Immunosuppression in patients with severe acute pancreatitis

Early prediction and prevention of infected pancreatic necrosis

Approximately 20%-30% of patients with acute necrotizing pancreatitis develop infected pancreatic necrosis (IPN), a highly morbid and potentially lethal complication. Early identification of patients at high risk of IPN may facilitate appropriate preventive measures to improve clinical outcomes. In the past two decades, several markers and predictive tools have been proposed and evaluated for this purpose. Conventional biomarkers like C-reactive protein, procalcitonin, lymphocyte count, interleukin-6, and interleukin-8, and newly developed biomarkers like angiopoietin-2 all showed significant association with IPN. On the other hand, scoring systems like the Acute Physiology and Chronic Health Evaluation II and Pancreatitis Activity Scoring System have also been tested, and the results showed that they may provide better accuracy. For early prevention of IPN, several new therapies were tested, including early enteral nutrition, antibiotics, probiotics, immune enhancement, etc., but the results varied. Taken together, several evidence-supported predictive markers and scoring systems are readily available for predicting IPN. However, effective treatments to reduce the incidence of IPN are still lacking apart from early enteral nutrition. In this editorial, we summarize evidence concerning early prediction and prevention of IPN, providing insights into future practice and study design. A more homogeneous patient population with reliable risk-stratification tools may help find effective treatments to reduce the risk of IPN, thereby achieving individualized treatment.

The Emerging Roles of the Adaptive Immune Response in Acute Pancreatitis

Acute pancreatitis (AP) is an abrupt, variable inflammatory condition of the pancreas, potentially escalating to severe systemic inflammation, rampant pancreatic necrosis, and multi-organ failure. Its complex pathogenesis involves an intricate immune response, with different T cell subsets (Th1, Th2, Th9, Th17, Th22, TFH, Treg, and CD8+ T cells) and B cells playing pivotal roles. Early T cell activation initiates the AP development, triggering cytokines associated with the Th1 response, which stimulate macrophages and neutrophils. Other T cell phenotypes contribute to AP's pathogenesis, and the balance between pro-inflammatory and anti-inflammatory cytokines influences its progression. Regulatory T and B cells are crucial for moderating the inflammatory response and promoting immune tolerance. B cells further contribute through antibody production, antigen presentation, and cytokine secretion. Understanding these immune cells' roles in AP could aid in developing new immunotherapies to enhance patient outcomes. However, further research is required to define these cells' precise roles in AP and their potential as therapeutic targets.

Association between pretreatment lymphocyte count and efficacy of immune-enhancing therapy in acute necrotising pancreatitis: a post-hoc analysis of the multicentre, randomised, placebo-controlled TRACE trial

Background

Immune-enhancing thymosin alpha 1 (Tα1) therapy may reduce infected pancreatic necrosis (IPN) in acute necrotising pancreatitis (ANP). However, the efficacy might be impacted by lymphocyte count due to the pharmacological action of Tα1. In this post-hoc analysis, we tested the hypothesis that pre-treatment absolute lymphocyte count (ALC) determines whether patients with ANP benefit from Tα1 therapy.

Methods

A post-hoc analysis of data from a multicentre, double-blind, randomised, placebo-controlled trial testing the efficacy of Tα1 therapy in patients with predicted severe ANP was performed. Patients from 16 hospitals of China were randomised to receive a subcutaneous injection of Tα1 1.6 mg every 12 h for the frst 7 days and 1.6 mg once a day for the following 7 days or a matching placebo during the same period. Patients who discontinued the Tα1 regimen prematurely were excluded. Three subgroup analyses were conducted using the baseline ALC (at randomisation), and the group allocation was maintained as intention-to-treat. The primary outcome was the incidence of IPN 90 days after randomisation. The fitted logistic regression model was applied to identify the range of baseline ALC where Tα1 therapy could exert a maximum effect. The original trial is registered with ClinicalTrials.gov, NCT02473406.

Findings

Between March 18, 2017, and December 10, 2020, a total of 508 patients were randomised in the original trial, and 502 were involved in this analysis, with 248 in the Tα1 group and 254 in the placebo group. Across the three subgroups, there was a uniform trend toward more significant treatment effects in patients with higher baseline ALC. Within the subgroup of patients with baseline ALC≥0.8 × 10ˆ9/L (n = 290), the Tα1 therapy significantly reduced the risk of IPN (covariate adjusted risk difference, -0.12; 95% CI, -0.21,-0.02; p = 0.015). Patients with baseline ALC between 0.79 and 2.00 × 10ˆ9/L benefited most from the Tα1 therapy in reducing IPN (n = 263).

Interpretation

This post-hoc analysis found that the efficacy of immune-enhancing Tα1 therapy on the incidence of IPN may be associated with pretreatment lymphocyte count in patients with acute necrotising pancreatitis.

Funding

National Natural Science Foundation of China.

Early mean absolute lymphocyte count in acute necrotizing pancreatitis is associated with infected pancreatic necrosis

OBJECTIVES

Peripheral absolute lymphocyte count (ALC) has the potential to predict infected pancreatic necrosis (IPN), but requires verification. This study aimed to assess whether early mean absolute lymphocyte count is associated with the development of IPN in ANP patients using pooled data from a multicenter, randomized controlled trial and a retrospective study.

METHODS

The study subjects are from the TRACE trial and a single-center cohort study. ALC during the first seven days was used to define early mean ALC. The entire cohort was then divided into quartiles of early mean ALC. Multivariable Cox proportional hazards regression (MCPHR) model was used to assess the association between early mean ALC and 90-day IPN.

RESULTS

A total of 660 patients (median age, 44 years; 63.8 % males) were included and 157 (23.8 %) developed IPN within a 90-day period. The median (interquartile range, IQR) of the early mean ALC is 1.07 (0.80-1.36). All the study subjects were evenly divided into 4 groups: quartile-1 (0.33-0.79*10^9/L), quartile-2 (0.80-1.06*10^9/L), quartile-3 (1.07-1.36*10^9/L) and quartile-4 (1.37-4.01*10^9/L). The incidence of 90-day IPN was 38.3 %, 25.7 %, 19.2 % and 12.2 % for each group, respectively. In the MCPHR model, the lowest early mean ALC (quartile-1) was found to be an independent risk factor of 90-day IPN with a hazard ratio (95 %CI) of 2.21 (1.28-3.81) compared to the highest mean ALC(quartile-4) group.

CONCLUSION

Among patients with ANP, early mean ALC was significantly associated with the development of IPN. Preventive strategies should be considered in patients with reduced ALC.

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.

Differential expression of plasma exosomal microRNA in severe acute pancreatitis

The incidence rate of acute pancreatitis is increasing, and severe acute pancreatitis (SAP) is associated with a high mortality rate, which may be reduced by a deeper understanding of its pathogenesis. In addition, an early determination of the severity of acute pancreatitis remains challenging. The aim of this study was to match potential biomarkers for early identification and monitoring of acute pancreatitis and to shed light on the underlying pathogenic mechanisms of SAP. The expression levels of plasma exosomal microRNA (miRNA) in patients with pancreatitis have been associated with the disease. Thus, this study compared the expression levels of exosomal miRNA in plasma collected from four patients with SAP and from four healthy participants. Analyses of the miRNA expression profiles indicated that three previously unreported miRNAs were differentially expressed in the patient group: Novel1, which was downregulated, and Novel2 and Novel3, which were upregulated. The miRNA target genes for those novel miRNAs were predicted using Metascape. Of these miRNA target genes, those that were also differentially expressed at different time points after disease induction in a mouse model of acute pancreatitis were determined. The gene for complement component 3 (C3), a target gene of Novel3, was the only gene matched in both the patient group and the mouse model. C3 appeared at most of the time points assessed after induction of acute pancreatitis in mice. These findings are foundational evidence that C3 warrants further study as an early biomarker of SAP, for investigating underlying pathogenic mechanisms of SAP, and as a therapeutic target for ameliorating the occurrence or development of SAP.

