Expert opinion: HLA-DR and ferritin are the most commonly used biomarkers to monitor immunomodulation in clinical practice whereas developing specific sepsis endotypes is the future target. New immunotherapy trials in sepsis need to incorporate biomarkers for a personalized treatment.

Immunosuppression is Inappropriately Qualifying the Immune Status of Septic and SIRS Patients

Immunosuppression is the most commonly used concept to qualify the immune status of patients with either sterile systemic inflammatory response syndrome (SIRS) or sepsis. In this review we attempt to demonstrate that the concept of immunosuppression is an oversimplification of the complex anti-inflammatory response that occurs in patients dealing with a severe sterile or infectious insult. Particularly, the immune status of leukocytes varies greatly depending on the compartment from where they are derived from. Furthermore, although certain functions of immune cells present in the blood stream or in the hematopoietic organs can be significantly diminished, other functions are either unchanged or even enhanced. This juxtaposition illustrates that there is no global defect. The mechanisms called reprogramming or trained innate immunity are probably aimed at preventing a generalized deleterious inflammatory reaction, and work to maintain the defense mechanisms at their due levels.

JAK-STAT Targeting Offers Novel Therapeutic Opportunities in Sepsis

Sepsis is a life-threatening condition caused by exaggerated host responses to infections taking place in two phases: (i) a systemic (hyper)inflammatory response syndrome (SIRS), participating in multiple organ failure (MOF), a major complication of septic shock, followed by (ii) a compensatory anti-inflammatory response syndrome (CARS), leading to sepsis-induced immunosuppression and resulting in late infections and long-term mortality. The Janus kinase-signal transducer and activator of transcription (JAK-STAT)-dependent signaling pathway is involved in both manifestations, hence playing a key role during sepsis. It is also involved in emergency myelopoiesis, which participates in host defense. The aim of this review is to highlight and refine the recent implications of this signaling pathway in sepsis and illustrate why its central position makes it a potential biomarker and therapeutic target.

The unleashing of the immune system in COVID-19 and sepsis: the calm before the storm?

The novel coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is sorely testing health care systems and economies around the world and is rightly considered as the major health emergency in a century. Despite the course of the disease appearing to be mild in many cases, a significant proportion of symptomatic patients develop pneumonia requiring hospitalisation or progress to manifest respiratory complications leading to intensive care treatment. Potential interventions for SARS-CoV2-associated pneumonia are being tested, some of which holding promise, but as of today none of these has yet demonstrated outstanding efficacy in treating COVID-19. In this article, we discuss fresh perspectives and insights into the potential role of immune dysregulation in COVID-19 as well as similarities with systemic inflammatory response in sepsis and the rationale for exploring novel treatment options affecting host immune response.

Biochemical value dynamics in patients with multidrug-resistant tuberculosis/hiv with CD4+ lymphocyte cells below 50 cells/μCL and its variability in the application of adjuvant immunoglobulin therapy

Context

Treatment of the patients with multidrug-resistant tuberculosis (MDR-TB)/HIV coinfection in a state of severely suppressed immune system remains under efficient.

Aims

The aim of this study was to assess the effectiveness of adjuvant immunoglobulin therapy in TB/HIV patients.

Settings and Design

The relationship between biochemical indexes in the patients with MDR-TB/HIV co-infection and adjuvant immunoglobulin therapy.

Materials and Methods

The study involved 52 HIV-positive patients with MDR-TB and CD4+ lymphocyte cells below 50 cells/μCL. Patients in control group (Group 1) and in basic group (Group 2) received standard treatment with second-line antituberculosis agents and antiretroviral agents. In addition patients in basic group were treated by immunoglobulin G intravenously. The evaluation of biochemical parameters such as bilirubin level, thymol test, the activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase (GGT) was carried out on automatic analyzer HumaStar 300 at the beginning and after 0.5-8 months of treatment. Statistical analysis was performed using the Statistica 10.0 software (Stat. Soft Inc., USA). Kruskal-Wallis, ANOVA, and Chi-square tests were used in this study.

Results

After 8 months of treatment, studied biochemical indexes were lower in Group 2 than in patients from Group 1. For example, the number of patients in Group 2 with increased bilirubin level was 1.7 times more than in Group 1 (p < 0.05), with increased ALT, AST, or GGT activity in 2.5 times (p < 0.01), 2.7 times (p < 0.01), or 2.4 times (p < 0.05) correspondently, comparatively with Group 1.

Conclusion

The usage of immunoglobulins intravenously in the group of patients with MDR-TB associated with HIV infection, with CD4+ level <50 cells/μCL, is appropriate and essential because it improves treatment outcome.

Biomarkers of Immunosuppression

It is now recognized that sepsis is not a uniformly proinflammatory state. There is a well-recognized counter anti-inflammatory response that occurs in many patients. The timing and magnitude of this response varies considerably and thus makes its identification and manipulation more difficult. Studies in animals and humans have now identified a small number of biologic responses that characterize this immunosuppressed state, such as lymphocyte death, HLA receptor downregulation, and monocyte exhaustion. Researchers are now trying to use these as markers of individual immunosuppression to predict outcomes and identify patients who would and would not benefit from new immune stimulatory therapies.

Pravastatin alleviates intracellular calcium dysregulation induced by Interleukin-6 via the mitochondrial ROS pathway in adult ventricular myocytes

Acute inflammation often contributes to the increased arrhythmogenesis in the cardiomyocytes. We investigated the protective effects of pravastatin on calcium disorders induced by acute administration of pro-inflammatory cytokines in isolated ventricular myocytes and its underlying mechanisms. Wild-type mice were intraperitoneally injected for five days with either pravastatin 20 mg/kg per day or an equal volume of normal saline. Cytosol Ca²⁺ handling was studied in freshly isolated ventricular myocytes after acute exposure of interleukin-6 (IL-6) (1 ng/ml) for 120 min by Ionoptix and confocal microscopy. Acute administration of clinically relevant concentrations of IL-6 disturbed calcium handling in ventricular myocytes, which presented as decreased amplitudes, prolonged decay times of Ca²⁺ transients, and reduced sarcoplasmic reticulum (SR) calcium stores. The frequency of spontaneous Ca²⁺ release, including calcium sparks and spontaneous calcium waves, was dramatically enhanced in the setting of IL-6. Notably, the pretreatment of pravastatin alleviated disturbed Ca²⁺ cycling, reduced spontaneous Ca²⁺ leakage induced by IL-6. Mitochondrial ROS pathway may constitute the underlying mechanism of the protective effects of pravastatin. Pravastatin protected the cardiomyocytes against calcium disorders induced by IL-6 via the mitochondrial ROS pathway, which suggests that pravastatin may represent a promising auxiliary therapeutic strategy for cardiac injury under acute inflammation.

