Intrapatient Tumor Heterogeneity in IHC Interpretation Using PD-L1 IHC 22C3 pharmDx

Tumor heterogeneity may impact immunohistochemical (IHC) interpretation, thus potentially affecting decision making by treating oncologists for cancer patient management. Programmed cell death ligand-1 (PD-L1) IHC 22C3 pharmDx is a companion diagnostic used as an aid in identifying patient eligibility for treatment with pembrolizumab (KEYTRUDA). This study aims to investigate tumor heterogeneity impact on IHC staining when evaluating PD-L1 expression using PD-L1 IHC 22C3 pharmDx. The effect of tumor heterogeneity was evaluated based on the PD-L1 diagnostic status of PD-L1 IHC 22C3 pharmDx stained tumor tissue sections at relevant diagnostic cutoffs for non-small cell lung carcinoma, gastric or gastroesophageal junction adenocarcinoma, urothelial carcinoma, head and neck squamous cell carcinoma, esophageal cancer and triple negative breast cancer. Overall agreement for the PD-L1 diagnostic status was assessed for each tumor type within a given specimen block (Intra-Block), between specimen blocks from the same surgical resection (Intra-Case), and between intrapatient primary and metastatic specimens. Intrablock and intracase point estimates were above 75%, and primary versus metastatic point estimates were above 50%. The results suggest that PD-L1 expression is consistent across cut sections through a minimum of 150 µm within a tissue block and between blocks from the same surgical resection and is significantly maintained across primary and metastatic blocks from the same patient despite changes to the tissue microenvironment. These data provide confidence for histopathologists and oncologists that evaluation of PD-L1 expression at clinically relevant cutoffs is reproducible among different assessments (or samplings) of a single tumor specimen.

Neurotransmitters and Neuropeptides decrease PD-1 in T cells of healthy subjects and patients with hepatocellular carcinoma (HCC), and increase their proliferation and eradication of HCC cells

T cells of aged people, and of patients with either cancer or severe infections (including COVID-19), are often exhausted, senescent and dysfunctional, leading to increased susceptibilities, complications and mortality. Neurotransmitters and Neuropeptides bind their receptors in T cells, and induce multiple beneficial T cell functions. Yet, T cells of different people vary in the expression levels of Neurotransmitter and Neuropeptide receptors, and in the magnitude of the corresponding effects. Therefore, we performed an individual-based study on T cells of 3 healthy subjects, and 3 Hepatocellular Carcinoma (HCC) patients. HCC usually develops due to chronic inflammation. The inflamed liver induces reduction and inhibition of CD4⁺ T cells and Natural Killer (NK) cells. Immune-based therapies for HCC are urgently needed. We tested if selected Neurotransmitters and Neuropeptides decrease the key checkpoint protein PD-1 in human T cells, and increase proliferation and killing of HCC cells. First, we confirmed human T cells express all dopamine receptors (DRs), and glutamate receptors (GluRs): AMPA-GluR3, NMDA-R and mGluR. Second, we discovered that either Dopamine, Glutamate, GnRH-II, Neuropeptide Y and/or CGRP (10nM), as well as DR and GluR agonists, induced the following effects: 1. Decreased significantly both %PD-1⁺ T cells and PD-1 expression level per cell (up to 60% decrease, within 1 h only); 2. Increased significantly the number of T cells that proliferated in the presence of HCC cells (up to 7 fold increase), 3. Increased significantly T cell killing of HCC cells (up to 2 fold increase). 4. Few non-conventional combinations of Neurotransmitters and Neuropeptides had surprising synergistic beneficial effects. We conclude that Dopamine, Glutamate, GnRH-II, Neuropeptide Y and CGRP, alone or in combinations, can decrease % PD-1⁺ T cells and PD-1 expression per cell, in T cells of both healthy subjects and HCC patients, and increase their proliferation in response to HCC cells and killing of HCC cells. Yet, testing T cells of many more cancer patients is absolutely needed. Based on these findings and previous ones, we designed a novel "Personalized Adoptive Neuro-Immunotherapy", calling for validation of safety and efficacy in clinical trials.

Expression of Immune Checkpoint Receptors in Placentae With Infectious and Non-Infectious Chronic Villitis

Pregnancy is an immunological paradox whereby maternal immunity accepts a genetically unique fetus (or fetuses), while maintaining protective innate and adaptive responses to infectious pathogens. This close contact between the genetically diverse mother and fetus requires numerous mechanisms of immune tolerance initiated by trophoblast cell signals. However, in a placental condition known as villitis of unknown etiology (VUE), there appears to be a breakdown in this tolerance allowing maternal cytotoxic T-cells to traffic into the placenta to destroy fetal villi. VUE is associated with several gestational complications and an increased risk of recurrence in a subsequent pregnancy, making it a significant obstetrical diagnosis. The cause of VUE remains unclear, but dysfunctional signaling through immune checkpoint pathways, which have a critical role in blunting immune responses, may play an important role. Therefore, using placental tissue from normal pregnancy (n=8), VUE (n=8) and cytomegalovirus (CMV) infected placentae (n=4), we aimed to identify differences in programmed cell death 1 (PD-1), programmed death ligand-1 (PD-L1), LAG3 and CTLA4 expression between these etiologies by immunohistochemistry (IHC). Results demonstrated significantly lower expression of PD-L1 on trophoblast cells from VUE placentae compared to control and CMV infection. Additionally, we observed significantly higher counts of PD-1+ (>100 cells/image) and LAG3+ (0-120 cells/image) cells infiltrating into the villi during VUE compared to infection and control. Minimal CTLA4 staining was observed in all placentae, with only a few Hofbauer cells staining positive. Together, this suggests that a loss of tolerance through immune checkpoint signaling may be an important mechanism leading to the activation and trafficking of maternal cells into fetal villi during VUE. Further mechanistic studies are warranted to understand possible allograft rejection more clearly and in developing effective strategies to prevent this condition from occurring in utero.

Immune Checkpoint Profiles in Luminal B Breast Cancer (Alliance)

BACKGROUND

Unlike estrogen receptor (ER)-negative breast cancer, ER-positive breast cancer outcome is less influenced by lymphocyte content, indicating the presence of immune tolerance mechanisms that may be specific to this disease subset.

METHODS

A supervised analysis of microarray data from the ACOSOG Z1031 (Alliance) neoadjuvant aromatase inhibitor (AI) trial identified upregulated genes in Luminal (Lum) B breast cancers that correlated with AI-resistant tumor proliferation (percentage of Ki67-positive cancer nuclei, Pearson r > 0.4) (33 cases Ki67 > 10% on AI) vs LumB breast cancers that were more AI sensitive (33 cases Ki67 < 10% on AI). Overrepresentation analysis was performed using WebGestalt. All statistical tests were two-sided.

RESULTS

Thirty candidate genes positively correlated (r ≥ 0.4) with AI-resistant proliferation in LumB and were upregulated greater than twofold. Gene ontologies identified that the targetable immune checkpoint (IC) components IDO1, LAG3, and PD1 were overrepresented resistance candidates (P ≤ .001). High IDO1 mRNA was associated with poor prognosis in LumB disease (Molecular Taxonomy of Breast Cancer International Consortium, hazard ratio = 1.43, 95% confidence interval = 1.04 to 1.98, P = .03). IDO1 also statistically significantly correlated with STAT1 at protein level in LumB disease (Pearson r = 0.74). As a composite immune tolerance signature, expression of IFN-γ/STAT1 pathway components was associated with higher baseline Ki67, lower estrogen, and progesterone receptor mRNA levels and worse disease-specific survival (P = .002). In a tissue microarray analysis, IDO1 was observed in stromal cells and tumor-associated macrophages, with a higher incidence in LumB cases. Furthermore, IDO1 expression was associated with a macrophage mRNA signature (M1 by CIBERSORT Pearson r = 0.62 ) and by tissue microarray analysis.

CONCLUSIONS

Targetable IC components are upregulated in the majority of endocrine therapy-resistant LumB cases. Our findings provide rationale for IC inhibition in poor-outcome ER-positive breast cancer.

Association between CD8 and PD-L1 expression and outcomes after radical prostatectomy for localized prostate cancer

BACKGROUND

Characterization of markers of both immune suppression and activation may provide more prognostic information than assessment of single markers in localized prostate cancer. We therefore sought to determine the association between CD8 and PD-L1 expression in localized prostate tumors and biochemical recurrence (BCR) and metastasis-free survival (MFS).

METHODS

Tissue microarrays were constructed on 109 men undergoing radical prostatectomy (RP) for localized prostate cancer at Dana-Farber Cancer Institute between 1991 and 2008. Fluorescence immunohistochemistry was used to evaluate the expression of six immune markers (CD3, CD4, CD8, PD-1, PD-L1, FOXP3). Quantitative multispectral imaging analysis was used to calculate the density of each marker, which was dichotomized by the median as "high" or "low." Cox proportional hazards regression models and Kaplan-Meier analyses were used to analyze associations between immune marker densities and time to BCR and MFS.

RESULTS

Over a median follow-up of 8.1 years, 55 (51%) and 39 (36%) men developed BCR and metastases, respectively. Median time to BCR was shorter in men with low CD8 (hazard ratio [HR] = 2.27 [1.27-4.08]) and high PD-L1 expression (HR = 2.03 [1.17-3.53]). While neither low CD8 or high PD-L1 alone were independent predictors of BCR or MFS on multivariable analysis, men with low CD8 and/or high PD-L1 had a significantly shorter time to BCR (median 3.5 years vs. NR) and MFS (median 10.8 vs. 18.4 years) compared to those with high CD8 and low PD-L1 expression. The main limitation is the retrospective and singe-center nature of the study.

CONCLUSION

The presence of higher CD8 and lower PD-L1 expression in prostatectomy specimens was associated a low risk of biochemical relapse and metastatic disease. These findings are hypothesis-generating and further study is needed.

