Increase of Soluble Programmed Cell Death Ligand 1 in Patients with Chronic Hepatitis C

Different Prognostic Role of Soluble PD-L1 in the Course of Severe and Non-Severe COVID-19

Understanding the link between COVID-19 and patient immune characteristics is crucial. We previously demonstrated that high levels of the soluble Programmed Death-Ligand1 (sPD-L1) at the beginning of the infection correlated with low lymphocyte number and high C-reactive protein (CRP), longer length of stay (LOS), and death. This study investigated whether sPD-L1 can be a prognosis biomarker during COVID-19. Severe and non-severe COVID-19 patients were enrolled at the University Hospital of Salerno. During hospitalization, at admission, and after 12-14 days, patients' data were collected, and sPD-L1 levels were measured by enzyme-linked immunosorbent assay. The peripheral lymphocyte number negatively correlated with the time of negativization (p = 0.006), length of stay (LOS) (p = 0.032), and CRP (p = 0.004), while sPD-L1 positively correlated with LOS (p = 0.015). Patients with increased sPD-L1 and lymphocyte number showed a shorter LOS than those with decreased sPD-L1 and lymphocyte number (p = 0.038) and those with increased sPD-L1 and decreased lymphocyte number (p = 0.025). Moreover, patients with increased sPD-L1 and decreased CRP had a shorter LOS than those with increased sPD-L1 and CRP (p = 0.034) and those with decreased sPD-L1 and CRP (p = 0.048). In conclusion, while at an early phase of COVID-19, sPD-L1 promotes an immune escape, later, it might act to dampen an excessive immune response, proving its role in COVID-19 prognosis.

Predictive plasma biomarkers of long-term increase in hepatic steatosis index after HCV eradication in HIV/HCV-coinfected patients

Hepatic steatosis is a common condition found in the liver of hepatitis C virus (HCV)-infected patients, contributing to more severe forms of liver disease. In addition, the human immunodeficiency virus (HIV) may accelerate this process. Alternatively, several immune checkpoint proteins have been reported to be upregulated and correlated with disease progression during HCV and HIV infections. In steatosis, a detrimental immune system activation has been established; however, the role of the immune checkpoints has not been addressed so far. Thus, this study aimed to evaluate the association between plasma immune checkpoint proteins at baseline (before antiviral therapy) with hepatic steatosis index (HSI) increase at the end of follow-up (∼ five years after sustained virologic response (SVR)). We performed a multicenter retrospective study in 62 patients coinfected with HIV/HCV who started antiviral therapy. Immune checkpoint proteins were analyzed at baseline using a Luminex 200TM analyzer. The statistical association analysis was carried out using Generalized Linear Models (GLM) and Partial Least Squares Discriminant Analysis (PLS-DA). Fifty-three percent of the patients showed HSI increase from baseline to the end of follow-up. Higher immune checkpoint protein levels of BTLA, CD137(4-1BB), CD80, GITR, LAG-3, and PD-L1 before HCV therapy were associated with a long-term increase in HSI after successful HCV therapy, suggesting a potential predictive role for early detection of progression towards steatosis in HIV/HCV-coinfected patients.

Role of soluble forms of follicular helper T-cell membrane molecules in the pathogenesis of myasthenia gravis

This study examined the role of Tfh and Treg associated molecules also known as checkpoint molecules, their ligands, and IL-21 in myasthenia gravis (MG) pathogenesis. Serum levels of sPD-1, sPD-L1, sICOS, sICOSLG, sCTLA4, and IL-21 were measured in 39 patients with acetylcholine receptor (AChR) antibody-positive generalized MG and 27 controls. sPD-1 and IL-21 levels were higher in MG patients than in controls. Additionally, sPD-1 levels correlated positively with the levels of IL-21, sICOSLG, sCTLA4, and AChR antibody titers. sICOS are correlated with MGADL and AChR antibody titers. These Tfh associated molecules could be used as biomarkers of MG disease activity.