General Adaptation in Critical Illness: Glucocorticoid Receptor-alpha Master Regulator of Homeostatic Corrections

In critical illness, homeostatic corrections representing the culmination of hundreds of millions of years of evolution, are modulated by the activated glucocorticoid receptor alpha (GRα) and are associated with an enormous bioenergetic and metabolic cost. Appreciation of how homeostatic corrections work and how they evolved provides a conceptual framework to understand the complex pathobiology of critical illness. Emerging literature place the activated GRα at the center of all phases of disease development and resolution, including activation and re-enforcement of innate immunity, downregulation of pro-inflammatory transcription factors, and restoration of anatomy and function. By the time critically ill patients necessitate vital organ support for survival, they have reached near exhaustion or exhaustion of neuroendocrine homeostatic compensation, cell bio-energetic and adaptation functions, and reserves of vital micronutrients. We review how critical illness-related corticosteroid insufficiency, mitochondrial dysfunction/damage, and hypovitaminosis collectively interact to accelerate an anti-homeostatic active process of natural selection. Importantly, the allostatic overload imposed by these homeostatic corrections impacts negatively on both acute and long-term morbidity and mortality. Since the bioenergetic and metabolic reserves to support homeostatic corrections are time-limited, early interventions should be directed at increasing GRα and mitochondria number and function. Present understanding of the activated GC-GRα's role in immunomodulation and disease resolution should be taken into account when re-evaluating how to administer glucocorticoid treatment and co-interventions to improve cellular responsiveness. The activated GRα interdependence with functional mitochondria and three vitamin reserves (B1, C, and D) provides a rationale for co-interventions that include prolonged glucocorticoid treatment in association with rapid correction of hypovitaminosis.

IgM-enriched immunoglobulins (Pentaglobin) may improve the microcirculation in sepsis: a pilot randomized trial

BACKGROUND

Polyclonal or IgM-enriched immunoglobulins may be beneficial during sepsis as an adjuvant immunomodulatory therapy. We aimed to test whether the infusion of IgM-enriched immunoglobulins improves microvascular perfusion during sepsis.

METHODS

Single-centre, randomized, double-blind, placebo-controlled phase II trial including adult patients with a diagnosis of sepsis or septic shock for less than 24 h. Patients received an intravenous infusion of 250 mg/kg (5 mL/kg) per day of IgM-enriched immunoglobulins (Pentaglobin, n = 10) for 72 h or placebo (NaCl 0.9%, n = 9). At baseline and after 24 and 72 h of infusion, the sublingual microcirculation was assessed with Incident Dark Field videomicroscopy. Thenar near-infrared spectroscopy (NIRS) was applied with a vascular occlusion test to assess tissue oxygenation and microvascular reactivity. Levels of interleukin (IL) 1-beta, IL-6, IL-8, IL-10 and tumour necrosis factor alpha were measured in the serum.

RESULTS

The perfused vessel density (PVD) for small vessels (diameter < 20 micron) increased in the Pentaglobin group (from 21.7 ± 4.7 to 25.5 ± 5.1 mm/mm²) and decreased in the placebo group (from 25 ± 5.8 to 20.7 ± 4.1 mm/mm², p for interaction < 0.001, two-way analysis of variance). The absolute between-group difference at 72 h was 4.77 (standard error 2.34), p = 0.140. The microvascular flow index for small vessels increased at 24 h in the Pentaglobin group (from 2.68 [2.38-2.78] to 2.93 [2.82-3], p < 0.01) and decreased at 72 h in the placebo group (from 2.83 [2.60-2.97] to 2.67 [2.48-2.73], p < 0.05). Changes in general parameters, cytokines and NIRS-derived parameters were similar between the two groups, except for IL-6 and IL-10 that significantly decreased at 72 h only in the Pentaglobin group.

CONCLUSIONS

A 72-h infusion of IgM-enriched immunoglobulins (Pentaglobin) in patients with sepsis or septic shock may be associated with an increase in sublingual microvascular perfusion. Further studies are needed to confirm our findings. Trial registration NCT02655133, www.ClinicalTrials.gov, date of registration 7th January 2016, https://www.clinicaltrials.gov/ct2/show/NCT02655133.

Effects of prophylactic administration of glutamine on CD4+ T cell polarisation and kidney injury in mice with polymicrobial sepsis

The present study investigated the effects of glutamine (GLN) pretreatment on CD4+ T cell polarisation and remote kidney injury in mice with gut-derived polymicrobial sepsis. Mice were randomly assigned to three groups: normal control fed with American Institute of Nutrition (AIN)-93G diet and two sepsis groups provided with either AIN-93G-based diet or identical components, except part of casein was replaced by GLN. Mice were given their respective diets for 2 weeks. Then, mice in the sepsis groups were performed with caecal ligation and puncture and were killed 72 h after the surgery. Blood, spleens and kidneys were collected for further examination. The results showed that sepsis resulted in decreased circulating and splenic total T lymphocyte and CD4+ T cell percentages, whereas IL-4-, and forkhead box p3 (Foxp3)-expressing CD4+ T cells percentages were up-regulated. Compared with the sepsis control group, pretreatment with GLN maintained blood T and CD4+ T cells and reduced percentages of IL-4- and Foxp3-expressing CD4+ T cells. Also, a more pronounced activation and increased anti-apoptotic Bcl-2 gene expression of splenic CD4+ T cells were observed. Concomitant with the decreased plasma IL-6, keratinocyte-derived chemokine (KC) levels, the gene expression of KC, macrophage inflammatory protein-2 and renal injury biomarker kidney injury molecule-1 (Kim-1) were down-regulated when GLN was administered. These findings suggest that antecedent of GLN administration elicit a more balanced blood T helper cell polarisation, sustained T cell populations, prevented splenic CD4+ T cell apoptosis and attenuated kidney injury at late phase of polymicrobial sepsis. GLN may have benefits in subjects at risk of abdominal infection.

A Comparative Review of Equine SIRS, Sepsis, and Neutrophils

The most recent definition of sepsis in human medicine can be summarized as organ dysfunction caused by a dysregulated host response to infection. In equine medicine, although no consensus definition is available, sepsis is commonly described as a dysregulated host systemic inflammatory response to infection. Defense against host infection is the primary role of innate immune cells known as neutrophils. Neutrophils also contribute to host injury during sepsis, making them important potential targets for sepsis prevention, diagnosis, and treatment. This review will present both historical and updated perspectives on the systemic inflammatory response (SIRS) and sepsis; it will also discuss the impact of sepsis on neutrophils, and the impact of neutrophils during sepsis. Future identification of clinically relevant sepsis diagnosis and therapy depends on a more thorough understanding of disease pathogenesis across species. To gain this understanding, there is a critical need for research that utilizes a clearly defined, and consistently applied, classification system for patients diagnosed with, and at risk of developing, sepsis.

Low interleukin-10 release after ex vivo stimulation of whole blood is associated with persistent organ dysfunction in sepsis: A prospective observational study

BACKGROUND

Sepsis profoundly alters immune homeostasis. Cytokine release after whole blood lipopolysaccharide (LPS)-stimulation reflects cell function across multiple immune cell classes and represents the immune response to LPS. The main goal of this study was to evaluate the prognostic value of ex vivo stimulation of whole blood with LPS in sepsis.

METHODS

Blood was drawn on day 1 and day 7 after admission, and stimulated ex vivo with LPS. Tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and IL-10 were measured with and without stimulation. Our primary outcome measure was the persistence of at least one organ dysfunction at day 7. Organ dysfunction was defined according to the SOFA components by a score ≥ 2.