Immune Checkpoint Inhibitor-Induced Thyroiditis Is Associated with Increased Intrathyroidal T Lymphocyte Subpopulations

Background: Immune checkpoint inhibitors (ICIs) frequently cause thyroid dysfunction but their underlying mechanism remains unclear. We have previously demonstrated increased circulating natural killer (NK) cells and human leukocyte antigen (HLA)-DR surface expression on inflammatory intermediate CD14⁺CD16⁺ monocytes in programmed cell death protein-1 (PD-1) inhibitor-treated patients. This study characterizes intrathyroidal and circulating immune cells and class II HLA in ICI-induced thyroiditis. Methods: This is a single-center prospective cohort study of 10 patients with ICI-induced thyroiditis by flow cytometry of thyroid fine needle aspirates (n = 9) and peripheral blood (n = 7) as compared with healthy thyroid samples (n = 5) and healthy volunteer blood samples (n = 44); HLA class II was tested in n = 9. Results: ICI-induced thyroiditis samples demonstrated overall increased T lymphocytes (61.3% vs. 20.1%, p = 0.00006), CD4^-CD8^- T lymphocytes (1.9% vs. 0.7%, p = 0.006), and, as a percent of T lymphocytes, increased CD8⁺T lymphocytes (38.6% vs. 25.7%; p = 0.0259) as compared with healthy thyroid samples. PD-1 inhibitor-induced thyroiditis had increased CD4⁺PD1⁺ T lymphocytes (40.4% vs. 0.8%; p = 0.021) and CD8⁺PD1⁺ T lymphocytes (28.8% vs. 1.5%; p = 0.038) in the thyroid compared with the blood. Circulating NK cells, certain T lymphocytes (CD4⁺CD8⁺, CD4^-CD8^- T, gamma-delta), and intermediate monocytes were increased in ICI-induced thyroiditis. Six patients typed as HLA-DR4-DR53 and three as HLA-DR15. Conclusions: ICI-induced thyroiditis is a T lymphocyte-mediated process with intra-thyroidal predominance of CD8⁺ and CD4^-CD8^- T lymphocytes. The HLA haplotypes may be involved but need further evaluation. These findings expand the limited understanding of ICI-induced thyroiditis, which could be further translated to guide immunomodulatory therapies for advanced thyroid cancer.

Inhibitory Immune Checkpoint Molecule Expression in Clinical Sepsis Studies: A Systematic Review

OBJECTIVES

Checkpoint inhibitors have been proposed for sepsis following reports of increased checkpoint molecule expression in septic patients. To determine whether clinical studies investigating checkpoint molecule expression provide strong evidence supporting trials of checkpoint inhibitors for sepsis.

DATA SOURCES

PubMed, EMBASE, Scopus, Web of Science, inception through October 2019.

STUDY SELECTION

Studies comparing checkpoint molecule expression in septic patients versus healthy controls or critically ill nonseptic patients or in sepsis nonsurvivors versus survivors.

DATA EXTRACTION

Two investigators extracted data and evaluated study quality.

DATA SYNTHESIS

Thirty-six studies were retrieved. Across 26 studies, compared with healthy controls, septic patients had significantly (p ≤ 0.05) increased CD4+ lymphocyte programmed death-1 and monocyte programmed death-ligand-1 expression in most studies. Other checkpoint molecule expressions were variable and studied less frequently. Across 11 studies, compared with critically ill nonseptic, septic patients had significantly increased checkpoint molecule expression in three or fewer studies. Septic patients had higher severity of illness scores, comorbidities, and mortality in three studies providing analysis. Across 12 studies, compared with septic survivors, nonsurvivors had significantly increased expression of any checkpoint molecule on any cell type in five or fewer studies. Of all 36 studies, none adjusted for nonseptic covariates reported to increase checkpoint molecule expression.

CONCLUSIONS

Although sepsis may increase some checkpoint molecule expression compared with healthy controls, the data are limited and inconsistent. Further, data from the more informative patient comparisons are potentially confounded by severity of illness. These clinical checkpoint molecule expression studies do not yet provide a strong rationale for trials of checkpoint inhibitor therapy for sepsis.

Delayed Expression of PD-1 and TIGIT on HIV-Specific CD8 T Cells in Untreated HLA-B*57:01 Individuals Followed from Early Infection

While the relationship of protective human leukocyte antigen (HLA) class I alleles and HIV progression is well defined, the interaction of HLA-mediated protection and CD8 T-cell exhaustion is less well characterized. To gain insight into the influence of HLA-B*57:01 on the deterioration of CD8 T-cell responses during HIV infection in the absence of antiretroviral treatment, we compared HLA-B*57:01-restricted HIV-specific CD8 T-cell responses to responses restricted by other HLA class I alleles longitudinally after control of peak viremia. Detailed characterization of polyfunctionality, differentiation phenotypes, transcription factor, and inhibitory receptor expression revealed progression of CD8 T-cell exhaustion over the course of the infection in both patient groups. However, early effects on the phenotype of the total CD8 T-cell population were apparent only in HLA-B*57-negative patients. The HLA-B*57:01-restricted, HIV epitope-specific CD8 T-cell responses showed beneficial functional patterns and significantly lower frequencies of inhibitory receptor expression, i.e., PD-1 and coexpression of PD-1 and TIGIT, within the first year of infection. Coexpression of PD-1 and TIGIT was correlated with clinical markers of disease progression and declining percentages of the T-bethi Eomesdim CD8 T-cell population. In accordance with clinical and immunological deterioration in the HLA-B*57:01 group, the difference in PD-1 and TIGIT receptor expression did not persist to later stages of the disease.IMPORTANCE Given the synergistic nature of TIGIT and PD-1, the coexpression of those inhibitory receptors should be considered when evaluating T-cell pathogenesis, developing immunomodulatory therapies or vaccines for HIV, and when using immunotherapy or vaccination for other causes in HIV-infected patients. HIV-mediated T-cell exhaustion influences the patient´s disease progression, immune system and subsequently non-AIDS complications, and efficacy of vaccinations against other pathogens. Consequently, the possibilities of interfering with exhaustion are numerous. Expanding the use of immunomodulatory therapies to include HIV treatment depends on information about possible targets and their role in the deterioration of the immune system. Furthermore, the rise of immunotherapies against cancer and elevated cancer incidence in HIV-infected patients together increase the need for detailed knowledge of T-cell exhaustion and possible interactions. A broader approach to counteract immune exhaustion to alleviate complications and improve efficacy of other vaccines also promises to increase patients' health and quality of life.

Gemcitabine and checkpoint blockade exhibit synergistic anti-tumor effects in a model of murine lung carcinoma

Lung cancer is leading cause of cancer death in the world. Chemotherapy is currently one of the standard treatments for lung cancer. Gemcitabine is a pyrimidine nucleoside drug which has been approved by FDA to treat lung cancer. However, acquired resistance inevitable develops after Gemcitabine treatment, limiting clinical efficacy. Lewis lung carcinoma (LLC) cells were treated with Gemcitabine and cell apoptosis and programmed cell death-ligand 1 (PD-L1) expression were analyzed by flow cytometry. LLC mouse model was established to analysis the proportion and programmed cell death-1 (PD-1) expression of CD8 + T cells. Anti-tumor effect by treating with Gemcitabine and anti-PD-1 antibody was measured through in vivo LLC mouse model. Gemcitabine treatment induces tumor cell apoptosis and PD-L1 expression. Further study showed that Gemcitabine treatment also increases CD8⁺ and CD4⁺ T cells proportion, PD-1 and PD-L1 expression in LLC mouse model. Combination therapy with Gemcitabine and αPD-1 not only has strong anti-tumor effect, but also could inhibit postsurgical recurrence of LLC. Our findings demonstrated that the combination therapy of Gemcitabine and αPD-1 is an effective therapeutic strategy for lung cancer.

Immune Checkpoint Inhibitors in Hepatocellular Cancer: Current Understanding on Mechanisms of Resistance and Biomarkers of Response to Treatment

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy worldwide and a leading cause of death worldwide. Its incidence continues to increase in the US due to hepatitis C infection and nonalcoholic steatohepatitis. Liver transplantation and resection remain the best therapeutic options for cure, but these are limited by the shortage of available organs for transplantation, diagnosis at advanced stage, and underlying chronic liver disease found in most patients with HCC. Immune checkpoint inhibitors (ICIs) have been shown to be an evolving novel treatment option in certain advanced solid tumors and have been recently approved for inoperable, advanced, and metastatic HCC. Unfortunately, a large cohort of patients with HCC fail to respond to immunotherapy. In this review, we discuss the ICIs currently approved for HCC treatment and their various mechanisms of action. We will highlight current understanding of mechanism of resistance and limitations to ICIs. Finally, we will describe emerging biomarkers of response to ICIs and address future direction on overcoming resistance to immune checkpoint therapy.

The programmed cell death protein-1/programmed cell death ligand 1 expression, CD3+ T cell infiltration, NY-ESO-1 expression, and microsatellite instability phenotype in primary cutaneous melanoma and mucosal melanoma and their clinical significance and prognostic value: a study of 89 consecutive cases

We evaluated the expression of programmed cell death protein-1 (PD-1), programmed cell death ligand 1 (PD-L1), and NY-ESO-1 antigen; the infiltration of CD3+ T cells; and the microsatellite instability (MSI) phenotype, as well as the relationship of each factor to survival in malignant melanoma patients. Malignant melanoma samples from 89 patients were stained by immunohistochemistry to evaluate PD-1, PD-L1, CD3+ tumor-infiltrating lymphocytes (TILs), NY-ESO-1, and MSI. PD-1 and PD-L1 were expressed in 19.1 and 32.6% of the 89 samples, respectively. There was a significant correlation between PD-1 and PD-L1 expression (r = 0.207, P = 0.046). High infiltration of CD3+ T cells was observed in 41.6% of the samples, and increased cell infiltration was associated with increased PD-1 expression (P = 0.001). NY-ESO-1 antigen was detected in 13.5% of all samples, and the expression of NY-ESO-1 was positively correlated with the expression of PD-1 (P < 0.001). In our research, MSI was detected in 18 samples (20.2%). Survival analysis showed that a high infiltration of CD3+ T cells was related to longer progression-free survival (PFS) [24.0 months, 95% confidence interval (CI): 7.4-40.6 vs. 11.0 months, 95% CI: 7.1-12.9, P = 0.031], similarly, the median overall survival (OS) of the CD3+ T cell high-infiltration patients was also longer (53.0 vs. 38.0 months), but with no statistical significance (P = 0.200). The results for the immune markers mentioned above provide a theoretical basis for the prognosis and immunotherapy selection of malignant melanoma patients.

