Immune function early in acute pancreatitis

Circulating Blood Lymphocytes and Acute Pancreatitis Severity: A Systematic Review

Acute pancreatitis is an acute inflammatory process of the pancreas with high prevalence and varying degrees of severity that can be potentially life-threatening. Much is still unknown about which mechanisms determine the course and severity of acute pancreatitis. The primary objective of this review is to identify the potential association between circulating lymphocytes and the severity of acute pancreatitis. A systematic search was performed in Medline, Web of Science, Cochrane Central Register of Controlled Trials and ClinicalTrails.gov. The authors independently did the selection process as well as data extraction that was recorded into a flow diagram following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P). Our initial search identified 27,783 studies which were narrowed down to 13 by applying strict inclusion and exclusion algorithms. The consistent findings across the studies indicated that peripheral blood lymphocytes are related to acute pancreatitis severity.

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.

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%.

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.

Protease inhibitors, inflammatory markers, and their association with outcome in dogs with naturally occurring acute pancreatitis

Background

Acute pancreatitis (AP) presumably is associated with pancreatic protease activation, protease inhibitor (PI) depletion, and inflammatory mediator secretion.

Objectives

Examine PIs and inflammatory mediator concentrations in dogs with AP and their association with death.

Animals

Thirty‐one dogs diagnosed with AP based on clinical signs, ultrasonographic findings, and increased canine pancreatic lipase immunoreactivity (cPLI) and 51 healthy control dogs.

Methods

Antithrombin and α₂‐antiplasmin activity (ATA and α₂AP, respectively) and concentrations of α₁‐proteinase inhibitor (α₁PI), α₂‐macroglobulin (α₂MG), C‐reactive protein (CRP), interleukins (ILs)‐2,6,8 and tumor necrosis factor‐α (TNF‐α) were prospectively measured. Severity of AP was assessed by clinical severity scoring systems.

Results

Mortality rate was 19%. Antithrombin activity was lower (P = .004) and maximal CRP, IL‐6, and TNF‐α concentrations higher (P < .04) in the AP group compared to the controls, whereas IL‐2, IL‐8, α₁PI, and α₂AP concentrations did not differ between groups. Serum α₂MG concentration was not reliably detected. Serum cPLI, CRP, and IL‐6 concentrations were significantly and positively correlated. The ATA was lower (P = .04), and canine acute pancreatitis severity (CAPS) scores higher (P = .009) in nonsurvivors compared to survivors. Higher CAPS scores were associated (P < .05) with decreased ATA and increased cPLI, CRP, and IL‐6 concentrations.

Conclusions and Clinical Importance

Systemic inflammation in dogs with AP is manifested by increased inflammatory mediator concentrations, correlating with cPLI and CRP concentrations. Hypoantithrombinemia is associated with death. Serum concentrations of α₂AP and α₁PI are less useful prognostic markers. The CAPS score is a useful prognostic marker in dogs with AP.

Bacterial translocation in acute pancreatitis

Bacterial translocation is a phenomenon in which live bacteria or their products cross the intestinal barrier to other organs or the circulatory system. Gut translocation of bacteria has been reported in both animal models, and clinical trials often accompany acute pancreatitis and are believed to be linked to patient outcome, especially in severe acute pancreatitis. Therefore, the mechanisms of intestinal bacterial translocation in acute pancreatitis have become a topic of interest in recent years. This review discusses Bacterial translocation in acute pancreatitis, identifies possible mechanisms of action, and provides an overview of the methods used to detect Bacterial translocation in acute pancreatitis. This review also highlights areas that require further research.

Delta neutrophil index as an early predictive marker of severe acute pancreatitis in the emergency department

Background

Predicting severe acute pancreatitis (AP) in the early clinical stage is important for low morbidity and mortality. Delta neutrophil index (DNI) is used to detect infection and inflammation, but no previous studies have evaluated the usefulness of DNI as an early predictor of progression to severe AP (SAP).

Methods

The medical records of patients who were diagnosed with AP at the emergency department (ED) of Wonju Severance Christian Hospital from January 2012 to August 2016 were retrospectively reviewed. The initial DNI obtained in the ED was compared with other inflammatory markers to predict SAP. Multivariate logistic regression was used for statistical analysis.

Results

Of the 209 cases included in the analysis, 13 were classified as SAP. Compared to the DNI of the mild to moderately SAP group, that in the SAP group was considerably higher. The DNI showed a positive correlation with the Atlanta classification and bedside index of severity in AP. Using multivariate logistic regression analysis, DNI was an independent predictor of early SAP detection (odds ratio 1.122, 95% CI 1.045-1.205, p = 0.001). Among the biomarkers, DNI had the highest predictive value for SAP.

Conclusions

The DNI measured in the ED at presentation is a potentially useful adjunctive marker to predict SAP.

B and NK Cells Closely Correlate with the Condition of Patients with Acute Pancreatitis

Purpose

Pancreatitis can lead to systemic inflammatory response, but the relationship between lymphocyte changes and patients with pancreatitis remains unclear. In this study, we evaluated the feedback function of changes in peripheral lymphocyte subsets on the condition of patients with pancreatitis.

