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

TRPV1 in Dorsal Root Ganglion Contributed to Chronic Pancreatitis Pain

Chronic pancreatitis presents a formidable challenge in pain management, often leading to significant suffering and reduced quality of life for affected individuals. The intricate interplay of factors contributing to this pain, including inflammation and neural sensitization, has garnered increasing attention in recent research. Among the key players in this scenario are the transient receptor potential vanilloid 1(TRPV1) channels located in dorsal root ganglion (DRG) neurons. These channels, known for their role in pain perception, exhibit heightened sensitivity and altered expression patterns in the context of chronic pancreatitis. Sensitization of TRPV1 channels amplifies their response to various pain triggers, exacerbating the perception of discomfort. Furthermore, dysregulated expression of TRPV1 within DRG neurons contributes to the chronic pain phenotype associated with pancreatitis. Understanding the nuanced mechanisms governing TRPV1 modulation in DRG neurons promises to unlock novel therapeutic avenues for managing chronic pancreatitis pain. By targeting TRPV1 channels specifically in DRG neurons, researchers aim to develop treatments that alleviate pain while minimizing adverse effects, ultimately offering hope for improved outcomes and enhanced well-being for individuals grappling with this debilitating condition.

Annexin A1 regulates inflammatory-immune response and reduces pancreatic and extra- pancreatic injury during severe acute pancreatitis

Severe acute pancreatitis (SAP) poses significant challenges due to its complex pathophysiology, which includes inflammatory-immune responses that cause considerable damage to both the pancreas and other tissues. In this study, we explored the role of Annexin A1 (Anxa1), a glucocorticoid-regulated protein recognized for its anti-inflammatory properties, in regulating inflammation during acute pancreatitis. Using flow cytometry, single-cell RNA sequencing, and gene expression analysis, we examined how Anxa1 expression is regulated in myeloid cells throughout acute pancreatitis, employing various animal models to evaluate the consequences of modulating Anxa1 on injuries induced by SAP. Our findings revealed dynamic regulation of Anxa1 expression in myeloid cells, with mice lacking Anxa1 exhibiting worsened pancreatic injury and heightened systemic inflammation, resulting in significant damage to extra-pancreatic organs such as the lungs, liver, and kidneys. In contrast, treatment with Ac2-26, a synthetic peptide derived from Anxa1, effectively mitigated both pancreatic and extra-pancreatic inflammation and tissue damage. Overall, this study highlights the critical role of Anxa1 in modulating inflammatory responses during acute pancreatitis. Targeting Anxa1 presents a promising therapeutic strategy to mitigate pancreatic injury and prevent systemic complications associated with severe acute pancreatitis.

Could we use PD-1 and PD-L1 expression on lymphocytes and monocytes as predictive markers for prognosis of acute biliary pancreatitis?

PURPOSE

This study aimed to assess the significance of immunophenotyping and serum cytokines in predicting the clinical progression of acute biliary pancreatitis (ABP).

MATERIALS AND METHODS

Cytokine levels, T-helper, cytotoxic T, natural killer (NK) cells, monocytes, HLA-DR, and PD-1, as well as PDL-1 immune checkpoints, were measured in ABP patients at the time of diagnosis and compared with results from healthy volunteers. The study also compared leukocyte counts, hematocrit, immunophenotyping results, cytokine statuses, and PD-1, PDL-1 expression between healthy volunteers and ABP subgroups categorized by pancreatitis severity.

RESULTS

The study included 65 ABP patients and 20 healthy volunteers. Significant differences were observed between groups in hematocrit, leukocyte counts, total monocytes, lymphocytes, CD3+ total T cells, CD4+ Th cells, PD-1 expression on CD4+ and CD8+T lymphocytes, HLA-DR expression on CD14+ monocytes, NK cells, PD-L1 expression on CD14+ monocytes, classical and intermediate monocytes, as well as levels of IL-6, IL-8, IL-10, IL-18, and IL-33 cytokines. Moderate correlations were found with lymphocyte counts, PD-1+CD4+ cells, PD-L1+CD14+ cells, and strong correlations with HLA-DR+CD14+ cells. Hematocrit, CD3+ total T cells, NK cells, CD4+PD-1 + T cells, and CD8+PD-1 + T cells showed independent associations with the severity of ABP. Lymphocyte counts, CD14+HLA-DR+ cells, CD14+PD-L1+ cells, CD4+PD-1 + T cells, classical, and intermediate monocytes exhibited the highest Area Under the Curve rates in determining organ failure.