Inactivation of Proprotein Convertases in T Cells Inhibits PD-1 Expression and Creates a Favorable Immune Microenvironment in Colorectal Cancer

Proprotein convertases (PC) activate precursor proteins that play crucial roles in various cancers. In this study, we investigated whether PC enzyme activity is required for expression of the checkpoint protein programmed cell death protein 1 (PD-1) on cytotoxic T lymphocytes (CTL) in colon cancer. Although altered expression of the PC secretory pathway was observed in human colon cancers, only furin showed highly diffuse expression throughout the tumors. Inhibition of PCs in T cells using the general protein-based inhibitor α1-PDX or the pharmacologic inhibitor Decanoyl-Arg-Val-Lys-Arg-chloromethylketone repressed PD-1 and exhausted CTLs via induction of T-cell proliferation and apoptosis inhibition, which improved CTL efficacy against microsatellite instable and microsatellite stable colon cancer cells. In vivo, inhibition of PCs enhanced CTL infiltration in colorectal tumors and increased tumor clearance in syngeneic mice compared with immunodeficient mice. Inhibition of PCs repressed PD-1 expression by blocking proteolytic maturation of the Notch precursor, inhibiting calcium/NFAT and NF-κB signaling, and enhancing ERK activation. These findings define a key role for PCs in regulating PD-1 expression and suggest targeting PCs as an adjunct approach to colorectal tumor immunotherapy. SIGNIFICANCE: Protein convertase enzymatic activity is required for PD-1 expression on T cells, and inhibition of protein convertase improves T-cell targeting of microsatellite instable and stable colorectal cancer. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/79/19/5008/F1.large.jpg.

Clinical significance of programmed death-1 and programmed death-ligand 1 expression in the tumor microenvironment of clear cell renal cell carcinoma

Recently, immunotherapy based on blocking immune checkpoints with programmed death-1 (PD-1) or PD-ligand 1 (PD-L1) Abs has been introduced for the treatment of advanced clear cell renal cell carcinoma (ccRCC), especially tumors resistant to vascular endothelial growth factor-tyrosine kinase inhibitors (VEGF-TKIs), but the significance of their expression in the tumor microenvironment is unclear. We investigated these immune checkpoint markers in tumor cells and tumor-infiltrating immune cells (TIIC) in the tumor microenvironment of 100 untreated and 25 VEGF-TKI-treated primary ccRCC tissues. Upregulated expression of PD-1 and PD-L1 by TIIC, and PD-L1 by tumor cells was associated with the histological grade and unfavorable prognosis of RCC patients. High PD-1 and PD-L1 expression by TIIC was associated with a poorer response to VEGF-TKI, whereas PD-L1 expression by tumor cells did not affect the efficacy of the treatment. Furthermore, increased PD-1-positive TIIC and PD-L1-positive TIIC were observed in tumors treated with VEGF-TKIs compared with those in untreated tumors. Our data suggest that PD-1 and PD-L1 expression by TIIC in the tumor microenvironment is involved in treatment resistance, and that sequential therapy with immune checkpoint inhibitors could be a promising therapeutic strategy for ccRCC resistant to VEGF-TKI treatment.

Age and sex have no impact on expression levels of markers of immune cell infiltration and immune checkpoint pathways in patients with muscle-invasive urothelial carcinoma of the bladder treated with radical cystectomy

OBJECTIVES

Advanced age and female sex have been associated with worse outcomes in patients undergoing radical cystectomy for muscle-invasive bladder cancer. A reduced immune response has been implicated as a mechanism. The objective of our study was to analyze the expression patterns of various cellular proteins active in bladder cancer immune pathways, and assess the correlation between age, sex, and the expression of these immune markers.

METHODS

We obtained surgical tissue samples from equally distributed male/female patients with/without lymph node metastasis who had undergone radical cystectomy for urothelial carcinoma (UC) of the bladder (n = 50). Immunohistochemistry (IHC) for CD3 (cluster of differentiation), CD4, CD8, CD56, LAG-3 (lymphocyte-activation gene), TIM-3 (T-cell immunoglobulin and mucin-domain), PD-1 (programmed death) and PD-L1 molecules was performed and scored by a single pathologist (high versus low). Spearman's correlation and Chi square tests investigated the association between age, sex, and IHC results.

RESULTS

Mean age at surgery was 67 years (range 50-78 years); all patients were Caucasians. The following percent of patients scored high for a stain: 18% CD3, 10% CD4, 0% CD8, 0% CD56, 20% LAG-3, 4% TIM-3, 0% PD-1 and 0% PD-L1. There was no association between patients' age, sex, and the expression of any of the immune markers (p > 0.05 for all).

CONCLUSIONS

The association between advanced age, female sex, and worse outcomes in bladder cancer may be independent of the immune pathways active in the disease that we examined in this study.

Programmed cell death-1 in patients with primary liver cancer and its effect on prognosis

PURPOSE

To detect the expression of programmed cell death-1 (PD-1) in peripheral blood T lymphocytes of patients with primary liver cancer and its effect on their prognosis.

METHODS

The medical records of 42 patients with primary liver cancer, 36 patients with chronic hepatitis B (CHB) and 38 healthy volunteers composed the liver cancer group, benign lesion group and control group, respectively. Fluorescence quantitative RT-PCR (qRT-PCR) was used for detecting the expression level of PD-1 mRNA in peripheral blood T lymphocytes of subjects in the three groups, and flow cytometry was used for detecting the positive expression of PD-l protein on the surface of T lymphocytes of subjects.

RESULTS

Patients in the control group and the benign lesion group had lower expression level of PD-1 mRNA than those in the liver cancer group (p<0.05). Patients in the control group had lower expression level of PD-1 mRNA than those in the benign lesion group (p<0.05). Patients in the control group and the benign lesion group had lower positive expression rate of PD-1 protein on the surface of T lymphocytes than those in the liver cancer group (p<0.05).

CONCLUSION

The expression of PD-1 in the peripheral blood was higher in patients with primary liver cancer. Patients in the PD-1 low expression group had significantly better prognosis than those in the PD-1 high expression group. PD-1 may be related to the occurrence and development of primary liver cancer and is worthy of further study.

Clinical impact of PD-L1 and PD-1 expression in squamous cell cancer of the vulva

PURPOSE

Squamous cell carcinoma of the vulva (SQCV) is the fifth most common cancer in women and accounts for about 5% of all genital cancers in women. The PD-L1 signaling pathway is activated in many malignant neoplasms and its blockade enhances anti-cancer immunity. The aim of our study was to examine the protein expression of PD-L1 and PD-1 in squamous cell cancer of the vulva, its correlations with clinicopathologic features and prognostic value.

METHODS

Patients with SQCV treated in one institution were used for the analyses. PD-L1 immunohistochemistry was performed on 4 µm-thick section of the respective FFPE tissue blocks using the 28-8 antibody. PD-L1 scoring was performed separately for tumour cells (TC) and tumour associated immune cells. DNA was extracted to determine HPV status. Kaplan-Meier estimates for disease-free-survival and overall-survival were calculated and compared by log-rank test.

RESULTS

PD-L1 expression in tumour cells could be observed in 32.9% of the patients. The expression of PD-L1 in peritumoural immune cells was confirmed in 91.4% of the patients. A significant correlation between PD-L1 expression in tumour cells and tumour stage was detected (p = 0.007). PD-L1 expression was independent from HPV status. Using the log-rank test we could not prove any significant differences in disease-free survival (p = 0.434) and overall survival (p = 0.858). Regression analysis showed that nodal status is a predictive factor of survival (p < 0.001).

CONCLUSION

The present study showed that a relevant amount of patients with squamous cell cancer of the vulva express PD-L1 in both, tumour cells and tumour-associated immune cells. Furthermore, the significant correlation of PD-L1 expression in TCs with tumour stage indicated the clinical impact of PD-L1 expression during tumour development. These data indicate that SQCV might be amenable to immune checkpoint-inhibition and constitute a rational for the future clinical trials.

The Combination of MEK Inhibitor With Immunomodulatory Antibodies Targeting Programmed Death 1 and Programmed Death Ligand 1 Results in Prolonged Survival in Kras/p53-Driven Lung Cancer

INTRODUCTION

This study aimed to characterize the tumor-infiltrating immune cells population in Kras/tumor protein 53 (Trp53)-driven lung tumors and to evaluate the combinatorial antitumor effect with MEK inhibitor (MEKi), trametinib, and immunomodulatory monoclonal antibodies (mAbs) targeting either programmed death -1 (PD-1) or programmed cell death ligand 1 (PD-L1) in vivo.

METHODS

Trp53^FloxFlox;Kras^G12D/+;Rosa26^{LSL-Luciferase/LSL-Luciferase} (PKL) genetically engineered mice were used to develop autochthonous lung tumors with intratracheal delivery of adenoviral Cre recombinase. Using these tumor-bearing lungs, tumor-infiltrating immune cells were characterized by both mass cytometry and flow cytometry. PKL-mediated immunocompetent syngeneic and transgenic lung cancer mouse models were treated with MEKi alone as well as in combination with either anti-PD-1 or anti-PD-L1 mAbs. Tumor growth and survival outcome were assessed. Finally, immune cell populations within spleens and tumors were evaluated by flow cytometry and immunohistochemistry.

RESULTS

Myeloid-derived suppressor cells (MDSCs) were significantly augmented in PKL-driven lung tumors compared to normal lungs of tumor-free mice. PD-L1 expression appeared to be highly positive in both lung tumor cells and, particularly MDSCs. The combinatory administration of MEKi with either anti-PD-1 or anti-PD-L1 mAbs synergistically increased antitumor response and survival outcome compared with single-agent therapy in both the PKL-mediated syngeneic and transgenic lung cancer models. Theses combinational treatments resulted in significant increases of tumor-infiltrating CD8⁺ and CD4⁺ T cells, whereas attenuation of CD11b⁺/Gr-1^high MDSCs, in particular, Ly6G^high polymorphonuclear-MDSCs in the syngeneic model.

CONCLUSIONS

These findings suggest a potential therapeutic approach for untargetable Kras/p53-driven lung cancers with synergy between targeted therapy using MEKi and immunotherapies.

Prognostic Impact of Tumor Cell Programmed Death Ligand 1 Expression and Immune Cell Infiltration in NSCLC

INTRODUCTION

Infiltration of T and B/plasma cells has been linked to NSCLC prognosis, but this has not been thoroughly investigated in relation to the expression of programmed death ligand 1 (PD-L1). Here, we determine the association of lymphocytes and PD-L1 with overall survival (OS) in two retrospective cohorts of operated NSCLC patients who were not treated with checkpoint inhibitors targeting the programmed death 1/PD-L1 axis. Moreover, we evaluate how PD-L1 positivity and clinicopathologic factors affect the prognostic association of lymphocytes.