Gene Expression Profiling: Identification of Novel Pathways and Potential Biomarkers in Severe Acute Pancreatitis

BACKGROUND

Determining the risk of developing severe acute pancreatitis (AP) on presentation to hospital is difficult but vital to enable early management decisions that reduce morbidity and mortality. The objective of this study was to determine global gene expression profiles of patients with different acute pancreatitis severity to identify genes and molecular mechanisms involved in the pathogenesis of severe AP.

STUDY DESIGN

AP patients (n = 87) were recruited within 24 hours of admission to the Emergency Department and were confirmed to exhibit at least 2 of the following features: (1) abdominal pain characteristic of AP, (2) serum amylase and/or lipase more than 3-fold the upper laboratory limit considered normal, and/or (3) radiographically demonstrated AP on CT scan. Severity was defined according to the Revised Atlanta classification. Thirty-two healthy volunteers were also recruited and peripheral venous blood was collected for performing RNA-Seq.

RESULTS

In severe AP, 422 genes (185 upregulated, 237 downregulated) were significantly differentially expressed when compared with moderately severe and mild cases. Pathway analysis revealed changes in specific innate and adaptive immune, sepsis-related, and surface modification pathways in severe AP. Data-driven approaches revealed distinct gene expression groups (endotypes), which were not entirely overlapping with the clinical Atlanta classification. Importantly, severe and moderately severe AP patients clustered away from healthy controls, whereas mild AP patients did not exhibit any clear separation, suggesting distinct underlying mechanisms that may influence severity of AP.

CONCLUSION

There were significant differences in gene expression affecting the severity of AP, revealing a central role of specific immunological pathways. Despite the existence of patient endotypes, a 4-gene transcriptomic signature (S100A8, S100A9, MMP25, and MT-ND4L) was determined that can predict severe AP with an accuracy of 64%.

Immune enhancement in patients with predicted severe acute necrotising pancreatitis: a multicentre double-blind randomised controlled trial

PURPOSE

Infected pancreatic necrosis (IPN) is a highly morbid complication of acute necrotising pancreatitis (ANP). Since there is evidence of early-onset immunosuppression in acute pancreatitis, immune enhancement may be a therapeutic option. This trial aimed to evaluate whether early immune-enhancing Thymosin alpha 1 (Tα1) treatment reduces the incidence of IPN in patients with predicted severe ANP.

METHODS

We conducted a multicentre, double-blind, randomised, placebo-controlled trial involving ANP patients with an Acute Physiology and Chronic Health Evaluation II (APACHE II) score ≥ 8 and a computed tomography (CT) severity score ≥ 5 admitted within 7 days of the advent of symptoms. Enrolled patients were assigned to receive a subcutaneous injection of Tα1 1.6 mg every 12 h for the first 7 days and 1.6 mg once a day for the subsequent 7 days or matching placebos (normal saline). The primary outcome was the development of IPN during the index admission.

RESULTS

A total of 508 patients were randomised, of whom 254 were assigned to receive Tα1 and 254 placebo. The vast majority of the participants required admission to the intensive care unit (ICU) (479/508, 94.3%). During the index admission, 40/254(15.7%) patients in the Tα1 group developed IPN compared with 46/254 patients (18.1%) in the placebo group (difference -2.4% [95% CI - 7.4 to 5.1%]; p = 0.48). The results were similar across four predefined subgroups. There was no difference in other major complications, including new-onset organ failure (10.6% vs. 15%), bleeding (6.3% vs. 3.5%), and gastrointestinal fistula (2% vs. 2.4%).

CONCLUSION

The immune-enhancing Tα1 treatment of patients with predicted severe ANP did not reduce the incidence of IPN during the index admission.

Trajectories of Lymphocyte Counts in the Early Phase of Acute Pancreatitis Are Associated With Infected Pancreatic Necrosis

INTRODUCTION

Infected pancreatic necrosis (IPN) is an important complication of acute pancreatitis (AP). Absolute lymphocyte count (ALC) was reported to be associated with immunosuppression and the development of IPN. The aim of this study was to describe the trajectory of ALC during the early phase of AP and assess its association with IPN.

METHODS

We retrospectively screened patients with AP admitted to our center between January 2016 and July 2019. The ALC levels for the first 7 days after admission were collected. Group-based trajectory modeling was performed to detect the trajectories. Cox proportional hazards regression model was adopted to identify potential risk factors of IPN.

RESULTS

Overall, 292 patients were enrolled for analysis. A triple-group trajectory model was developed, assigning 116 patients to the low-level ALC group, 133 to the medium-level ALC group, and 43 to the high-level ALC group. There was no overall significant difference regarding the incidence of IPN among the 3 groups (P = 0.066). In pairwise comparison, patients in the low-level ALC group had significantly higher incidence of IPN than those in the high-level ALC group (hazard ratio: 3.50; 95% confidence interval: 1.22-10.00, P = 0.020). Length of hospital stay and intensive care unit stay differed significantly among patients with different trajectories (P = 0.042 and 0.033, respectively).

DISCUSSION

Despite the fact that the trajectories of ALC is overall insignificant for the development of IPN, patients with persistent low ALC trajectories during the early phase of AP are more likely to develop IPN when compared with patients with high ALC trajectories.

Serum soluble PD-1 plays a role in predicting infection complications in patients with acute pancreatitis

Background

Most of acute pancreatitis (AP) are mild and self‐limiting, however, 15%–20% of patients develop severe acute pancreatitis (SAP) or moderately acute pancreatitis (MSAP) with local or systemic complications. Infection complications (ICs) result in 40%–70% morbidity and high mortality rates among SAP and MSAP patients. It is more important to early recognize of ICs of MSAP or SAP. Several studies have indicated that serum soluble programmed cell death protein (sPD‐1) or programmed cell death 1 ligand (sPD‐L1) levels were higher in patients with severe sepsis than in healthy volunteers and have a predictive capacity for mortality. However, the role of serum sPD‐1/sPD‐L1 in AP remains unclear. This study aimed to investigate whether the ICs of AP patients is associated with their sPD‐1 and sPD‐L1 levels, which were determined via enzyme‐linked immunosorbent assay of peripheral blood samples from 63 MSAP and SAP patients and 30 healthy volunteers.