Sensitive biosensors based on topological insulator Bi2Se3 and peptide

In this work, we designed a facile and label-free electrochemical biosensor based on intrinsic topological insulator (TI) Bi₂Se₃ and peptide for the detection of immune checkpoint molecules. With topological protection, Bi₂Se₃ could have robust surface states with low electronic noise, which was beneficial for the stable and sensitive electron transport between electrode and electrolyte interface. The peptides are easily synthesized and chemically modified, and have good biocompatibility and bioavailability, which is a suitable candidate as the recognition units for immune checkpoint molecules. Therefore, the peptide/Bi₂Se₃ was developed as a suitable working electrode for the electrochemical biosensor. The basic performance of the designed peptide/Bi₂Se₃ biosensor was investigated to determine the Anti-HA Tag Antibody and PD-L1 molecules. The linear detection range was from 3.6 × 10^-10 mg mL^-1 to 3.6 × 10^-5 mg mL^-1, and the detection limit was 1.07 × 10^-11 mg mL^-1. Moreover, the biosensor also displayed good selectivity and stability.

Upregulation of PD-1 Expression and High sPD-L1 Levels Associated with COVID-19 Severity

COVID-19 has several mechanisms that can lead to lymphocyte depletion/exhaustion. The checkpoint inhibitor molecule programmed death protein 1 (PD-1) and its programmed death-ligand 1 (PDL-1) play an important role in inhibiting cellular activity as well as the depletion of these cells. In this study, we evaluated PD-1 expression in TCD4+, TCD8+, and CD19+ lymphocytes from SARS-CoV-2-infected patients. A decreased frequency of total lymphocytes and an increased PD-1 expression in TCD4+ and CD19+ lymphocytes were verified in severe/critical COVID-19 patients. In addition, we found a decreased frequency of total monocytes with an increased PD-1 expression on CD14+ monocytes in severe/critical patients in association with the time of infection. Moreover, we observed an increase in sPD-L1 circulant levels associated with the severity of the disease. Overall, these data indicate an important role of the PD-1/PDL-1 axis in COVID-19 and may provide a severity-associated biomarker and therapeutic target during SARS-CoV-2 infection.

Association of PD-L1 gene polymorphisms and circulating sPD-L1 levels with HBV infection susceptibility and related liver disease progression

Soluble molecules of programmed death ligand 1 (sPD-L1) are known to modulate T-cell depletion, an important mechanism of hepatitis B virus (HBV) persistence and liver disease progression. In addition, PD-L1 polymorphisms in the 3'-UTR can influence PD-L1 expression and have been associated with cancer risk, although not definitively. The purpose of this study was to investigate the association of PD-L1 polymorphisms and circulating levels of sPD-L1 in HBV infection and live disease progression. In this study, five hundred fifty-one HBV infected patients of the three clinically well-defined subgroups chronic hepatitis B (CHB, n = 186), liver cirrhosis (LC, n = 142) and hepatocellular carcinoma (HCC, n = 223) and 240 healthy individuals (HC) were enrolled. PD-L1 polymorphisms (rs2297136 and rs4143815) were genotyped by in-house validated ARMS assays. Logistic regression models were applied in order to determine the association of PD-L1 polymorphisms with HBV infection as well as with progression of related liver diseases. Plasma sPD-L1 levels were quantified by ELISA assays. The PD-L1 rs2297136 AA genotype was associated with HBV infection susceptibility (HBV vs. HC: OR = 1.6; 95%CI = 1.1-2.3; p = 0.0087) and disease progression (LC vs. CHB: OR = 1.8; 95%CI = 1.1-2.9; p = 0.018). Whereas, the rs2297136 GG genotype was a protective factor for HCC development. Plasma sPD-L1 levels were significantly high in HBV patients (p < 0.0001) and higher in the LC followed by CHB and HCC groups. High sPD-L1 levels correlated with increased liver enzymes and with advanced liver disease progression (Child-pugh C > B > A, p < 0.0001) and BCLC classification (BCLC D > C > B > A, p = 0.031). We could, for the first time, conclude that PD-L1 rs2297136 polymorphism and plasma sPD-L1 protein levels associate with HBV infection and HBV-related liver disease progression.

