Human leukocyte antigen-DR expression on peripheral monocytes as a predictive marker of sepsis during acute pancreatitis

Monocytic HLA-DR Expression in Immune Responses of Acute Pancreatitis and COVID-19

Acute pancreatitis is a common gastrointestinal disease with increasing incidence worldwide. COVID-19 is a potentially life-threatening contagious disease spread throughout the world, caused by severe acute respiratory syndrome coronavirus 2. More severe forms of both diseases exhibit commonalities with dysregulated immune responses resulting in amplified inflammation and susceptibility to infection. Human leucocyte antigen (HLA)-DR, expressed on antigen-presenting cells, acts as an indicator of immune function. Research advances have highlighted the predictive values of monocytic HLA-DR (mHLA-DR) expression for disease severity and infectious complications in both acute pancreatitis and COVID-19 patients. While the regulatory mechanism of altered mHLA-DR expression remains unclear, HLA-DR^-/low monocytic myeloid-derived suppressor cells are potent drivers of immunosuppression and poor outcomes in these diseases. Future studies with mHLA-DR-guided enrollment or targeted immunotherapy are warranted in more severe cases of patients with acute pancreatitis and COVID-19.

Fire in the belly: A scoping review of the immunopathological mechanisms of acute pancreatitis

Introduction

Acute pancreatitis (AP) is characterised by an inflammatory response that in its most severe form can cause a systemic dysregulated immune response and progression to acute multi-organ dysfunction. The pathobiology of the disease is unclear and as a result no targeted, disease-modifying therapies exist. We performed a scoping review of data pertaining to the human immunology of AP to summarise the current field and to identify future research opportunities.

Methods

A scoping review of all clinical studies of AP immunology was performed across multiple databases. Studies were included if they were human studies of AP with an immunological outcome or intervention.

Results

205 studies met the inclusion criteria for the review. Severe AP is characterised by significant immune dysregulation compared to the milder form of the disease. Broadly, this immune dysfunction was categorised into: innate immune responses (including profound release of damage-associated molecular patterns and heightened activity of pattern recognition receptors), cytokine profile dysregulation (particularly IL-1, 6, 10 and TNF-α), lymphocyte abnormalities, paradoxical immunosuppression (including HLA-DR suppression and increased co-inhibitory molecule expression), and failure of the intestinal barrier function. Studies including interventions were also included. Several limitations in the existing literature have been identified; consolidation and consistency across studies is required if progress is to be made in our understanding of this disease.

Conclusions

AP, particularly the more severe spectrum of the disease, is characterised by a multifaceted immune response that drives tissue injury and contributes to the associated morbidity and mortality. Significant work is required to develop our understanding of the immunopathology of this disease if disease-modifying therapies are to be established.

Circulating monocytes in acute pancreatitis

Acute pancreatitis is a common gastrointestinal disease characterized by inflammation of the exocrine pancreas and manifesting itself through acute onset of abdominal pain. It is frequently associated with organ failure, pancreatic necrosis, and death. Mounting evidence describes monocytes - phagocytic, antigen presenting, and regulatory cells of the innate immune system - as key contributors and regulators of the inflammatory response and subsequent organ failure in acute pancreatitis. This review highlights the recent advances of dynamic change of numbers, phenotypes, and functions of circulating monocytes as well as their underling regulatory mechanisms with a special focus on the role of lipid modulation during acute pancreatitis.

Prospective multicentre study of host response signatures in neonatal sepsis in Sub Saharan Africa

Few biomarkers for sepsis diagnosis are commonly used in neonatal sepsis. While the role of host response is increasingly recognized in sepsis pathogenesis and prognosis, there is a need for evaluating new biomarkers targeting host response in regions where sepsis burden is high and medico-economic resources are scarce. The objective of the study is to evaluate diagnostic and prognostic accuracy of biomarkers of neonatal sepsis in Sub Saharan Africa. This prospective multicentre study included newborn infants delivered in the Abomey-Calavi region in South Benin and their follow-up from birth to 3 months of age. Accuracy of transcriptional (CD74, CX3CR1), proteic (PCT, IL-6, IL-10, IP-10) biomarkers and clinical characteristics to diagnose and prognose neonatal sepsis were measured. At delivery, cord blood from all consecutive newborns were sampled and analysed, and infants were followed for a 12 weeks' period. Five hundred and eighty-one newborns were enrolled. One hundred and seventy-two newborns developed neonatal sepsis (29.6%) and death occurred in forty-nine infants (8.4%). Although PCT, IL-6 and IP-10 levels were independently associated with sepsis diagnosis, diagnostic accuracy of clinical variables combinations was similar to combinations with biomarkers and superior to biomarkers alone. Nonetheless, CD74, being the only biomarkers independently associated with mortality, showed elevated prognosis accuracy (AUC > 0.9) either alone or in combination with other biomarkers (eg. CD74/IP-10) or clinical criterion (eg. Apgar 1, birth weight). These results suggest that cord blood PCT had a low accuracy for diagnosing early onset neonatal sepsis in Sub Saharan African neonates, while association of clinical criterion showed to be more accurate than any biomarkers taken independently. At birth, CD74, either associated with IP-10 or clinical criterion, had the best accuracy in prognosing sepsis mortality.Trial registration Clinicaltrial.gov registration number: NCT03780712. Registered 19 December 2018. Retrospectively registered.

Flow cytometry-based high-throughput RNAi screening for miRNAs regulating MHC class II HLA-DR surface expression

HLA‐DR isotype is a MHC‐II cell‐surface receptor found on APCs and plays a key role in initiating immune responses. In severely immunocompromised patients with conditions like sepsis, the number of HLA‐DR molecules expressed on leukocytes is considered to correlate with infectious complications and patients’ probability of survival. The underlying regulatory mechanisms of HLA‐DR expression remain largely unknown. One probable path to regulation is through microRNAs (miRNAs), which have been implicated as regulatory elements of both innate and adaptive immune system development and function. In our study, flow cytometry‐based high‐throughput miRNA screening was performed in a stable HLA‐DR‐expressing human melanoma cell line, MelJuSo, for either up‐ or downregulating miRNAs of the surface HLA‐DR expression. By the end of the screening, the top ten upregulators and top five downregulators were identified, and both the HLA‐DR protein and mRNA regulations were further verified and validated. In‐silico approaches were applied for functional miRNA‐mRNA interaction prediction. The potential underlying gene regulations of different miRNAs were proposed. Our results promote the study of miRNA‐mediated HLA‐DR regulation under both physiological and pathological conditions, and may pave the way for potential clinical applications.

Concomitant Assessment of Monocyte HLA-DR Expression and Ex Vivo TNF-α Release as Markers of Adverse Outcome after Various Injuries—Insights from the REALISM Study

Intensive care unit (ICU) patients develop an altered host immune response after severe injuries. This response may evolve towards a state of persistent immunosuppression that is associated with adverse clinical outcomes. The expression of human leukocyte antigen DR on circulating monocytes (mHLA-DR) and ex vivo release of tumor necrosis factor α (TNF-α) by lipopolysaccharide-stimulated whole blood are two related biomarkers offered to characterize this phenomenon. The purpose of this study was to concomitantly evaluate the association between mHLA-DR and TNF-α release and adverse clinical outcome (i.e., death or secondary infection) after severe trauma, sepsis or surgery in a cohort of 353 ICU patients. mHLA-DR and TNF-α release was similarly and significantly reduced in patients whatever the type of injury. Persistent decreases in both markers at days 5–7 (post-admission) were significantly associated with adverse outcomes. Overall, mHLA-DR (measured by flow cytometry) appears to be a more robust and standardized parameter. Each marker can be used individually as a surrogate of immunosuppression, depending on center facilities. Combining these two parameters could be of interest to identify the most immunosuppressed patients presenting with a high risk of worsening. This last aspect deserves further exploration.

Immunomonitoring of Monocyte and Neutrophil Function in Critically Ill Patients: From Sepsis and/or Trauma to COVID-19

Immune cells and mediators play a crucial role in the critical care setting but are understudied. This review explores the concept of sepsis and/or injury-induced immunosuppression and immuno-inflammatory response in COVID-19 and reiterates the need for more accurate functional immunomonitoring of monocyte and neutrophil function in these critically ill patients. in addition, the feasibility of circulating and cell-surface immune biomarkers as predictors of infection and/or outcome in critically ill patients is explored. It is clear that, for critically ill, one size does not fit all and that immune phenotyping of critically ill patients may allow the development of a more personalized approach with tailored immunotherapy for the specific patient. In addition, at this point in time, caution is advised regarding the quality of evidence of some COVID-19 studies in the literature.