Results

The serum sPD‐1 levels in AP patients on Days 1, 3, and 10 after onset were significantly increased in a time‐dependent manner compared with that in healthy volunteers. Moreover, the AP patients with ICs had significantly higher serum sPD‐1 levels than the AP without ICs. While serum sPD‐L1 levels in AP were similar to that in healthy volunteers. Besides, serum levels of sPD‐1/sPD‐L1 were negatively correlated with circulating lymphocytes. Univariate and multivariate regression analyses showed that the upregulated serum sPD‐1 level was an independent risk factor for ICs in AP. The area under the receiver operating characteristics curve indicated that combination with Acute Physiology and Chronic Health Evaluation II score and serum sPD‐1 level had a high accuracy in predicting ICs in AP.

Conclusion

Serum sPD‐1/sPD‐L1 may be involved in the immunosuppressive process in AP. Moreover, the serum sPD‐1 level may be an independent risk factor for predicting ICs in AP patients.

The Role of Pancreatic Infiltrating Innate Immune Cells in Acute Pancreatitis

Acute pancreatitis (AP) is a leading cause of gastrointestinal-related hospital admissions with significant morbidity and mortality. Although the underlying pathophysiology of AP is rather complex, which greatly limits the treatment options, more and more studies have revealed that infiltrating immune cells play a critical role in the pathogenesis of AP and determine disease severity. Thus, immunomodulatory therapy targeting immune cells and related inflammatory mediators is expected to be a novel treatment modality for AP which may improve the prognosis of patients. Cells of the innate immune system, including macrophages, neutrophils, dendritic cells, and mast cells, represent the majority of infiltrating cells during AP. In this review, an overview of different populations of innate immune cells and their role during AP will be discussed, with a special focus on neutrophils and macrophages.

Circulating Lymphocyte Subsets Induce Secondary Infection in Acute Pancreatitis

Acute pancreatitis (AP) is considered a cascade of immune responses triggered by acinar cell necrosis. AP involves two main processes of systemic inflammatory response syndrome and subsequent compensatory anti-inflammatory response syndrome. Although great efforts have been made regarding AP therapy, the mortality rate of AP remains high. Secondary infection acts a lethal factor in AP. Lymphocytes act as major immune mediators in immune responses in the course of this disease. However, the relationship between lymphocytes and secondary infection in AP is unclear. This review summarizes the variation of lymphocytes and infection in AP. Knowledge of the characterization of circulating lymphocyte abnormalities is relevant for understanding the pathophysiology of AP.

The early predictive role of complement C3 and C4 in patients with acute pancreatitis

Objective

The prognostic role of complement C3 and C4 in peripheral blood in early stage of acute pancreatitis (AP) is unknown. In this study, we aimed to evaluate the prognostic value of C3 and C4 in early stage of AP.

Methods

A total of 164 patients were enrolled in this study. The blood samples were collected within 24 hours after AP onset. We compared C3 and C4 levels in patients with different AP severity. The optimal cutoff value for them to predict severe AP (SAP) was determined by receiver operating characteristic (ROC) curve analysis.

Results

The reduction of C3 and C4 levels was observed. For prediction of MSAP and SAP, the AUC of C3 and C4 levels was 0.695 (95% CI: 0.612‐0.779) and 0.739 (95% CI: 0.657‐0.821). The cutoff value of C3 and C4 levels was 0.705 and 0.145 g/L, with the sensitivity of 0.612 and 0.735, and the specificity of 0.735 and 0.710. For prediction of SAP, the AUC of C3 and C4 levels was 0.749 (95% CI: 0.607‐0.891) and 0.766 (95% CI: 0.596‐0.936). The cutoff value of C3 and C4 levels was 0.400 and 0.125 g/L, with the sensitivity of 0.859 and 0.767, and the specificity of 0.600 and 0.786.

Conclusions

A marked change of complement C3 and C4 was observed in peripheral blood of patients with AP, suggesting the participation of complement system in the early phase of AP. C3 and C4 levels were sensitive and accurate in judging the severity of AP.

Gastrointestinal microecology: a crucial and potential target in acute pancreatitis

In the early stage of acute pancreatitis (AP), abundant cytokines induced by local pancreatic inflammation enter the bloodstream, further cause systemic inflammatory response syndrome (SIRS) by "trigger effect", which eventually leads to multiple organ dysfunction syndrome (MODS). During SIRS and MODS, the intestinal barrier function was seriously damaged accompanied by the occurrence of gut-derived infection which forms a "second hit summit" by inflammatory overabundance. Gastrointestinal microecology, namely the biologic barrier, could be transformed into a pathogenic state, which is called microflora dysbiosis when interfered by the inflammatory stress during AP. More and more evidences indicate that gastrointestinal microflora dysbiosis plays a key role in "the second hit" induced by AP gut-derived infection. Therefore, the maintenance of gastrointestinal microecology balance is likely to provide an effective method in modulating systemic infection of AP. This article reviewed the progress of gastrointestinal microecology in AP to provide a reference for deeply understanding the pathogenic mechanisms of AP and identifying new therapeutic targets.

Adaptive Immune Cell Dysregulation and Role in Acute Pancreatitis Disease Progression and Treatment

Acute pancreatitis (AP) is an inflammation of the pancreas caused by various stimuli including excessive alcohol consumption, gallstone disease and certain viral infections. Managing specifically the severe form of AP is limited due to lack of an understanding of the complex immune events that occur during AP involving immune cells and inflammatory molecules such as cytokines. The relative abundance of various immune cells resulting from the immune dysregulation drives disease progression. In this review, we examine the literature on the adaptive immune cells in AP, the prognostic value of these cells in stratifying patients into appropriate care and treatment strategies based on cell frequency in different AP severities are discussed.

The utility of neutrophil to lymphocyte ratio and fluid sequestration as an early predictor of severe acute pancreatitis

It is important to identify the patients with high-risk progression to develop severe acute pancreatitis (SAP). The study was to assess whether neutrophil to lymphocyte ratio (NLR) and fluid sequestration (FS) could represent useful markers for predicting the severity. A total of 1639 patients who underwent clinical diagnosis of AP was performed. Various serologic and clinical parameters on admission were investigated. Chronologic change in NLR and FS were analyzed, and theirs utility for predicting severity of AP was evaluated by receiver operator characteristic (ROC) curve analysis. Correlation analysis was assessed by Spearman's rank test. NLR and FS levels were both increased significantly in SAP and positively correlated with Ranson score and hospital stays. The ROC curve analyses showed the optimal cut-off values of NLR for admission with day0, day1, day2 were 9.64, 6.66 and 6.50, giving sensitivity of 77-82%. The optimal cut-off values of FS for admission with day1, day2, day3 were 1375 ml, 2345 ml and 3424 ml, giving sensitivity of 62-75%. Moreover, measurement of NLR and FS together exhibited a similar area under curve (AUC) and sensitivity for SAP prediction compared with the those of Ranson score. Increase of NLR and FS are correlated with severity and can be suggested as a predictive factor in an early stage of AP.

Immunology of pancreatitis and environmental factors

PURPOSE OF REVIEW

This report reviews recent aspects of pancreatitis immunology and environmental factors that link to development and progression of disease.

RECENT FINDINGS

Limited human and animal model studies have recently attempted to understand immune mechanisms that lead to the pathogenesis of acute and chronic pancreatitis. Based on these studies innate immune responses emerge as critical elements in disease pathogenesis and severity of inflammation. The immune basis for environmental factors such as smoking, which are highly associated with disease progression highlight novel cross talk mechanisms between immune and nonimmune pancreatic cells such as the pancreatic stellate cells.