RESULTS

Forty-nine patients with sepsis from a 21-bed intensive care unit, and 23 healthy volunteers were enrolled. The blood of septic patients was less responsive to ex vivo stimulation with LPS than that of healthy controls at day 1 and 7, as demonstrated by lower TNF-α, IL-1β, IL-6 and IL-10 release. Persistent organ dysfunction was more frequent in patients with lower IL-10 release at day 1 but such an association was not found for pro-inflammatory cytokines. A persistent low IL-10 release at day 7 was also associated with persistent organ dysfunction.

CONCLUSION

These data suggest that the capacity to produce IL-10 in response to whole blood ex vivo stimulation early in sepsis, as well as persistent low IL-10 response over time, may help in prognostication and patient stratification. These results will need to be confirmed in future studies.

Antecedent Administration of Glutamine Benefits the Homeostasis of CD4+ T Cells and Attenuates Lung Injury in Mice With Gut-Derived Polymicrobial Sepsis

BACKGROUND

Sepsis is a syndrome with CD4⁺ T-cell dysfunction and dysregulation of T helper (Th) and regulatory T (Treg) cells. Glutamine (Gln) is a nutrient with immunomodulatory properties. This study investigated the effects of dietary Gln pretreatment on Th and Treg cell homeostasis and lung injury in mice with gut-derived polymicrobial sepsis.

METHODS

Mice were randomly assigned to 4 groups with 2 control (C and G) and 2 sepsis groups (SC and SG). The C and SC groups were fed a common semipurified diet, whereas the G and SG groups received an identical diet except that part of the casein was replaced by Gln. Mice were administered these diets for 2 weeks. Then mice in the control groups underwent a sham operation, whereas operations in the sepsis groups were performed with cecal ligation and puncture. Mice were killed 24 hours after the surgery. Blood, spleens, and lungs were collected for further examination.

RESULTS

Sepsis resulted in a decreased blood T-lymphocyte percentage, whereas percentages of interferon-γ-expressing, interleukin (IL)-4-expressing, and IL-17-expressing CD4⁺ T cells were upregulated. Compared with the SC group, Gln administration before sepsis reduced blood Th1, Th2, and Th17 but increased Treg percentages. Also, percentages of CD69-expressing CD4⁺ and CD8⁺ cells in the spleen increased. Concomitant with the decreased plasma IL-6 and keratinocyte-derived chemokine levels, the SG group exhibited a lower injury score of the lungs.

CONCLUSIONS

Pretreatment with Gln may elicit more balanced Th polarization, alleviate inflammatory response, and attenuate lung injury induced by polymicrobial sepsis.

Immune therapy in sepsis: Are we ready to try again?

Immune therapy to ease the burden of sepsis has thus far failed to consistently improve patient outcomes. Advances in cancer immune therapy and awareness that prolonged immune-suppression in sepsis can leave patients vulnerable to secondary infection and death have driven resurgence in the field of sepsis immune-therapy investigation. As we develop and evaluate these novel therapies, we must learn from past experiences where single-mediator targeted immune therapies were blindly delivered to heterogeneous patient cohorts with complex and evolving immune responses. Advances in genomics, proteomics, metabolomics, and point-of-care technology, coupled with a better understanding of sepsis pathogenesis, have meant that personalised immune-therapy is on the horizon. Here, we review the complex immune pathogenesis in sepsis and the contemporary immune therapies that are being investigated to manipulate this response. An outline of the immune biomarkers that may be used to support this approach is also provided.

Sepsis and Nosocomial Infection: Patient Characteristics, Mechanisms, and Modulation

Sepsis is a leading cause of death worldwide. After initial trials modulating the hyperinflammatory phase of sepsis failed, generations of researchers have focused on evaluating hypo-inflammatory immune phenotypes. The main goal has been to develop prognostic biomarkers and therapies to reduce organ dysfunction, nosocomial infection, and death. The depressed host defense in sepsis has been characterized by broad cellular reprogramming including lymphocyte exhaustion, apoptosis, and depressed cytokine responses. Despite major advances in this field, our understanding of the dynamics of the septic host response and the balance of inflammatory and anti-inflammatory cellular programs remains limited. This review aims to summarize the epidemiology of nosocomial infections and characteristic immune responses associated with sepsis, as well as immunostimulatory therapies currently under clinical investigation.

Post-operative immune suppression is mediated via reversible, Interleukin-10 dependent pathways in circulating monocytes following major abdominal surgery

Introduction

Post-operative infections occur frequently following major surgery. The magnitude of the post-operative immune response is associated with an increased risk of post-operative infections, although the mechanisms driving post-operative immune-dysfunction and the potential reversibility of this response with immune stimulants are not well understood. This study aims to describe the immediate immune response to major surgery and establish links to both post-operative infection and functional aspects of immune dysregulation. We also investigate the potential of clinically available immune stimulants to reverse features of post-operative immune-dysfunction.

Methods

Patients over 45 years old undergoing elective gastro-intestinal surgery with planned post-operative surgical ICU admission were recruited. The expression of selected genes was determined pre-operatively and at 2, 24 and 48 hours post-operatively using qRT-PCR. Circulating levels of Interleukin-10 protein were determined by ELISA. Peri-operative cell surface monocyte HLA-DR (mHLA-DR) expression was determined using flow cytometry. Gene expression and mHLA-DR levels were determined in healthy monocytes cultured in peri-operative serum with and without neutralising antibodies and immune stimulants.

Results

119 patients were recruited; 44 developed a post-operative infection. Interleukin-10 mRNA and protein increased 4-fold post-operatively (P<0.0001), peaking within 2 hours of the procedure. Higher post-operative Interleukin-10 mRNA (P = 0.007) and protein (P = 0.001) levels were associated with an increased risk of infection. Cell surface mHLA-DR expression fell post-operatively (P<0.0001). Reduced production, rather than intracellular sequestration, accounted for the post-operative decline in cell surface mHLA-DR expression. Interleukin-10 antibody prevented the decrease in mHLA-DR expression observed when post-operative serum was added to healthy monocytes. GM-CSF and IFN-γ prevented the decline in mHLA-DR production through distinct pathways.

Conclusions

Monocyte dysfunction and features of immune suppression occur frequently after major surgery. Greater post-operative Interleukin-10 production is associated with later infection. Interleukin-10 is an important mediator of post-operative reductions in mHLA-DR expression, while clinically available immune stimulants can restore mHLA-DR levels.

Interleukin-6 as a diagnostic marker for infection in critically ill patients: A systematic review and meta-analysis

BACKGROUND

The ability of blood levels of interleukin (IL)-6 to differentiate between infection and non-infection in critically ill patients with suspected infection is unclear. We assessed the diagnostic accuracy of serum IL-6 levels for the diagnosis of infection in critically ill patients.

METHODS

We systematically searched the PubMed, MEDLINE, Cochrane Resister of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL, and Igaku Chuo Zasshi databases for studies published from 1986 to August 2016 that evaluated the accuracy of IL-6 levels for the diagnosis of infection. We constructed 2 × 2 tables and calculated summary estimates of sensitivity and specificity using a bivariate random-effects model.