Immune Dysfunction is Associated with Readmission in Survivors of Sepsis Following Infected Pancreatic Necrosis

Objective

Immunosuppression is common in patients with infected pancreatic necrosis (IPN) and associated with morbidity and mortality. This study aimed to investigate the impact of immune status on mortality and readmission after hospital discharge in patients with IPN-related sepsis.

Methods

In this prospective observational study, eligible adult patients with IPN-related sepsis requiring ICU admission were included. Monocytic human leukocyte antigen DR (mHLA-DR), expression of regulatory T cells (Treg), and neutrophil CD88 (nCD88) were measured on the diagnosis of sepsis, ICU discharge, hospital discharge, and 15, 30, 60 days after hospital discharge. Logistic regression model was used to assess potential risk factors for readmission 60-days within the index discharge.

Results

A total of 53 patients were included, 13 died during hospitalization and one withdrew the consent soon after discharge. Among the survivors, a tendency of immune recovery was observed during the consecutive follow-ups, evidenced by the increased expression of mHLA-DR. Sixteen patients (41.03%) were readmitted within 60 days after the index discharge. In the multivariable regression model, APACHE II score when sepsis was diagnosed >9 and mHLA-DR at discharged <14,591 AB/C were found to be independent risk factors affecting readmission.

Conclusion

Immunosuppression is common in patients with IPN-related sepsis and can persist until two months after discharge. The compromised mHLA-DR level at discharge was associated with readmission within two months after discharge.

Prognostic value of peripheral blood CD14+HLA-DR+ monocytes in patients with acute pancreatitis

Acute pancreatitis (AP) is characterized by a potent pro-inflammatory response and concomitant anti-inflammatory response leading to a state of immunosuppression. Decreased HLA (Human Leukocyte Antigen)-DR expression on monocytes is a reliable cellular marker of immune suppression. The main objective of this study was to investigate the clinical value of the percentage of peripheral blood CD14+ HLA-DR+ monocytes (mHLA-DR) for diagnosis and assessment of severity, development of organ failures (OF), local complications (LC), and infected necrosis (IN), and outcome in patients with AP. Flow cytometry was used to measure the percentage of peripheral blood mHLA-DR at different time points in 82 patients with AP enrolled during the period of 2012-2018 admitted to University Hospital Stara Zagora, Bulgaria. The percentages of peripheral blood mHLA-DR in AP patients were significantly associated with severity, development of LC, OF, IN (measured at admission, on the 48^th hour and on the 5^th day) and with outcome (measured on the 5^th day) of AP. The value of peripheral blood mHLA-DR may be used as a biological marker in the diagnosis and assessment of severity, development of OF, LC, IN and to predict outcome in AP.

Effects of perioperative transcutaneous electrical acupoint stimulation on monocytic HLA-DR expression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass: study protocol for a double-blind randomized controlled trial

BACKGROUND

Cardiac surgery involving cardiopulmonary bypass (CPB) is known to be associated with a transient postoperative immunosuppression. When severe and persistent, this immune dysfunction predisposes patients to infectious complications, which contributes to a prolonged stay in the intensive care unit (ICU), and even mortality. Effective prevention and treatment methods are still lacking. Recent studies revealed that acupuncture-related techniques, such as electroacupuncture and transcutaneous electrical acupoint stimulation (TEAS), are able to produce effective cardioprotection and immunomodulation in adult and pediatric patients undergoing cardiac surgery with CPB, which leads to enhanced recovery. However, whether perioperative application of TEAS, a non-invasive technique, is able to improve immunosuppression of the patients with post-cardiosurgical conditions is unknown. Thus, as a preliminary study, the main objective is to evaluate the effects of TEAS on the postoperative expression of monocytic human leukocyte antigen (-D related) (mHLA-DR), a standardized "global" biomarker of injury or sepsis-associated immunosuppression, in patients receiving on-pump coronary artery bypass grafting (CABG).

METHODS

This study is a single-center clinical trial. The 88 patients scheduled to receive CABG under CPB will be randomized into two groups: the group receiving TEAS, and the group receiving transcutaneous acupoint pseudo-electric stimulation (Sham TEAS). Expression of mHLA-DR serves as a primary endpoint, and other laboratory parameters (e.g., interleukin [IL]-6, IL-10) and clinical outcomes (e.g., postoperative infectious complications, ICU stay time, and mortality) as the secondary endpoints. In addition, immune indicators, such as high mobility group box 1 protein and regulatory T cells will also be measured.

DISCUSSION

The current study is a preliminary monocentric clinical trial with a non-clinical primary endpoint, expression of mHLA-DR, aiming at determining whether perioperative application of TEAS has a potential to reverse CABG-associated immunosuppression. Although the immediate clinical impact of this study is limited, its results would inform further large-sample clinical trials using relevant patient-centered clinical outcomes as primary endpoints.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02933996. Registered on 13 October 2016.

Improvement of Immune Dysfunction in Patients with Severe Acute Pancreatitis by High-Volume Hemofiltration: A Preliminary Report

Objective

The aim of this study was to investigate the effect of high-volume hemofiltration (HVHF) on ameliorating immune dysfunction in patients with severe acute pancreatitis (SAP).

Methods

Twelve patients diagnosed with SAP admitted to the intensive care unit of general surgery, Jinling Hospital, from January 2004 to December 2006 were included in this study. They were assigned to the standard medical therapy group (SMT group, n=4) or HVHF group (n=8) immediately after enrollment, in a 1:2 ratio. The SMT group were given standard treatment for SAP, while the HVHF group were given standard as well as 72-hour HVHF treatment initiated within 2 hours after enrollment. Patients in the 2 groups were comparable for the baseline clinical parameters. All patients were monitored over a 72-hour observation period for continuous clinical status, blood cell counts including monocytes, CD4+ and CD8+ T cells, and HLA-DR expression on monocytes. Blood samples were collected from those patients at 0, 6, 12, 24, 48, and 72 hour after enrollment for measurement of plasma Th1-type cytokines (interleukin-1 [IL-1], IL-2, interferon-γ [IFN-γ], and tumor necrosis factor-α [TNF-α]) and Th2-type cytokines (IL-4, IL-5, IL-6, IL-10, and IL-13) using ELISA.

Results

Within 72 hours, all measured cytokines except IL-4 were maintained at high levels, accompanied with a low level of peripheral monocytes, CD4+ and CD8+ T cell counts, and HLA-DR expression. Seventy-two hours later, plasma cytokines IFN-γ, IL-1, IL-2, IL-5, IL-10, and IL-13 (p<0.05), but not TNF-α and IL-6, in patients in the HVHF group were significantly reduced, while there was no change for these parameters in the SMT group. Plasma levels of IFN-γ, TNF-α, IL-1, IL-2, IL-5, and IL-13 in the HVHF group were significantly lower than those in the SMT group. Peripheral CD4+ and CD8+ T cells, monocyte count, and HLA-DR expression were increased significantly (p<0.05) only in the HVHF group, not in the SMT group. HLA-DR expression in the HVHF group was significant higher than that in the SMT group (p<0.05).

Conclusions

HVHF significantly reduced plasma inflammatory cytokine concentrations including those of IFN-γ, TNF-α, IL-1, IL-2, IL-5, and IL-13, while it increased monocyte HLA-DR expression in patients with SAP. The association of plasma cytokine reduction and cellular immune function recovery and clinical outcome needs further investigation.

Association of Systemic Inflammatory and Anti-inflammatory Responses with Adverse Outcomes in Acute Pancreatitis: Preliminary Results of an Ongoing Study

INTRODUCTION

This paper reports preliminary data of an ongoing study that evaluates the association of systemic inflammatory response (SIRS) with early severe acute pancreatitis (ESAP) and compensatory anti-inflammatory response syndrome (characterized by HLA-DR down-regulation) with infected pancreatic necrosis (IPN).

METHODS

Consecutive patients presenting within 72 h of symptom onset with organ dysfunction and/or local complications were included. Following parameters were recorded: demographics, etiology, SIRS, APACHE II, creatinine, BUN. Circulating IL-8, IL-6, IL-10, TNF-alpha concentrations and expression of HLA-DR and IL-10 by qRT-PCR in PBMCs were measured. Strength of associations of cytokine concentration and HLA-DR/IL-10 expression with outcomes was expressed as Hedges' G and relative risk (95% CI).