Materials and Methods

131 acute pancreatitis (AP) patients and 11 chronic pancreatitis (CP) patients constituted the patients' group; 20 healthy individuals were enrolled as healthy controls (HC). Serum concentration of C-reactive protein (CRP), amylase, and lipase and the frequency and absolute number of many types of peripheral lymphocytes (including T, B, NK, CD16+/CD56+ T, CD4+ T, CD8+ T, CD4+CD8+ T, and CD4−CD8− T cells) were detected on admission and the seventh day of standard treatment. Besides, the length of hospital stay was recorded.

Results

The absolute number of all lymphocytes we studied decreased in patients with CP and in patients with almost all types of AP. The frequency change of lymphocytes varies among the different types of AP. During disease onset, B cell frequency correlated positively with CRP concentration and NK cell frequency correlated positively with amylase and lipase concentration. B cell frequency and CD4+ T cell absolute number were recovering towards normal after short-term treatment. The frequency of B cells and NK cells correlated positively with the length of hospital stay.

Conclusions

B cells and NK cells closely correlate with patients' condition and may help to diagnose AP more accurately and reflect treatment effect of AP in time, affecting the recovery speed of patients with M-AP, which may help physicians to better understand the pathophysiology of pancreatitis.

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.

Mitochondrial dysfunction in peripheral blood mononuclear cells in early experimental and clinical acute pancreatitis

BACKGROUND/OBJECTIVES

Mitochondrial dysfunction occurs in vital organs in experimental acute pancreatitis (AP) and may play an important role in determining severity of AP. However, obtaining vital organ biopsies to measure mitochondrial function (MtF) in patients with AP poses considerable risk of harm. Being able to measure MtF from peripheral blood will bypass this problem. Furthermore, whether mitochondrial dysfunction is detectable in peripheral blood in mild AP is unknown. Therefore, the objective was to evaluate peripheral blood MtF in experimental and clinical AP.

METHOD

Mitochondrial respiration was measured using high resolution oxygraphy in an experimental study in caerulein induced AP and in a separate study, in patients with mild AP. Superoxide, cytochrome c, mitochondrial membrane potential (ΔΨ) and adenine triphosphate (ATP) were also measured as other markers of MtF.

RESULTS

Even though some states of mitochondrial respiration were increased in both experimental and clinical AP, this did not lead to an increase in net ATP in patients with AP. The increased leak respiration in both studies was further proof of dyscoupled mitochondria. In the clinical study there were also features of mitochondrial dysfunction with increased leak flux control ratio, superoxide, ΔΨ and decreased cytochrome c.

CONCLUSION

There is evidence of mitochondrial dysfunction with dyscoupled mitochondria, increased superoxide and decreased cytochrome c in patients with mild acute pancreatitis. Further studies should now determine whether mitochondrial function alters with severity in AP and whether mitochondrial dysfunction responds to treatments.

Clinical observation of immunity for severe acute pancreatitis

The aim of our study was to observe the dynamic changes of immunity for patients with severe acute pancreatitis (SAP) and intervention by traditional Chinese medicine. Twenty-three patients who met the inclusion criteria were randomized to combined treatment of traditional Chinese medicine and Western medicine (TCM) or conventional western medicine treatment (WM) groups. The clinical data for all patients were collected. Peripheral venous blood samples were obtained from patients on days 1, 7, 14, and 28 after admission. Biochemical data including the percentage of CD4+/CD8+/natural killer (NK) cells/B lymphocytes/HLA-DR and CD4+/CD8+ ratio in serum were determined by flow cytometer. Patients' characteristics and immunity at admission were similar between the two groups. The secondary infection was different. The levels of T-lymphocyte subsets in the TCM group were quite different from the WM group, with much more the percentage of CD4+ and the CD4+/CD8+ ratio on days 7, 14, and 28 and much less the percentage of CD8+ on days 4 and 28. On days 14 and 28, the levels of NK cells and B lymphocytes were significantly higher in the TCM group compared with the controls. Compared with the TCM group, the levels of HLA-DR were significantly decreased in the WM group on days 7, 14, and 28. The immune dysregulation exists in the development and progression of SAP. The combined treatment of traditional Chinese medicine and western medicine can upregulate the patient's immune and maintain the immune balance.

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.

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.

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.

Thymosin alpha 1 improves severe acute pancreatitis in rats via regulation of peripheral T cell number and cytokine serum level

AIM

The aim of this study was to investigate the effect of thymosin alpha 1 (TA1) on severe acute pancreatitis (SAP) in rats.

