PD-1: an inhibitory immunoreceptor involved in peripheral tolerance

Clinical relevance of PD-L1 and PD-L2 overexpression in patients with esophageal squamous cell carcinoma

Background

Even with the advance of diagnosis and the treatment, the 5-year survival rate for esophageal cancer patients is still poor. The checkpoint protein inhibition provides another choice to improve the survival. The expression of the programmed death ligand-1 (PD-L1) was reported but the clinical relevance remained inconsistent in esophageal cancer. Besides, there were few references about the other ligand, programed death ligand-2 (PD-L2). In this study, we evaluated the expressions of PD-L1 and PD-L2 in patients with esophageal squamous cell carcinoma (ESCC) and assessed their clinical relevance.

Methods

From 1996 to 2011, 150 patients undergone complete surgical resection for ESCC were enrolled. Clinical data were recorded. Expression of PD-L1 and PD-L2 on cytoplasm in paraffin embedded tumor samples were analyzed by immunohistochemistry staining and scored with a semi-quantitative method.

Results

Of the patients, 96 (64.0%) patients had PD-L1 overexpression and 63 (42.0%) had PD-L2 overexpression. There was a correlation between the expression of PD-L1 and PD-L2 (P<0.001). Patients without overexpression of PD-L1, pathological T1-2 and N0 status, pathological stage I-II and no post-operative adjuvant treatment had a better disease free survival (DFS). In multivariate analysis, PD-L1 expression and pathological stage were the independent prognostic factors for DFS. The expression of PD-L2 did not influence the DFS. Although not statistically significant, patients without overexpression of PD-L1 and PD-L2 seem to have a better overall survival (OS).

Conclusions

The overexpression of PD-L1 on cytoplasm, not PD-L2, is an independent prognostic factor for DFS in patients with ESCC undergone esophagectomy. However, there is a trend which suggested that patients without overexpression of PD-L1 and PD-L2 had a better OS.

Phase 1 clinical trial evaluating abatacept in patients with steroid-refractory chronic graft-versus-host disease

Costimulatory blockade using abatacept represents a novel therapeutic approach for the treatment of cGVHD. Abatacept resulted in a clinical response in 44% of patients with both decreased prednisone use and T-cell PD-1 expression in responders.

The binding of an anti-PD-1 antibody to FcγRΙ has a profound impact on its biological functions

Antibodies targeting PD-1 have been demonstrated durable anti-cancer activity in certain cancer types. However, the anti-PD-1 antibodies are less or not efficacious in many situations, which might be attributed to co-expression of multiple inhibitory receptors or presence of immunosuppressive cells in the tumor microenvironment. Most of the anti-PD-1 antibodies used in clinical studies are of IgG4 isotype with the S228P mutation (IgG4_S228P). The functional impact by the interaction of anti-PD-1 IgG4_S228P antibody with Fc gamma receptors (FcγRs) is poorly understood. To assess the effects, we generated a pair of anti-PD-1 antibodies: BGB-A317/IgG4_S228P and BGB-A317/IgG4-variant (abbreviated as BGB-A317), with the same variable regions but two different IgG4 Fc-hinge sequences. There was no significant difference between these two antibodies in binding to PD-1. However, BGB-A317/IgG4_S228P binds to human FcγRI with high affinity and mediates crosslinking between PD-1 and FcγRI. In contrast, BGB-A317 does neither. Further cell-based assays showed that such crosslinking could reverse the function of an anti-PD-1 antibody from blocking to activating. More importantly, the crosslinking induces FcγRI⁺ macrophages to phagocytose PD-1⁺ T cells. In a mouse model transplanted with allogeneic human cancer cells and PBMCs, BGB-A317 showed significant tumor growth inhibition, whereas BGB-A317/IgG4_S228P had no such inhibition. Immunohistochemistry study revealed an inverse correlation between FcγRI⁺ murine macrophage infiltration and the density of CD8⁺PD-1⁺ human T cells within tumors in the BGB-A317/IgG4_S228P-treated group. These evidences suggested that FcγRI⁺ binding and crosslinking had negative impact on the anti-PD-1 antibody-mediated anti-cancer activity.