RESULTS

Twenty-eight patients (10 MSAP; 18 SAP) fulfilled inclusion criteria. Twelve patients had ESAP and eight presented with organ failure. Admission SIRS worsened in eight (28.6%) patients over 48 h. Sixteen (57.1%) patients developed primary IPN. Twenty-one (75%) patients had HLA-DR down-regulation during the first week, which persisted to the second week in 12 (42.9%) patients. IL-8, IL-6, and TNF-α progressively increased from healthy controls to MAP to MSAP to SAP. IL-6 and TNF-α was higher in the patients who developed ESAP (p = 0.01 and 0.05, respectively). Patients who died within the first week also had a significantly elevated concentration of IL-6 and TNF-α (p = 0.02 and 0.01, respectively). The relative risk (95% CI) of developing primary IPN with persistent HLA-DR down-regulation till the second week of illness was 11.3 (1.6-82.4; p = 0.01).

CONCLUSIONS

Our study objectively demonstrates significant association of ESAP and early mortality with primary cytokine response, and development of IPN with persistent HLA-DR down-regulation.

Assessment of immune organ dysfunction in critical illness: utility of innate immune response markers

In critically ill patients, organ dysfunctions are routinely assessed, monitored, and treated. Mounting data show that substantial critical illness-induced changes in the immune system can be observed in most ICU patients and that not only "hyper-inflammation" but also persistence of an anti-inflammatory phenotype (as in sepsis-associated immunosuppression) is associated with increased morbidity and mortality. Despite common perception, changes in functional immunity cannot be adequately assessed by routine inflammatory biomarkers such as C-reactive protein, procalcitonin, or numerical analysis of leukocyte (sub)-counts. Cytokines appear also not suited due to their short half-life and pleiotropy, their unexclusive origin from immune cells, and their potential to undergo antagonization by circulating inactivating molecules. Thus, beyond leukocyte quantification and use of routine biomarkers, direct assessment of immune cell function seems required to characterize the immune systems' status. This may include determination of, e.g., ex vivo cellular cytokine release, phagocytosis activity, and/or antigen-presenting capacity. In this regard, standardized flow-cytometric assessment of the major histocompatibility-II complex human leukocyte antigen (-D related) (HLA-DR) has gained particular interest. Monocytic HLA-DR (mHLA-DR) controls the interplay between innate and adaptive immunity and may serve as a "global" biomarker of injury-associated immunosuppression, and its decreased expression is associated with adverse clinical outcomes (e.g., secondary infection risk, mortality). Importantly, recent data demonstrate that injury-associated immunosuppression can be reversed-opening up new therapeutic avenues in affected patients. Here we discuss the potential scientific and clinical value of assessment of functional immunity with a focus on monocytes/macrophages and review the current state of knowledge and potential perspectives for affected critically ill patients.

Management of Sepsis-Induced Immunosuppression

It is now well established that profound immunosuppression develops within a few days after sepsis onset in patients. This should be considered additional organ failure because it is associated with increased rate of nosocomial infections, mortality, and long-term complications, thus constituting the rationale for immunomodulation in patients. Nevertheless, the demonstration of the efficacy of such therapeutic strategy in improving deleterious outcomes in sepsis remains to be made. Results from clinical trials based on interleukin 7 and granulocyte macrophage colony-stimulating factor immunoadjuvant therapies in septic shock patients are expected for 2018.

Development of a Modular Assay for Detailed Immunophenotyping of Peripheral Human Whole Blood Samples by Multicolor Flow Cytometry

The monitoring of immune cells gained great significance in prognosis and prediction of therapy responses. For analyzing blood samples, the multicolor flow cytometry has become the method of choice as it combines high specificity on single cell level with multiple parameters and high throughput. Here, we present a modular assay for the detailed immunophenotyping of blood (DIoB) that was optimized for an easy and direct application in whole blood samples. The DIoB assay characterizes 34 immune cell subsets that circulate the peripheral blood including all major immune cells such as T cells, B cells, natural killer (NK) cells, monocytes, dendritic cells (DCs), neutrophils, eosinophils, and basophils. In addition, it evaluates their functional state and a few non-leukocytes that also have been associated with the outcome of cancer therapy. This DIoB assay allows a longitudinal and close-meshed monitoring of a detailed immune status in patients requiring only 2.0 mL of peripheral blood and it is not restricted to peripheral blood mononuclear cells. It is currently applied for the immune monitoring of patients with glioblastoma multiforme (IMMO-GLIO-01 trial, NCT02022384), pancreatic cancer (CONKO-007 trial, NCT01827553), and head and neck cancer (DIREKHT trial, NCT02528955) and might pave the way for immune biomarker identification for prediction and prognosis of therapy outcome.

Reduced lymphocyte count as an early marker for predicting infected pancreatic necrosis

BACKGROUND

Early occurrence of immunosuppression is a risk factor for infected pancreatic necrosis (IPN) in the patients with acute pancreatitis (AP). However, current measures for the immune systems are too cumbersome and not widely available. Significantly decreased lymphocyte count has been shown in patients with severe but not mild type of AP. Whereas, the correlation between the absolute lymphocyte count and IPN is still unknown. We conduct this study to reveal the exact relationship between early lymphocyte count and the development of IPN in the population of AP patients.

METHODS

One hundred and fifty-three patients with acute pancreatitis admitted to Jinling Hospital during the period of January 2012 to July 2014 were included in this retrospective study. The absolute lymphocyte count and other relevant parameters were measured on admission. The diagnosis of IPN was based on the definition of the revised Atlanta classification.

RESULTS

Patients were divided into two groups according to the presence of IPN. Thirty patients developed infected necrotizing pancreatitis during the disease course. The absolute lymphocyte count in patients with IPN was significantly lower on admission (0.62 × 10(9)/L, interquartile range [IQR]: 0.46-0.87 × 10(9)/L vs. 0.91 × 10(9)/L, IQR: 0.72-1.27 × 10(9)/L, p < 0.001) and throughout the whole clinical course than those without IPN. Logistic regression indicated that reduced lymphocyte count was an independent risk factor for IPN. The optimal cut-offs from ROC curve was 0.66 × 10(9)/L giving sensitivity of 83.7 % and specificity of 66.7 %.

CONCLUSIONS

Reduced lymphocyte count within 48 h of AP onset is significantly and independently associated with the development of IPN.

HLA-DR expression on monocytes is decreased in polytraumatized patients

BACKGROUND

Sepsis, systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) remain the most frequent causes of complications and death in severely injured patients. A main reason for the development of these syndromes is a post-traumatic dysregulation of the immune system. Several studies in intensive care unit (ICU) patients could detect a pivotal role of HLA-DR expression on monocytes. So far, its importance for development of SIRS, sepsis or MODS in the severely injured patient is not clear.

METHODS

Therefore, we have analysed HLA-DR expression on monocytes from severely injured patients (ISS > 16) during the post-traumatic course, which was on the day of trauma, as well as on days 3, 7 and 14 post trauma. Clinical data were analysed and the HLA-DR expression levels of patients who developed post-traumatic sepsis, SIRS or MODS were compared to those with a more favourable outcome. Young and healthy volunteers as well as patients undergoing prosthetic hip replacement after trauma were enrolled as control groups. HLA-DR molecules on monocytes were marked with PE-conjugated antibodies and the mean fluorescence intensity (MFI) was analysed via flow cytometry.

RESULTS

24 severely injured patients (mean age 34 ± 2.7 years) mainly after high energy motor vehicle accidents as well as 8 controls (total hip replacement) and 9 healthy volunteers (mean age 26.2 ± 1.2 years) were enrolled. A total of eight patients suffered from sepsis (33.3 %) (six males, two females) and 17 patients suffered from SIRS (70.9 %) (10 males, 7 females). MODS was present in five patients (20.8 %), three male and two female patients. In four of these five patients the MODS developed subsequent to sepsis. HLA-DR expression significantly decreased after trauma and slowly returned to normal after 14 days, irrespective of the complications developed.

CONCLUSION

In conclusion, post-traumatic HLA-DR expression on monocytes is significantly reduced after multiple trauma and it is back to normal on day 14. No significant changes in HLA-DR expression on monocytes from severely injured patients suffering from SIRS, MODS or sepsis compared to those who did not have complications could be detected. Nevertheless, HLA-DR expression on monocytes may be used to identify the immunological pro- or anti-inflammatory phase the patient is going through.