SUMMARY

Better understanding of immune responses and signaling pathways are emerging as important contributors in pancreatitis development and progression. Such mechanisms are likely to offer future targetable therapies that can either halt or reverse disease progression.

sPD-L1 Expression is Associated with Immunosuppression and Infectious Complications in Patients with Acute Pancreatitis

Acute pancreatitis (AP) with infectious complications has high mortality because of early-stage immunosuppression. The programmed cell death-1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway is an important host immunosuppression mechanism. Soluble PD-L1 (sPD-L1) expression regulates co-inhibitory signals in malignancies or autoimmune disorders; however, its effects in AP are unknown. Here, we evaluated whether serum sPD-L1 is involved in immune dysfunction and assessed its relationship with infectious complications in early AP. Blood samples were obtained from 56 patients with acute pancreatitis and 21 healthy individuals in this prospective study. Serum sPD-L1 levels within 48 h after AP onset were tested by enzyme-linked immunosorbent assays. Relevant immune parameters (human leucocyte antigen-DR, lymphocyte count) and inflammatory markers (C-reactive protein, white blood cell count) were analysed. sPD-L1 was significantly upregulated in patients with early AP, especially those with infectious complications, compared to healthy controls. Significant negative correlations were observed among monocyte HLA-DR expression, lymphocyte count and sPD-L1 levels in AP. Multivariate regression indicated that sPD-L1 was an independent risk factor for infectious complications in AP. The findings suggest that increased sPD-L1 expression appears to be involved in the development of immunosuppression in the early stage of AP and that sPD-L1 might be an early parameter for prediction of infectious complications in patients with AP.

The long-term quality of life in patients with persistent inflammation-immunosuppression and catabolism syndrome after severe acute pancreatitis: A retrospective cohort study

PURPOSE

To explore clinical characteristics and long-term quality of life (QOL) in severe acute pancreatitis (SAP) patients with persistent inflammation-immunosuppression and catabolism syndrome (PICS).

MATERIALS AND METHODS

SAP patients admitted to ICU were eligible for the retrospective cohort study if they needed prolonged intensive care (>14days). Post-ICU QOL was assessed by a questionnaire, including 36-item Short Form Health Survey (SF-36) and record of re-work in a long-term follow-up.

RESULTS

214 SAP patients were enrolled, in which 149 (69.6%) patients met the criteria of PICS. PICS patients had more complications and ICU days compared to non-PICS patients (P<0.001), and their post-ICU mortality was higher (P=0.046). When adjusted for confounders, PICS was independently associated with higher post-ICU mortality (hazard ratio 4.5; 95% CI, 1.2 to 16.3; P=0.024). The 36-item Short Form Health Survey (SF-36) score was lower for PICS group in six subscales (P<0.001). Only 28.8% patients in the PICS group returned to work compared to 60% patients in the non-PICS group (P=0.001) CONCLUSIONS: SAP patients with prolonged ICU stay had a high morbidity of PICS, which was a risk factor for the post-ICU mortality and poor long-term QOL.

The diffuse reduction in spleen density: an indicator of severe acute pancreatitis?

We observed that acute pancreatitis (AP) was associated with diffuse reduction in spleen density (DROSD) in some patients. Furthermore, the condition of these patients was more serious, and the potential relationship between DROSD and structural and functional injury of the spleen remained unclear. Therefore, we performed a preliminary exploration of these factors. We analysed pertinent clinical data for AP patients with normal spleen density (control group) and for those with DROSD (reduction group) at the First Affiliated Hospital of Harbin Medical University (June 2013–June 2015). We measured the immunoglobulin M (IgM) B-cells of the AP patients and examined pancreatic and splenic tissues from AP rats with optical microscopy and TEM. The reduction group had a higher acute physiology and chronic health evaluation II (APACHE II) score, a longer length of stay (LOS) and lower serum calcium than the control group. The levels of triglycerides (TG) and total cholesterol (TC) did not differ significantly between the two groups. The percentage of IgM memory B-cells was significantly lower in the DROSD group than in the control group. TEM revealed that the spleen T-lymphocytes were normal in AP rats, but pyroptotic and necrotic spleen B-cells were observed in the severe AP rats. In AP, DROSD was an independent indicator of more severe conditions. Furthermore, spleen B-lymphocytes showed obvious damage at the cellular level, and the immunological function of the spleen was down-regulated when AP was associated with DROSD.

The predominance of a naive T helper cell subset in the immune response of experimental acute pancreatitis

INTRODUCTION

In necrotizing acute pancreatitis (NAP), systemic inflammatory response syndrome (SIRS) and the compensatory anti-inflammatory response syndrome (CARS) decide overall outcome and mortality. In patients, low lymphocyte counts were found, but T-helper cells seemed to conversely increase. Our aim was to further categorize T-helper cells within the context of NAP induced SIRS and CARS.

METHODS

NAP was induced by injection of sodium-taurocholate into the common bile duct of male BALB/c mice; sham treated animals received saline infusion. The animals were sacrificed at 6, 12, 24 and 48 h later. Lymphocytes from blood, liver and spleen were isolated and examined by flow cytometry. Staining was performed for CD4, CD8, CD19, CD45RB, CD25, CD69, and CD152. CD4⁺ cells were sorted for their CD45RB expression and sought for gene regulation associated to T_H1/T_H2 cells by quantitative RT-PCR.

RESULTS

In NAP, CD4⁺ was solely increased in all compartments. CD8⁺ remained without substantial alterations. CD45RB showed significant expression in RB^high in T-helper cells, confirmed by the CD45RB^high/low ratio (Liver, 24 h: NAP 2.2, SHAM 0.6; p < 0.001). CD45RB^high and ^-low cells were not associated to patterns of T_H1/T_H2 expression. In NAP, CCR4 expression was significantly decreased within RB^high cells (fold change: 0.04, p < 0.05), while TLR6 showed significant overexpression (fold change: 2.36, p < 0.05).

CONCLUSION

T-helper cells increase in NAP, leaning towards CD45RB^high expression. They resemble naive T-cells, in which NAP leads to expression profiles associated with an innate immune response. This suggests new findings in immunological pathomechanisms of NAP.

Early enteral nutrition improves intestinal immune barrier in a rat model of severe acute pancreatitis

BACKGROUND

The aim of the present study was to investigate the role of early enteral nutrition (EEN) in the intestinal immune barrier in severe acute pancreatitis (SAP), and to explore its potential mechanisms.

METHODS

Sixty rats were randomly assigned to three groups: sham-operated group (SO group, n = 20), SAP group receiving EEN (SAP + EEN group, n = 20), and SAP group receiving total parental nutrition (SAP + TPN group, n = 20). SAP was induced by infusion of sodium taurocholate. Rats were killed 5 days after nutritional support. The pathological damage of the intestine was determined using HE staining. The expression of MAdCAM-1, CD⁴⁺ , and CD⁸⁺ in Peyer's lymph nodes of the distal ilium was examined by immunohistochemistry. Serum levels of endotoxin and bacterial translocation were determined.

RESULTS

The survival rate in the SAP + TPN (50%) and SAP + EEN (75%) groups was significantly lower than in the SO group (100%) (P < 0.05). The survival rate in the SAP + EEN group was significantly higher than in the SAP + TPN group (P < 0.05). The expression of MAdCAM-1, CD⁴⁺ and CD⁸⁺ in the intestine was decreased in SAP rats. EEN significantly increased the expression of MAdCAM-1, CD⁴⁺ and CD⁸⁺ compared with TPN, accompanied by a decrease in the serum levels of endotoxin and bacterial translocation.