METHODS

Cluster of differentiation (CD) 3 (CD3)-, CD8-, CD4-, forkhead box P3 (FOXP3)-, CD20-, CD79A-, and immunoglobulin kappa constant (IGKC)-positive immune cells, and tumor PD-L1 positivity, were determined by immunohistochemistry on tissue microarrays (n = 705). Affymetrix data was analyzed for a patient subset, and supplemented with publicly available transcriptomics data (N = 1724). Associations with OS were assessed by Kaplan-Meier plots and uni- and multivariate Cox regression.

RESULTS

Higher levels of T and B plasma cells were associated with longer OS (p = 0.004 and p < 0.001, for CD8 and IGKC, respectively). Highly proliferative tumors with few lymphocytes had the worst outcome. No association of PD-L1 positivity with OS was observed in a nonstratified patient population; however, a significant association with shorter OS was observed in never-smokers (p = 0.009 and p = 0.002, 5% and 50% cutoff). Lymphocyte infiltration was not associated with OS in PD-L1-positive tumors (50% cutoff). The prognostic association of lymphocyte infiltration also depended on the patients' smoking history and histologic subtype.

CONCLUSIONS

Proliferation, PD-L1 status, smoking history, and histology should be considered if lymphocyte infiltration is to be used as a prognostic biomarker.

PD-1 and PD-L1 Expression in Male Breast Cancer in Comparison with Female Breast Cancer

BACKGROUND

Male breast cancer is rare, as it represents less than 1% of all breast cancer cases. In addition, male breast cancer appears to have a different biology than female breast cancer. Programmed death-1 (PD-1) and its ligand, programmed death-ligand 1 (PD-L1), seem to have prognostic and predictive values in a variety of cancers, including female breast cancer. However, the role of PD-1 and PD-L1 expression in male breast cancer has not yet been studied.

OBJECTIVES

To compare PD-1 and PD-L1 expression in male breast cancer to female breast cancer and to evaluate prognostic values in both groups.

PATIENTS AND METHODS

Tissue microarrays from formalin-fixed paraffin-embedded resection material of 247 female and 164 male breast cancer patients were stained for PD-1 and PD-L1 by immunohistochemistry.

RESULTS

PD-1 expression on tumor-infiltrating lymphocytes was significantly less frequent in male than in female cancers (48.9 vs. 65.3%, p = 0.002). In contrast, PD-L1 expression on tumor and immune cells did not differ between the two groups. In male breast cancer, PD-1 and tumor PD-L1 were associated with grade 3 tumors. In female breast cancer, PD-1 and PD-L1 were associated with comparably worse clinicopathological variables. In a survival analysis, no prognostic value was observed for PD-1 and PD-L1 in either male and female breast cancer. In a subgroup analysis, female patients with grade 3/tumor PD-L1-negative or ER-negative/immune PD-L1-negative tumors had worse overall survival.

CONCLUSIONS

PD-1 seems to be less often expressed in male breast cancer compared to female breast cancer. Although PD-1 and PD-L1 are not definite indicators for good or bad responses, male breast cancer patients may therefore respond differently to checkpoint immunotherapy with PD-1 inhibitors than female patients.

Expression of PD-1 and PD-L1 increase in consecutive biopsies in patients with classical Hodgkin lymphoma

High expression of programmed death receptor 1 (PD-1) and its ligand (PD-L1) by leukocytes in primary classical Hodgkin lymphoma (cHL) is associated with inferior outcome. However, it is unclear how expression varies during disease progression, and in the event of relapse. Our aim was to study PD-1 and PD-L1 in consecutive biopsies from untreated and treated cHL patients. We screened pathology registries from 3500 cHL patients. Eleven patients had a diagnostic cHL biopsy and a previous benign lymph node biopsy reclassified as cHL when reviewed and designated as the untreated. Thirty patients had a primary and a relapse biopsy, designated as the treated. Biopsies were immunostained to detect PD-1+ and PD-L1+ leukocytes, and PD-L1+ tumor cells. In the untreated, none of the markers were statistically significantly different when biopsies 1 and 2 were compared. In the treated, 19, 22, and 18 of 30 cases had increased proportions of PD-1+ leukocytes, PD-L1+ leukocytes and PD-L1+ tumor cells, respectively, and were all statistically significantly increased when primary and relapse biopsies were compared. PD-1 and PD-L1 most likely increase due to primary treatment with chemotherapy and radiotherapy, which could have implications regarding treatment with PD-1 inhibitors.

Anti-PD-1/PD-L1 Antibody Therapy for Pretreated Advanced or Metastatic Nonsmall Cell Lung Carcinomas and the Correlation between PD-L1 Expression and Treatment Effectiveness: An Update Meta-Analysis of Randomized Clinical Trials

PURPOSE

This meta-analysis systematically evaluated the efficacy and safety of anti-PD-1/PD-L1 antibodies for pretreated advanced or metastatic nonsmall cell lung cancer (NSCLC) and investigated the correlation between PD-L1 expression levels and effectiveness of anti-PD-1/PD-L1 antibody.

METHODS

The methodology was based on the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) and the Cochrane Collaboration guidelines.

RESULTS

Our research included five randomized-controlled trials involving 3,025 patients. We compared anti-PD-1/PD-L1 antibodies (nivolumab, pembrolizumab, and atezolizumab) with docetaxel in pretreated patients with advanced or metastatic NSCLC. The pooled hazard ratio (HR) for overall survival (OS) and progression-free survival (PFS) was 0.69 (95%CI: 0.63-0.75, P<0.0001, and Ph=0.67) and 0.87 (95%CI: 0.81-0.94, P=0.0004, and Ph=0.11), respectively. Meanwhile, the pooled risk ratio (RR) for objective response rate (ORR) was 1.53 (95% CI: 1.16-2.01, P=0.003, and Ph=0.03) in all patients. Subgroup analyses showed that anti-PD-1/PD-L1 treatment significantly improved OS in patients with PD-L1 expression at any level, even in patients with PD-L1<1%. The RR for occurrence of grades 3 to 5 treatment-related adverse effects was 0.23 (95% CI: 0.15-0.36, and P<0.001).

CONCLUSION

OS, PFS, and ORR were significantly more improved for patients treated with anti-PD-1/PD-L1 antibodies than for those treated with docetaxel. Anti-PD-1/PD-L1 therapy resulted in longer OS than docetaxel, regardless of PD-L1 expression; however, higher PD-L1 levels were likely to correlate with better outcome. Anti-PD-1/PD-L1 antibodies also had a better safety profile than docetaxel.

The expression of selected molecular markers of immune tolerance in psoriatic patients

BACKGROUND

Psoriasis is a chronic autoinflammatory disease whose underlying molecular mechanisms remain unclear. The disease is mediated by the cells and molecules of both the innate and adaptive immune systems. Some T cell surface molecules, including neuropilin-1 (NRP1), programmed death 1 (PD-1) and the human leukocyte antigen G (HLA-G), are known to play a role in the maintenance of immune tolerance.

OBJECTIVES

The aim of this study was to investigate HLA-G, NRP1 and programmed cell death gene (PDCD1) mRNA expression in psoriatic patients.

MATERIAL AND METHODS

The study included 72 psoriatic patients and 35 healthy individuals. Twentyone patients (29.17%) suffered from concomitant psoriatic arthritis. The mRNA expression of HLA-G, NRP1, and PDCD1 were determined using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). The severity of skin lesions was assessed by means of the Psoriasis Area and Severity Index (PASI), Body Surface Area (BSA), the Patient Global Assessment (PGA), and the Dermatology Life Quality Index (DLQI).

RESULTS

The median value of the PASI was 11.5, and of BSA was 15.8%. The expressions of NRP1 and PDCD1, but not HLA-G, were significantly lower in psoriatic patients in comparison with the control group. The expression of HLA-G, NRP1 and PDCD1 were not significantly different in the psoriatic arthritis and psoriasis vulgaris patients.

CONCLUSIONS

The results of this study suggest that the molecular markers of immune tolerance, i.e., HLA-G, NRP1, and PD-1, may be involved in the immune response in psoriatic patients.

Expression Patterns, Prognostic Value, and Intratumoral Heterogeneity of PD-L1 and PD-1 in Thymoma and Thymic Carcinoma

INTRODUCTION

Thymic epithelial tumors (TETs) including thymoma and thymic carcinoma are rare tumors with little data available to guide treatment. Immunotherapy with checkpoint blockade has shown promising activity, but data regarding the expression patterns and prognostic implications of programmed death 1 (PD-1) and its ligand (PD-L1) in TETs have yielded conflicting results. Intratumoral heterogeneity of PD-1/L1 expression has been shown in other cancers, but has not been described in the TET literature.

METHODS

We performed a retrospective single-center review of 35 patients with resected TET. PD-1/L1 expression was assessed by immunohistochemistry using PD-1 clone: NAT105 and PD-L1 clone: 22C3. Tumor samples from 35 patients were evaluated including 32 patients with thymoma and 3 patients with thymic carcinoma.

RESULTS

PD-L1 expression was detected in 83% (29 of 35) tumor samples, including 100% (3 of 3) of thymic carcinoma patients and 81% (26 of 32) of thymoma patients. PD-1 expression was detected in 77% (27 of 35), including 33% (1 of 3) of thymic carcinoma patients and 81% (26 of 32) thymoma patients. High PD-1 expression was associated with lower grade tumors. Unlike prior studies, PD-L1 expression was not associated with higher grade tumors or higher stage. Neither PD-L1 nor PD-1 expression was significantly associated with survival. Three patients with thymoma had multiple tumor sections evaluated for expression of PD-1/L1, with differing expression patterns of both PD-L1 and PD-1 observed in two patients.

CONCLUSIONS

This study confirms high expression of PD-L1 and PD-1 in TET and shows for the first time intratumoral heterogeneity of PD-L1 and PD-1 in thymoma patients.