METHODS

Healthy Sprague-Dawley rats (n = 72) were randomly divided into four groups: control group, SAP group, and two TA1 treated groups. SAP was induced by injection of 5% sterile sodium taurocholate into the biliopancreatic duct (BPD), after which TA1 was given subcutaneously at 0 and 2 h at a dose of 100 microg/kg. The rats were killed at 3, 6 and 12 h, respectively. Serum amylase and lipase, interleukin (IL)-1beta, tumor necrosis factor-alpha (TNF-alpha), pancreatic wet/dry weight ratio and the percentage of CD3/CD4+/CD8+ T cells in peripheral blood mononuclear cells (PBMC) were measured. Next, 30 rats were randomly divided into three groups (each group containing 10 animals): SAP group (S) and two TA1 treated groups. The effects of TA1 on the survival of SAP were assessed 72 h after the induction of SAP.

RESULTS

There was no significant change in the serum amylase and lipase levels after TA1 administration. Levels of serum IL-1beta, TNF-alpha and pancreatic wet/dry weight ratio were significantly reduced after TA1-treatment. Application of TA1 significantly balanced CD3/CD4+/CD8+ T cells of PBMC and improved histological scores and the survival rate.

CONCLUSION

TA1 can reduce pancreatic inflammation by regulating differentiation of CD3/CD4+ T cells and decreasing the release of cytokines, thus attenuates pancreatic severity in SAP rats.

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.

Severe acute pancreatitis: Clinical course and management

Severe acute pancreatitis (SAP) develops in about 25% of patients with acute pancreatitis (AP). Severity of AP is linked to the presence of systemic organ dysfunctions and/or necrotizing pancreatitis pathomorphologically. Risk factors determining independently the outcome of SAP are early multi-organ failure, infection of necrosis and extended necrosis (>50%). Up to one third of patients with necrotizing pancreatitis develop in the late course infection of necroses. Morbidity of SAP is biphasic, in the first week strongly related to early and persistence of organ or multi-organ dysfunction. Clinical sepsis caused by infected necrosis leading to multi-organ failure syndrome (MOFS) occurs in the later course after the first week. To predict sepsis, MOFS or deaths in the first 48-72 h, the highest predictive accuracy has been objectified for procalcitonin and IL-8; the Sepsis-Related Organ Failure Assessment (SOFA)-score predicts the outcome in the first 48 h, and provides a daily assessment of treatment response with a high positive predictive value. Contrast-enhanced CT provides the highest diagnostic accuracy for necrotizing pancreatitis when performed after the first week of disease. Patients who suffer early organ dysfunctions or at risk of developing a severe disease require early intensive care treatment. Early vigorous intravenous fluid replacement is of foremost importance. The goal is to decrease the hematocrit or restore normal cardiocirculatory functions. Antibiotic prophylaxis has not been shown as an effective preventive treatment. Early enteral feeding is based on a high level of evidence, resulting in a reduction of local and systemic infection. Patients suffering infected necrosis causing clinical sepsis, pancreatic abscess or surgical acute abdomen are candidates for early intervention. Hospital mortality of SAP after interventional or surgical debridement has decreased in high volume centers to below 20%.

Severe acute pancreatitis: Clinical course and management

Severe acute pancreatitis (SAP) develops in about 25% of patients with acute pancreatitis (AP). Severity of AP is linked to the presence of systemic organ dysfunctions and/or necrotizing pancreatitis pathomorphologically. Risk factors determining independently the outcome of SAP are early multi-organ failure, infection of necrosis and extended necrosis (> 50%). Up to one third of patients with necrotizing pancreatitis develop in the late course infection of necroses. Morbidity of SAP is biphasic, in the first week strongly related to early and persistence of organ or multi-organ dysfunction. Clinical sepsis caused by infected necrosis leading to multi-organ failure syndrome (MOFS) occurs in the later course after the first week. To predict sepsis, MOFS or deaths in the first 48-72 h, the highest predictive accuracy has been objectified for procalcitonin and IL-8; the Sepsis-Related Organ Failure Assessment (SOFA)-score predicts the outcome in the first 48 h, and provides a daily assessment of treatment response with a high positive predictive value. Contrast-enhanced CT provides the highest diagnostic accuracy for necrotizing pancreatitis when performed after the first week of disease. Patients who suffer early organ dysfunctions or at risk of developing a severe disease require early intensive care treatment. Early vigorous intravenous fluid replacement is of foremost importance. The goal is to decrease the hematocrit or restore normal cardiocirculatory functions. Antibiotic prophylaxis has not been shown as an effective preventive treatment. Early enteral feeding is based on a high level of evidence, resulting in a reduction of local and systemic infection. Patients suffering infected necrosis causing clinical sepsis, pancreatic abscess or surgical acute abdomen are candidates for early intervention. Hospital mortality of SAP after interventional or surgical debridement has decreased in high volume centers to below 20%.

Effect of somatostatin on immune inflammatory response in patients with severe acute pancreatitis

OBJECTIVE

Somatostatin regulates immune inflammatory response via apoptosis and adhesion of leukocytes in many diseases. This article reported a study that aimed to observe the mechanism and effect of somatostatin on the immune inflammatory response through apoptosis and adhesion of leukocytes in severe acute pancreatitis.