CONCLUSIONS

Early enteral nutrition improves intestinal immune barrier, thus reducing bacterial and endotoxin translocation and improving the survival rate in SAP rats.

Therapeutic implications of innate immune system in acute pancreatitis

INTRODUCTION

Acute pancreatitis (AP) is an inflammatory disorder of the pancreas encompassing a cascade of cellular and molecular events. It starts from premature activation of zymogens with the involvement of innate immune system to a potential systemic inflammatory response and multiple organ failure. Leukocytes are the major cell population that participate in the propagation of the disease. Current understanding of the course of AP is still far from complete, limiting treatment options mostly to conservative supportive care. Emerging evidence has pointed to modulation of the immune system for strategic therapeutic development, by mitigating the inflammatory response and severity of AP. In the current review, we have focused on the role of innate immunity in the condition and highlighted therapeutics targeting it for treatment of this challenging disease.

AREAS COVERED

The current review has aimed to elaborate in-depth understanding of specific roles of innate immune cells, derived mediators and inflammatory pathways that are involved in AP. Summarizing the recent therapeutics and approaches applied experimentally that target immune responses to attenuate AP.

EXPERT OPINION

The current state of knowledge on AP, limitations of presently available therapeutic approaches and the promise of therapeutic implications of innate immune system in AP are discussed.

Overexpression of Fas and FasL is associated with infectious complications and severity of experimental severe acute pancreatitis by promoting apoptosis of lymphocytes

This study investigated the relationship of Fas and Fas ligand (FasL) expression and apoptosis of lymphocytes in relation to the pathogenic immune response and infectious complications observed in experimental severe acute pancreatitis in mice. Forty male Balb/c mice were randomly divided into control, mild (MAP), and severe acute pancreatitis (SAP) groups. Overexpression of Fas/FasL messenger ribonucleic acid (mRNA) and protein was observed in spleen-derived lymphocytes in SAP (p < 0.01). Apoptosis of these resulted in a depletion of circulating lymphocytes in this group (p < 0.05). A further significant change in the SAP group with infectious complications was observed. A positive relationship was found between the Fas/FasL expression and lymphocyte apoptosis, and negative relationships were observed between Fas/FasL expression and CD4⁺ and CD19⁺ lymphocytes and the CD4⁺/CD8⁺ ratio in SAP mice (p < 0.01). The results suggest that the overexpression of Fas/FasL is associated with infectious complications and severity of experimental severe acute pancreatitis by promoting apoptosis of lymphocytes.

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.

Heme oxygenase-1 gene promoter polymorphism is associated with the development of necrotizing acute pancreatitis

OBJECTIVES

Acute pancreatitis is a severe and frequently life-threatening disease, which can lead to pancreatic necrosis, acute lung injury, systemic inflammatory response syndrome, and other complications. In this study, we hypothesized that the expression of heme oxygenase-1 determined by the number of guanidinium thiocyanate (GT) repeats can influence the occurrence of acute pancreatitis.

METHODS

Patients with acute pancreatitis (n = 131) and age- and sex-matched healthy controls (n = 108) were studied. The polymerase chain reaction products were analyzed by ABI 3130 genetic analyzer and the exact size of the polymerase chain reaction products was determined by GeneMapper software. A short allele was defined as containing 27 GT repeats or fewer, whereas a long allele was more than 27 repeats.

RESULTS

The subjects were categorized into 3 groups on the basis of the genotype results: 1 short and 1 long, 2 short, and 2 long alleles (L/L). Patients with necrotizing disease more frequently were carriers of LL genotype compared with those who had edematous acute pancreatitis. Furthermore, logistic regression analysis revealed that the presence of L/L allele type doubles the risk for developing pancreatic necrosis in patients with acute pancreatitis.

CONCLUSIONS

The polymorphism of the GT repeats in the heme oxygenase-1 promoter region may be a risk factor for developing severe and necrotizing acute pancreatitis.

A systematic review of the extra-pancreatic infectious complications in acute pancreatitis

BACKGROUND AND AIM

Extra-pancreatic infectious complications in acute pancreatitis increase morbidity, but their incidence and association with infected pancreatic necrosis is unknown. Half of bacterial cultures of pancreatic necrosis are of non-enteric origin, raising the possibility of other sources of infection. The aim of this systematic review was to assess the incidence of extra-pancreatic infectious complications in acute pancreatitis, their timing, and relation to severity of pancreatitis and mortality.

METHODS

A systematic review was performed using Ovid MEDLINE, Embase and Cochrane Libraries, following PRISMA guidelines. Search terms were "Pancreatitis" AND "Infection" AND ("Complication" OR "Outcome").

RESULTS

19 studies with 1741 patients were included. Extra-pancreatic infectious complication incidence was 32% (95% CI 23-41%), with the commonest being respiratory infection (9.2%) and bacteraemia (8.4%). Extra-pancreatic infectious complications were not associated with the predicted severity or the mortality of acute pancreatitis. Only 3 studies reported a relation of timing between extra-pancreatic and pancreatic infectious complications.

CONCLUSIONS

This is the first systematic review to evaluate the incidence of extra-pancreatic infectious complications in acute pancreatitis, which a third of patients with acute pancreatitis will develop. Implications are vigilance and prompt treatment of extra-pancreatic infection, to reduce possibility of progression to infected pancreatic necrosis.

Complex role for the immune system in initiation and progression of pancreatic cancer

The immune system plays a complex role in the development and progression of pancreatic cancer. Inflammation can promote the formation of premalignant lesions and accelerate pancreatic cancer development. Conversely, pancreatic cancer is characterized by an immunosuppressive environment, which is thought to promote tumor progression and invasion. Here we review the current literature describing the role of the immune response in the progressive development of pancreatic cancer, with a focus on the mechanisms that drive recruitment and activation of immune cells at the tumor site, and our current understanding of the function of the immune cell types at the tumor. Recent clinical and preclinical data are reviewed, detailing the involvement of the immune response in pancreatitis and pancreatic cancer, including the role of specific cytokines and implications for disease outcome. Acute pancreatitis is characterized by a predominantly innate immune response, while chronic pancreatitis elicits an immune response that involves both innate and adaptive immune cells, and often results in profound systemic immune-suppression. Pancreatic adenocarcinoma is characterized by marked immune dysfunction driven by immunosuppressive cell types, tumor-promoting immune cells, and defective or absent inflammatory cells. Recent studies reveal that immune cells interact with cancer stem cells and tumor stromal cells, and these interactions have an impact on development and progression of pancreatic ductal adenocarcinoma (PDAC). Finally, current PDAC therapies are reviewed and the potential for harnessing the actions of the immune response to assist in targeting pancreatic cancer using immunotherapy is discussed.

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.