RESULTS

The literature search identified 775 articles, six of which with a total of 527 patients were included according to the predefined criteria. The pooled sensitivity, specificity, and diagnostic odds ratio were 0.73 (95% confidence interval [CI], 0.61-0.82), 0.76 (95% CI, 0.61-0.87), and 2.31 (95% CI, 1.20-3.48), respectively. The area under the curve (AUC) of the summary receiver operator characteristic (SROC) curve was 0.81 (95% CI, 0.78-0.85). In the secondary analysis of two studies with a total of 263 adult critically ill patients with organ dysfunction, the pooled sensitivity, specificity, and diagnostic odds ratio were 0.81 (95% CI, 0.75-0.86), 0.77 (95% CI, 0.67-0.84), and 2.87 (95% CI 2.15-3.60), respectively.

CONCLUSIONS

Blood levels of IL-6 have a moderate diagnostic value and a potential clinical utility to differentiate infection in critically ill patients with suspected infection.

Distinct T-helper cell responses to Staphylococcus aureus bacteremia reflect immunologic comorbidities and correlate with mortality

BACKGROUND

The dysregulated host immune response that defines sepsis varies as a function of both the immune status of the host and the distinct nature of the pathogen. The degree to which immunocompromising comorbidities or immunosuppressive medications affect the immune response to infection is poorly understood because these patients are often excluded from studies about septic immunity. The objectives of this study were to determine the immune response to a single pathogen (Staphylococcus aureus) among a diverse case mix of patients and to determine whether comorbidities affect immune and clinical outcomes.

METHODS

Blood samples were drawn from 95 adult inpatients at multiple time points after the first positive S. aureus blood culture. Cox proportional hazards modeling was used to determine the associations between admission neutrophil counts, admission lymphocyte counts, cytokine levels, and 90-day mortality. A nested case-control flow cytometric analysis was conducted to determine T-helper type 1 (Th1), Th2, Th17, and regulatory T-cell (Treg) subsets among a subgroup of 28 patients. In a secondary analysis, we categorized patients as either having immunocompromising disorders (human immunodeficiency virus and hematologic malignancies), receiving immunosuppressive medications, or being not immunocompromised.

RESULTS

Higher neutrophil-to-lymphocyte count ratios and higher Th17 cytokine responses relative to Th1 cytokine responses early after infection were independently associated with mortality and did not depend on the immune state of the patient (HR 1.93, 95% CI 1.17-3.17, p = 0.01; and HR 1.13, 95% CI 1.01-1.27, p = 0.03, respectively). On the basis of flow cytometric analysis of CD4 T-helper subsets, an increasing Th17/Treg response over the course of the infection was most strongly associated with increased mortality (HR 4.41, 95% CI 1.69-11.5, p < 0.01). This type of immune response was most common among patients who were not immunocompromised. In contrast, among immunocompromised patients who died, a decreasing Th1/Treg response was most common.

CONCLUSIONS

The association of both increased Th17 responses and increased neutrophil counts relative to lymphocyte counts with mortality suggests that an overwhelming inflammatory response is detrimental. However, the differential responses of patients according to immune state suggest that immune status is an important clinical indicator that should be accounted for in the management of septic patients, as well as in the development of novel immunomodulatory therapies.

Interleukin-6 is a key factor for immunoglobulin-like transcript-4-mediated immune injury in sepsis

Background

ILT4⁺ monocytes seem to be associated with poor prognosis of sepsis in humans, but the exact mechanisms are unknown. This study aimed to examine the biological behaviors and effects of immunoglobulin-like transcript-4 (ILT4) levels on monocytes during sepsis and on the prognosis of sepsis.

Methods

ILT4^+/+ (WT) and ILT4-knockout (ILT4^-/-) male BALB/c mice were used for sepsis modeling using cecal ligation puncture (CLP). Flow cytometry was used to measure the levels of ILT4 and major histocompatibility complex class II (MHC-II) on peripheral blood monocytes 24 h after CLP. ELISA was used to measure the serum levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6, and IL-12 at 0, 6, 12, and 24 h after CLP. Survival and prognosis were monitored over the course of 168 h.

Results

ILT4 was highly expressed in peripheral blood monocytes of septic mice 24 h after CLP (1292.00 ± 143.70 vs. 193.50 ± 52.54, p < 0.05). MHC-II levels on peripheral blood monocytes in ILT4^-/- mice were significantly higher than those in WT mice (49.38 ± 5.66% vs. 24.25 ± 6.76%, p < 0.05). Serum IL-6 was significantly elevated 24 h after CLP (470.75 ± 88.03 vs. 54.25 ± 20.04, p < 0.05). The serum IL-6 levels were significantly lower in ILT4^-/- mice compared with those in WT mice after CLP (241.25 ± 45.10 vs. 470.75 ± 88.03, p < 0.05), but TNF-α, IL-1β, and IL-12 were not changed. The survival of ILT4^-/- mice was significantly better after CLP compared with that of WT mice.

Conclusions

High levels of ILT4 on monocytes were observed in peripheral blood during sepsis and found to be associated with high serum IL-6 levels and low MHC-II levels on monocytes, possibly associated with higher mortality. ILT-4-IL-6-MHC-II could be a potential signaling pathway involved in sepsis.

Endothelial biomarkers in human sepsis: pathogenesis and prognosis for ARDS

Experimental models of sepsis in small and large animals and a variety of in vitro preparations have established several basic mechanisms that drive endothelial injury. This review is focused on what can be learned from the results of clinical studies of plasma biomarkers of endothelial injury and inflammation in patients with sepsis. There is excellent evidence that elevated plasma levels of several biomarkers of endothelial injury, including von Willebrand factor antigen (VWF), angiopoietin-2 (Ang-2), and soluble fms-like tyrosine kinase 1 (sFLT-1), and biomarkers of inflammation, especially interleukin-8 (IL-8) and soluble tumor necrosis factor receptor (sTNFr), identify sepsis patients with a higher mortality. There are also some data that elevated levels of endothelial biomarkers can identify which patients with non-pulmonary sepsis will develop acute respiratory distress syndrome (ARDS). If ARDS patients are divided among those with indirect versus direct lung injury, then there is an association of elevated levels of endothelial biomarkers in indirect injury and markers of inflammation and alveolar epithelial injury in patients with direct lung injury. New research suggests that the combination of biologic and clinical markers may make it possible to segregate patients with ARDS into hypo- versus hyper-inflammatory phenotypes that may have implications for therapeutic responses to fluid therapy. Taken together, the studies reviewed here support a primary role of the microcirculation in the pathogenesis and prognosis of ARDS after sepsis. Biological differences identified by molecular patterns could explain heterogeneity of treatment effects that are not explained by clinical factors alone.

Dynamics of monocytic HLA-DR expression differs between bacterial etiologies during the course of bloodstream infection

Objective

In the pathogenesis of sepsis, activation of both pro- and anti-inflammatory responses are key components, but knowledge is lacking on the association between bacterial etiology and development of dysregulated responses with sustained immunosuppression. The aim of this study was to evaluate how the immunosupression marker HLA-DR on monocytes (mHLA-DR) is associated with bacterial etiology and markers of inflammation during the clinical trajectory of bloodstream infection (BSI).

Methods

Ninety-one adults, predominantly non-ICU patients, with BSI caused by Streptococcus pneumoniae (n = 27), Staphylococcus aureus (n = 22), Escherichia coli/Klebsiella pneumoniae (n = 23), and other species (n = 19) were prospectively included, and sampled on admission (day 0) and on days 1–2, 3, 7±1, 14±2, and 28±4.