METHODS

Thirty-eight patients with severe acute pancreatitis, that fulfilled the guidelines for the treatment of severe acute pancreatitis of China and Balthazar computed tomography severity index (>or=5) were enrolled consecutively. Nineteen of these patients received our routine treatment and 19 received additional somatostatin. In all patients the expressions of CD4, CD8, CD95/CD95 ligand and CD18/CD62 ligand on leukocytes were determined by flow cytometry, both upon admission and on the fourth day. Thirty healthy volunteers constituted the normal healthy group.

RESULTS

In the treatment group, CD4, CD4:CD8 ratio and CD62 ligand on leukocytes increased from 11.4+/-8.2, 0.47+/-0.10 and 25.5+/-9.2 to 22.1+/-9.7, 0.68+/-0.11 and 36.2+/-11.7 (P<0.05) respectively, while CD95 ligand on both lymphocyte and polymorphonuclear cells increased from 0.65+/-0.21 and 0.76+/-0.29 to 1.18+/-0.32 and 1.58+/-0.43 after treatment with somatostatin (P<0.05). Furthermore, lactate dehydrogenase, aspartate aminotransferase, amylase, C reactive protein and acute physiology and chronic healthy evaluation (APACHE II) score in the treatment group reduced faster than those in the control group (P<0.05), though there was no difference in mortality (15.7% vs 5.3%) between the two patient groups (P>0.05).

CONCLUSION

Somatostatin can modulate the immune inflammatory response and the severity of severe acute pancreatitis through apoptosis and adhesion of leukocytes, but this modulatory effect by itself is not strong enough to improve the final.

Alteration of peripheral blood lymphocyte subsets in acute pancreatitis

AIM: To evaluate peripheral blood lymphocyte subsets in patients with acute pancreatitis (AP).

METHODS: Twenty patients with mild AP (M-AP) and 15 with severe AP (S-AP) were included in our study. Peripheral blood lymphocytes were examined at d 1-3, 5, 10 and 30 by means of flow cytometry.

RESULTS: A significant depletion of circulating lymphocytes was found in AP. In the early AP, the magnitude of depletion was similar for T- and B- lymphocytes. In the late course of S-AP, B-lymphocytes were much more depleted than T-lymphocytes. At d 10, strong shift in the CD7+/CD19+ ratio implicating predominance of T- over B-lymphocytes in S-AP was found. Among T-lymphocytes, the significant depletion of the CD4+ population was observed in M-AP and S-AP, while CD8+ cells were in the normal range. Lymphocytes were found to strongly express activation markers: CD69, CD25, CD28, CD38 and CD122. Serum interleukin-2 (IL-2), IL-4, IL-5, IL-10, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) levels were significantly increased in both forms of AP. The magnitude of elevation of cytokines known to be produced by Th2 was much higher than cytokines produced by Th1 cells.

CONCLUSION: AP in humans is characterized by significant reduction of peripheral blood T- and B-lymphocytes.

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.

Neutrophil engagement and septic challenge in acute experimental pancreatitis in rats

AIM: To investigate the influence of neutrophil adhesion molecule blockade with monoclonal antibody (MoAb CD11b) and E. coli lipopolysaccharide (LPS) administration on experimental acute pancreatitis (AP).

METHODS: AP was induced by four ip injections of cerulein (Cn) at 1-h intervals. MoAb CD 11b and LPS were administered at the beginning of the experiment.

RESULTS: The neutrophil count and chemiluminescence were diminished at the beginning of AP. The oxidative stress parameters were found within the pancreatic gland. MoAb CD 11b used for AP resulted in a significant reduction of pancreatic infiltration and pancreatitis oxidative stress parameters. Serum interleukin-6 (IL-6) was not detected in AP animals, whereas high serum IL-6 concentration was noted only in animals receiving LPS.

CONCLUSION: Neutrophils are involved in pancreatic damage in the early stage of AP. Neutrophil infiltration reduction protects the pancreatic gland from destruction during AP. LPS does not change the early course of Cn pancreatitis in rats.

Intravenous antioxidant modulation of end-organ damage in L-arginine-induced experimental acute pancreatitis

BACKGROUND

Oxidative stress mediates acinar injury in experimental acute pancreatitis (AP) and antioxidants are depleted in human AP. This study tests the hypothesis that exogenous antioxidant supplementation ameliorates experimental AP.

METHODS

Male Sprague-Dawley rats were randomly allocated to 1 of 4 groups (n = 5/group) and sacrificed at 72 h. AP was induced by 250 mg per 100 g body weight of 20% L-arginine hydrochloride in 0.15 mol/l sodium chloride. Group allocations were: group 1 (control) no intervention; group 2 AP; group 3 early multiple antioxidant (MAOX) intervention comprising 15 microg/kg selenium, 30 microg/kg ascorbate and 300 mg/kg N-acetylcysteine given at 6 and 30 h and group 4 the MAOX combination above given at 24 and 48 h. Endpoints were: serum amylase, antioxidant levels, bronchoalveolar lavage (BAL) protein and lung myeloperoxidase (MPO) activity and histological assessment of pancreatic injury.