CONCLUSIONS

Hematocrit, lymphocyte counts, CD14+HLA-DR+ cells, CD14+PD-L1+ cells, and intermediate monocytes emerged as parameters most closely associated with the severity and these parameters could be useful in predicting the severity of ABP.

The implication of targeting PD-1:PD-L1 pathway in treating sepsis through immunostimulatory and anti-inflammatory pathways

Sepsis currently remains a major contributor to mortality in the intensive care unit (ICU), with 48.9 million cases reported globally and a mortality rate of 22.5% in 2017, accounting for almost 20% of all-cause mortality worldwide. This highlights the urgent need to improve the understanding and treatment of this condition. Sepsis is now recognized as a dysregulation of the host immune response to infection, characterized by an excessive inflammatory response and immune paralysis. This dysregulation leads to secondary infections, multiple organ dysfunction syndrome (MODS), and ultimately death. PD-L1, a co-inhibitory molecule expressed in immune cells, has emerged as a critical factor in sepsis. Numerous studies have found a significant association between the expression of PD-1/PD-L1 and sepsis, with a particular focus on PD-L1 expressed on neutrophils recently. This review explores the role of PD-1/PD-L1 in immunostimulatory and anti-inflammatory pathways, illustrates the intricate link between PD-1/PD-L1 and sepsis, and summarizes current therapeutic approaches against PD-1/PD-L1 in the treatment and prognosis of sepsis in preclinical and clinical studies.

Impact of age group on bloodstream infection risk evaluation in immunosuppressed patients: a retrospective, single-centre, 5-year cohort study

INTRODUCTION

Elderly patients in immunosuppressive status may have an increased occurrence of illness and risk of poor prognosis. It is a generally overlooked population that we should pay more attention to their risk factors of sickness and mortality.

METHODS

Eight hundred and nine patients who were diagnosed with bloodstream infection in immunosuppressive states during accepting treatment in our hospital were selected from 2015 to 2019.The demographic data, underlying diseases, comorbidity, inducement, complications, pathogen sources, etiologies, and the antibiotics therapy were analyzed between ages > 65 years groups and ages < 65 years groups.

RESULTS

The clinical characteristics of totally 809 immunosuppressed people diagnosed with bloodstream infection were analyzed, and among those people about 371 were ages > 65 years. By univariate logistic regression analysis and multivariate logistic regression analysis, we found that hypertension (OR: 2.864, 95% CI 2.024-4.051, P < 0.0001), cerebral Infarction (OR: 4.687, 95% CI 2.056-10.686, P < 0.0001), coronary heart disease (OR: 1.942, 95% CI 1.168-3.230, P = 0.011), acute pancreatitis (OR: 3.964, 95% CI 2.059-7.632, P < 0.0001), infective endocarditis (OR: 6.846, 95% CI 1.828-25.644, P = 0.004), aortic dissection (OR: 9.131, 95% CI 3.190-26.085, P < 0.0001), chemotherapy (OR: 3.462, 95% CI 1.815-6.603, P < 0.0001), transplant status (OR: 20.031, 95% CI 4.193-95.697, P < 0.0001), and respiratory tract infection (OR: 2.096, 95% CI 1.269-3.461, P = 0.004) were significantly different between ages > 65 years groups and ages < 65 years groups.

CONCLUSION

Hypertension, cerebral Infarction, coronary heart disease, acute pancreatitis, infective endocarditis, aortic dissection, chemotherapy, transplant status, and pathogen source of respiratory tract were the independent risk factors of ages > 65 years in immunosuppressed patients, which would have the benefit to discriminate the prognostic factors in immunosuppressive elderly people with bloodstream infection.