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.

Role of Soluble T-Cell Immunoglobulin Mucin Domain-3 in Differentiating Nontuberculous Mycobacterial Lung Disease from Pulmonary Colonization

BACKGROUND

Differentiating between nontuberculous mycobacterial lung disease (NTM-LD) and pulmonary NTM colonization (NTM-Col) is difficult. Compared with healthy controls, patients with NTM-LD generally present immune tolerance along with increased expressions of T-cell immunoglobulin mucin domain-3 (TIM-3) and programmed cell death-1 (PD-1) on T lymphocytes. However, the role of soluble TIM-3 (sTIM-3) and soluble PD-1 (sPD-1) in differentiating NTM-LD from NTM colonization (NTM-Col) remains unclear.

METHODS

Patients with NTM-positive respiratory samples and controls were enrolled from 2016 to 2019. Patients were classified into NTM-Col and NTM-LD groups. Levels of sTIM-3, sPD-1, soluble PD-ligand-1 (sPD-L1), and TIM-3 expression were measured. Factors associated with NTM-LD were analyzed by logistical regression.

RESULTS

TIM-3 expression on CD4+ and CD8+ T lymphocytes were highest in NTM-LD group, followed by NTM-Col, and control (P=.017 and P=.011 for trend). sTIM-3 elevated in the NTM-Col group compared with the NTM-LD and control groups (856.3±518.7 vs. 595.3±352.6pg/mL, P=.009; vs. 437.0±267.4pg/mL, P<.001). Levels of sPD-1 and sPD-L1 were similar among groups. Among the 79 NTM-positive patients, sTIM-3 was associated with NTM-LD (100-pg/mL increase, adjusted odds ratio (aOR) 0.658 [95% CI, 0.502-0.864], P=.003). Patients with ≥2 risk factors (sTIM-3≤530pg/mL, BMI≤22.5, and radiographic score ≥5) were 13 times more likely to exhibit NTM-LD than those without (aOR 13.234 [2.983-58.709], P=.001).

CONCLUSIONS

sTIM-3 was an independent factor for differentiating NTM-LD from NTM-Col, suggesting the immunologic role of sTIM-3 in NTM-LD pathogenesis. By assessing sTIM-3 levels and other risk factors, physicians may be able to identify NTM-LD cases in a simplified manner.

Serum levels of soluble programmed death-ligand 1 (sPD-L1): A possible biomarker in predicting post-treatment outcomes in patients with early hepatocellular carcinoma

BACKGROUND

There have been great advances in hepatocellular carcinoma management over the last years. However, there are still no prognostic biomarkers that can identify patients who will benefit the most from curative treatments. We aimed to investigate whether sPD-L1 levels measured before curative treatment is a prognostic biomarker of survival in patients with HCC.

METHODS

HCC patients from a prospectively collected database were selected and soluble programmed death-ligand1(sPD-L1) levels were determined. The association of sPD-L1 levels and overall survival (OS) and disease-free survival (DFS) was assessed.

RESULTS

One hundred twenty-one patients with HCC were included. The best cut-off value of sPD-L1 for both DFS and OS was 96 pg/mL. Patients with a high sPD-L1 value (>96 pg/mL) had a shorter disease free survival and OS (hazard ratio 5.42, 95% confidence interval 2.28-12.91, p < 0.001, and hazard ratio 9.67, 95% confidence interval 4.33-21.59, p < 0.001). High sPD-L1 levels were associated with mortality independently from other known survival predictors. We found a positive correlation between sPD-L1 and PD-L1 expression in cancer cells (p = 0.01). In 16 out of 38 patients, sPD-L1 levels decreased from baseline value on week 6 after treatment and in 22 out of 38 patients, sPD-L1 levels increased from the baseline value. However, fluctuations of sPD-L1 in time had no influence on survival (p = 0.148).