Immunohistochemical analysis and prognostic significance of PD-L1, PD-1, and CD8+ tumor-infiltrating lymphocytes in Ewing's sarcoma family of tumors (ESFT)

Ewing's sarcoma family of tumors (ESFT) are aggressive neoplasms with scant tumor-infiltrating lymphocytes. We analyzed the immunohistochemical (IHC) expression of PD-L1 and PD-1 and their prognostic significance in clinically localized neoplasms in a cohort of 370 ESFT. Slides prepared from tissue microarrays were stained for PD-L1, PD-1, and CD8. Membranous/cytoplasmic staining over 5% of tumor cells was regarded as positive for PD-L1 and PD-1. Prognostic analysis was done considering only clinically localized tumors (n = 217). PD-L1 expression was present in 19% of ESFT, while PD-1 was expressed in 26%. Forty-eight percent of tumors were negative and 12% were positive for both PD-L1 and PD-1. Metastatic tumors displayed higher expression of PD-L1 (p < 0.0001). Histological subtypes were not correlated with PD-L1 or PD-1 positivity. ESFT with elevated proliferation index (Ki-67) were associated with higher PD-L1 expression (p = 0.049). Regarding prognosis, no significant association was found between PD-L1 expression and progression-free survival (PFS) or overall survival (OS), whereas lack of PD-1 expression in tumor cells was correlated with both poor PFS (p = 0.02) and poor OS (p = 0.004). Tumor-infiltrating CD8(+) T lymphocytes were observed in 15.4% of ESFT with informative results (347 tumors). No correlation was found between tumor-infiltrating CD8(+) T lymphocytes and ESFT histological subtypes, tumor location, or PD-1 and PD-L1 expression, nor with PFS (p = 0.473) or OS (p = 0.087). PD-L1 expression was not significantly related to prognosis. PD-1 was expressed in 26% of ESFT tumor cells and may have prognostic and therapeutic implications. CD8 expression in tumor-infiltrating lymphocytes was not related to prognosis.

PD-1/PD-L1 and VEGF-A/VEGF-C expression in lymph node microenvironment and association with melanoma metastasis and survival

Regional lymph nodes are affected frequently by melanoma metastasis. Its microenvironment may be associated with tumor progression. We investigated sentinel nodes with and without tumor and negative nodes surrounding positive nodes, looking for patterns related to tumor immune interaction and lymphovascular progression. We quantified programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1, vascular endothelial growth factor (VEGF)-A/VEGF-C expressions in lymph nodes of 103 patients who underwent sentinel lymph node biopsy. Two groups were studied: negative sentinel lymph nodes and positive ones. Negative lymph nodes of sequential lymphadenectomy from positive cases were also studied. Markers were assessed by immunohistochemistry. Results were related to clinical/histological outcomes. VEGF-A/VEGF-C analysis showed higher positivity in metastatic nodes and higher positivity in the surrounding negative nodes from positive cases in comparison with nonmetastatic patients. Programmed cell death-ligand 1, studied only in metastasis, presented high positivity, not associated with prognosis. PD-1 expressions were similar in the groups with a 1% cutoff and higher in the metastasis with a 5% cutoff. Higher VEGF-A expression was related to higher pathological stages. PD-1 expression in the lymph node was associated with higher survival. Other clinical and histopatological variables were not associated with marker expression patterns. VEGF-A and VEGF-C expressions in lymph nodes were associated with the presence of lymph node metastasis. PD-1 expression in the lymph node was related to higher survival rates and this should be explored in the context of adjuvant immunotherapy.

PD-L1 inhibits acute and chronic pain by suppressing nociceptive neuron activity via PD-1

Programmed cell death ligand-1 (PD-L1) is typically produced by cancer cells and suppresses immunity through the receptor PD-1 expressed on T cells. However, the role of PD-L1 and PD-1 in regulating pain and neuronal function is unclear. Here we report that both melanoma and normal neural tissues including dorsal root ganglion (DRG) produce PD-L1 that can potently inhibit acute and chronic pain. Intraplantar injection of PD-L1 evoked analgesia in naive mice via PD-1, whereas PD-L1 neutralization or PD-1 blockade induced mechanical allodynia. Mice lacking Pd1 (Pdcd1) exhibited thermal and mechanical hypersensitivity. PD-1 activation in DRG nociceptive neurons by PD-L1 induced phosphorylation of the tyrosine phosphatase SHP-1, inhibited sodium channels and caused hyperpolarization through activation of TREK2 K⁺ channels. PD-L1 also potently suppressed nociceptive neuron excitability in human DRGs. Notably, blocking PD-L1 or PD-1 elicited spontaneous pain and allodynia in melanoma-bearing mice. Our findings identify a previously unrecognized role of PD-L1 as an endogenous pain inhibitor and a neuromodulator.

Cancer immunotherapy - immune checkpoint blockade and associated endocrinopathies

Advances in cancer therapy in the past few years include the development of medications that modulate immune checkpoint proteins. Cytotoxic T-lymphocyte antigen 4 (CTLA4) and programmed cell death protein 1 (PD1) are two co-inhibitory receptors that are expressed on activated T cells against which therapeutic blocking antibodies have reached routine clinical use. Immune checkpoint blockade can induce inflammatory adverse effects, termed immune-related adverse events (IRAEs), which resemble autoimmune disease. In this Review, we describe the current data regarding immune-related endocrinopathies, including hypophysitis, thyroid dysfunction and diabetes mellitus. We discuss the clinical management of these endocrinopathies within the context of our current understanding of the mechanisms of IRAEs.

CD4+ T Cells Expressing PD-1, TIGIT and LAG-3 Contribute to HIV Persistence during ART

HIV persists in a small pool of latently infected cells despite antiretroviral therapy (ART). Identifying cellular markers expressed at the surface of these cells may lead to novel therapeutic strategies to reduce the size of the HIV reservoir. We hypothesized that CD4+ T cells expressing immune checkpoint molecules would be enriched in HIV-infected cells in individuals receiving suppressive ART. Expression levels of 7 immune checkpoint molecules (PD-1, CTLA-4, LAG-3, TIGIT, TIM-3, CD160 and 2B4) as well as 4 markers of HIV persistence (integrated and total HIV DNA, 2-LTR circles and cell-associated unspliced HIV RNA) were measured in PBMCs from 48 virally suppressed individuals. Using negative binomial regression models, we identified PD-1, TIGIT and LAG-3 as immune checkpoint molecules positively associated with the frequency of CD4+ T cells harboring integrated HIV DNA. The frequency of CD4+ T cells co-expressing PD-1, TIGIT and LAG-3 independently predicted the frequency of cells harboring integrated HIV DNA. Quantification of HIV genomes in highly purified cell subsets from blood further revealed that expressions of PD-1, TIGIT and LAG-3 were associated with HIV-infected cells in distinct memory CD4+ T cell subsets. CD4+ T cells co-expressing the three markers were highly enriched for integrated viral genomes (median of 8.2 fold compared to total CD4+ T cells). Importantly, most cells carrying inducible HIV genomes expressed at least one of these markers (median contribution of cells expressing LAG-3, PD-1 or TIGIT to the inducible reservoir = 76%). Our data provide evidence that CD4+ T cells expressing PD-1, TIGIT and LAG-3 alone or in combination are enriched for persistent HIV during ART and suggest that immune checkpoint blockers directed against these receptors may represent valuable tools to target latently infected cells in virally suppressed individuals.

Exhaustion of Activated CD8 T Cells Predicts Disease Progression in Primary HIV-1 Infection

The rate at which HIV-1 infected individuals progress to AIDS is highly variable and impacted by T cell immunity. CD8 T cell inhibitory molecules are up-regulated in HIV-1 infection and associate with immune dysfunction. We evaluated participants (n = 122) recruited to the SPARTAC randomised clinical trial to determine whether CD8 T cell exhaustion markers PD-1, Lag-3 and Tim-3 were associated with immune activation and disease progression. Expression of PD-1, Tim-3, Lag-3 and CD38 on CD8 T cells from the closest pre-therapy time-point to seroconversion was measured by flow cytometry, and correlated with surrogate markers of HIV-1 disease (HIV-1 plasma viral load (pVL) and CD4 T cell count) and the trial endpoint (time to CD4 count <350 cells/μl or initiation of antiretroviral therapy). To explore the functional significance of these markers, co-expression of Eomes, T-bet and CD39 was assessed. Expression of PD-1 on CD8 and CD38 CD8 T cells correlated with pVL and CD4 count at baseline, and predicted time to the trial endpoint. Lag-3 expression was associated with pVL but not CD4 count. For all exhaustion markers, expression of CD38 on CD8 T cells increased the strength of associations. In Cox models, progression to the trial endpoint was most marked for PD-1/CD38 co-expressing cells, with evidence for a stronger effect within 12 weeks from confirmed diagnosis of PHI. The effect of PD-1 and Lag-3 expression on CD8 T cells retained statistical significance in Cox proportional hazards models including antiretroviral therapy and CD4 count, but not pVL as co-variants. Expression of 'exhaustion' or 'immune checkpoint' markers in early HIV-1 infection is associated with clinical progression and is impacted by immune activation and the duration of infection. New markers to identify exhausted T cells and novel interventions to reverse exhaustion may inform the development of novel immunotherapeutic approaches.

Immune Signatures Following Single Dose Trastuzumab Predict Pathologic Response to PreoperativeTrastuzumab and Chemotherapy in HER2-Positive Early Breast Cancer

PURPOSE

Recent data suggest that intrinsic subtype and immune cell infiltration may predict response to trastuzumab-based therapy. We studied the interaction between these factors, changes in immune signatures following brief exposure to trastuzumab, and achievement of pathologic complete response (pCR) to subsequent preoperative trastuzumab and chemotherapy in HER2-positive breast cancer.

EXPERIMENTAL DESIGN

In patients enrolled on two multicenter trials (03-311 and 211B), tumor core biopsies were obtained at baseline and after brief exposure to single-agent trastuzumab or nab-paclitaxel. Gene expression profiles were assessed to assign PAM50 subtypes, measure immune cell activation, and were correlated with response.

RESULTS

The pCR rate was significantly higher in HER2-enriched tumors in the Discovery, 03-311 (36%, P = 0.043) dataset, as compared with other subtypes, which validated in 211B (50%, P = 0.048). Significant increases in a signature of immune cell admixture (Immune Index) were observed only following brief exposure to trastuzumab in HER2-enriched tumors (Discovery/03-311, P = 0.05; Validation/211B, P = 0.02). Increased Immune Index was predictive of response after brief exposure (03-311, P = 0.03; 211B, P = 0.04), but not at baseline, in addition to increased expression of a CD4(+) follicular helper T-cell signature (03-311, P = 0.05; 211B, P = 0.04). Brief exposure to trastuzumab significantly increased gene expression of the T-cell marker PD-1 in HER2-enriched tumors (Discovery/03-311, P = 0.045) and PD-1 positivity by IHC (Validation/211B, P = 0.035).