Results

The dynamics of mHLA-DR, measured by flow cytometry, differed significantly between etiology groups (p<0.001). Patients with S. pneumoniae and S. aureus BSI demonstrated low initial mHLA-DR, with the S. aureus group showing delayed recovery over time. Eleven patients (55% S. aureus) had negative outcome (secondary bacteremia or death) and they demonstrated sustained C-reactive protein elevation, neutrophilia, lymphocytopenia, and loss of mHLA-DR.

Conclusions

Dynamics of mHLA-DR varied according to the bacterial etiology of infection, with delayed recovery in patients with S. aureus BSI. Patients with negative outcome showed sustained CRP elevation, neutrophilia, lymphocytopenia, and low levels of mHLA-DR, supporting the theory of a dysregulated host response with persistent inflammation and immunosuppression in late stages of deleterious sepsis.

Interleukin-6 Levels Act as a Diagnostic Marker for Infection and a Prognostic Marker in Patients with Organ Dysfunction in Intensive Care Units

INTRODUCTION

There are significant unmet requirements for rapid differential diagnosis of infection in patients admitted to intensive care units. Serum levels of interleukin-6 (IL-6), procalcitonin (PCT), presepsin, and C-reactive protein (CRP) are measured in clinical practice; however, their clinical utility in patients with organ dysfunction has not been tested adequately. Thus, we investigated the diagnostic and prognostic value of IL-6, PCT, presepsin, and CRP in critically ill patients who had organ dysfunction with suspicion of infection.

METHODS

In 100 consecutive critically ill patients with organ dysfunction and suspected infection, serum levels of IL-6, PCT, presepsin, and CRP were measured upon suspicion of infection and serially every other day up to 7 days (cohort 1). The primary outcome variable was the presence of infections. The diagnostic value of IL-6 was further tested in cohort 2 (n = 72, case-control matched). The secondary outcome variables were the sequential organ failure assessment (SOFA) score, serum creatinine levels, and 28-day mortality.

RESULTS

Among the four biomarkers, serum IL-6 levels had the highest area under the curve (AUC) value of 0.824 (95% confidence interval [CI] 0.735-0.913) for diagnosing infection in critically ill patients with organ dysfunction and suspected infection in cohort 1 (AUC [95% CI] for the other biomarkers: PCT, 0.813 [0.714-0.911]; CRP, 0.764 [0.645-0.883]; presepsin, 0.681 [0.513-0.849]). In cohort 2, the sensitivity and specificity of IL-6 for diagnosing infection were 0.861 and 0.806, respectively. The presepsin levels were significantly correlated with the SOFA score and serum creatinine levels upon suspicion of infection (r > 0.5), especially serum creatinine levels in the patients without infection (r = 0.789). Serum IL-6 levels were significant predictors of 28-day mortality. The AUC value of serum IL-6 levels for 28-day mortality increased over time; the serum IL-6 levels on Day 7 had the highest AUC value of 0.883 (95% CI, 0.788-0.978) for 28-day mortality.

CONCLUSION

Among serum IL-6, PCT, presepsin, and CRP levels, serum IL-6 levels had the highest diagnostic value for infection. They were also significant predictors of 28-day mortality. Hence, they may improve diagnosis of infection and prediction of 28-day mortality in critically ill patients with organ dysfunction.

Critical Illness-Related Corticosteroid Insufficiency (CIRCI): A Narrative Review from a Multispecialty Task Force of the Society of Critical Care Medicine (SCCM) and the European Society of Intensive Care Medicine (ESICM)

OBJECTIVE

To provide a narrative review of the latest concepts and understanding of the pathophysiology of critical illness-related corticosteroid insufficiency (CIRCI).

PARTICIPANTS

A multi-specialty task force of international experts in critical care medicine and endocrinology and members of the Society of Critical Care Medicine and the European Society of Intensive Care Medicine.

DATA SOURCES

Medline, Database of Abstracts of Reviews of Effects (DARE), Cochrane Central Register of Controlled Trials (CENTRAL) and the Cochrane Database of Systematic Reviews.

RESULTS

Three major pathophysiologic events were considered to constitute CIRCI: dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, altered cortisol metabolism, and tissue resistance to glucocorticoids. The dysregulation of the HPA axis is complex, involving multidirectional crosstalk between the CRH/ACTH pathways, autonomic nervous system, vasopressinergic system, and immune system. Recent studies have demonstrated that plasma clearance of cortisol is markedly reduced during critical illness, explained by suppressed expression and activity of the primary cortisol-metabolizing enzymes in the liver and kidney. Despite the elevated cortisol levels during critical illness, tissue resistance to glucocorticoids is believed to occur due to insufficient glucocorticoid alpha-mediated anti-inflammatory activity.

CONCLUSIONS

Novel insights into the pathophysiology of CIRCI add to the limitations of the current diagnostic tools to identify at-risk patients and may also impact how corticosteroids are used in patients with CIRCI.

Variants in LTA, TNF, IL1B and IL10 genes associated with the clinical course of sepsis

The aim of this study was to explore the association between some SNPs of the TNF, LTA, IL1B and IL10 genes with cytokine concentrations and clinical course in Colombian septic patients. We conducted a cross-sectional study to genotype 415 septic patients and 205 patients without sepsis for the SNPs -308(G/A) rs1800629 of TNF; +252 (G/A) rs909253 of LTA; -511(A/G) rs16944 and +3953(C/T) rs1143634 of IL1B; and -1082(A/G) rs1800896, -819(C/T) rs1800871 and -592(C/A) rs1800872 of IL10. The association of theses SNPs with the following parameters was evaluated: (1) the presence of sepsis; (2) severity and clinical outcomes; (3) APACHE II and SOFA scores; and (4) procalcitonin, C-reactive protein, tumor necrosis factor, lymphotoxin alpha, interleukin 1 beta and interleukin 10 plasma concentrations. We found an association between the SNP LTA +252 with the development of sepsis [OR 1.29 (1.00-1.68)]; the SNP IL10 -1082 with sepsis severity [OR 0.53 (0.29-0.97)]; the TNF -308 with mortality [OR 0.33 (0.12-0.95)]; and the IL10 -592 and IL10 -1082 with admission to the intensive care unit (ICU) [OR 3.36 (1.57-7.18)] and [OR 0.18 (0.04-0.86)], respectively. None of the SNPs were associated with cytokine levels, procalcitonin and C-reactive protein serum concentrations, nor with APACHE II and SOFA scores. Our results suggest that these genetic variants play an important role in the development of sepsis and its clinical course.

Ex vivo Stimulation of Lymphocytes with IL-10 Mimics Sepsis-Induced Intrinsic T-Cell Alterations

Profound T-cell alterations are observed in septic patients in association with increased risk of secondary infection and mortality. The pathophysiological mechanisms leading to such dysfunctions are not completely understood and direct and indirect mechanisms have been described. In this study we evaluated whether ex vivo stimulation of lymphocytes with IL-10, an immunosuppressive cytokine released at the systemic level during sepsis, could mimic sepsis-induced intrinsic T-cell alterations. We showed that recombinant human IL-10 priming of T cells altered their proliferative response to anti-CD2/CD3/CD28 antibody-coated beads and PHA stimulations, in a dose-dependent manner independently of accessory cells. This priming also significantly decreased T-cell secretion of IL-2 and IFNγ following stimulation. Furthermore, we demonstrated that IL-10 reduction of T-cell functionality was associated with increased FOXP3 expression in CD4⁺CD25⁺CD127^- regulatory T cells as observed in sepsis. Finally, we found that blocking the increased IL-10 concentration in plasma from septic shock patients increased the proliferative response of responding T cells from healthy controls. We describe here an ex vivo model recapitulating features of sepsis-induced intrinsic T-cell alterations. This should help, in further studies, to decipher the pathophysiological mechanisms of T-cell alterations induced after septic shock.