Acute pancreatitis in HIV/AIDS patients: an issue of concern

Pancreatitis is a well-described complication of human immunodeficiency virus (HIV) itself and its combination antiretroviral therapy. Historically, this has been predominantly associated with the usage of nucleoside reverse transcriptase inhibitors such as didanosine and stavudine, but only rarely with the usage of protease inhibitors via the induction of hypertriglyceridemia. Pancreatitis rates in HIV/AIDS population may have been exceedingly high because of the comorbid conditions prevalent in HIV/AIDS patients (e.g. ethanol use and biliary disease), and the use of non-combination antiretroviral therapy medications such as pentamidine, corticosteroids, ketoconazole, sulphonamides, metronidazole, isoniazid and opportunistic infections (e.g. cytomegalovirus, cryptosporidiosis, mycobacterial disease). In resource limited settings, where didanosine and stavudine are widely available in cheaper generic fixed dose combinations it is likely that their usage will remain in the first line HIV treatment in common. In such settings management or estimation of a patient's risk of pancreatitis still remains an issue of concern.

Implications of culture positivity in acute pancreatitis: does the source matter?

BACKGROUND AND AIMS

Sepsis is an important complication and cause of morbidity and mortality in acute pancreatitis (AP). The source of sepsis may be infected pancreatic and peripancreatic collections and/or necrosis or extrapancreatic including infections in the bloodstream or respiratory and urinary tracts. We studied the implications of the source of sepsis on various outcome parameters in AP like persistent organ failure (POF), length of hospital (LOH) stay, and mortality.

METHODS

A retrospective analysis of culture reports of AP patients was done, and the outcome parameters were recorded.

RESULTS

Three hundred fifty-seven patients (229 M; age: 40.3 ± 14.04 years) of AP who had detailed culture reports were included. Eighty-four (23.5%) patients had pancreatic (or peripancreatic) source (group 1), 52 (14.6%) patients had other (extrapancreatic) sources (group 2), 20 (5.6%) patients were noted to have positive cultures from sources, which were both pancreatic and extrapancreatic (combined) sources (group 3), while 201 patients had sterile cultures. POF was seen in 147 (48%) patients (group 1: 67.8%; group 2: 65%; group 3: 90%; group 4: 34% [P < 0.001]). The mean LOH stay was 22.1 ± 20.26 days (group 1: 30.2 ± 20.64 days; group 2: 26.4 ± 26.82 days; group 3: 47.3 ± 32.60 days; group 4: 15.2 ± 11.34 days [P < 0.001]). Seventy (19.7%) patients succumbed to their illness (group 1 [22.9%]; group 2 [36.5%]; group 3 [40%]; group 4 [12%] [P < 0.001]).

CONCLUSIONS

POF and LOH stay were more common in patients with combined pancreatic and extrapancreatic sources of sepsis. Mortality was significantly higher in patients with sepsis (groups 1, 2, 3) compared with sterile groups.

Correlation of Fas expression and apoptosis of lymphocytes with occurrence of sepsis in patients with severe acute pancreatitis

AIM: To investigate Fas expression and apoptosis of lymphocytes in severe acute pancreatitis (SAP) patients with and without sepsis.

METHODS: Fas expression and apoptosis of lymphocytes were examined by flow cytometry. Serum soluble Fas (sFas) levels were measured by enzyme-linked immunosorbent assay (ELISA) in 18 SAP patients (10 cases with sepsis, 8 cases without sepsis), 20 patients with mild acute pancreatitis (MAP), and 20 healthy volunteers (control).

RESULTS: Compared to the MAP and control groups, Fas expression, apoptosis of lymphocytes, and serum sFas levels increased significantly in the SAP group (all P < 0.01), and these changes were more significant in SAP patients with sepsis than in those without sepsis (38.37% ± 4.33% vs 26.34% ± 2.65%, 13.45% ± 2.99% vs 6.33% ± 2.05%, 9.89 ng/mL ± 1.25 ng/mL vs 7.36 ng/mL ± 0.95 ng/mL, all P < 0.01). There was no significant difference in Fas expression, apoptosis of lymphocytes, and serum sFas levels between the normal control group and MAP group. A significant positive relationship was observed between Fas expression and apoptosis of lymphocytes in SAP patients with sepsis (r = 0.988, P < 0.01).

CONCLUSION: The Fas signaling pathway may be involved in apoptosis of lymphocytes and is closely related to the severity of pancreatitis. Excessive apoptosis of lymphocytes appears to be related to immunosuppression and thereby results in the occurrence and development of sepsis in SAP patients.

The day when infection is confirmed is a better time point for mortality prediction in patients with severe acute pancreatitis

OBJECTIVES

The objective of the study was to compare the accuracy of predictive methods for mortality in patients with severe acute pancreatitis (SAP) on admission and on the day when infection was confirmed.

METHODS

Medical records of patients admitted for SAP in our hospital during January 2000 to November 2010 were retrospectively reviewed. Among those with infectious complications, time when infection was confirmed (TIC) and Acute Physiology and Chronic Health Evaluation II (APACHE II) score on admission and at the time when infection was confirmed (APACHE II OTIC) were studied. The correlations among the APACHE II score on admission, APACHE II OTIC score, and TIC were analyzed. The predictive accuracy was assessed by the area under the receiver operating characteristic curve.

RESULTS

Time when infection was confirmed correlated negatively with the APACHE II score on admission and the APACHE II OTIC score (P < 0.05). The optimum cutoff value and the corresponding areas under the receiver operating characteristic curve for APACHE II score on admission, APACHE II OTIC score, and TIC were greater than 8, greater than 5, 12 days or less, and 0.67 (95% confidence interval [CI], 0.54-0.77), 0.84 (95% CI, 0.73-0.91), and 0.73 (95% CI, 0.61-0.82), respectively. Compared with the APACHE II score on admission, the APACHE II OTIC score was more accurate in predicting mortality (P = 0.029).

CONCLUSIONS

The time when infection is confirmed is a better time point for the reassessment of the outcome in patients with SAP.

Changes in adaptive and innate immunity in patients with acute pancreatitis and systemic inflammatory response syndrome

BACKGROUND

Acute pancreatitis is a form of inflammation with clinical features ranging from pancreatic inflammation to fatal systemic manifestations. The aim of this study was to clarify changes in lymphocyte subsets and alterations in the functioning of natural killer (NK) cells.

PATIENTS AND METHODS

Forty-five patients were enrolled into the study; 35 with acute pancreatitis and systemic inflammatory response syndrome (SIRS) and 10 healthy subjects. Blood was sampled early from all patients. Blood immune cells were studied on days 1 and 4 by flow cytometry. Tumor necrosis factor-α (TNFα) and interleukin (IL)-6 were estimated from supernatants of NK cells before/after stimulation with lipopolysaccharide (LPS).

RESULTS

Apoptosis in patients was significantly different on days 1 and 4 compared with controls. Apoptosis of CD4(+) lymphocytes was significantly correlated with the days to resolution of SIRS (r = +0.586, p = 0.022). Significant differences were observed in TNFα and IL-6 on day 1 with/without LPS stimulation between patients and healthy individuals. Significantly increased levels of TNFα and IL-6 were found after LPS stimulation compared with unstimulated supernatants in day 1.

CONCLUSION

NK cells altered their secretory status when stimulated with LPS. This finding could be explained by the cellular reprogramming of NK cells in the field of acute pancreatitis and SIRS.