CONCLUSION

We conclude that a high sPD-L1 level is a biomarkerfor a poor outcome in HCC. The predictive value of sPD-L1 levels for a successful anti-PD1/PD-L1 therapy should be investigated in the future.

Study of Serum Soluble Programmed Death Ligand 1 as a Prognostic Factor in Hepatocellular Carcinoma in Egyptian Patients

BACKGROUND

The expression of programmed cell death ligands on tumor cells has a role in the suppression of antitumor immunity, resulting in tumor immune evasion.

OBJECTIVE

In this study, we evaluated the prognostic value of the soluble form of programmed death-ligand1 (sPD-L1) in Egyptian hepatocellular carcinoma (HCC) patients.

METHODS

This prospective cohort study was performed between November 2016 to November 2018 on 85 individuals (25 HCC patients, 25 HCC with vascular invasion and/or extrahepatic metastasis, 25 patients with liver cirrhosis, 10 healthy controls). The levels of sPD-L1 were determined in all subjects and compared in different groups and stages of cirrhosis and HCC. The association between sPD-L1 levels and overall survival (OS) was assessed.

RESULTS

Significant statistical difference in sPD-L1 was detected between different study groups. The cut-off value for normal sPD-L1 was defined by high sPD-L1 levels determined in a healthy control cohort. It was 2.522 ng/ml. In HCC patients, cut-off value was 7.42 ng/ml (sensitivity 88%, specificity 100%). In HCC with vascular invasion or metastasis, cut-off value was 9.62 ng/ml (sensitivity 88%, specificity 88%). Patients with high serum sPD-L1 or serum bilirubin concentrations had an increased risk of mortality.

CONCLUSION

High sPD-L1 level could be a possible prognostic indicator for a poor outcome in liver cirrhosis and HCC patients. The predictive value of sPD-L1 levels for a successful anti- PD1/PD-L1 therapy should be investigated in the future.

PD-L1 in Systemic Immunity: Unraveling Its Contribution to PD-1/PD-L1 Blockade Immunotherapy

The use of monoclonal antibodies targeting PD-1/PD-L1 axis completely changed anticancer treatment strategies. However, despite the significant improvement in overall survival and progression-free survival of patients undergoing these immunotherapy treatments, the only clinically accepted biomarker with some prediction capabilities for the outcome of the treatment is PD-L1 expression in tumor biopsies. Nevertheless, even when having PD-L1-positive tumors, numerous patients do not respond to these treatments. Considering the high cost of these therapies and the risk of immune-related adverse events during therapy, it is necessary to identify additional biomarkers that would facilitate stratifying patients in potential responders and non-responders before the start of immunotherapies. Here, we review the utility of PD-L1 expression not only in tumor cells but in immune system cells and their influence on the antitumor activity of immune cell subsets.

Profiles of serum soluble programmed death-1 and programmed death-ligand 1 levels in chronic hepatitis B virus-infected patients with different disease phases and after anti-viral treatment

BACKGROUND

Soluble programmed death-1 (sPD-1) and soluble programmed death-ligand 1 (sPD-L1) play a role in immune regulation of chronic hepatitis B virus (HBV) infection.

AIM

To investigate the profiles of serum sPD-1 and sPD-L1 in chronic HBV-infected patients with different disease phases and after anti-viral treatment.

METHODS

A total of 99 chronic HBV-infected patients were enrolled and divided into HBeAg-positive chronic HBV infection (EPI) group, HBeAg-positive chronic hepatitis B (EPH) group, HBeAg-negative chronic hepatitis B (ENH) group and HBeAg-negative chronic HBV infection (ENI) group. Eleven healthy subjects were included as healthy controls (HCs). Thirty-two EPH patients received anti-viral treatment with nucleos(t)ide analogues and were followed up to 5 years. Serum sPD-1 and sPD-L1 levels were detected by Multiplex Immunoassays.