CONCLUSIONS

Correlations between pCR rates, increases in Immune Index and markers of T-cell activity following brief exposure to trastuzumab in HER2-enriched tumors provide novel insights into the interaction between tumor biology, antitumor immunity, and response to treatment, and suggest potential clinically useful biomarkers in HER2(+) breast cancers. Clin Cancer Res; 22(13); 3249-59. ©2016 AACR.

Immunohistochemical Analysis of PD-L1 Expression in Canine Malignant Cancers and PD-1 Expression on Lymphocytes in Canine Oral Melanoma

Spontaneous cancers are common diseases in dogs. Among these, some malignant cancers such as oral melanoma, osteosarcoma, hemangiosarcoma, and mast cell tumor are often recognized as clinical problems because, despite their high frequencies, current treatments for these cancers may not always achieve satisfying outcomes. The absence of effective systemic therapies against these cancers leads researchers to investigate novel therapeutic modalities, including immunotherapy. Programmed death 1 (PD-1) is a costimulatory receptor with immunosuppressive function. When it binds its ligands, PD-ligand 1 (PD-L1) or PD-L2, PD-1 on T cells negatively regulates activating signals from the T cell receptor, resulting in the inhibition of the effector function of cytotoxic T lymphocytes. Aberrant PD-L1 expression has been reported in many human cancers and is considered an immune escape mechanism for cancers. In clinical trials, anti-PD-1 or anti-PD-L1 antibodies induced tumor regression for several malignancies, including advanced melanoma, non-small cell lung carcinoma, and renal cell carcinoma. In this study, to assess the potential of the PD-1/PD-L1 axis as a novel therapeutic target for canine cancer immunotherapy, immunohistochemical analysis of PD-L1 expression in various malignant cancers of dogs was performed. Here, we show that dog oral melanoma, osteosarcoma, hemangiosarcoma, mast cell tumor, mammary adenocarcinoma, and prostate adenocarcinoma expressed PD-L1, whereas some other types of cancer did not. In addition, PD-1 was highly expressed on tumor-infiltrating lymphocytes obtained from oral melanoma, showing that lymphocytes in this cancer type might have been functionally exhausted. These results strongly encourage the clinical application of PD-1/PD-L1 inhibitors as novel therapeutic agents against these cancers in dogs.

Do programmed death 1 (PD-1) and its ligand (PD-L1) play a role in patients with non-clear cell renal cell carcinoma?

Clinical trials targeting programmed death 1 (PD-1) and its ligand PD-L1 (PD-L1) for metastatic renal cell cancer (RCC) are ongoing. The aim of this study is to validate their roles as prognostic markers in non-clear cell (non-cc) RCC. Sixty-four non-cc RCC tissue specimens were collected from patients undergoing renal tumor surgery. Expressions of biomarkers were assessed using immunohistochemistry and compared with clinical characteristics. Survival analyses were performed with a median follow-up of 77.5 (range: 0-176) months. No significant correlations were found for PD-1(+) tumor-infiltrating mononuclear cells (TIMC) or PD-L1(+) expression and clinical attributes in patients with non-cc RCC. Kaplan-Meier analysis revealed no differences in 5- and 10-year cancer-specific survival (CSS) for PD-1(-) TIMC compared to PD-1(+) TIMC (71.4 and 63 % versus 72.2 and 61.9 %; p = 0.88). Intratumoral expression of PD-L1 did not appear to influence the 5- and 10-year CSS significantly, even though a trend was identified (68 and 53.6 % versus 80.1 and 75.7 %; p = 0.08). In multivariate analysis, neither PD-1(+) TIMC nor intratumoral PD-L1(+) expression proved to be independent predictors of CSS (p = 0.99 and p = 0.68, respectively). Our study demonstrates that PD-1(+) TIMC and intratumoral PD-L1(+) expression did not significantly impact tumor aggressiveness or clinical outcome in non-ccRCC specimens. Due to rare incidence of non-cc RCC in particular according to PD-L1 expression, further analyzes are warranted.

Programmed Cell Death Ligand 1 Expression in Canine Cancer

BACKGROUND

Antibody therapy targeting programmed cell death-1 (PD-1) and programmed cell death-ligand 1 (PD-L1) is a promising therapy in human cancer, but only limited information on PD-L1 expression in canine tumors is available.

MATERIALS AND METHODS

PD-L1 expression was examined in 31 canine tumor cell lines of various origins by flow cytometry and western blotting, and in canine tumor and normal tissue specimens by immunohistochemistry.

RESULTS

PD-L1 was only expressed on the cell surface of a small number of cell lines but was found expressed within the cells of almost all cell lines. Immunohistochemistry revealed that PD-L1 is frequently expressed in malignant melanoma, mammary gland tumor, mast cell tumor and lymphoma, but less frequently in soft-tissue sarcoma and hemangiosarcoma. PD-L1 was also expressed in some of the cells of normal canine tissue specimens.

CONCLUSION

Canine tumors with PD-L1 expression that were identified in this study are potential candidates for antiPD-1 and antiPD-L1 therapy.

Chronic mTOR inhibition in mice with rapamycin alters T, B, myeloid, and innate lymphoid cells and gut flora and prolongs life of immune-deficient mice

The mammalian (mechanistic) target of rapamycin (mTOR) regulates critical immune processes that remain incompletely defined. Interest in mTOR inhibitor drugs is heightened by recent demonstrations that the mTOR inhibitor rapamycin extends lifespan and healthspan in mice. Rapamycin or related analogues (rapalogues) also mitigate age-related debilities including increasing antigen-specific immunity, improving vaccine responses in elderly humans, and treating cancers and autoimmunity, suggesting important new clinical applications. Nonetheless, immune toxicity concerns for long-term mTOR inhibition, particularly immunosuppression, persist. Although mTOR is pivotal to fundamental, important immune pathways, little is reported on immune effects of mTOR inhibition in lifespan or healthspan extension, or with chronic mTOR inhibitor use. We comprehensively analyzed immune effects of rapamycin as used in lifespan extension studies. Gene expression profiling found many and novel changes in genes affecting differentiation, function, homeostasis, exhaustion, cell death, and inflammation in distinct T- and B-lymphocyte and myeloid cell subpopulations. Immune functions relevant to aging and inflammation, and to cancer and infections, and innate lymphoid cell effects were validated in vitro and in vivo. Rapamycin markedly prolonged lifespan and healthspan in cancer- and infection-prone mice supporting disease mitigation as a mechanism for mTOR suppression-mediated longevity extension. It modestly altered gut metagenomes, and some metagenomic effects were linked to immune outcomes. Our data show novel mTOR inhibitor immune effects meriting further studies in relation to longevity and healthspan extension.

The Association Between PD-L1 Expression and the Clinical Outcomes to Vascular Endothelial Growth Factor-Targeted Therapy in Patients With Metastatic Clear Cell Renal Cell Carcinoma

BACKGROUND

Vascular endothelial growth factor pathway (VEGF)-tyrosine kinase inhibitors (TKIs) are used as the first-line treatment for patients with metastatic clear cell renal cell carcinoma (mCCRCC). Recently, programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) blockade emerged as promising therapy for renal cell carcinoma. However, the expression pattern and prognostic implication of programmed death-ligands (PD-Ls) in mCCRCC patients receiving VEGF-TKI remain unclear.

PATIENTS AND METHODS

PD-L1 and PD-L2 expression in tumor cells and the quantities of PD-1+ tumor-infiltrating lymphocytes were immunohistochemically evaluated in 91 mCCRCC patients treated with VEGF-TKI, and their associations with VEGF-TKI responsiveness and clinical outcome were analyzed.

RESULTS

PD-L1 immunopositivity was observed in 17.6% and significantly associated with a high International Society of Urological Pathology grade (p = .031) and sarcomatoid features (p = .014). PD-L2 immunopositivity was observed in 39.6% and was not associated with any of the assessed clinicopathological variables. PD-L1-positive cases showed poor VEGF-TKI responsiveness (p = .012) compared with PD-L1-negative cases. In univariate survival analysis, PD-L1 immunopositivity was significantly associated with shorter overall survival (OS) (p = .037) and progression-free survival (PFS) (p = .043). Multivariate survival analysis revealed that PD-L1 expression was independently associated with poor OS (p = .038) and PFS (p = .013) in addition to tumor necrosis (p = .006; p = .029, respectively) and Memorial Sloan Kettering Cancer Center score (p = .018; p = .032, respectively). PD-L2 expression was neither associated with VEGF-TKI responsiveness nor patients' outcome.

CONCLUSION

PD-L1 expression was significantly related to lack of VEGF-TKI responsiveness and independently associated with shorter survival in mCCRCC patients after VEGF-TKI treatment. PD-L1 may have a predictive and prognostic value for determining the value of VEGF-TKI treatment in patients with mCCRCC.

IMPLICATIONS FOR PRACTICE

Vascular endothelial growth factor pathway (VEGF)-tyrosine kinase inhibitors (TKIs) are essential for the treatment of metastatic renal cell carcinoma patients, but the treatment suffers from a lack of predictive markers. This study demonstrates that PD-L1 expression is a predictor for unfavorable response to VEGF-TKI and a prognostic indicator for poor overall survival and progression-free survival in patients with metastatic clear cell renal cell carcinoma receiving VEGF-TKI.