Mannan-binding lectin and mannan-binding lectin-associated serine protease 2 in acute pancreatitis

OBJECTIVES

Complement activation may play a prominent role in acute pancreatitis (AP). Mannan-binding lectin (MBL) and MBL-associated serine protease 2 (MASP-2) participate in complement activation. The objective of the present study was to evaluate the role of MBL and MASP-2 as markers in AP with regard to etiology, inflammatory activity, severity, and development of multiorgan failure.

METHODS

Sixty patients with AP were included. All patients were diagnosed and treated according to a standardized regimen. Blood samples were obtained immediately on admission and again on days 1, 2, and 14.

RESULTS

Both MBL (P < 0.001) and MASP-2 (P = 0.002) levels changed significantly over time, but without any significant relation to severity, multiorgan failure, or mortality. We found significantly higher levels of MBL (P = 0.04) in alcohol- than in gallstone-induced AP, but no significant difference in MASP-2 levels.

CONCLUSIONS

The MBL and MASP-2 acted as acute-phase reactants, but overall, they were not markers for severity, multiorgan failure, nor for mortality in AP. Our results suggest that MBL and MASP-2 play only a minor role in the inflammatory response in AP.

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.

Immune dysregulation in patients with severe acute pancreatitis

To investigate patients with severe acute pancreatitis (SAP) by dynamic levels of pro-/anti-inflammatory cytokines and endotoxin (ET) in plasma and the relationship between immunity and infection, organ dysfunction. Seventy-two patients with SAP were recruited. The ET, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), and interleukin-4 (IL-4) were determined on admission and days 3, 7, and 14. For comparison, patients were analyzed through infection group versus non-infection group, multiple organ dysfunction syndrome (MODS) group versus non-MODS group. There were sixteen patients with secondary infection, twenty-two with MODS, and nine deaths. The infection group had higher levels of ET than the non-infection group on days 3 and 7. The dynamic cytokine levels of patients in the MODS group were unanimous with those outcomes in the infection group. The levels of cytokines in the infection group were different from the non-infection group, with more levels of TNF-α, IL-6 on days 3 and 7 and less on days 14, and more levels of IL-10, IL-4 on days 7 and 14. The levels of TNF-α, IL-6 in the MODS group were different from the non-MODS group, with more levels on days 3 and 7, and less levels on days 14. Immune dysregulation may play an important role in infection and organ dysfunction for patients with SAP.

Different profiles of cytokine expression during mild and severe acute pancreatitis

AIM

To study secretion patterns of pro- and anti-inflammatory cytokines, and activation of various cellular subsets of leukocytes in peripheral blood.

METHODS

We have conducted a prospective observational study. One hundred and eight patients with a diagnosis of acute pancreatitis and onset of the disease within last 72 h were included in this study. The mRNA expression of 25 different types of cytokines in white blood cells was determined by quantitative real time polymerase chain reaction. Levels of 8 different cytokines in blood serum were measured by enzyme linked immunosorbent assay. Clinical data and cytokine expression results were subjected to statistical analysis.

RESULTS

Severe and necrotizing acute pancreatitis (AP) is characterized by the significant depletion of circulating lymphocytes. Severe acute pancreatitis is associated with a typical systemic inflammatory response syndrome and over-expression of pro-inflammatory cytokines [interleukin (IL)-6, IL-8, macrophage migration inhibitory factor (MIF)]. Serum IL-6 and MIF concentrations are the best discriminators of severe and necrotizing AP as well as possible fatal outcome during the early course of the disease.

CONCLUSION

Deregulation of cellular immune system is a key event leading to severe and necrotizing AP. IL-6 and MIF could be used as early predictors of complications.

Effect of dexamethasone on peripheral blood leukocyte immune response in bile-pancreatic duct obstruction-induced acute pancreatitis

Our aim was to analyze the effects of dexamethasone (Dx) (1mg/kg), prophylactically or therapeutically administered, on the inflammatory response triggered by peripheral blood leukocytes during acute pancreatitis (AP) induced in rats by bile-pancreatic duct obstruction (BPDO) and their consequences in the progress of the disease. Flow cytometry was used to analyze the distribution of the major leukocyte populations, the CD45 expression and the activated state of monocytes as reflected by the membrane-bound intercellular adhesion molecule-1 (ICAM-1) and the production of tumor necrosis factor-alpha (TNF-alpha) and monocyte chemoattract protein-1 (MCP-1) in response to lipopolysaccaride (LPS). Interleukin-6 (IL-6) plasma levels, pancreatic fluid content and histology of pancreas sections were also evaluated. Dx, given either before or after AP, blunted the monocyte increase induced by BPDO-induced AP, but did not change lymphocyte and neutrophil counts. Membrane-bound ICAM-1 expression did not vary in circulating monocytes during BPDO, either in Dx-treated or non-treated rats. Both Dx treatments inhibited TNF-alpha and MCP-1 production in non-stimulated and LPS-stimulated monocytes, whose response was found to be higher than in controls from early AP. Leukocyte CD45 expression was found to be reduced in rats with AP and shifted to control values in Dx-post-treated rats. Cytokinemia as well as pancreatic edema and leukocyte infiltration found in BPDO rats were reduced by Dx given either before or after AP. We conclude that prophylactic and therapeutic Dx treatments inhibited the inflammatory response triggered by circulating leukocytes in rats with BPDO-induced AP, thus contributing to reducing the severity of the disease.

Advances in researches on the immune dysregulation and therapy of severe acute pancreatitis

During the development and progression of severe acute pancreatitis (SAP), conspicuous immune dysregulation develops, which is mainly manifested as excessive immune response in the early stage and immunosuppression in the late stage. This process involves complex changes in a variety of immune molecules and cells, such as cytokines, complements, lymphocytes, and leukocytes. With the gradual deepening of studies on the development and progression of SAP, the role of immune dysregulation in the pathogenesis of SAP has attracted more and more attention. In this article, we review the advances in research on the immune dysregulation in SAP and the immunotherapy of this disease through exploring the formation of excessive immune response and immune suppression as well as their mutual transformation.

Advancement of intestinal function disorders in severe acute pancreatitis

Recent studies indicate that increased intestinal permeability and changes of intestinal mucosal immune function are very common in patients with severe acute pancreatitis (SAP). And they may be the main reasons for bacterial and endotoxin translocation, which are associated with secondary infection and multiorgan dysfunction syndrome in SAP. However, the accurate mechanism underlying the abnormality of intestinal mucosal immune dysfunction is not clarified, which deserves further study.

Usefulness of serum IgG4 in the diagnosis and follow up of autoimmune pancreatitis: A systematic literature review and meta-analysis

High circulating serum immunoglobulin G4 (IgG4) levels have been proposed as a marker of autoimmune pancreatitis (AIP). The aim of the present study was to review the data existing in the English literature on the usefulness of the IgG4 serum levels in the diagnosis and follow up of patients with AIP. A total of 159 patients with AIP and 1099 controls were described in seven selected papers reporting the usefulness of serum IgG4 in diagnosing AIP. In total, 304 controls had pancreatic cancer, 96 had autoimmune diseases, and the remaining 699 had other conditions. The summary receiver-operating characteristic curve analysis was carried out by means of Meta-DiSc open-access software. Serum IgG4 showed good accuracy in distinguishing between AIP and the overall controls, pancreatic cancer and other autoimmune diseases (area under the curve [+/- SE]: 0.920 +/- 0.073, 0.914 +/- 0.191, and 0.949 +/- 0.024, respectively). The studies analyzed showed significantly heterogeneous specificity values in each of the three analyses performed. The analysis of the four studies comparing AIP and pancreatic cancers also showed significantly heterogeneous values of sensitivities and odds ratios. Regarding the usefulness of IgG4 as a marker of efficacy of steroid treatment, a decrease in the serum concentrations of IgG4 was found in the four available studies. The serum IgG4 subclass is a good marker of AIP, and its determination should be included in the diagnostic workup of this disease. However, the heterogeneity of the studies published until now means that more studies are necessary in order to better evaluate the true accuracy of IgG4 in discriminating AIP versus other autoimmune diseases.