Host response biomarkers in the diagnosis of sepsis: a general overview

Critically ill patients who display a systemic inflammatory response syndrome (SIRS) are prone to develop nosocomial infections. The challenge remains to distinguish as early as possible among SIRS patients those who are developing sepsis. Following a sterile insult, damage-associated molecular patterns (DAMPs) released by damaged tissues and necrotic cells initiate an inflammatory response close to that observed during sepsis. During sepsis, pathogen-associated molecular patterns (PAMPs) trigger the release of host mediators involved in innate immunity and inflammation through identical receptors as DAMPs. In both clinical settings, a compensatory anti-inflammatory response syndrome (CARS) is concomitantly initiated. The exacerbated production of pro- or anti-inflammatory mediators allows their detection in biological fluids and particularly within the bloodstream. Some of these mediators can be used as biomarkers to decipher among the patients those who developed sepsis, and eventually they can be used as prognosis markers. In addition to plasma biomarkers, the analysis of some surface markers on circulating leukocytes or the study of mRNA and miRNA can be helpful. While there is no magic marker, a combination of few biomarkers might offer a high accuracy for diagnosis.

Immunomodulatory therapies for acute pancreatitis

It is currently difficult for conventional treatments of acute pancreatitis (AP), which primarily consist of anti-inflammatory therapies, to prevent the progression of AP or to improve its outcome. This may be because the occurrence and progression of AP, which involves various inflammatory cells and cytokines, includes a series of complex immune events. Considering the complex immune system alterations during the course of AP, it is necessary to monitor the indicators related to immune cells and inflammatory mediators and to develop more individualized interventions for AP patients using immunomodulatory therapy. This review discusses the recent advances in immunomodulatory therapies. It has been suggested that overactive inflammatory responses should be inhibited and excessive immunosuppression should be avoided in the early stages of AP. The optimal duration of anti-inflammatory therapy may be shorter than previously expected (< 24 h), and appropriate immunostimulatory therapies should be administered during the period from the 3^rd d to the 14^th d in the course of AP. A combination therapy of anti-inflammatory and immune-stimulating drugs would hopefully constitute an alternative to anti-inflammatory drug monotherapy. Additionally, the detection of the genotypes of critical inflammatory mediators may be useful for screening populations of AP patients at high risk of severe infections to enable the administration of early interventions to improve their prognosis.

The role of Fas expression on the occurrence of immunosuppression in severe acute pancreatitis

BACKGROUND

Severe acute pancreatitis (SAP) is a dangerous illness with high mortality where most patients do not die of excessive inflammation, but die of immunosuppression and multiple infections at a later stage. The mechanism of immunosuppression in SAP is unknown.

AIM

The purpose of this study was to analyze the role of Fas expression on the occurrence of immunosuppression in patients with SAP.

METHODS

Forty-eight patients with pancreatitis were divided into two groups: 20 cases with SAP (7 cases with sepsis, 13 cases without sepsis) and 28 cases with mild acute pancreatitis (MAP). Twenty-eight healthy volunteers were selected as controls. Fas mRNA expression in peripheral blood was detected by qPCR and Fas protein of lymphocyte membranes; T lymphocyte subsets and expression of monocyte Human leukocyte antigen DR (HLA-DR) in peripheral blood were detected by flow cytometry.

RESULTS

Compared with MAP and control groups, expression level of Fas mRNA and lymphocyte Fas protein in peripheral blood were significantly increased in the SAP group (all P < 0.01). There was a further significant increase in the SAP group with sepsis compared to those without sepsis (all P < 0.01). The CD4(+) T cell ratio, CD4(+)/CD8(+) ratio and monocyte HLA-DR expression in the SAP group were decreased significantly compared with MAP and control groups (all P < 0.01). Significant negative relationships were observed between Fas mRNA expression and CD4(+) T-cell ratio, CD4(+)/CD8(+) ratio, and monocyte HLA-DR expression in SAP patients with sepsis (all P < 0.05).

CONCLUSIONS

The results suggest that expression level of Fas is related to severity and immune status of pancreatitis. Overexpression of Fas may lead to the occurrence of immunosuppression and sepsis.

Effects of corticotropin-releasing hormone on proopiomelanocortin derivatives and monocytic HLA-DR expression in patients with septic shock

Little is known about interactions between immune and neuro-endocrine systems in patients with septic shock. We therefore evaluated whether the corticotropin-releasing hormone (CRH) and/or proopiomelanocortin (POMC) derivatives [ACTH, β-endorphin (β-END), β-lipotropin (β-LPH), α-melanocyte stimulating hormone (α-MSH) or N-acetyl-β-END (Nac-β-END)] have any influences on monocyte deactivation as a major factor of immunosuppression under septic shock conditions. Sixteen patients with septic shock were enrolled in a double-blind, cross-over and placebo controlled clinical study; 0.5μg/(kgbodyweighth) CRH (or placebo) were intravenously administered for 24h. Using flow cytometry we investigated the immunosuppression in patients as far as related to the loss of leukocyte surface antigen-DR expression on circulating monocytes (mHLA-DR). ACTH, β-END immunoreacive material (IRM), β-LPH IRM, α-MSH and Nac-β-END IRM as well as TNF-α and mHLA-DR expression were determined before, during and after treatment with CRH (or placebo). A significant correlation between plasma concentration of α-MSH and mHLA-DR expression and an inverse correlation between mHLA-DR expression and TNF-α plasma level were found. Additionally, a significant increase of mHLA-DR expression was observed 16h after starting the CRH infusion; 8h later, the mHLA-DR expression had decreased again. Our results indicate that the up-regulation of mHLA-DR expression after CRH infusion is not dependent on the release of POMC derivatives. From the correlation between plasma concentration of α-MSH and mHLA-DR expression, we conclude that in patients with septic shock the down-regulation of mHAL-DR expression is accompanied by the loss of monocytic release of α-MSH into the cardiovascular compartment.

CD14, CD16 and HLA-DR reliably identifies human monocytes and their subsets in the context of pathologically reduced HLA-DR expression by CD14(hi) /CD16(neg) monocytes: Expansion of CD14(hi) /CD16(pos) and contraction of CD14(lo) /CD16(pos) monocytes in acute liver failure

Changes in monocytes and their subsets (CD14(hi)/CD16(neg), CD14(hi)/CD16(pos) and CD14(lo)/CD16(pos)) have been described in several diseases. The combination of CD14, CD16 and HLA-DR has been suggested to discriminate monocytes from the CD16(pos) /HLA-DR(neg) NK-cells and neutrophils but no data exist whether this strategy can be used in situations when monocyte HLA-DR expression is pathologically reduced. Monocytes and their subsets were concurrently identified through negative (exclusion of CD66b(pos) neutrophils, CD56(pos) NKcells, CD19(pos) B-cells, and CD3(pos) T-cells) and positive gating (inclusion of monocytes by expression of CD14, CD16, and HLA-DR) strategies on 30 occasions [9 healthy controls (HC) and 21 patients with conditions associated with low monocyte HLA-DR expression]. Bland-Altman and Passing and Bablok regression statistics did not demonstrate any significant measurement bias between the two strategies of monocyte identification. Monocyte subset phenotype was then compared in 18 HC and 41 patients with acute liver failure (ALF). Compared with HC, in ALF, the percentage of CD14(hi)/CD16(pos) monocytes was higher (7% vs 4%) whilst the percentage of CD14(lo)/CD16(pos) was lower (1.9% vs. 7%) (P ≤ 0.001); HLA-DR and CD86 MFIs on all monocyte subsets were lower, whilst CCR5, CD64, and CD11b MFIs were higher (P < 0.05). The relative expression by monocyte subsets of HLA-DR, CCR2, CCR5, CX3CR1, and CD11a was similar in ALF patients and HCs. Repeat analysis of an identical antibody-fluorochrome "backbone" targeting HLA-DR, CD14, and CD16 was assessed in 189 samples across 5 different experiments. There was excellent agreement in the results obtained using the positive gating strategy (interclass correlation coefficients > 0.8). Monocytes and their subsets can be reliably identified using an antibody-fluorochrome "backbone" of HLA-DR, CD14, and CD16. CD16(pos) monocytes continue to constitutively express HLA-DR even in conditions where HLA-DR is pathologically reduced on CD14(hi)/CD16(neg) monocytes. Understanding the changes in monocyte pheontype in ALF and similar clinico-pathological diseases may allow the development of novel biomarkers or therapeutic strategies.