Heteroclitic Peptides Increase Proliferation and Reduce Evidence of Human Immunodeficiency Virus-Specific CD8⁺ T Cell Dysfunction

Human immunodeficiency virus (HIV)-specific CD8(+) T cell dysfunction parallels disease progression; therefore, restoring potent HIV-specific CD8(+) T cell responses is a key therapeutic goal. Certain CD8(+) T cell peptide epitope variants, termed heteroclitic, enhance cytokine production by the HIV-specific CD8(+) T cells of some individuals. In this study, we investigated whether heteroclitic peptides that enhance cytokine production by HIV-specific CD8(+) T cells also reduce functional and phenotypic evidence of HIV-specific CD8(+) T cell exhaustion in those instances. Twenty-four variant peptides of human histocompatibility-linked leukocyte antigen (HLA)-A2-restricted reference HIV peptide epitopes designated as A2-7; Nef 83→91, A2-8; Nef 135→143, A2-Gag; Gag 77→85 and A2-9; Gag 433→440 were synthesized with conservative and semiconservative amino acid substitutions at positions 3, 5, and 7 or 3, 5, and 8 of Gag 433→440. Variants that enhanced interferon-gamma (IFN-γ) and/or interleukin-2 (IL-2) production in enzyme-linked immunospot assays (29 cases overall) were subsequently tested by 7-day in vitro peptide stimulation for their effects on HIV-specific CD8(+) T cell proliferation and programmed death-1 (PD-1) expression. Heteroclitic variants enhanced HIV-specific CD8(+) T cell proliferation by >20% in 13/29 cases tested, reduced PD-1 expression on proliferating cells by 15-50% in 10 cases, and reduced PD-1 expression on proliferating cells by >50% in 3 cases. In five cases, the same heteroclitic peptide increased proliferation by >20% and reduced PD-1 expression by >15%. These data demonstrate that heteroclitic peptides can alter the magnitude and character of HIV-specific CD8(+) cell responses relative to reference peptides and may have a unique immunotherapeutic value in therapeutic vaccines.

A Threshold Level of Intratumor CD8+ T-cell PD1 Expression Dictates Therapeutic Response to Anti-PD1

Despite successes, thus far, a significant proportion of the patients treated with anti-PD1 antibodies have failed to respond. We use mouse tumor models of anti-PD1 sensitivity and resistance and flow cytometry to assess tumor-infiltrating immune cells immediately after therapy. We demonstrate that the expression levels of T-cell PD1 (PD1(lo)), myeloid, and T-cell PDL1 (PDL1(hi)) in the tumor microenvironment inversely correlate and dictate the efficacy of anti-PD1 mAb and function of intratumor CD8(+) T cells. In sensitive tumors, we reveal a threshold for PD1 downregulation on tumor-infiltrating CD8(+) T cells below which the release of adaptive immune resistance is achieved. In contrast, PD1(hi) T cells in resistant tumors fail to be rescued by anti-PD1 therapy and remain dysfunctional unless intratumor PDL1(lo) immune cells are targeted. Intratumor Tregs are partly responsible for the development of anti-PD1-resistant tumors and PD1(hi) CD8(+) T cells. Our analyses provide a framework to interrogate intratumor CD8(+) T-cell PD1 and immune PDL1 levels and response in human cancer.

Expression of Programmed Death 1 Ligand in Different Compartments of Chronic Lymphocytic Leukemia

BACKGROUND

The programmed death 1 (PD-1) receptor pathway is responsible for the negative regulation of both T and B lymphocytes upon activation of these cells. There is growing evidence that chronic lymphocytic leukemia (CLL) cells exploit the PD-1 ligand (PD-L1) to resist antitumor immune reactions and maintain their survival by shaping their own microenvironment.

METHODS

We used a quantitative RT-PCR method to analyze PD-L1 gene expression in bone marrow and peripheral blood mononuclear cells, representing the proliferation and accumulation compartments of CLL.

RESULTS

PD-L1 expression was found to be significantly higher in 112 CLL patients than in controls. Levels of PD-L1 expression in bone marrow and peripheral blood were comparable and showed a positive correlation. Furthermore, expression of PDL1 strongly correlated with expression of PD-1 receptor in mononuclear cells from the same compartment, and was not affected by incubation with immunomodulatory drug thalidomide.

CONCLUSION

PD-L1 expression is shared between CLL cells localized in distinct disease compartments, demonstrating that PD-1/PD-L1 a universal target for therapy.

Impaired Phenotype and Function of T Follicular Helper Cells in HIV-1-Infected Children Receiving ART

T follicular helper (Tfh) cells are important components in development of specific humoral immune responses; whether the number and biology of Tfh cells is impaired in HIV-1-infected children is not yet studied.The frequency, phenotype, and function of Tfh cells and B cells were determined in blood of HIV-1-infected children receiving antiretroviral therapy (ART) and age-matched controls. Flow cytometry was used to characterize the frequency of Tfh cells and B cell subsets. Cytokine expression was measured after in vitro activation of Tfh cells.A reduced frequency of memory Tfh cells (P < 0.001) was identified in HIV-1-infected children and, on these cells, a reduced expression of programmed death-1 (PD-1) and inducible T cell costimulator (ICOS) (P < 0.001 and P < 0.01). Upon activation, the capacity of Tfh cells to express IL-4, an important cytokine for B cell function, was impaired in HIV-1-infected children.B cell subpopulations in HIV-1-infected children displayed significant differences from the control group: the frequency of resting memory (RM) B cells was reduced (P < 0.01) whereas the frequency of exhausted memory B cells increased (P < 0.001). Interestingly, the decline of RM cells correlated with the reduction of memory Tfh cells (P = 0.02).Our study shows that function and phenotype of Tfh cells, pivotal cells for establishment of adaptive B cell responses, are impaired during HIV-1 infection in children. A consistent reduction of memory Tfh cells is associated with declined frequencies of RM B cells, creating a novel link between dysfunctional features of these cell types, major players in establishment of humoral immunity.

TIGIT and PD-1 impair tumor antigen-specific CD8⁺ T cells in melanoma patients

T cell Ig and ITIM domain (TIGIT) is an inhibitory receptor expressed by activated T cells, Tregs, and NK cells. Here, we determined that TIGIT is upregulated on tumor antigen-specific (TA-specific) CD8⁺ T cells and CD8⁺ tumor-infiltrating lymphocytes (TILs) from patients with melanoma, and these TIGIT-expressing CD8⁺ T cells often coexpress the inhibitory receptor PD-1. Moreover, CD8⁺ TILs from patients exhibited downregulation of the costimulatory molecule CD226, which competes with TIGIT for the same ligand, supporting a TIGIT/CD226 imbalance in metastatic melanoma. TIGIT marked early T cell activation and was further upregulated by T cells upon PD-1 blockade and in dysfunctional PD-1⁺TIM-3⁺ TA-specific CD8⁺ T cells. PD-1⁺TIGIT⁺, PD-1⁻TIGIT⁺, and PD-1⁺TIGIT⁻ CD8⁺ TILs had similar functional capacities ex vivo, suggesting that TIGIT alone, or together with PD-1, is not indicative of T cell dysfunction. However, in the presence of TIGIT ligand-expressing cells, TIGIT and PD-1 blockade additively increased proliferation, cytokine production, and degranulation of both TA-specific CD8⁺ T cells and CD8⁺ TILs. Collectively, our results show that TIGIT and PD-1 regulate the expansion and function of TA-specific CD8⁺ T cells and CD8⁺ TILs in melanoma patients and suggest that dual TIGIT and PD-1 blockade should be further explored to elicit potent antitumor CD8⁺ T cell responses in patients with advanced melanoma.

Polyclonal, newly derived T cells with low expression of inhibitory molecule PD-1 in tonsils define the phenotype of lymphocytes in children with Periodic Fever, Aphtous Stomatitis, Pharyngitis and Adenitis (PFAPA) syndrome

PURPOSE

PFAPA syndrome is a benign, recurrent inflammatory disease of childhood. Tonsillectomy is one of the therapeutic options with a yet unexplained biological mechanism. We tested whether specific lymphocyte subsets recruited from blood to human tonsils participate in PFAPA pathogenesis.

METHODS

Paired tonsils/peripheral blood (PB) samples were investigated (a) from children with PFAPA that successfully resolved after tonsillectomy (n=10) (b) from children with obstructive sleep apnoea syndrome as controls (n=10). The lymphocyte profiles were analysed using 8-colour flow cytometry, immunoglobulin (IGH) and T-cell receptor (TCR) gene rearrangements via PCR and next generation sequencing; a TREC/KREC analysis was performed using qPCR.

RESULTS

The PFAPA tonsils in the asymptomatic phase had a lower percentage of B-lymphocytes than controls; T-lymphocyte counts were significantly higher in PB. The percentages of cytotoxic CD8pos T-lymphocytes were approximately 2-fold higher in PFAPA tonsils; the transitional B cells and naïve stages of both the CD4pos and CD8pos T-lymphocytes with a low expression of PD-1 molecule and high numbers of TREC were also increased. With the exception of elevated plasmablasts, no other differences were significant in PB. The expression levels of CXCL10, CXCL9 and CCL19 genes were significantly higher in PFAPA tonsils. The IGH/TCR pattern showed no clonal/oligoclonal expansion. DNA from the Epstein-Barr virus, Human Herpervirus-6 or adenovirus was detected in 7 of 10 PFAPA tonsils but also in 7 of 9 controls.

CONCLUSIONS

Our findings suggest that the uninhibited, polyclonal response of newly derived lymphocytes participate in the pathogenesis of PFAPA. Because most of the observed changes were restricted to tonsils and were not present in PB, they partly explain the therapeutic success of tonsillectomy in PFAPA syndrome.

T-bet is critical for the development of acute graft-versus-host disease through controlling T cell differentiation and function

T-bet is a master regulator for IFN-γ production and Th1 differentiation. We evaluated the roles of T-bet and IFN-γ in T cell responses in acute graft-versus-host disease (GVHD) and found that T-bet(-/-) T cells induced significantly less GVHD compared with wild-type or IFN-γ(-/-) counterparts in both MHC-mismatched and MHC-matched but minor histocompatibility Ag-mismatched models driven by CD4 T cells. T-bet(-/-), but not IFN-γ(-/-), CD4 T cells had a markedly reduced ability to cause tissue damage in liver and gut. This distinct outcome is reflected by the differential gene expression on donor CD4 T cells deficient for T-bet or IFN-γ. At mRNA and protein levels, we defined several T-bet-dependent molecules that may account for the impaired ability of T-bet(-/-) T cells to migrate into target organs and to produce Th1-related cytokines. Moreover, these molecules were independent of either endogenous IFN-γ, such as CXCR3 and programmed death-1, or systematic IFN-γ, such as NKG2D, I-A(b), and granzyme B. Although both T-bet(-/-) and IFN-γ(-/-) CD4 T cells are prone to differentiate into Th17 cells, polarized Th17 cells deficient for T-bet but not for IFN-γ had a significantly reduced ability to cause GVHD. Finally, T-bet(-/-) T cells had a compromised graft-versus-leukemia effect, which could be essentially reversed by neutralization of IL-17 in the recipients. We conclude that T-bet is required for Th1 differentiation and migration, as well as for optimal function of Th17 cells. Thus, targeting T-bet or regulating its downstream effectors independent of IFN-γ may be a promising strategy to control GVHD in the clinic.