Immune and inflammatory responses to stroke: good or bad?

Inflammatory and immune responses play important roles following ischaemic stroke. Inflammatory responses contribute to damage and also contribute to repair. Injury to tissue triggers an immune response. This is initiated through activation of the innate immune system. In stroke there is microglial activation. This is followed by an influx of lymphocytes and macrophages into the brain, triggered by production of pro-inflammatory cytokines. This inflammatory response contributes to further tissue injury. There is also a systemic immune response to stroke, and there is a degree of immunosuppression that may contribute to the stroke patient's risk of infection. This immunosuppressive response may also be protective, with regulatory lymphocytes producing cytokines and growth factors that are neuroprotective. The specific targets of the immune response after stroke are not known, and the details of the immune and inflammatory responses are only partly understood. The role of inflammation and immune responses after stroke is twofold. The immune system may contribute to damage after stroke, but may also contribute to repair processes. The possibility that some of the immune response after stroke may be neuroprotective is exciting and suggests that deliberate enhancement of these responses may be a therapeutic option.

Serum immunosuppressive acidic protein levels in patients with severe acute pancreatitis

OBJECTIVES

In severe acute pancreatitis (SAP), immunologic impairment in the early phase may be linked to subsequent infectious complications. Immunosuppressive acidic protein (IAP) is an immunosuppressive factor to be present in serum and ascites of cancer patients, and it is used as a tumor marker and an index of immune status of cancer hosts.

METHODS

We measured serum IAP levels in 42 patients with SAP (Japanese severity score [JSS] > or = 2) on admission and analyzed the relationships with disease severity, pancreatic necrosis, blood biochemical parameters on admission, and clinical outcome (infection and death).

RESULTS

Serum IAP level increased 791 +/- 285 microg/mL (range, 159-1430 microg/mL) on admission and recognized abnormal high level (normal range, < 500 microg/mL) in 37 patients (88.1%). Serum IAP level was significantly lower in patients of stages 3 and 4 (JSS > or = 9) (678 +/- 187 microg/mL) than that in patients of stage 2 (2 < or = JSS < or = 8) (848 +/- 311 microg/mL). It was also significantly lower in patients whose Ranson score was 5 or higher (674 +/- 287 microg/mL) than that in patients whose Ranson score was 4 or less (910 +/- 287 microg/mL). Moreover, it was significantly lower in patients with pancreatic necrosis (693 +/- 194 microg/mL) than that in patients without pancreatic necrosis (922 +/- 336 microg/mL). Among the blood biochemical parameters on admission, serum IAP was significantly negatively correlated with hematocrit, serum lipase, and serum interferon gamma and was significantly positively correlated with serum total protein. Serum IAP levels in patients of stage 2 reached higher peak at 7 days after admission and decreased more rapidly than those in patients of stages 3 and 4.

CONCLUSIONS

Serum IAP levels were elevated in patients with SAP but were significantly lower in patients with higher grade of severity or pancreatic necrosis. These results suggest that serum IAP levels may be related to systemic inflammatory response and reflect the immunoresponsiveness in patients with SAP.

Serum interleukin-15 level is a useful predictor of the complications and mortality in severe acute pancreatitis

BACKGROUND

In severe acute pancreatitis, multiple organ dysfunction syndrome and infectious complications are contributors to high mortality. Interleukin (IL)-15 is a novel cytokine that shares many biologic properties with IL-2. Serum IL-15 levels have not yet been determined in SAP.

METHODS

Serum IL-15 concentrations were measured in 54 patients with severe acute pancreatitis on admission. The relationships with severity, organ dysfunction, infection, and prognosis were analyzed. Utility of IL-15 for the prediction of clinical outcome was evaluated by receiver operator characteristic (ROC) curve analysis.

RESULTS

Serum IL-15 levels were increased significantly in severe acute pancreatitis (5.8 +/- 0.5 pg/mL), and they were correlated with Ranson, APACHE II, and Japanese severity score. Serum IL-15 levels were greater in patients with organ dysfunction, patients with infection, and nonsurvivors (P < 05 each). Incidences of organ dysfunction in patients whose IL-15 levels were less than 3.0, 3.0-5.3, and greater than or equal to 5.3 pg/mL, were 8%, 31%, and 89%, respectively (P < .001). Usefulness of IL-15 for the prediction of organ dysfunction was superior to CRP, IL-6, and IL-8, and it was similar to Ranson, APACHE II, and Japanese severity score. Incidences of infection in patients whose IL-15 levels were less than 5.5, 5.5-9.0, and greater than or equal to 9.0 pg/mL, were 7%, 25%, and 50%, respectively (P < .05). Mortality rates in patients whose IL-15 levels were less than 5.5, 5.5-9.0, and greater than or equal to 9.0 pg/mL, were 11%, 25%, and 80%, respectively (P < .001). Usefulness of IL-15 for the prediction of death was superior to CRP, IL-6, and IL-8.

CONCLUSIONS

Serum IL-15 level is a useful predictor of the complications (especially organ dysfunction) and mortality in severe acute pancreatitis.

Treatment outcome of selective digestive decontamination and enteral nutrition in patients with severe acute pancreatitis

BACKGROUND/PURPOSE

Sepsis due to infected pancreatic necrosis is the most serious complication in the late phase of severe acute pancreatitis (SAP). Bacterial translocation from the gut is thought to be the main cause of pancreatic infection. The possibility has recently been reported that selective digestive decontamination (SDD) and enteral nutrition (EN) may alleviate the complications and reduce the mortality rate in patients with SAP. We analyzed the treatment outcome of SDD and EN in patients with SAP.

METHODS

We divided 90 patients with SAP into three groups: SDD(-)EN(-),group A; SDD(+)EN(-), group B; and SDD(+)EN(+), group C. Clinical outcome was analyzed retrospectively. The effect of SDD was compared in groups A and B, and the effect of EN was compared in groups B and C.

RESULTS

The background of patients was not significantly different between the groups. SDD reduced the incidence of organ dysfunction (from 70% to 59%) and the mortality rate (from 40% to 28%), but the differences were not significant. EN reduced the incidence of infected pancreatic necrosis (from 31% to 24%) and the frequency of surgery for pancreas (from 28% to 18%), and further reduced the mortality rate (from 28% for SDD to 16%), but the differences were not significant. The peripheral lymphocyte count was significantly increased in patients with EN.

CONCLUSIONS

SDD and EN did not significantly affect the treatment outcome in SAP. However, the results in this study raise the possibility that SDD and EN may decrease the complications and reduce the mortality rate in SAP. The efficacy of SDD and EN for SAP should be evaluated in a randomized controlled trial.