RESULTS

L-arginine induced AP characterised by oedema, neutrophil infiltration, acinar cell degranulation and elevated serum amylase. Early MAOX reduced pulmonary MPO and BAL protein and reduced acinar swelling, degranulation and pancreatic parenchymal infiltration by inflammatory cells. These features were absent when intervention was delayed.

CONCLUSION

In this model, early but not late antioxidant intervention ameliorates pancreatic and pulmonary injury.

Influence of molecule CD 11b blockade on the course of acute ceruleine pancreatitis in rats

Polymorphonuclear cells (PMN) activation is an essential step in acute pancreatitis (AP). We investigated the activation status of PMN, oxidative stress and pancreatic damage in early stage of experimental ceruleine pancreatitis in rats. The PMN action was modulated by monoclonal antibody CD 11b administration. The circulating WBC and polymorphonuclear cells count was reduced after AP induction. Chemiluminescence of whole blood PMN was remarkably reduced in AP group and increased after MoAb CD 11b administration. The CD 11b blockade significantly reduced the WBC infiltration and malondialdehyde (MDA) concentration within pancreatic gland. These data suggest that activated PMN are an important factor in early AP pathogenesis. Neutrophil aggregation within pancreatic gland modulated by monoclonal antibody CD11b contribute to the extent of injury during the early stage of ceruleine experimental pancreatitis in rats.

Cholecystokinin blockade alters the systemic immune response in rats with acute pancreatitis

Acute pancreatitis (AP) is characterized by initial pancreatic injury resulting from the activation of digestive enzymes and, later, widespread inflammation to distant organs. The aim of this study was to study whether the time-course of inflammatory events during AP induced by bile-pancreatic duct obstruction (BPDO) varies after lowering the acinar enzyme content by L364,718 (0.1 mg/kg/day) administration over 7 days before inducing AP. Flow cytometric immunophenotyping was used to analyse the following at different AP stages: distribution of major circulating leucocyte subsets, activation state of circulating neutrophils and monocytes as reflected by CD11b expression and tumour necrosis factor-alpha (TNF-alpha) production and the contribution of T-cell-derived pro-(TNF-alpha) and anti-(IL-10) inflammatory mediators. TNF-alpha plasma levels and neutrophil infiltration in pancreas and lung were also measured. At early BPDO times, L364,718 treatment partially inhibited leukocytosis and increase in peripheral blood neutrophils and monocytes as well as TNF-alpha expression by monocytes. However, from 6 h onwards after BPDO, L364,718 treatment was unable to prevent either pancreatic and lung neutrophil infiltration or the release of TNF-alpha from activated monocytes. By its action on circulating lymphocytes, L364,718 treatment enhanced the severity of the inflammatory response induced by BPDO. Peripheral blood lymphocytes were recruited from earlier BPDO times, and 12 h after BPDO, T cells displayed a significantly higher reserve of TNF-alpha able to be released under stimulation but lower functional reserve of interleukin-10 (IL-10) than observed in untreated rats. It is concluded that lowering the acinar enzyme content through L364,718 treatment prevents earlier systemic immune events in BPDO-induced AP. However, at the point of maximal injury, the inflammatory response became pronounced, largely due to the role played by activated T lymphocytes.

Immunologic characterization of acute pancreatitis in rats induced by dibutyltin dichloride (DBTC)

There is little information available regarding the role of inflammatory cells and cytokines in the pancreatic tissue during acute interstitial pancreatitis. The single intravenous application of dibutyltin dichloride (DBTC) induces a pancreatitis in rats with a dosage dependent course. We analyzed the infiltrating leukocytes and the cytokine expression profile in the experimental model of DBTC-initiated mild interstitial pancreatitis during a time course of 4 weeks. Macrophages dominated among the infiltrating inflammatory cells detected by immunohistochemistry. The expression of IL-1beta, IL-10, and TGFbeta1 was shown to be elevated 24 hours after onset of pancreatitis reaching a maximum during the first week. Positive immunostaining of IL-1beta, IL-10, or TGFbeta1 was not restricted to infiltrating leukocytes but was found to various degrees in pancreatic cells. Transcripts of collagen type 1 reached high levels in the first week, but were down regulated thereafter. There was no significant expression of IL-2, IL-2 receptor, IL-4, TNFalpha, or IFNgamma. Our data show that the experimental interstitial pancreatitis was characterized by macrophage infiltration accompanied by elevated cytokine expression that lasted longer than the visible morphologic lesions. These inflammatory processes might create the environment that makes the pancreas more susceptible to further damaging effects.

Immune function in patients with acute pancreatitis

BACKGROUND

The aim of this study was to clarify the relationship between the balance of T-helper (Th)1 and Th2 cytokines, and the numbers of CD4+ T and CD8+ T-cells, and was investigated, together with the plasma concentration of the antigen, an apoptosis marker, in patients with mild and acute pancreatitis (AP).

METHODS

Plasma concentrations of soluble (s) CD4, sCD8, sIL-2-R, IL-12, IFN-gamma and sFas antigen were measured by ELISA, and CD4+ T, and CD8+ T lymphocyte counts were measured by flow cytometry.