The transcription factor FoxO1 sustains expression of the inhibitory receptor PD-1 and survival of antiviral CD8(+) T cells during chronic infection

Protein kinase B (also known as AKT) and the mechanistic target of rapamycin (mTOR) are central regulators of T cell differentiation, proliferation, metabolism, and survival. Here, we show that during chronic murine lymphocytic choriomeningitis virus infection, activation of AKT and mTOR are impaired in antiviral cytotoxic T lymphocytes (CTLs), resulting in enhanced activity of the transcription factor FoxO1. Blockade of inhibitory receptor programmed cell death protein 1 (PD-1) in vivo increased mTOR activity in virus-specific CTLs, and its therapeutic effects were abrogated by the mTOR inhibitor rapamycin. FoxO1 functioned as a transcriptional activator of PD-1 that promoted the differentiation of terminally exhausted CTLs. Importantly, FoxO1-null CTLs failed to persist and control chronic viral infection. Collectively, this study shows that CTLs adapt to persistent infection through a positive feedback pathway (PD-1?FoxO1?PD-1) that functions to both desensitize virus-specific CTLs to antigen and support their survival during chronic viral infection.

Anti-PD-1-targeted therapies focusing on lymphatic malignancies: biological rationale, clinical challenges and opportunities

Cancer immunotherapy with tumor-directed antibodies has generally been very successful, while T-cell immunotherapy has been less effective. Some lymphoid malignancies can be cured with immunochemotherapy but nevertheless many patients relapse or progress in spite of maximal therapy. Both solid tumors and lymphoid malignancies develop mechanisms in order to escape destruction by the intact immune system. One such mechanism is mediated through immune checkpoints. PD-1 (programmed cell death protein-1, which is expressed on activated T and B cells, natural killer cells and myeloid cells, is one of those checkpoints. This review focuses on the effect of PD-1 activation on lymphoid malignancies and its role as a therapeutic target.

The effect of adjuvanting cancer vaccines with herpes simplex virus glycoprotein D on melanoma-driven CD8+ T cell exhaustion

Two vaccines expressing CD4(+) and CD8(+) T cell epitopes of melanoma-associated Ags (MAAs) by a chimpanzee-derived replication-defective AdC68 vector were compared in a mouse model of melanoma. In one vaccine, termed AdC68-gDMelapoly, the epitopes were expressed as a fusion protein within HSV-1 glycoprotein D (gD), which blocks immunoinhibitory signaling through the herpes virus entry mediator pathway. The other vaccine, termed AdC68-Melapoly, expressed only the MAA epitopes. AdC68-gDMelapoly induced more potent MAA-specific CD8(+) T cell responses especially to the subdominant MAA epitopes. Upon prophylactic vaccination, mice that developed CD8(+) T cell responses to the two vaccines that were comparable in magnitude showed equal protection against tumor challenge. When mice were first challenged with tumor cells and then vaccinated results differed. In animals with comparable CD8(+) T cell responses, the AdC68-gDMelapoly vaccine was more efficacious compared with the AdC68-Melapoly vaccine in delaying tumor growth. This effect was linked to reduced expression of 2B4, LAG-3, and programmed death-1 on tumor-infiltrating MAA-specific CD8(+) T cells elicited by the gD-adjuvanted vaccine, suggesting that CD8(+) T cells induced in presence of gD are less susceptible to tumor-driven exhaustion.

Regulatory phenotype, PD-1 and TLR3 expression in T cells and monocytes from HCV patients undergoing antiviral therapy: a randomized clinical trial

BACKGROUND & AIMS

The cellular immunity has a profound impact on the status of hepatitis C virus (HCV) infection. However, the response of cellular immunity on the virological response in patients with antiviral treatment remains largely unclear. We aimed to clarify the response of peripheral T cells and monocytes in chronic hepatitis C patients with antiviral treatment.

METHODS

Patients with chronic hepatitis C were treated either with interferon alpha-2b plus ribavirin (n = 37) or with pegylated interferon alpha-2a plus ribavirin (n = 33) for up to 24 weeks. Frequencies of peripheral regulatory T-cells (Tregs), programmed death-1 (PD-1) expressing CD4+ T-cells or CD8+ T-cells and toll-like receptor (TLR) 3 expressing CD14+ monocytes were evaluated by flow cytometry in patients at baseline, 12 and 24 weeks following treatment and in 20 healthy controls.

RESULTS

Frequencies of Tregs, PD-1 and TLR3 expressing cells were higher in patients than those in control subjects (P<0.05). Patients with complete early virological response (cEVR) showed lower Tregs, PD-1 expressing CD4+ or CD8+ T-cells than those without cEVR at 12 weeks (P<0.05). Patients with low TLR3 expressing CD14+ monocytes at baseline had a high rate of cEVR (P<0.05).

CONCLUSIONS

Low peripheral TLR3 expressing CD14+ monocytes at baseline could serve as a predictor for cEVR of antiviral therapy in chronic HCV-infected patients. The cEVR rates were significantly increased in the patients with reduced circulating Tregs, PD-1 expressing CD4+ or CD8+ T-cells.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR10001090.

[Expression of programmed death-1 and programmed death ligand-1 in the peripheral T-lymphocytes from patients with chronic periodontitis]

OBJECTIVE

To investigate the expression of programmed death-1 (PD-1) and programmed death ligand-1(PD-L1) in peripheral T-lymphocytes from patients with chronic periodontitis and its significance and to clarify its role in the development of chronic periodontitis.

METHODS

A total of 73 subjects were included in the study and divided into three groups, chronic periodontitis(30 cases), chronic gingivitis(25 cases) and 18 healthy controls. The peripheral blood was collected and PD-1/PD-L1 expression in the surface of CD(+)4 T lymphocytes and CD(+)8 T lymphocytes was examined by flow cytometry. Blood samples from 16 chronic periodontitis patients were collected at week 0 and 6 after initial therapy for 6 weeks and PD-1 and PD-L1 expression in the surface of CD(+)4 and CD(+)8 T lymphocytes was also determined by flow cytometry. The data were statistically analyzed.

RESULTS

The percentage of PD-1 expression in CD(+)4 and CD(+)8 T lymphocytes of chronic periodontitis group[(16.7 ± 5.5)%,(20.8 ± 5.1)%]and chronic gingivitis group[(14.2 ± 6.1)%,(14.5 ± 4.3)%]were higher than that of healthy controls[(9.5 ± 2.1)%, (8.1 ± 1.9)%](P < 0.05). The percentage of PD-L1 expression in CD(+)4 and CD(+)8 T lymphocytes of chronic periodontitis group[(24.2 ± 7.1)%,(15.3 ± 6.8)%]and chronic gingivitis group[(12.4 ± 6.0)%,(11.2 ± 5.5)%]were higher than that of healthy controls[(4.7 ± 1.2)%, (3.2 ± 2.3)%] (P < 0.05). The percentage of PD-1/PD-L1 expression in CD(+)4 T lymphocytes and CD(+)8 T lymphocytes of the chronic periodontitis group were significantly decreased after initial therapy(P < 0.05).

CONCLUSIONS

The expression of PD-1 and PD-L1 in peripheral CD(+)4 T lymphocytes and CD(+)8 T lymphocyte of chronic periodontitis patients was up-regulated and was associated with periodontal condition. The initial therapy reduced the expression of PD-1 and PD-L1.

Immune targeting of PD-1(hi) expressing cells during and after antiretroviral therapy in SIV-infected rhesus macaques

High-level T cell expression of PD-1 during SIV infection is correlated with impaired proliferation and function. We evaluated the phenotype and distribution of T cells and Tregs during antiretroviral therapy plus PD-1 modulation (using a B7-DC-Ig fusion protein) and post-ART. Chronically SIV-infected rhesus macaques received: 11 weeks of ART (Group A); 11 weeks of ART plus B7-DC-Ig (Group B); 11 weeks of ART plus B7-DC-Ig, then 12 weeks of B7-DC-Ig alone (Group C). Continuous B7-DC-Ig treatment (Group C) decreased rebound viremia post-ART compared to pre-ART levels, associated with decreased PD-1(hi) expressing T cells and Tregs in PBMCs, and PD-1(hi) Tregs in lymph nodes. It transiently decreased expression of Ki67 and α4β7 in PBMC CD4(+) and CD8(+) Tregs for up to 8 weeks post-ART and maintained Ag-specific T-cell responses at low levels. Continued immune modulation targeting PD-1(hi) cells during and post-ART helps maintain lower viremia, keeps a favorable T cell/Treg repertoire and modulates antigen-specific responses.

PD-1-expressing tumor-infiltrating T cells are a favorable prognostic biomarker in HPV-associated head and neck cancer

Head and neck cancers positive for human papillomavirus (HPV) have a more favorable clinical outcome than HPV-negative cancers, but it is unknown why this is the case. We hypothesized that prognosis was affected by intrinsic features of HPV-infected tumor cells or differences in host immune response. In this study, we focused on a comparison of regulatory Foxp3(+) T cells and programmed death-1 (PD-1)(+) T cells in the microenvironment of tumors that were positive or negative for HPV, in two groups that were matched for various clinical and biologic parameters. HPV-positive head and neck cancers were more heavily infiltrated by regulatory T cells and PD-1(+) T cells and the levels of PD-1(+) cells were positively correlated with a favorable clinical outcome. In explaining this paradoxical result, we showed that these PD-1(+) T cells expressed activation markers and were functional after blockade of the PD-1-PD-L1 axis in vitro. Approximately 50% of PD-1(+) tumor-infiltrating T cells lacked Tim-3 expression and may indeed represent activated T cells. In mice, administration of a cancer vaccine increased PD-1 on T cells with concomitant tumor regression. In this setting, PD-1 blockade synergized with vaccine in eliciting antitumor efficacy. Our findings prompt a need to revisit the significance of PD-1-infiltrating T cells in cancer, where we suggest that PD-1 detection may reflect a previous immune response against tumors that might be reactivated by PD-1/PD-L1 blockade.