[Host inflammatory and anti-inflammatory response during sepsis]

Sepsis still remains the major complication for patients admitted in intensive care units (ICU), and is responsible for numerous deaths. ICU patients admitted after sepsis, hemorrhagic shock, severe trauma, severe burns or major surgery show a systemic inflammatory response syndrome (SIRS). This syndrome is characterized by an exacerbation of inflammation, with increased levels of pro- (IL-1β, TNFα, IL-6, IL-8) as well as anti-inflammatory (IL-10, IL-1Ra, TGFβ) cytokines into their bloodstream. During sepsis, the bacteria release microbial motifs such as peptidoglycan, lipopolysaccharide (LPS) and DNA that initiate the inflammatory response, and are involved in the onset of multiple organ failure. The same microbial motifs can also be found in patients with a SIRS of non-infectious origin, following the translocation of bacteria from their digestive tract. This translocation is certainly contributing to the difficulty of discriminating between septic and SIRS patients using biological markers. Furthermore, the host response is accompanied by an alteration of the ex vivo response of circulating leukocytes, particularly monocytes. This hyporesponsiveness to LPS is associated with a decreased activation of the transcription factor NF-κB (required for the expression of pro-inflammatory cytokines) and an increased expression of negative regulators of the NF-κB pathway. However, the leukocyte hyporesponsiveness is not a global phenomenon, it depends on the type of patient, on the receptor-activator pair, on the timing, and on the cytokine.

Early interleukin-6 and slope of monocyte human leukocyte antigen-DR: a powerful association to predict the development of sepsis after major trauma

OBJECTIVE

Major trauma is characterized by a pro-inflammatory response, followed by an immunosuppression. Recently, in trauma patients, the lack of recovery of monocyte Human Leukocyte Antigen DR (mHLA-DR, a biomarker of ICU-acquired immunosuppression) between days 1-2 and days 3-4 has been demonstrated to be independently associated with sepsis development. The main objective of this study was to determine whether early measurements of IL-6 (interleukin-6) and IL-10 plasma concentrations (as markers of initial severity) could improve, in association with mHLA-DR recovery, the prediction of sepsis occurrence in severe trauma patients.

DESIGN

Prospective observational study over 24 months in a Trauma ICU at university hospital.

PATIENTS

Trauma patients with an ISS over 25 and age over 18 were included.

MEASUREMENTS AND MAIN RESULTS

mHLA-DR was assessed by flow cytometry, IL-6 and IL-10 concentrations by ELISA. 100 consecutive severely injured patients were monitored (mean ISS 37±10). 37 patients developed sepsis. IL-6 concentrations and slope of mHLA-DR expression between days 1-2 and days 3-4 were significantly different between septic and non-septic patients. IL-10 was not detectable in most patients. After adjustment for usual clinical confounders, when assessed as a pair, multivariate logistic regression analysis revealed that a slope of mHLA-DR expression (days 3-4/days 1-2)≤1.1 and a IL-6 concentration ≥ 67.1 pg/ml remained highly associated with the development of sepsis (adjusted OR 18.4, 95% CI 4.9; 69.4, p = .00002).

CONCLUSIONS

After multivariate regression logistic analysis, when assessed as a pair, a high IL-6 concentration and a persistent mHLA-DR decreased expression were found to be in relation with the development of sepsis with the best predictive value. This study underlines the usefulness of daily monitoring of immune function to identify trauma patients at a high risk of infection.

Thymosin alpha 1 is associated with improved cellular immunity and reduced infection rate in severe acute pancreatitis patients in a double-blind randomized control study

The aim of this prospective, double-blinded pilot trial study was to evaluate the effects of Thymosin alpha 1 use in the early phase on immunomodulation and clinical outcomes in patients with severe acute pancreatitis (SAP). A total of 24 patients with SAP were randomized to receive either conventional therapy for SAP or immunomodulatory therapy (TA1 group). The patients in the thymosin group were injected with Talpha1 3.2 mg twice per day for 7 days. The serum level of HLA-DR and CD4/CD8 ratio and other immune parameters were measured on admission, the 8th day and the 28th day. There was a low expression of monocyte HLA-DR in both groups on admission, and more rapid alterations in the HLA-DR were found in the TA1 group. The positive rates of blood and abdominal drainage culture were statistically significant during the 28th follow-up period. The duration of ICU stay was shorter after TA1 treatment. Improves cell-induced immunity and reduces infection rate in severe acute pancreatitis patients.

Lack of recovery in monocyte human leukocyte antigen-DR expression is independently associated with the development of sepsis after major trauma

Introduction

Major trauma is characterized by an overwhelming pro-inflammatory response and an accompanying anti-inflammatory response that lead to a state of immunosuppression, as observed after septic shock. Diminished monocyte Human Leukocyte Antigen DR (mHLA-DR) is a reliable marker of monocyte dysfunction and immunosuppression. The main objective of this study was to determine the relation between mHLA-DR expression in severe trauma patients and the development of sepsis.

Methods

We conducted a prospective observational study over 23 months in a trauma intensive care unit at a university hospital. Patients with an Injury Severity Score (ISS) over 25 and age over 18 were included. mHLA-DR was assessed by flow cytometry protocol according to standardized protocol. Mann-Whitney U-test for continuous non-parametric variables, independent paired t test for continuous parametric variables and chi-square test for categorical data were used.

Results

mHLA-DR was measured three times a week during the first 14 days. One hundred five consecutive severely injured patients were monitored (ISS 38 ± 17, SAPS II 37 ± 16). Thirty-seven patients (35%) developed sepsis over the 14 days post-trauma. At days 1-2, mHLA-DR was diminished in the whole patient population, with no difference with the development of sepsis. At days 3-4, a highly significant difference appeared between septic and non-septic patients. Non- septic patients showed an increase in mHLA-DR levels, whereas septic patients did not (13,723 ± 7,766 versus 9,271 ± 6,029 antibodies per cell, p = .004). Most importantly, multivariate logistic regression analysis, after adjustment for usual clinical confounders (adjusted OR 5.41, 95% CI 1.42-20.52), revealed that a slope of mHLA-DR expression between days1-2 and days 3-4 below 1.2 remained associated with the development of sepsis.

Conclusions

Major trauma induced an immunosuppression, characterized by a decrease in mHLA-DR expression. Importantly, after multivariate regression logistic analysis, persistent decreased expression was assessed to be in relation with the development of sepsis. This is the first study in trauma patients showing a link between the lack of immune recovery and the development of sepsis on the basis of the standardized protocol. Monitoring immune function by mHLA-DR measurement could be useful to identify trauma patients at a high risk of infection.

Low monocyte human leukocyte antigen-DR is independently associated with nosocomial infections after septic shock

PURPOSE

Sepsis-induced immunosuppression is postulated to contribute to a heightened risk of nosocomial infection (NI). This prospective, single-center, observational study was conducted to assess whether low monocyte human leukocyte antigen-DR expression (mHLA-DR), proposed as a global biomarker of sepsis immunosuppression, was associated with an increased incidence of NI after septic shock.

METHODS

The study included 209 septic shock patients. mHLA-DR was measured by flow cytometry at days (D) 3-4 and 6-9 after the onset of shock. After septic shock, patients were screened daily for NI at four sites (microbiologically documented pulmonary, urinary tract, bloodstream, and catheter-related infections). A competing risk approach was used to evaluate the impact of low mHLA-DR on the incidence of NI.

RESULTS

At D3-4, we obtained measurements in 153 patients. Non-survivors (n = 51) exhibited lower mHLA-DR values expressed as means of fluorescence intensities than survivors (n = 102) (33 vs. 67; p < 0.001). The patients who developed NI (n = 37) exhibited lower mHLA-DR values than those without NI (n = 116) (39 vs. 65; p = 0.008). mHLA-DR ≤ 54 remained independently associated with NI occurrence after adjustment for clinical parameters (gender, simplified acute physiology score II, sepsis-related organ failure assessment, intubation, and central venous catheterization) with an adjusted hazards ratio (aHR) of 2.52 (95% CI 1.20-5.30); p = 0.02. Similarly, at D6-9, low mHLA-DR (≤ 57) remained independently associated with NI with an aHR of 2.18 (95% CI 1.04-4.59); p = 0.04.

CONCLUSIONS

In septic shock patients, after adjustment with usual clinical confounders (including ventilation and central venous catheterization), persistent low mHLA-DR expression remained independently associated with the development of secondary NI.