RESULTS

Serum sPD-1 and sPD-L1 levels of chronic HBV infected patients were significantly higher than that of HCs (P < 0.01). Patients in EPH, ENH and EPI groups had higher serum sPD-1 and sPD-L1 levels than that in HCs (P < 0.01). After anti-viral treatment, serum sPD-1 and sPD-L1 levels declined rapidly. EPH patients with HBeAg clearance after 2 years of anti-viral treatment showed lower baseline HBeAg and sPD-1 levels compared to those without HBeAg clearance.

CONCLUSIONS

Serum sPD-1 and sPD-L1 levels varied among chronic HBV infected patients with different disease phases. Lower baseline sPD-1 levels were associated with HBeAg clearance after 2 years of anti-viral treatment in EPH patients.

Establishing peripheral PD-L1 as a prognostic marker in hepatocellular carcinoma patients: how long will it come true?

BACKGROUND

The prognostic role of intratumoral programmed cell death ligand 1 (PD-L1) expression in hepatocellular carcinoma (HCC) has been investigated by several meta-analyses. However, the prognostic value of pretreatment peripheral PD-L1 (PPPD-L1) level in HCC remains undetermined. Thus, this systemic review aimed to establish PPPD-L1 as a new prognostic marker in HCC according to available evidence.

METHODS

Case-control studies investigating the prognostic role of PPPD-L1 in HCC were systemically sought in the database of PubMed and Web of Science until March 25th, 2020. Our main concern is survival results, including overall survival (OS), disease-free survival (DFS), and progression-free survival (PFS). The combined results were summarized in narrative form according to data extracted from each included study.

RESULTS

Finally, nine studies published from 2011 to 2019, were incorporated into this systemic review. Among these, six studies evaluated the PD-L1 expression by enzyme-linked immunosorbent assay (ELISA) from blood serum, and three studies evaluated the PD-L1 expression by flow cytometric analysis from peripheral blood mononuclear cells (PBMC). According to the extracted evidence, high PPPD-L1 expression, measured in either blood serum or PBMC, is associated with poor OS, poor DFS, and poor PFS. Meanwhile, PPPD-L1 was also correlated with enlarged tumor size and more likely with advanced tumor stage as well as vascular invasion.

CONCLUSION

High PPPD-L1 level is associated with increased mortality rate and increased recurrence rate in HCC. As a convenient serum marker, PPPD-L1 could be a promising marker of prognosis in HCC patients.

The role of programed death-ligand 1 in renal diseases

Programed death-ligand 1 (PD-L1, B7-H1, CD274) is a coinhibitory molecule that plays a vital role in the pathogenesis of both neoplastic and nonneoplastic diseases. However, the role of PD-L1 in primary and secondary renal diseases remains to be clarified. Previous studies have shown that both intracellular and intercellular PD-L1 participate in renal diseases via complex mechanisms. PD-L1 plays a dual role in lupus nephritis and has a protective effect in renal ischemia reperfusion injury and nephrotoxic nephritis but not in proliferative immune complex glomerulonephritis. PD-L1 supplementation, anti-PD-L1 antibodies, and D-peptide antagonists have promising application prospects in the treatment of renal diseases. In this review, we summarize the available data published on PD-L1 in renal diseases for the first time.

Clinical role of serum programmed death ligand 1 in patients with hepatocellular carcinoma: Where does it come from?

PURPOSES

Programmed death ligand 1 (PD-L1) is a key target for the treatment of several malignancies. The present study was conducted to clarify the role of serum PD-L1 in hepatocellular carcinoma (HCC).