Pyruvate enhancement of cardiac performance: Cellular mechanisms and clinical application

Cardiac contractile function is adenosine-5'-triphosphate (ATP)-intensive, and the myocardium's high demand for oxygen and energy substrates leaves it acutely vulnerable to interruptions in its blood supply. The myriad cardioprotective properties of the natural intermediary metabolite pyruvate make it a potentially powerful intervention against the complex injury cascade ignited by myocardial ischemia-reperfusion. A readily oxidized metabolic substrate, pyruvate augments myocardial free energy of ATP hydrolysis to a greater extent than the physiological fuels glucose, lactate and fatty acids, particularly when it is provided at supra-physiological plasma concentrations. Pyruvate also exerts antioxidant effects by detoxifying reactive oxygen and nitrogen intermediates, and by increasing nicotinamide adenine dinucleotide phosphate reduced form (NADPH) production to maintain glutathione redox state. These enhancements of free energy and antioxidant defenses combine to augment sarcoplasmic reticular Ca²⁺ release and re-uptake central to cardiac mechanical performance and to restore β-adrenergic signaling of ischemically stunned myocardium. By minimizing Ca²⁺ mismanagement and oxidative stress, pyruvate suppresses inflammation in post-ischemic myocardium. Thus, pyruvate administration stabilized cardiac performance, augmented free energy of ATP hydrolysis and glutathione redox systems, and/or quelled inflammation in a porcine model of cardiopulmonary bypass, a canine model of cardiac arrest-resuscitation, and a caprine model of hypovolemia and hindlimb ischemia-reperfusion. Pyruvate's myriad benefits in preclinical models provide the mechanistic framework for its clinical application as metabolic support for myocardium at risk. Phase one trials have demonstrated pyruvate's safety and efficacy for intravenous resuscitation for septic shock, intracoronary infusion for heart failure and as a component of cardioplegia for cardiopulmonary bypass. The favorable outcomes of these trials, which argue for expanded, phase three investigations of pyruvate therapy, mirror findings in isolated, perfused hearts, underscoring the pivotal role of preclinical research in identifying clinical interventions for cardiovascular diseases. Impact statement This article reviews pyruvate's cardioprotective properties as an energy-yielding metabolic fuel, antioxidant and anti-inflammatory agent in mammalian myocardium. Preclinical research has shown these properties make pyruvate a powerful intervention to curb the complex injury cascade ignited by ischemia and reperfusion. In ischemically stunned isolated hearts and in large mammal models of cardiopulmonary bypass, cardiac arrest-resuscitation and hypovolemia, intracoronary pyruvate supports recovery of myocardial contractile function, intracellular Ca²⁺ homeostasis and free energy of ATP hydrolysis, and its antioxidant actions restore β-adrenergic signaling and suppress inflammation. The first clinical trials of pyruvate for cardiopulmonary bypass, fluid resuscitation and intracoronary intervention for congestive heart failure have been reported. Receiver operating characteristic analyses show remarkable concordance between pyruvate's beneficial functional and metabolic effects in isolated, perfused hearts and in patients recovering from cardiopulmonary bypass in which they received pyruvate- vs. L-lactate-fortified cardioplegia. This research exemplifies the translation of mechanism-oriented preclinical studies to clinical application and outcomes.

Development and validation of immune dysfunction score to predict 28-day mortality of sepsis patients

BACKGROUND

Sepsis-induced immune dysfunction ranging from cytokines storm to immunoparalysis impacts outcomes. Monitoring immune dysfunction enables better risk stratification and mortality prediction and is mandatory before widely application of immunoadjuvant therapies. We aimed to develop and validate a scoring system according to patients' immune dysfunction status for 28-day mortality prediction.

METHODS

A prospective observational study from a cohort of adult sepsis patients admitted to ICU between August 2013 and June 2016 at Kaohsiung Chang Gung Memorial Hospital in Taiwan. We evaluated immune dysfunction status through measurement of baseline plasma Cytokine levels, Monocyte human leukocyte-DR expression by flow cytometry, and stimulated immune response using post LPS stimulated cytokine elevation ratio. An immune dysfunction score was created for 28-day mortality prediction and was validated.

RESULTS

A total of 151 patients were enrolled. Data of the first consecutive 106 septic patients comprised the training cohort, and of other 45 patients comprised the validation cohort. Among the 106 patients, 21 died and 85 were still alive on day 28 after ICU admission. (mortality rate, 19.8%). Independent predictive factors revealed via multivariate logistic regression analysis included segmented neutrophil-to-monocyte ratio, granulocyte-colony stimulating factor, interleukin-10, and monocyte human leukocyte antigen-antigen D-related levels, all of which were selected to construct the score, which predicted 28-day mortality with area under the curve of 0.853 and 0.789 in the training and validation cohorts, respectively.

CONCLUSIONS

The immune dysfunction scoring system developed here included plasma granulocyte-colony stimulating factor level, interleukin-10 level, serum segmented neutrophil-to-monocyte ratio, and monocyte human leukocyte antigen-antigen D-related expression appears valid and reproducible for predicting 28-day mortality.

Immune Activation in Sepsis

Sepsis is caused by a dysregulated host response to infection. Immune responses determine the characteristics of sepsis. The body's protection against infection involves danger signal surveillance and recognition from nonself, effector functions in response to sensing danger signals, homeostatic regulation, and generation of immunologic memory. During sepsis, the immune system is activated by pathogen-associated and host-derived molecular patterns. Detecting these molecular patterns generates multisystem responses. Impaired organ function remote to the site of infection is the unifying feature. The processes by which an appropriate response to a microbial invader change from adaptive to maladaptive and dysregulated remain unclear.

An Unbalanced Inflammatory Cytokine Response Is Not Associated With Mortality Following Sepsis: A Prospective Cohort Study

OBJECTIVE

The prevailing theory of host response during sepsis states that an excessive production of pro-inflammatory mediators causes early deaths, whereas a predominantly anti-inflammatory response may lead to immunosuppression, secondary infection, and late deaths. We assessed inflammatory (im)balance by measuring pro-inflammatory interleukin-6 and anti-inflammatory interleukin-10 during three distinct time periods after sepsis, and assessed its association with mortality.

DESIGN

Prospective observational cohort.

SETTING

Two tertiary mixed ICUs in The Netherlands.