Admission levels and early changes in serum interleukin-10 are predictive of poor outcome in acute liver failure and decompensated cirrhosis

BACKGROUND & AIM

Immunoparesis contributes to prognosis in acute liver failure (ALF) and decompensated cirrhosis, a phenomenon thought to be mediated by the anti-inflammatory cytokine interleukin (IL)-10. We investigated the prognostic value of admission IL-10 levels and their evolution during the early phase of treatment in intensive care, in comparison to the pro-inflammatory cytokines IL-6 and tumour necrosis factor (TNF)-alpha.

METHODS

We measured these cytokines within 48 h of admission in 51 ALF and 39 decompensated cirrhosis patients admitted to intensive care, and obtained follow-up measurement a median of 2 days later in 35 patients.

RESULTS

Levels of all cytokines were higher in those with a poor outcome. IL-10 performed as well as TNF-alpha and IL-6 in the whole cohort (area under receiver operator curve 0.73 vs 0.66 and 0.72). However IL-10 outperfomed pro-inflammatory cytokines in the subgroups with ALF (0.80 vs 0.63 and 0.70) and acetaminophen-induced ALF (0.92 vs 0.67 and 0.81). Levels of all cytokines rose significantly in non-surviving patients (n=15); IL-10 by a factor of 2, TNF-alpha by 2.6 and IL-6 by 1.13. No significant changes were seen in the surviving patients. In ALF, IL-10 was an independent predictor of outcome in multivariate analysis.

CONCLUSION

The magnitude of the compensatory anti-inflammatory response at admission, and its development during the early phase of treatment, predicts outcome as well as the pro-inflammatory response in acute hepatic syndromes and supports a vital role for this immunological phenomenon in the outcome of these patients.

Differential down-regulation of HLA-DR on monocyte subpopulations during systemic inflammation

Introduction

Decreased expression of human leukocyte antigen class II (HLA-DR) on monocytes is a hallmark of altered immune status in patients with a systemic inflammatory response syndrome (SIRS). So far, the analyses were mainly performed without taking into account monocytes subpopulations.

Methods

We studied this modification on CD14^HIGH and CD14^LOW monocytes of 20 SIRS patients undergoing abdominal aortic surgery (AAS), 20 patients undergoing carotid artery surgery (CAS), and 9 healthy controls, and we investigated mediators and intracellular molecules that may be involved in this process.

Results

HLA-DR on CD14^HIGH monocytes started to decrease during surgery, after blood reperfusion, and was further reduced post-surgery. In contrast, HLA-DR expression on CD14^LOW cells only decreased after surgery, and to a lesser extent than on CD14^HIGH monocytes. Negative correlations were found between the reduction of HLA-DR expression and the change in cortisol levels for both subpopulations, whereas a negative correlation between interleukin-10 (IL-10) levels and HLA-DR modulation was only observed for CD14^HIGH cells. In accordance with these ex vivo results, HLA-DR on CD14^HIGH and CD14^LOW monocytes of healthy donors was reduced following incubation with hydrocortisone, whereas IL-10 only acted on CD14^HIGH subpopulation. Furthermore, flow cytometry revealed that the expression of IL-10 receptor was higher on CD14^HIGH versus CD14^LOW monocytes. In addition, hydrocortisone, and to a lesser extent IL-10, reversed the up-regulation of HLA-DR induced by bacterial products. Finally, membrane-associated RING-CH-1 protein (MARCH1) mRNA, a negative regulator of MHC class II, was up-regulated in monocytes of AAS patients on Day 1 post-surgery, and in those of healthy subjects exposed to hydrocortisone.

Conclusions

This study reveals that HLA-DR expression is modulated differently on CD14^HIGH (classical) versus CD14^LOW (inflammatory) monocytes after systemic inflammation.

Monocytic HLA-DR expression in intensive care patients: interest for prognosis and secondary infection prediction

OBJECTIVES

To test early measurement of human leukocyte antigen-DR expression on circulating monocytes (mHLA-DR) as prognostic marker, and the trend of mHLA-DR recovery for the prediction of late secondary infection risk in a large intensive care unit population.

DESIGN

Prospective, observational study over 16 mos.

SETTING

Intensive care unit in a tertiary teaching hospital.

INCLUSION CRITERIA

Simplified Acute Physiology Score II >15, age >18 yrs.

MEASUREMENTS AND MAIN RESULTS

The mHLA-DR was measured by flow cytometry within the first 3 days and twice a week until discharge. We used a logistic regression model for outcome prediction, and a competing risk approach to test the relationship between mHLA-DR recovery (log (mHLA-DR) slope) and incidence of secondary infection. A total of 283 consecutive patients suffering from various pathologies were monitored (Simplified Acute Physiology Score II = 39, Sepsis-related Organ Failure Assessment of 5 on day 0). Early mHLA-DR was decreased in the whole population, however, more deeply in sepsis (p < .0001). Low mHLA-DR was associated with mortality in the whole population (p = .003), as in subgroups (nonseptic, neurologic, and septic), but not when adjusted on Simplified Acute Physiology Score II. In patients with a length of stay of >7 days (n = 70), the lower the slope of mHLA-DR recovery, the higher the incidence of the first secondary infection (adjusted on early mHLA-DR, p = .04).

CONCLUSIONS

For a given severity, mHLA-DR proved not to a predictive marker of outcome, but a weak trend of mHLA-DR recovery was associated with an increased risk of secondary infection. Monitoring immune functions through mHLA-DR in intensive care unit patients therefore could be useful to identify a high risk of secondary infection.

B7-H1 (PD-L1, CD274) suppresses host immunity in T-cell lymphoproliferative disorders

Stromal elements present within the tumor microenvironment may suppress host immunity and promote the growth of malignant lymphocytes in B cell-derived non-Hodgkin lymphoma (NHL). In contrast, little is known about the microenvironment's role in T cell-derived NHL. B7-H1 (PD-L1, CD274), a member of the B7 family of costimulatory/co-inhibitory ligands expressed by both malignant cells and stromal cells within the tumor microenvironment, has emerged as an important immune modulator capable of suppressing host immunity. Therefore, B7-H1 expression and function were analyzed in cutaneous and peripheral T-cell NHL. B7-H1 was expressed by tumor cells, monocytes, and monocyte-derived cells within the tumor microenvironment in T-cell NHL and was found to inhibit T-cell proliferation and promote the induction of FoxP3(+) regulatory T cells. Collectively, the data presented provide the first evidence implicating B7-H1 in the suppression of host immunity in T-cell lymphoproliferative disorders and suggest that the targeting of B7-H1 may represent a novel therapeutic approach.

Triggering receptor expressed on myeloid cells-1 expression on monocytes is associated with inflammation but not with infection in acute pancreatitis

Introduction

Acute pancreatitis (AP) is usually a mild and self-limiting disease, but some patients develop a severe form that is associated with high mortality. In AP, local inflammation is followed first by the systemic inflammatory response syndrome and then by the compensatory anti-inflammatory response syndrome, which is defined by low human leukocyte antigen (HLA)-DR expression on monocytes, increased concentration of the anti-inflammatory cytokine IL-10, and decreased monocyte function. Our aim was to measure the expression of triggering receptor expressed on myeloid cells (TREM)-1 (a proposed marker of infection or inflammation) and HLA-DR on monocytes, and the serum concentrations of IL-6 (a proinflammatory cytokine) and IL-10 in patients with AP to determine whether these markers can identify patients at high risk of developing severe AP or infection.

Methods

Fifty healthy volunteers, 18 patients with mild AP, and 11 patients with severe AP were included in this study. Samples were taken at admission and one and three days later. TREM-1 and HLA-DR expression was evaluated by flow cytometry, and soluble TREM-1, IL-6 and IL-10 concentrations were measured by ELISA.

Results

TREM-1 expression was higher in patients with AP than in healthy volunteers, but there was no difference between patients with mild and severe AP. TREM-1 expression was not associated with mortality or with the presence of infection. Soluble TREM-1 concentration in serum was higher in non-survivors than in survivors. HLA-DR expression was lower and IL-6 concentration higher in patients with severe AP and in infected patients.

Conclusions

Increased TREM-1 expression was associated with the presence of inflammation but not infection in AP. In patients with AP, low HLA-DR expression and high IL-6 concentration could predict severity and infection in samples taken shortly after admission.

Monocyte subsets and natural killer cells in acute pancreatitis

BACKGROUND

Alteration of the immune system is one of the major mechanisms responsible for complications in severe acute pancreatitis (AP). The aim of our study was to provide a complex evaluation of peripheral blood monocyte subsets, natural killer cells (NK cells) and cytotoxic T lymphocytes in patients with different severity forms of AP.