Prediction of acute pancreatitis complications using routine blood parameters during early admission

BACKGROUND

There have been many reports on biomarkers for predicting the severity of acute pancreatitis (AP), but few studies on biomarkers for predicting complications; some simple and inexpensive indicators, in particular, are worth exploring.

METHODS

We retrospectively collected clinical data of 809 AP patients, including medical history and results of routine blood tests, and grouped them according to the occurrence of complications. Differences in clinical characteristics between groups with and without complications were compared using t-test or χ2 test. Receiver operating curve (ROC) and area under the curve were calculated to evaluate the ability of predicting the occurrence of complications for the routine blood parameters with statistical differences. Then, through univariate and multivariate analyses, independent risk factors closely associated with complications were identified. Finally, we built a three-parameter prediction system and evaluated its ability to predict AP complications.

RESULTS

Compared with the group without complications, the patients in the complication group had higher white blood cells, neutrophils, C-reactive protein, and erythrocyte sedimentation rate (ESR), and lower red blood cells and hemoglobin (Hb) (all p < .05), and most of them had severe pancreatitis. In addition, pseudocysts were more common in patients with alcoholic etiology, recurrence, low BMI, and high platelet (PLT) and plateletocrit. Acute respiratory failure was more common in patients with first onset and high mean PLT volume (MPV). Sepsis was more common in patients with lipogenic etiology, high MPV, and low lymphocytes. Infectious pancreatic necrosis was more common in patients with alcoholic etiology. Acute renal failure was more common in patients with monocytes and high MPV and low PLT. Multivariate analysis showed that PLT and ESR were risk factors for pseudocyst development. The ROC showed that the combination of Hb, PLT and ESR had a significantly higher predictive ability for pseudocyst than the single parameter.

CONCLUSION

Routine blood parameters can be used to predict the complications of AP. A predictive model combining ESR, PLT, and Hb may be an effective tool for identifying pseudocysts in AP patients.

Pancreatic injury following immune checkpoint inhibitors: A systematic review and meta-analysis

Background: Pancreatic injury (pancreatitis, amylase/lipase elevation) is a rare adverse event of immune checkpoint inhibitors (ICIs). With the high number of clinical studies on ICIs, the incidence and characteristics of associated pancreatic injury (PI) need to be reevaluated.

Methods: A systematic review and meta-analysis was conducted to assess the incidence of PI in cancer patients who received ICIs in randomized controlled trials (RCTs). PubMed, Embase, the ASCO, ESMO, and AACR conference proceedings before 1 April 2022, were investigated for relevant research.

Results: 50 RCTs involving 35,223 patients were included. The incidence of ICIs-PI was 2.22% (95% CI = 1.94%–2.53%). The incidence of PI was 3.76% (95% CI = 1.84–7.67%) when combining two ICIs, which was higher than single ICIs [2.25% (95% CI = 1.91–2.65%)]. The ICIs were ranked from high to low based on PI incidence: PD-L1 inhibitors 3.01% (95% CI = 1.86–4.87%), CTLA-4 inhibitors 2.92% (95% CI = 0.99–8.65%) and PD-1 Inhibitor 2% (95% CI = 1.67–2.39%). The ICI with the highest rate of PI was pembrolizumab 7.23.% (95% CI = 1.69–30.89%). In addition, the incidence of severe ICIs-PI was 2.08% (95% CI = 1.76–2.46%); and the incidence of severe PI was 2.32% (95% CI = 1.76–3.06%) when combining two ICIs, which was higher than single ICI [1.95% (95% CI = 1.58–2.41%)]. The ICIs were ranked from high to low according to the incidence of severe PI: PD-L1 inhibitors 3.1% (95% CI = 1.7–5.64%), CTLA-4 inhibitors 2.69% (95% CI = 0.76–9.49%), PD-1 inhibitors 1.80% (95% CI = 1.41–2.29%).