PATIENTS

Consecutive patients presenting with severe sepsis or septic shock from 2011 to 2013.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We repeatedly measured plasma interleukin-6 and interleukin-10 concentrations using cytometric bead array. Poisson regression was used to analyze the relation between inflammatory markers measured on 1) ICU admission and day 4 mortality, 2) day 4 and day 28 mortality, and 3) ICU discharge and 1-year mortality. Secondary outcome was development of ICU-acquired infections. Among 708 patients, 86 (12%) died within 4 days, 140 (20%) died between days 4 and 28, and an additional 155 (22%) died before 1 year. Interleukin-6 and interleukin-10 levels were both independently associated with mortality, but the balance of this response as modelled by an interleukin-6 and interleukin-10 interaction term was not (relative risk, 0.99; 95% CI, 0.95-1.04 on admission; relative risk, 1.02; 95% CI, 0.98-1.06 on day 4; and relative risk, 1.12; 95% CI, 0.98-1.29 at ICU discharge). However, inflammatory imbalance on day 4 was associated with development of ICU-acquired infections (subdistribution hazard ratio, 0.87; 95% CI, 0.77-0.98).

CONCLUSIONS

Although both interleukin-6 and interleukin-10 productions are associated with death, the balance of these inflammatory mediators does not seem to impact either early, intermediate, or late mortality in patients presenting to the ICU with sepsis.

Association between mRNA expression of CD74 and IL10 and risk of ICU-acquired infections: a multicenter cohort study

Purpose

Intensive care unit (ICU)-acquired infections (IAI) result in increased hospital and ICU stay, costs and mortality. To date, no biomarker has shown sufficient evidence and ease of application in clinical routine for the identification of patients at risk of IAI. We evaluated the association of the systemic mRNA expression of two host response biomarkers, CD74 and IL10, with IAI occurrence in a large cohort of ICU patients.

Methods

ICU patients were prospectively enrolled in a multicenter cohort study. Whole blood was collected on the day of admission (D1) and on day 3 (D3) and day 6 (D6) after admission. Patients were screened daily for IAI occurrence and data were censored after IAI diagnosis. mRNA expression levels of biomarkers were measured using RT-qPCR. Fine and Gray competing risk models were used to assess the association between gene expression and IAI occurrence.

Results

A total of 725 patients were analyzed. At least one IAI episode occurred in 137 patients (19%). After adjustment for shock and sepsis status at admission, CD74 and IL10 levels were found to be significantly associated with IAI occurrence [subdistribution hazard ratio (95% confidence interval) 0.67 (0.46–0.97) for CD74 D3/D1 expression ratio and 2.21 (1.63–3.00) for IL10 at D3]. IAI cumulative incidence was significantly different between groups stratified according to CD74 or IL10 expression (Gray tests p < 0.001).

Conclusion

Our results suggest that two immune biomarkers, CD74 and IL10, could be relevant tools for the identification of IAI risk in ICU patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-017-4805-1) contains supplementary material, which is available to authorized users.

Increased PD-1 Expression and Altered T Cell Repertoire Diversity Predict Mortality in Patients with Septic Shock: A Preliminary Study

Sepsis causes impairment of innate and adaptive immunity by multiple mechanisms, including depletion of immune effector cells and T cell exhaustion. Although lymphocyte dysfunction is associated with increased mortality and potential reactivation of latent viral infection in patients with septic shock, the relation between viral reactivation and lymphocyte dysfunction is obscure. The objectives of this study were 1) to determine the relation of lymphocyte dysfunction to viral reactivation and mortality, and 2) to evaluate recovery of lymphocyte function during septic shock, including T cell receptor (TCR) diversity and the expression of programmed death 1 (PD-1). In 18 patients with septic shock and latent cytomegalovirus (CMV) infection, serial blood samples were obtained on days 1, 3, and 7 after the onset of shock, and immune cell subsets and receptor expression were characterized by flow cytometry. TCR diversity of peripheral blood mononuclear cells was analyzed by Multi-N-plex PCR, and CMV DNA was quantified using a real-time PCR kit. A decrease of TCR diversity and monocyte HLA-DR expression were observed in the early stage of septic shock, while CD4+ T cells displayed an increase of PD-1 expression. Significant lymphopenia persisted for at least 7 days following the onset of septic shock. Normalization of TCR diversity and PD-1 expression was observed by day 7, except in patients who died. CMV reactivation was detected in 3 of the 18 patients during the first week of their ICU stay and all 3 patients died. These changes are consistent with the early stage of immune cell exhaustion and indicate the importance of normal lymphocyte function for recovery from septic shock. Ongoing lymphocyte dysfunction is associated with CMV reactivation and dissemination, as well as with unfavorable outcomes.

Characterization of a model of systemic inflammation in humans in vivo elicited by continuous infusion of endotoxin

Investigating the systemic inflammatory response in patients with critical illness such as sepsis, trauma and burns is complicated due to uncertainties about the onset, duration and severity of the insult. Therefore, in vivo models of inflammation are essential to study the pathophysiology and to evaluate immunomodulatory therapies. Intravenous bolus administration of endotoxin to healthy volunteers is a well-established model of a short-lived systemic inflammatory response, characterized by increased plasma cytokine levels, flu-like symptoms and fever. In contrast, patients suffering from systemic inflammation are often exposed to inflammatory stimuli for an extended period of time. Therefore, continuous infusion of endotoxin may better reflect the kinetics of the inflammatory response encountered in these patients. Herein, we characterize a novel model of systemic inflammation elicited by a bolus infusion of 1 ng/kg, followed by a 3hr continuous infusion of 1 ng/kg/h of endotoxin in healthy volunteers, and compared it with models of bolus administrations of 1 and 2 ng/kg of endotoxin. The novel model was well-tolerated and resulted in a more pronounced increase in plasma cytokine levels with different kinetics and more prolonged symptoms and fever compared with the bolus-only models. Therefore, the continuous endotoxin infusion model provides novel insights into kinetics of the inflammatory response during continuous inflammatory stimuli and accommodates a larger time window to evaluate immunomodulating therapies.

New horizon in the treatment of sepsis: a systematic review of alternative medicine

BackgroundDespite great advancement in treatment of sepsis, mortality of sepsis remains unacceptably high, even with the modern antibiotic and intensive care technologies. Considering the key role of immune dysfunction in sepsis pathophysiology, different treatments were evaluated, but failed to improve survival of patients. Natural remedies have been tested in various studies to overcome sepsis. In this study, we aim to review some of the evidence from clinical, in vitro and in vivo studies about the effect of alternative medicine on sepsis management. MethodsThe following databases were searched up to March 2014: PubMed, Scopus, Web of Science, Ovid and Google Scholar using combination of Mesh term. All in vitro and in vivo studies, also clinical trials, published in English, which evaluated alternative medicine in management of sepsis were included. Results Out of 95 relevant studies, the inclusion criteria were met for 79 cases. Among them, 18 studies were performed on humans. The most herbal medicine, including Xubijing (n=10) and then Rhubarb (n=3). Most of the reviewed botanical medicines modulate the immune system. Reduction of mortality was also reported in studies. ConclusionsModulation of immune system, anti-inflammatory activities and improvement of survival were the action of herbal medicine. A monovalent approach is not enough for treatment of sepsis, we recommend further studies to identify active component of herbal and use them in combination. Also an animal model of sepsis does not exactly mimic human sepsis, so more clinical studies should be performed. With no new drug on the horizon, herbal medicine will be promising for treatment of sepsis.