METHODS

20 patients with mild AP and 15 with severe AP (S-AP) were included in our study. Peripheral blood mononuclear cells were studied on days 1-3, 5, 10 and 30, by means of flow cytometry.

RESULTS

In peripheral blood of patients with pancreatitis, we found a marked increase in total monocyte count. In S-AP, circulating monocytes were significantly activated, which was presumed from increased expression of HLA-DR, CD54, CD69 and CD25. Concurrent increased expression of CD95 (FasR) may indicate enhanced susceptibility of these cells to apoptosis. In patients with S-AP, a dramatic depletion of circulating NK cells (CD16/56 and CD3- CD8+) was found along with a reduction of circulating CD3+ CD8+ lymphocytes (cytotoxic T lymphocytes).

CONCLUSION

Our findings suggest profound disturbances of innate cellular immunity in patients with S-AP.

Monitoring immune dysfunctions in the septic patient: a new skin for the old ceremony

Septic syndromes represent a major although largely underrecognized healthcare problem worldwide, accounting for thousands of deaths every year. It is now agreed that sepsis deeply perturbs immune homeostasis by inducing an initial tremendous systemic inflammatory response which is accompanied by an antiinflammatory process, acting as negative feedback. This compensatory inhibitory response secondly becomes deleterious as nearly all immune functions are compromised. These alterations might be directly responsible for worsening outcome, as they may play a major role in the decreased resistance to nosocomial infections in patients who survived initial resuscitation. Consequently, immunostimulatory therapies may now be assessed for the treatment of sepsis. This review focuses on immune dysfunctions described in septic patients and on their potential use as markers on a routine standardized basis for prediction of adverse outcome or of occurrence of secondary nosocomial infections. This constitutes a prerequisite to a staging system for individualized treatment for these hitherto deadly syndromes.

Decreased monocyte human leukocyte antigen-DR expression after severe burn injury: Correlation with severity and secondary septic shock

OBJECTIVE

Severe thermal injury causes immune dysfunctions involving both pro- and anti-inflammatory mechanisms. It subsequently leads to a state of immune deficiency that shares some similarities with sepsis-induced immunosuppression. A hallmark of the latter is established by decreased monocyte human leukocyte antigen-DR (mHLA-DR) measurements. The main objective of the current study was to characterize the appearance and the duration of low mHLA-DR expression after severe burn as well as to determine its correlation with mortality and septic complications.

DESIGN

Observational study.

SETTING

Burn unit (intensive care unit) in a university hospital.

PATIENTS

Severe burn patients (total burn surface area >30%, n = 14) and healthy individuals (n = 29).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were immunologically monitored during 15 days. We quantified mHLA-DR expression with a standardized flow cytometry protocol. Every patient presented with decreased mHLA-DR expression at days 2-3 after burn. Then, from days 4-6, this expression increased in patients who would survive whereas it remained low in nonsurvivors. As early as days 7-10 after burn, patients who were going to develop secondary septic shock exhibited significantly lower mHLA-DR expression in comparison with patients recovering without severe septic complications. Using quantitative reverse transcriptase-polymerase chain reaction, at days 4-6, we found that the RNA level of the nonpolymorphic HLA-DRA chain and the transcription factor class II transactivator were also significantly decreased compared with healthy controls; however, plasma cytokines (interleukin-6, tumor necrosis factor-alpha, and interleukin-10) did not provide any significant prognostic information.

CONCLUSIONS

Severe burn injury induced a marked reduction in mHLA-DR expression at both protein and messenger RNA levels. Its persistent decrease was associated with mortality and the development of septic complications.

Up-regulation of interleukin-10 mRNA expression in peripheral leukocytes predicts poor outcome and diminished human leukocyte antigen-DR expression on monocytes in septic patients

BACKGROUND

None of the parameters can predict the deterioration of sepsis early enough. A new predictor allowing earlier detection of changes in septic patients' condition is indispensable.

METHODS

We examined whether cytokine-related mRNA expression in peripheral leukocytes, cytokine blood level, and monocyte human leukocyte antigen (HLA)-DR expression rate could be useful predictors of deterioration of sepsis. Twenty septic patients were enrolled. mRNA expression levels were quantified using real-time reverse transcriptase-polymerase chain reaction and assessed by percent changes during the first 24 h. Cytokine blood levels on admission and day 3 and monocyte HLA-DR expression rate on day 3 were also measured. Correlations between each of these parameters, and between these parameters and outcome were analyzed.

RESULTS

Among seven kinds of cytokines studied, only IL-10 mRNA level showed significant difference between survivors and non-survivors (P < 0.05). Mortality rate of interleukin (IL)-10 mRNA level up-regulated group was significantly higher than that of IL-10 mRNA level down-regulated group (P < 0.05). HLA-DR expression rate in non-survivors were significantly lower than that in survivors (P < 0.05). Although IL-10 blood level on day 3 significantly correlated with HLA-DR expression on day 3(r = 0.54, P < 0.05), IL-10 blood level on admission did not correlate with it. Contrarily, the degree of up-regulation of IL-10 mRNA expression during the first 24 h significantly correlated with the degree of diminished HLA-DR expression on day 3 (r = 0.78, P < 0.001).

CONCLUSIONS

Up-regulated IL-10 mRNA expression and diminished HLA-DR expression could be indicators of poor outcome. Furthermore, IL-10 mRNA expression measurement could predict the onset of immunoparalysis indicated by diminished HLA-DR expression earlier than IL-10 blood level measurement, leading to earlier commencement of the treatment.

Alterations of Toll-like receptor 4 expression on peripheral blood monocytes during the early stage of human acute pancreatitis

We sought to study Toll-like receptor 4 (TLR4) expression on peripheral blood mononuclear cells (PBMCs) during the early stage of human acute pancreatitis (AP). Thirty consecutive patients with acute pancreatitis admitted within 24 hr of onset of abdominal pain were enrolled prospectively in this study. Blood samples were taken by venipuncture at admission and on the third and seventh days after admission. PBMCs were isolated, and TLR4 and CD14 expression on PBMCs was detected by flow cytometer. Serum tumor necrosis factor (TNF)-alpha, interleukin, and lipase were detected simultaneously. Relations among these parameters were analysis. In mild AP, TLR4 expression increased on the first day of admission and then continued to decline for several days. On the seventh day, TLR4 expression was almost normal compared with that of the normal control. The alteration of serum TNF-alpha was coincidence with TLR4. We conclude that mononuclear-macrophages might be ignited through TLR4 (the gatekeeper of the innate immune system) and lead to production of TNF-alpha.

Predicting severity of acute pancreatitis

Severity stratification is a critical issue in acute pancreatitis that strongly influences diagnostic and therapeutic decision making. According to the widely used Atlanta classification, "severe" disease comprises various local and systemic complications that are associated with an increased risk of mortality. However, results from recent clinical studies indicate that these complications vary in their effect on outcome, and many are not necessarily life threatening on their own. Therefore, "severe," as defined by Atlanta, must be distinguished from "prognostic," aiming at nonsurvival. In the first week after disease onset, pancreatitis-related organ failure is the preferred variable for predicting severity and prognosis because it outweighs morphologic complications. Contrast-enhanced CT and MRI allow for accurate stratification of local severity beyond the first week after symptom onset. Among the biochemical markers, C-reactive protein is still the parameter of choice to assess attack severity, although prognostic estimation is not possible. Other markers, including pancreatic protease activation peptides, interleukins-6 and -8, and polymorphonuclear elastase are useful early indicators of severity. Procalcitonin is one of the most promising single markers for assessment of major complications and prognosis throughout the disease course.

Endotoxemia contributes to the immune paralysis in patients with cirrhosis

BACKGROUND/AIMS

Immune paralysis, defined as decreased HLA-DR expression on monocytes and indicated immune dysfunctions, was found in sepsis, severe acute pancreatitis and acute liver failure. However, the relationship between HLA-DR expression and cirrhosis is unclear.

METHODS

We enrolled 64 patients with liver cirrhosis and 23 healthy volunteers. HLA-DR expressions, functions of monocyte, serum cytokines and endotoxin levels were measured.