Conclusion: Treatment with multiple ICIs result in a higher incidence of PI compared to single ICIs, irrespective of the grade of pancreatic injury. The incidence of PI caused by PD-L1 inhibitors is higher than that of CTLA-4 inhibitors and PD-1 Inhibitor, and Pembrolizumab has the highest rate of ICIs-PI. Although the incidence of ICIs-PI is not high, they are usually severe (≥ grade 3 events).

Soluble PD-L1 in blood correlates positively with neutrophil and negatively with lymphocyte mRNA markers and implies adverse sepsis outcome

Sepsis causes a myriad of immunological reactions that result in life-threatening alterations in the human body. Immunosuppression in sepsis is partly attributed to the programmed death receptor (PD-1) and its associated ligand (PD-L1) via the regulation of lymphocytes and neutrophils. Although the soluble forms of these proteins (i.e., sPD-1 and sPD-L1, respectively) are recognized as possible sepsis biomarkers, their functional implications are yet to be elucidated. Our research assessed the correlation between sPD-1 and sPD-L1 and blood mRNA markers and sepsis outcome. Blood samples of septic patients of urogenital origin versus control patients (both groups: n = 18) were analyzed. Blood serum sPD-1 and sPD-L1 levels were determined using the enzyme-linked immunosorbent assay (ELISA). The whole blood mRNA concentrations of PD-1, PD-L1, neutrophil markers (CEACAM8 and MPO), and T-lymphocyte markers (TCRβ, CD4 and CD8) were determined via reverse transcriptase quantitative PCR (RT-qPCR). sPD-L1 levels were significantly increased in septic patients when compared to the controls, whereas sPD-1 levels were unaltered. Patients with high sPD-L1 levels, as dichotomized to the median, had a significantly shorter survival rate than those with low sPD-L1 levels. The sensitivity/specificity characteristics of sPD-L1 proved significant for sepsis detection. Furthermore, sPD-L1 correlated with the mRNA concentrations of PD-L1, CEACAM, and MPO, as well as major inflammatory markers (C-reactive protein and procalcitonin). However, sPD-L1 negatively correlated with TCRβ, CD4, and CD8 mRNAs. sPD-L1 was found to be significantly increased in septic patients. Notably, sPD-L1 correlated with PD-L1 mRNA and neutrophil markers and was indicative of adverse outcomes.

Circulating levels of sPD-1 and PD-1 genetic variants are associated with hepatitis B infection and related liver disease progression

BACKGROUND

Programmed cell death-1 (PD-1) variants and circulating levels of soluble PD-1 are associated with susceptibility to malignant and infectious disease. This study aimed to examine the association of PD-1.5 and PD-1.9 variants, and plasma sPD-1 levels with HBV infection and disease progression.

METHODS

The study cohort consists of HBV-infected adults (n=513) stratified by clinical course, including chronic hepatitis B (CHB, n=173), liver cirrhosis (LC, n=134), hepatocellular carcinoma (HCC, n=206), and matched healthy controls (HC, n=196). The PD-1.5 (rs2227981 C/T) and PD-1.9 (rs2227982 C/T) genetic variants were genotyped by Sanger sequencing, and plasma sPD-1 levels were quantified by enzyme immunoassay.

RESULTS

The plasma sPD-1 levels were significantly high among HBV patients. The highest plasma sPD-1 levels were observed in CHB patients, followed by the LC and HCC groups. In addition, the plasma sPD-1 levels correlated positively with liver inflammation (aspartate transaminase, AST: rho=0.57, P<0.0001 and alanine aminotransferase, ALT: rho=0.57, P<0.0001) and were positively correlated with liver fibrosis (AST to Platelet Ratio Index, APRI score: rho=0.53, P<0.0001). The PD-1.9 TT genotype was less frequent in CHB patients compared to LC, HCC and HCC+LC patients in both codominant and recessive models (P<0.01) and was found to be a risk factor for HCC predisposition [HCC vs. non-HCC: OR=2.0 (95% CI: 1.13-3.7), P_adj=0.017]. The PD-1.5 CT genotype was associated with a reduced risk of acquiring HCC [OR=0.6 (95%CI: 0.4-0.9), P_adj=0.031].