Mice Survival and Plasmatic Cytokine Secretion in a "Two Hit" Model of Sepsis Depend on Intratracheal Pseudomonas Aeruginosa Bacterial Load

Sepsis is characterized by pro- and anti-inflammatory responses following infection. While inflammation is responsible for widespread organ damage, anti-inflammatory mediators lead to immunoparalysis increasing susceptibility to secondary infections (nosocomial pneumonia). We aimed to investigate the impact of bacterial load on survival and cytokine release in a two-hit murine (C57BL/6J) model of CLP followed by P. aeruginosa pneumonia. Plasmatic TNFα, IL-6, IL-10, sTNFr I and II were quantified until 13 days. At D5, splenocytes were processed for immunological assays or mice were intratracheally instilled with Pseudomonas aeruginosa (5.10⁶, 2.10⁷ and 10⁸ CFU) to evaluate survival and cytokines production. TNFα, sTNFrs, IL-6 and IL-10 increased 2h post CLP. TNFα and sTNFrs declined respectively one and two days later. In CLP mice, IL-6 and IL-10 remained high for the whole experiment, as compared to Sham. At D5, for CLP mice, whereas total T cells population (CD3+) decreased, Treg fraction (CD4+/CD25+) increased. In parallel, T cells proliferation and LPS-stimulated splenocytes ability to release TNFα decreased. At D13, survival was 100% after 5.10⁶ CFU, 50% for CLP mice after 2.10⁷ CFU and 0% for CLP and Sham after 10⁸ CFU. After instillation, IL-10 and IL-6 increased and appeared to be dose and time dependent. Pseudomonas was detected in all CLP and Sham’s lungs; in spleen and liver only in CLP at 2.10⁷ CFU, and in CLP and Sham at 10⁸ CFU. We demonstrated that post-CLP immunosuppression followed by Pseudomonas aeruginosa lung instillation increases mortality reactivates cytokines secretion and is associated with systemic dissemination in septic mice depending on bacterial load.

Innate Immunity and Asthma Risk in Amish and Hutterite Farm Children

BACKGROUND

The Amish and Hutterites are U.S. agricultural populations whose lifestyles are remarkably similar in many respects but whose farming practices, in particular, are distinct; the former follow traditional farming practices whereas the latter use industrialized farming practices. The populations also show striking disparities in the prevalence of asthma, and little is known about the immune responses underlying these disparities.

METHODS

We studied environmental exposures, genetic ancestry, and immune profiles among 60 Amish and Hutterite children, measuring levels of allergens and endotoxins and assessing the microbiome composition of indoor dust samples. Whole blood was collected to measure serum IgE levels, cytokine responses, and gene expression, and peripheral-blood leukocytes were phenotyped with flow cytometry. The effects of dust extracts obtained from Amish and Hutterite homes on immune and airway responses were assessed in a murine model of experimental allergic asthma.

RESULTS

Despite the similar genetic ancestries and lifestyles of Amish and Hutterite children, the prevalence of asthma and allergic sensitization was 4 and 6 times as low in the Amish, whereas median endotoxin levels in Amish house dust was 6.8 times as high. Differences in microbial composition were also observed in dust samples from Amish and Hutterite homes. Profound differences in the proportions, phenotypes, and functions of innate immune cells were also found between the two groups of children. In a mouse model of experimental allergic asthma, the intranasal instillation of dust extracts from Amish but not Hutterite homes significantly inhibited airway hyperreactivity and eosinophilia. These protective effects were abrogated in mice that were deficient in MyD88 and Trif, molecules that are critical in innate immune signaling.

CONCLUSIONS

The results of our studies in humans and mice indicate that the Amish environment provides protection against asthma by engaging and shaping the innate immune response. (Funded by the National Institutes of Health and others.).

TNF-related apoptosis-inducing ligand deficiency enhances survival in murine colon ascendens stent peritonitis

Background

Apart from inducing apoptosis in tumor cells, tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) influences inflammatory reactions. Murine colon ascendens stent peritonitis (CASP) represents a model of diffuse peritonitis. Recently, it has been demonstrated that administration of exogenous TRAIL not only induces apoptosis in neutrophils but also enhances survival in this model. The aim of this study was to examine the impact of genetic TRAIL deficiency on the course of CASP.

Methods

Peritonitis was induced in 6- to 8-week-old female TRAIL^−/− mice as well as in wild-type mice. The sepsis severity score and survival of mice were monitored. Bacterial loads in blood as well as in the lymphoid organs were examined. Additionally, the number of apoptotic cells within the lymphoid organs was determined.

Results

As early as 8 hours postinduction of CASP, TRAIL^−/− mice were significantly more affected by sepsis than wild-type mice, as measured by the sepsis severity score. However, during the further course of sepsis, TRAIL deficiency led to significantly decreased sepsis severity scores, resulting in an enhanced overall survival in TRAIL^−/− mice. The better survival of TRAIL^−/− mice was accompanied by a decreased bacterial load within the blood. In marked contrast, the number of apoptotic cells within the lymphoid organs was highly increased in TRAIL^−/− mice 20 hours after induction of CASP.

Conclusion

Hence, exogenous and endogenous TRAIL is protective during the early phase of sepsis, while endogenous TRAIL appears to be detrimental in the later course of this disease.

A Transcriptomic Biomarker to Quantify Systemic Inflammation in Sepsis - A Prospective Multicenter Phase II Diagnostic Study

Development of a dysregulated immune response discriminates sepsis from uncomplicated infection. Currently used biomarkers fail to describe simultaneously occurring pro- and anti-inflammatory responses potentially amenable to therapy.

Marker candidates were screened by microarray and, after transfer to a platform allowing point-of-care testing, validated in a confirmation set of 246 medical and surgical patients. We identified up-regulated pathways reflecting innate effector mechanisms, while down-regulated pathways related to adaptive lymphocyte functions. A panel of markers composed of three up- (Toll-like receptor 5; Protectin; Clusterin) and 4 down-regulated transcripts (Fibrinogen-like 2; Interleukin-7 receptor; Major histocompatibility complex class II, DP alpha1; Carboxypeptidase, vitellogenic-like) described the magnitude of immune alterations. The created gene expression score was significantly greater in patients with definite as well as with possible/probable infection than with no infection (median (Q25/Q75): 80 (60/101)) and 81 (58/97 vs. 49 (27/66), AUC-ROC = 0.812 (95%-CI 0.755–0.869), p < 0.0001). Down-regulated lymphocyte markers were associated with prognosis with good sensitivity but limited specificity.

Quantifying systemic inflammation by assessment of both pro- and anti-inflammatory innate and adaptive immune responses provides a novel option to identify patients-at-risk and may facilitate immune interventions in sepsis.

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Pro- and anti-inflammatory signaling occurs simultaneously in the host response to infection.

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This response is currently monitored using biomarkers restricted to the pro-inflammatory component of innate immunity.

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We developed a biomarker panel consisting of 7 transcripts that can assess both facets at the point of care.

The concept that a selective, overwhelming systemic inflammation, the “Systemic Inflammatory Response Syndrome (SIRS)”, triggers organ failure subsequent to infection has lately been abandoned as it neglects parallel occurring anti-inflammatory responses or defects in the adaptive immune system.

The present findings suggest that a compound panel of nucleic acid biomarkers that was developed in independent training and verification cohorts and transferred to a point-of-care platform can more comprehensively describe the host response. Quantification of an enhanced innate immunity might inform studies of anti-inflammatory therapies, while measurement of derangements in specific immunity might guide strategies to restore immune effector functions.