RESULTS

Both CD4+ T and CD8+ T-cells were reduced in number; in the severe cases the reduction in the former was more pronounced. A significant positive correlation was noted among the concentrations of sCD4, sIL-2-R and IL-12, and a significant positive correlation was also found between sCD4 and sFas. During the early stage of AP, the concentrations of sCD4, sCD8, sIL-2-R, IL-12 and IFN-gamma increased more in the severe cases compared with those who had milder symptoms; however, these increases were moderated during the clinical course.

CONCLUSION

We considered that these Th1 type CD4+ T cells probably induce the activation of macrophages and further pro-inflammatory reactions during the early stage of AP, as well as exerting direct cytotoxicity effects through Fas/Fas ligand expression.

Contribution of circulating leukocytes to cytokine production in pancreatic duct obstruction-induced acute pancreatitis in rats

Little information is available regarding the role of circulating leukocytes in the pathogenesis of acute pancreatitis (AP). Our aim was to explore the time-course of the potential role of inflammatory peripheral blood (PB) cells during AP induced in rats by pancreatic duct obstruction (PDO). Flow cytometry immunophenotyping was used to analyse the distribution of the major circulating leukocyte subsets, the activation state of circulating monocytes as reflected by both CD11b expression and TNF-alpha production and the relative contribution of T-cell derived pro- (TNF-alpha) and anti- (IL-10) inflammatory mediators at different stages of PDO-induced AP. A progressive increase in PB neutrophils and monocytes was observed up to 6h after PDO whereas lymphocytes, as well as CD4(+) and CD8(+) T-cell subsets, rose as early as 1.5 h after PDO and decreased thereafter. Monocytes were activated in PB from 6 h after inducing AP as reflected by increases in both CD11b expression and spontaneous TNF-alpha production; nevertheless, they showed the capability of producing TNF-alpha at earlier AP stages by lipopolysaccharide (LPS) stimulation. In contrast, T-cells were unable to produce TNF-alpha during AP neither spontaneously nor after stimulation with PMA/Ionomycin. Therefore, only PB monocytes contribute to increase TNF-alpha levels in plasma as observed from 12 h onwards after inducing AP. Interleukin-10 was produced by T-cells 6 h after PDO only after PMA/Ionomycin stimulation. We conclude that systemic inflammatory events are triggered off at early stages of PDO-induced AP, with the activation of circulating monocytes, though not T-cells, playing a central role.

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

INTRODUCTION

The mortality associated with severe acute pancreatitis is still high, and death in the later stage of the disease is chiefly due to bacterial infection and sepsis. However, objective parameters for the risk of sepsis in acute pancreatitis have not been established.

AIM

To investigate the value of human leukocyte antigen-DR (HLA-DR) on peripheral monocytes for predicting the development of sepsis during acute pancreatitis.

METHODOLOGY

The expression of HLA-DR on peripheral monocytes was measured in 64 patients by flow cytometry at admission and 7 and 14 days after the onset of acute pancreatitis. Twenty-eight patients with severe acute pancreatitis and 36 with mild acute pancreatitis, as determined by the Atlanta classification, were enrolled.

RESULTS

Six patients had sepsis, and two of them died during the hospital stay. At admission, the percentage of HLA-DR-expressing cells in the monocyte population was significantly lower in the patients who had sepsis in the later course than in the patients who did not have sepsis. A percentage lower than 80% at admission was observed in 17 patients, and the patients who had persistently low percentages of HLA-DR-expressing monocytes throughout the observation period had sepsis in the later clinical course, whereas the patients in whom expression recovered to the normal range were spared the development of sepsis.

CONCLUSION

In acute pancreatitis, the low percentage of HLA-DR-expressing cells in the monocyte population is a reliable predictor of the development of sepsis. Monitoring of monocyte HLA-DR expression may be a useful marker for identifying the patients who are at high risk of sepsis in acute pancreatitis.

New laboratory tests in acute pancreatitis

Acute pancreatitis (AP) is a common disease with wide variation of severity. The diagnosis of AP is usually based on high serum amylase or lipase values but the accuracy of these methods is considered unsatisfactory. One in five of the patients develops a severe disease and carries a considerable risk of development of organ failure and high mortality. Early detection of patients with severe AP and especially those with increased risk of organ failure is importance since such patients seem to benefit from treatment in an intensive care unit started as soon as possible after presentation. In addition to enzymological methods, increasing interest has been focused on laboratory markers reflecting the level of inflammatory response in AP. At present, in routine clinical work the most commonly used severity marker is serum C-reactive protein, the concentration of which rises too slowly to be used for early prediction of severity. New therapies aiming at modifying the course of systemic inflammation in AP are being developed and therefore monitoring the patient's immune inflammatory status is needed. In this review article we present the current knowledge of laboratory tests, which has been evaluated for diagnostic and prognostic purposes in AP.