CONCLUSION

Our study concludes that sPD-1 levels are associated with liver inflammation and progression of liver fibrosis and the PD-1.5 and PD-1.9 variants are associated with HBV infection and progression of liver disease.

Elevated Plasma Soluble PD-L1 Levels in Out-of-Hospital Cardiac Arrest Patients

Background: A deregulated immune system has been implicated in the pathogenesis of post-cardiac arrest syndrome (PCAS). A soluble form of programmed cell death-1 (PD-1) ligand (sPD-L1) has been found at increased levels in cancer and sustained inflammation, thereby deregulating immune functions. Here, we aim to study the possible involvement of sPD-L1 in PCAS. Methods: Thirty out-of-hospital cardiac arrest (OHCA) patients consecutively admitted to the ER of Mie University Hospital were prospectively enrolled. Plasma concentrations of sPD-L1 were measured by an enzyme-linked immunosorbent assay in blood samples of all 30 OHCA patients obtained during cardiopulmonary resuscitation (CPR). In 13 patients who achieved return-of-spontaneous-circulation (ROSC), sPD-L1 levels were also measured daily in the ICU. Results: The plasma concentrations of sPD-L1 in OHCA were significantly increased; in fact, to levels as high as those observed in sepsis. sPD-L1 levels during CPR correlated with reduced peripheral lymphocyte counts and increased C-reactive protein levels. Of 13 ROSC patients, 7 cases survived in the ICU for more than 4 days. A longitudinal analysis of sPD-L1 levels in the 7 ROSC cases revealed that sPD-L1 levels occurred in parallel with organ failure. Conclusions: This study suggests that ischemia- reperfusion during CPR may aberrantly activate immune and endothelial cells to release sPD-L1 into circulation, which may play a role in the pathogenesis of immune exhaustion and organ failures associated with PCAS.

Soluble Programmed Death Ligand-1 (sPD-L1): A Pool of Circulating Proteins Implicated in Health and Diseases

Upon T-cell receptor stimulation, the Programmed cell Death-1 receptor (PD-1) expressed on T-cells can interact with its ligand PD-L1 expressed at the surface of cancer cells or antigen-presenting cells. Monoclonal antibodies targeting PD-1 or PD-L1 are routinely used for the treatment of cancers, but their clinical efficacy varies largely across the variety of tumor types. A part of the variability is linked to the existence of several forms of PD-L1, either expressed on the plasma membrane (mPD-L1), at the surface of secreted cellular exosomes (exoPD-L1), in cell nuclei (nPD-L1), or as a circulating, soluble protein (sPD-L1). Here, we have reviewed the different origins and roles of sPD-L1 in humans to highlight the biochemical and functional heterogeneity of the soluble protein. sPD-L1 isoforms can be generated essentially by two non-exclusive processes: (i) proteolysis of m/exoPD-L1 by metalloproteases, such as metalloproteinases (MMP) and A disintegrin and metalloproteases (ADAM), which are capable of shedding membrane PD-L1 to release an active soluble form, and (ii) the alternative splicing of PD-L1 pre-mRNA, leading in some cases to the release of sPD-L1 protein isoforms lacking the transmembrane domain. The expression and secretion of sPD-L1 have been observed in a large variety of pathologies, well beyond cancer, notably in different pulmonary diseases, chronic inflammatory and autoimmune disorders, and viral diseases. The expression and role of sPD-L1 during pregnancy are also evoked. The structural heterogeneity of sPD-L1 proteins, and associated functional/cellular plurality, should be kept in mind when considering sPD-L1 as a biomarker or as a drug target. The membrane, exosomal and soluble forms of PD-L1 are all integral parts of the highly dynamic PD-1/PD-L1 signaling pathway, essential for immune-tolerance or immune-escape.

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.