METHODS

Serum PD-L1 (sPD-L1) was examined by an enzyme-linked immunosorbent assay in 153 patients with HCC who underwent curative hepatectomy at Kumamoto University in 2011-2016. The expression of PD-L1 in tissue (tPD-L1) was investigated by immunohistochemistry. The clinical roles of the PD-L1 expression in both serum and tissue were examined.

RESULTS

The sPD-L1 was significantly elevated in HCC patients compared to patients without any malignant or inflammatory disease (234 vs. 93 pg/mL, p < 0.0001). The percentage of the tPD-L1-positive area (%tPD-L1) in the background liver was significantly higher than in the tumor (1.52% vs. 0.48%, p < 0.0001). The %tPD-L1 in the background liver but not in the tumor was significantly correlated with the sPD-L1 level (p = 0.0079). The sPD-L1, %tPD-L1 in the tumor, and %tPD-L1 in the background liver were not correlated with the overall survival after surgery.

CONCLUSION

PD-L1-expressing cells in the background liver, but not in the tumor tissue, appeared to contribute to the sPD-L1 level. The sPD-L1 level may thus not indicate the tumor burden in patients with HCC.

Liquid biopsy in the era of immuno-oncology: is it ready for prime-time use for cancer patients?

The emergence of immunotherapy in oncology requires the discovery, validation and subsequent adoption of robust, sensitive and specific predictive and prognostic biomarkers for daily practice. Until now, anti-PD-L1 immunohistochemistry (IHC) on tissue sections has been the only validated companion diagnostic test for first-line immunotherapy for advanced and metastatic cancer, notably non-small-cell lung cancer (NSCLC). However, detection of this biomarker presents limitations that have stimulated the development of other biomarkers and other approaches. Within this context, the use of a liquid biopsy (LB) could provide an important complementary or alternative added value to PD-L1 IHC. In this review, we discuss how LBs have been used in the field of immuno-oncology (I-O) to predict response, relapse or adverse advents for patients undergoing immune-checkpoint inhibitor (ICI) therapy (anti-PD-1/PD-L1 and CTLA-4) and we highlight recent developments. Circulating tumor cells (CTCs), cell-free DNA (cfDNA), proteins and cytokines detected in plasma as well as circulating T-lymphocytes are discussed as potential sources for developing new I-O biomarkers. The quantification of cfDNA as a predictive biomarker, as well as its sequencing for the determination of tumor mutational burden, is already well advanced. Additionally, the quantification of PD-L1 from CTCs, bound on exosomes or free in plasma, as well as the determination of cytokines, are also being actively investigated with promising results having recently been published. Lastly, analysis of T-lymphocytes, especially by analyzing the T-cell receptor, has recently emerged as a valuable biomarker that might become relevant for the prediction of response to ICIs. While LBs have not yet been implemented in routine I-O clinical practice, recent promising data and rapidly advancing technologies indicate that this approach has the potential to soon personalize the clinical management of cancer patients receiving ICIs.

Pre-treatment serum levels of soluble programmed cell death-ligand 1 predict prognosis in patients with hepatitis B-related hepatocellular carcinoma

PURPOSE

Anti-programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) therapy has shown promise in tumor immunotherapy. Our objectives were to measure pre-treatment serum-soluble PD-L1 (sPD-L1) levels and to assess the relationships between sPD-L1 levels and clinical characteristics, prognosis, and tumor tissue PD-L1 expression in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).

METHODS

Pre-treatment serum sPD-L1 levels were measured with an enzyme-linked immunosorbent assay (ELISA) in 81 patients with HBV-related HCC and compared to those in 49 healthy controls. The association between serum sPD-L1 levels and prognosis was assessed using survival analysis. The correlation between paired serum sPD-L1 levels and tumor PD-L1 expression (in resected tissue homogenates) was assessed in a separate group of 20 patients with HBV-related HCC.