Cellular markers of systemic inflammation and immune suppression in patients with organ failure due to severe acute pancreatitis

BACKGROUND

Few data are available on cellular markers of systemic inflammation and immune suppression in early acute pancreatitis. The aim of this study was to describe the cellular immune inflammatory status of patients with acute pancreatitis in relation to development of organ failure.

METHODS

Prospective study including 89 patients who presented within 72 h of onset of pain. Fifty-eight of them had mild disease (Grade I group), 19 had severe disease with no organ dysfunction (Grade II group) and 12 had severe disease with organ dysfunction (Grade III group). Serial blood samples were collected on admission and following 2 days. Phagocyte surface markers were analysed using flow cytometry.

RESULTS

The proportion of HLA-DR-positive monocytes, a marker of immune suppression, and CD11b expression level on neutrophils and monocytes, a marker of systemic inflammation, were related to Grades I-III (P for trend <0.001). In Grade III patients, the proportion of HLA-DR-positive monocytes was low on presentation, or decreased rapidly during follow-up, whereas CD11b expression levels were persistently high. L-selectin and monocyte CD14 expression levels were not related to disease severity.

CONCLUSIONS

Immune suppression develops early, rapidly and unexpectedly in patients with acute pancreatitis. Monitoring immune inflammatory status may provide the means by which to identify patients who benefit from biological response modifier therapy.

Opsonin receptor expression on peritoneal exudative and circulatory neutrophils in murine acute pancreatitis

Acute severe (necrotizing) pancreatitis is often associated with pancreatic or peripancreatic infection. Decreased bacterial clearance due to impaired immune defense may cause local infection. We investigated expressions of surface opsonin receptors (CD11b, complement receptor 3; CD32/CD16, immunoglobulin G Fc receptor) on local and circulatory neutrophils, in murine acute pancreatitis. The mild and severe forms of acute pancreatitis were induced by seven and 13 subcutaneous injections of caerulein, respectively. Peritoneal exudative and circulatory neutrophils were counted and assayed for receptor expressions by flow cytometry, serially at 1-72 hours after pancreatitis induction. Histologically, mild and severe forms showed edematous and necrotizing pancreatitis, respectively. The peritoneal exudative neutrophil count was greater in mild than in severe pancreatitis. Expressions of CD11b and CD32/CD16 on local neutrophils were upregulated early in mild pancreatitis. This upregulation was attenuated in severe pancreatitis. The circulatory neutrophil count was elevated in severe pancreatitis but was unchanged in mild pancreatitis. Opsonin receptor expression on circulatory neutrophils showed a transient, modest upregulation in the early phase of mild pancreatitis. Receptor-positive circulatory neutrophils showed a marked elevation that persisted throughout the course of severe pancreatitis. In conclusion, severe (necrotizing) pancreatitis is associated with reduced opsonin receptor expression on local neutrophils and enhanced expression on circulatory neutrophils, as compared with mild (edematous) pancreatitis. These changes may contribute to local infectious complications and multiple organ failure, in severe pancreatitis.

Endothelial-derived selectins in the development of organ dysfunction in acute pancreatitis

OBJECTIVE

The development of organ dysfunction is the principal determinant of outcome in acute pancreatitis and is mediated through a systemic inflammatory response characterized by leukocyte and endothelial cell activation. Up-regulation of the endothelial cell adhesion molecules, E-selectin and P-selectin, is important for endothelial/leukocyte interactions. Levels of serum-soluble E-selectin and P-selectin have been suggested as markers of endothelial activation. This study examines the kinetics of serum-soluble selectins in patients with acute pancreatitis complicated by organ dysfunction.

DESIGN

Prospective observational study.

SETTING

University teaching hospital with a specialist hepato-pancreatico-biliary service.

PATIENTS

Eighteen patients with acute pancreatitis were studied, nine of whom had organ dysfunction.

MEASUREMENTS AND MAIN RESULTS

Serial venous blood samples were collected on the first 3 days after admission for measurement of soluble E-selectin and P-selectin by enzyme-linked immunosorbent assay. In all patients, soluble P-selectin concentrations decreased significantly during the study period. Nonsurvivors had significantly higher levels of soluble P-selectin than survivors. In contrast, soluble E-selectin increased significantly during the study period in patients with organ dysfunction, whereas it remained constant in patients without evidence of organ dysfunction.

CONCLUSIONS

These results suggest a role for endothelial-derived selectins in the development of organ dysfunction in patients with acute pancreatitis. The observed temporal differences in serum selectin concentrations is in keeping with in vitro observations of endothelial selectin expression.

Reticuloendothelial system blockade promotes progression from mild to severe acute pancreatitis in the opossum

OBJECTIVE

To examine the relation between hepatic reticuloendothelial system (RES) dysfunction and the development of acute biliary pancreatitis. In an opossum model, the authors tested the hypothesis that RES blockade can turn the mild pancreatitis seen after pancreatic duct obstruction (PDO) into the severe form.

SUMMARY BACKGROUND DATA

Biliary obstruction is considered the decisive event in gallstone pancreatitis. Suppression of the RES occurs during biliary obstruction.