RESULTS

Compared to healthy volunteers, HLA-DR expressions were significantly lower in Child-Pugh class C cirrhotic patients (89.28% vs 69.29%, p<0.001). These low-HLA-DR-expressed monocytes were with decreased ability of tumor necrosis factor (TNF)-alpha secretion, decreased expression of inducible nitric oxide synthetase (iNOS) and decreased allo-stimulatory ability but normal phagocytosis ability. The co-stimulatory molecules like CD40 and CD86 were down-regulated as well but not CD80. Furthermore, HLA-DR expression was linearly correlated with the presence of hepatic encephalopathy (r(2)=0.2642; p=0.008) and serum interleukin-10 (IL-10) (r(2)=0.2167; p=0.019) in patients with Child-Pugh class C. Serum endotoxin level was in linear relationship to serum IL-10 level (r(2)=0.1868; p=0.002) and HLA-DR expression (r(2)=0.0924; p=0.036). In addition, endotoxin, mediated by IL-10, could down-regulate the HLA-DR expression.

CONCLUSIONS

Child-Pugh class C cirrhotic patients suffer from down-regulation of HLA-DR expression. Endotoxemia, possibly mediated by IL-10, contributes to this HLA-DR down-regulation.

Reduced monocyte CD86 expression in postinflammatory immunodeficiency

OBJECTIVE

Major surgery, polytrauma, stroke, and pancreatitis frequently lead to a compensatory anti-inflammatory response syndrome that often predisposes patients to lethal infections. This temporary postinflammatory immunodeficiency is characterized by altered function of blood monocytes. These cells show strongly reduced inflammatory and antigen-presentation capacity. Diminished monocyte expression of the major histocompatibility complex class II molecule human leukocyte antigen (HLA)-DR is a well-established diagnostic marker of this immunodeficiency. To further characterize the monocytic cells in this clinical state, we analyzed their expression of CD86, the most important co-stimulatory molecule.

DESIGN

Analysis of blood samples that entered the clinical immunologic diagnostics and of cells from an in vitro model of postinflammatory immunodeficiency.

SETTING

University laboratory.

SUBJECTS

Healthy donors and intensive care unit (ICU) patients at the university hospital.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The expression of HLA-DR on monocytes and of CD86 and CD80 on monocytes and B cells was analyzed by flow cytometry. Messenger RNA expression of CD86 was analyzed in isolated monocytes by real-time polymerase chain reaction on reverse transcribed. The normal range of monocyte CD86 expression in healthy subjects was established to be from 2128 to 5102 surface molecules per cell and was independent of age, gender, and leukocyte and monocyte count. The CD86 expression on monocytes in ICU patients correlated with HLA-DR expression. Approximately 40% of the ICU patients with long-term reduced monocyte HLA-DR expression had a long-term reduction of CD86 expression. Patients in whom the expression of both molecules was diminished had an unfavorable prognosis. The diminished number of CD86 surface molecules on monocytes was associated with reduced CD86 messenger RNA levels in these cells. The expression of CD86 in B cells was not diminished in immunodeficient patients. The expression of CD80 in both monocytes and B-cells was minimal in healthy donors and not clearly changed in patients.

CONCLUSIONS

The monocyte CD86 expression may be a helpful diagnostic variable in ICU patients.

Immunosuppression in patients with severe acute pancreatitis

BACKGROUND

In severe acute pancreatitis (SAP), immunologic impairment in the early phase may be linked to subsequent infectious complications. In this study, immunologic alterations in patients with SAP were analyzed, and immunologic parameters related to infectious complications were clarified.

METHODS

A total of 101 patients with SAP were analyzed retrospectively. Various immunologic parameters on admission were analyzed and compared between the infection group and noninfection group during SAP. Furthermore, chronologic change in the lymphocyte count was investigated, and its utility for predicting infection was compared with conventional scoring systems.

RESULTS

Serum immunoglobulin G (IgG), serum IgM, lymphokine-activated killer cell activity, and natural killer cell activity were low, and the incidence of abnormally low values was 50.0%, 65.0%, 45.5%, and 42.4%, respectively. Serum complement factor 3 was significantly negatively correlated with the APACHE II score. The lymphocyte count was decreased below the normal range, and was significantly negatively correlated with the APACHE II score. CD4-, CD8-, and CD20-positive lymphocyte counts were below the normal range, and CD4- and CD8-positive lymphocyte counts were significantly lower in the infection group. The lymphocyte count on day 14 after admission was significantly lower in the infection group and was more useful for predicting infection than conventional scoring systems.

CONCLUSIONS

Immunosuppression occurs from the early phase in SAP, and quantitative impairment of lymphocytes, mainly T lymphocytes, may be closely related to infectious complications during SAP. CD4- and CD8-positive lymphocyte counts on admission and the lymphocyte count on day 14 after admission may be useful for predicting infection.

Effects of immunosuppressive and immunostimulative treatment on pancreatic injury and mortality in severe acute experimental pancreatitis

OBJECTIVES

Acute pancreatitis is associated with substantial alterations of the immunologic host response which has been claimed to promote remote organ dysfunction, septic complications, and mortality. Treatment with immunomodulating substances has been subject of few experimental studies with still conflicting results.

METHODS

We used the taurocholate-induced model of severe acute pancreatitis (SAP) in rats which were assigned to different treatment regimen: isotonic saline (SAP-S) for nontreated controls, recombinant rat interferon-gamma for immunostimulation (SAP-IFN-gamma), and FK506 for immunosuppression (SAP-FK506). Animals were killed after 3, 6, and 24 hours as well as 3 and 7 days, and parameters of local and systemic severity were assessed.

RESULTS

Treatment with IFN-gamma and FK506 attenuated the progression of intrapancreatic necrosis within the first 24 hours after pancreatitis induction along with a substantial reduction of subsequent neutrophil tissue infiltration as shown by decreased myeloperoxidase activity. Enhanced cell death by apoptosis during the postacute course was reduced in FK506-treated animals only. Pancreatic interleukin (IL) 1beta messenger RNA up-regulation occurred early and was slightly suppressed in both treatment groups; tumor necrosis factor alpha (TNF-alpha) and IL-2 messenger RNA expression paralleled the onset of apoptosis and was markedly decreased in IFN-gamma- and FK506-treated rats. The 2 therapeutic regimens had similar effects on intrapancreatic and systemic IL-1beta and TNF-alpha protein release; however, the profiles of both cytokines were differently influenced. Whereas IFN-gamma and FK506 treatment lead to an enhanced intrapancreatic and systemic TNF-alpha protein release during the early course, IL-1beta concentrations were significantly reduced within the late intervals. Seven-day mortality was 44% in saline-, 29% in IFN-gamma-, and 25% in FK506-treated rats (P = not significant).

CONCLUSIONS

Severe acute pancreatitis is associated with early alterations of the immune response comprising overt T-cell activation and impaired monocyte/macrophage function alike. Targeting either immunologic derangement improves local pancreatic damage and systemic severity. However, because mortality was not improved, a therapeutic benefit of immunomodulating substances in clinical SAP remains to be defined.

Persisting low monocyte human leukocyte antigen-DR expression predicts mortality in septic shock

OBJECTIVE

The immediate overwhelming release of inflammatory mediators in septic shock is rapidly followed by strong anti-inflammatory responses inducing a state of immunosuppression. The patients who survive the initial hyper-inflammatory step of septic shock but subsequently die may be those who do not recover from immunosuppression. We assessed whether a low monocyte human leukocyte antigen-DR (mHLA-DR) expression, proposed as a marker of immunosuppression, is an independent predictor of mortality in patients who survived the initial 48 h of septic shock.

DESIGN AND SETTING

Prospective observational study performed in two adult intensive care units at a university hospital.

PATIENTS

93 consecutive patients with septic shock.

MEASUREMENTS AND RESULTS

At days 1-2, mHLA-DR values (determined by flow cytometry) were not significantly different between survivors and non-survivors. A sharp difference became highly significant at days 3-4 when survivors had increased their values, while non-survivors had not (43% vs. 18%, percentage of HLA-DR positive monocyte, p < 0.001). Multivariate logistic regression analysis revealed that low mHLA-DR (< 30%) at days 3-4 remained independently associated with mortality after adjustment for usual clinical confounders, adjusted odds ratio (CI): 6.48 (95% CI: 1.62-25.93).

CONCLUSION

The present preliminary results show that mHLA-DR is an independent predictor of mortality in septic shock patients. Being a marker of immune failure, low mHLA-DR may provide a rationale for initiating therapy to reverse immunosuppression. After validation of the current results in multicenter studies, mHLA-DR may help to stratify patients when designing a mediator-directed therapy in a time-dependent manner.