RESULTS

Median sPD-L1 concentration in patients with HBV-related HCC was 5.129 (range 0.140-12.391) ng/mL and in healthy controls was 0.836 (range 0.105-2.168) ng/mL (p < 0.001). On multivariate analysis, sPD-L1 levels were significant independent predictors of disease-free survival (hazard ratio [HR] 3.503; 95% confidence interval [CI], 1.559-7.871; p = 0.002) and overall survival (HR 3.399; 95% CI 1.308-8.831; p = 0.012). Positive correlation (r = 0.527, p = 0.017) between serum sPD-L1 and tumor PD-L1 expression was observed. Tumor expression of PD-L1 was significantly higher in those with serum sPD-L1 concentrations above vs. below the median level of 5.471 ng/ml (p = 0.012).

CONCLUSIONS

In patients with HBV-related HCC, serum sPD-L1 concentrations were elevated, and positively correlated with tumor PD-L1 expression. Lower pre-treatment serum sPD-L1 levels were predictors of more favorable disease-free and overall survival. Serum sPD-L1 testing has a potential role in HBV-related HCC disease assessment, systemic therapy choices and survival prediction.

Increased levels of soluble co-stimulatory molecule PD-L1 (B7-H1) in the plasma of viraemic HIV-1+ individuals

Recent evidence has revealed that PD-L1 is expressed in two functional forms, namely, a membrane-bound form (mPD-L1) and a soluble form (sPD-L1). The identification of the soluble form of PD-L1 represents the discovery of a new potential mechanism for the activation of the PD-1 pathway that may mediate a physiological apoptotic mechanism through a cell-cell signalling-independent pathway and may also favour T cell dysfunction during HIV infection. Since the presence of sPD-L1 has not been well established in the scenario of chronic viral infection, we investigated the presence of sPD-L1 in the plasma of viraemic HIV⁺ individuals and the potential mechanism that promotes its production. We report the following: 1) the level of the soluble form of PD-L1 is increased in the plasma of viraemic HIV⁺ individuals, 2) the level of the soluble form of PD-L1 in viraemic HIV⁺ individuals correlates with markers of microbial product translocation and inflammation, 3) the expression of the membrane-bound form of PD-L1 on conventional dendritic cells from viraemic HIV⁺ individuals correlates with the levels of soluble PD-L1 and MMP-2, and 4) monocyte-derived dendritic cells not only increase their expression of mPD-L1 and MMP-2 but also produce sPD-L1 after LPS and TNF-α stimulation, as demonstrated by functional in vitro experiments, which provides insight into the potential source of sPD-L1 production.

Is high serum programmed death ligand 1 level a risk factor for poor survival in patients with gastric cancer?

BACKGROUND AND AIM

Although the clinicopathological significance of the expression of programmed death ligand 1(PD-L1) in various cancer tissues has been reported, serum PD-L1 level has not been evaluated in patients with surgically treated gastric cancer. Therefore, we evaluated the clinicopathological characteristics and prognostic significance of preoperative serum PD-L1 levels in patients with gastric cancer.

PATIENTS AND METHODS

Serum samples were obtained before surgery from 152 patients with gastric cancer, including 75 patients with stage I, 31 with stage II, 23 with stage III, and 23 with stage IV gastric cancer. The samples were analyzed using enzyme-linked immunosorbent assay to detect soluble PD-L1. Using the median serum PD-L1 level of 50 pg/mL, patients were divided into two groups, namely high serum and low serum PD-L1 level groups. Clinicopathological characteristics and prognosis were compared between these two groups using univariate and multivariate analysis.

RESULTS

Serum PD-L1 level was significantly associated with older age, positive cancer antigen 19-9 (CA19-9), C-reactive protein levels, and albumin levels but not with tumor stage. Patients in the high serum PD-L1 group showed significantly worse overall survival and recurrence-free survival than those in the low serum PD-L1 group (P < .05). Multivariate analysis showed that high serum PD-L1 level was an independent risk factor for poor overall survival (P = .02).

CONCLUSION

High serum PD-L1 level was a prognostic factor for reduced overall survival in patients with surgically treated gastric cancer.