METHODS

Eighteen opossums were placed into three groups of six animals each: group A, RES blockade with lambda-carrageenan; group B, PDO; and group C, PDO and RES blockade with carrageenan. The severity of pancreatitis was evaluated by enzyme serum levels and percentage of pancreatic tissue necrosis. RES capacity was measured by dynamic liver scintigraphy, and hepatic blood flow was documented using the hydrogen clearance technique.

RESULTS

No changes in hepatic blood flow occurred in groups A to C. RES capacity was suppressed in groups A and C; in group B, RES function remained unchanged. In group A, amylase and lipase levels remained normal, 3 +/- 1.9% of pancreatic tissue were necrotic. The animals in group B developed mild edematous pancreatitis with an increase in amylase and lipase levels and 15 +/- 10% of pancreatic necrosis. In group C, amylase and lipase increased significantly and histology revealed severe necrotizing pancreatitis, with 72 +/- 11% of necrotic areas.

CONCLUSIONS

Artificial RES blockade can promote the progression from mild pancreatitis as observed after PDO to the severe necrotizing form of the disease. Thus, RES dysfunction resulting from biliary obstruction might be an important cofactor in the pathogenesis of bile-induced pancreatitis.

Leucocyte activation markers in clinical practice

The response against tissue injury and infection begins with the early activation of molecular and cellular elements of the inflammatory and immune response. Severe tissue injury, necrosis, and infection induce imbalanced inflammation associated with leukocyte over-stimulation and excessive or dysregulated release of cellular mediators. Clinical and experimental studies have shown that these mediators are directly related to progressive post-injury complications. Persistent increased levels of pro-inflammatory mediators produce tissue injury. Excessive production and activity of anti-inflammatory mediators cause anergy and/or immune dysfunction with increased susceptibility to infection. Leukocyte activation is assessed by cell surface phenotype expression, cellular mediators determination, or by measuring functional responses using isolated cells. Potential routine clinical uses are: evaluation of severity and prognosis in critically ill patients, immunomonitoring of sepsis, and detection of tissue injury, necrosis, and infection. In practice, the determination of cellular activation markers is restricted by a limited number of automated methods and by the cost of reagents. The availability of flow cytometry and immunoassay automated systems can contribute to a wider use in practice. Here we review the immunopathophysiology of polymorphonuclear neutrophil, monocyte, macrophage, and lymphocyte activation in response to tissue injury and infection. In addition, laboratory methods for their determination, and clinical applications in practice, are discussed.

Glutamine-supplemented total parenteral nutrition reduces blood mononuclear cell interleukin-8 release in severe acute pancreatitis

Glutamine, a conditionally essential amino acid, is important for immune function. It is now being formulated for incorporation into total parenteral nutrition (TPN). The aims of this study were to examine the effect of glutamine administration on lymphocyte proliferation and proinflammatory cytokine release in patients with severe acute pancreatitis. Fourteen patients were randomized (in a double-blind fashion) to receive either conventional or isocaloric, isonitrogenous glutamine-supplemented (0.22 g glutamine x kg(-1) x d(-1) as glycyl-glutamine) TPN for 7 d. DNA synthesis (index of lymphocyte proliferation) and the 24-h release of tumor necrosis factor (TNF), interleukin (IL)-6, and IL-8 from peripheral blood mononuclear cells were measured in vitro on days 0, 4, and 7. Thirteen patients completed the study protocol (6 glutamine TPN, 7 conventional TPN). Glutamine supplementation increased median DNA synthesis by 3099 cpm over the study period against 219 cpm in the conventional group (increase not significantly different between the two groups) . Glutamine supplementation did not significantly influence TNF or IL-6 release, but, in contrast, median IL-8 release was reduced by day 7 in the glutamine group while it was increased in the conventional group (-17.7 ng/mL (median change over study period) versus +43.3 ng/mL, respectively; P=0.045). Small patient numbers and substantial interindividual variation limit the conclusions, but there is a trend for the glutamine group to have improved lymphocyte proliferation, and in the case of IL-8, reduced proinflammatory cytokine release.

The role of cytokines in the pathogenesis of acute pancreatitis

BACKGROUND

The systemic manifestations of acute pancreatitis are responsible for the majority of pancreatitis-associated morbidity and mortality and are now believed to be due to the actions of specific inflammatory cytokines. This report summarizes what is known about the role of cytokines in the pathogenesis of acute pancreatitis.

METHODS

Comprehensive literature review of experimental pancreatitis as well as all reports of cytokine involvement during clinical pancreatitis.

RESULTS

Several cytokines and other noncytokine inflammatory mediators are produced rapidly during pancreatitis. These mediators arise in many tissues in a predictable fashion independent of the animal model used or the underlying etiology in human disease. Preventing the activities of these mediators has a profound beneficial effect in experimental animals.

CONCLUSIONS

A few recently described inflammatory mediators are believed to be primarily responsible for the systemic manifestations of acute pancreatitis and its associated distant organ dysfunction. The predictable nature in which they are produced may allow for novel approaches to treating this disease. Am J Surg.