Gastrointestinal toxicity of immune checkpoint inhibitors: from mechanisms to management

Immune checkpoint inhibitor therapies are a novel group of monoclonal antibodies with proven effectiveness in a wide range of malignancies, including melanoma, renal cell carcinoma, non-small-cell lung cancer, urothelial carcinoma and Hodgkin lymphoma. Their use in a range of other indications, such as gastrointestinal and head and neck cancer, is currently under investigation. The number of agents included in this drug group is increasing, as is their use. Although they have the potential to improve the treatment of advanced malignancies, they are also associated with a substantial risk of immune-related adverse events. The incidence of gastrointestinal toxicity associated with their use is second only in frequency to dermatological toxicity. Thus, gastroenterologists can expect to be increasingly frequently consulted by oncologists as part of a multidisciplinary approach to managing toxicity. Here, we describe this novel group of agents and their mechanisms of action. We review the manifestations of gastrointestinal toxicity associated with their use so that it can be recognized early and diagnosed accurately. We also discuss the proposed mechanisms underlying this toxicity and describe an algorithmic and, wherever possible, evidence-based approach to its management.

ALT-803 Transiently Reduces Simian Immunodeficiency Virus Replication in the Absence of Antiretroviral Treatment

Developing biological interventions to control human immunodeficiency virus (HIV) replication in the absence of antiretroviral therapy (ART) could contribute to the development of a functional cure. As a potential alternative to ART, the interleukin-15 (IL-15) superagonist ALT-803 has been shown to boost the number and function of HIV-specific CD8⁺ T and NK cell populations in vitro Four simian immunodeficiency virus (SIV)-positive rhesus macaques, three of whom possessed major histocompatibility complex alleles associated with control of SIV and all of whom had received SIV vaccine vectors that had the potential to elicit CD8⁺ T cell responses, were given ALT-803 in three treatment cycles. The first and second cycles of treatment were separated by 2 weeks, while the third cycle was administered after a 29-week break. ALT-803 transiently elevated the total CD8⁺ effector and central memory T cell and NK cell populations in peripheral blood, while viral loads transiently decreased by ∼2 logs in all animals. Virus suppression was not sustained as T cells became less responsive to ALT-803 and waned in numbers. No effect on viral loads was observed in the second cycle of ALT-803, concurrent with downregulation of the IL-2/15 common γC and β chain receptors on both CD8⁺ T cells and NK cells. Furthermore, populations of immunosuppressive T cells increased during the second cycle of ALT-803 treatment. During the third treatment cycle, responsiveness to ALT-803 was restored. CD8⁺ T cells and NK cells increased again 3- to 5-fold, and viral loads transiently decreased again by 1 to 2 logs.IMPORTANCE Overall, our data show that ALT-803 has the potential to be used as an immunomodulatory agent to elicit effective immune control of HIV/SIV replication. We identify mechanisms to explain why virus control is transient, so that this model can be used to define a clinically appropriate treatment regimen.

PD-L1 expression in colorectal cancer defines three subsets of tumor immune microenvironments

Objectives

We investigated the PD-L1 expression in colorectal cancer (CRC) and in its microenvironment.

Results

PD-L1 was expressed in neoplastic cells (NCs) and tumor-infiltrating immune cells (IICs). All samples PD-L1+ on NCs were also on IICs. Three types of cancers could be grouped: group A(NCs-/ IICs-); group B (NCs-/ IICs+); group C (NCs+/IICs+). To group A belong tumors characterized by poorly immunogenic competence, poor immune response but massive granulocyte infiltrate, justifying the absence of PD-L1 as an immunoinhibitor receptor. To Group B probably belong more immunogenic CRCs, justifying the strong IICs-mediated immune response, and up-regulation of PD-L1 expression only on IICs. To group C belong CRCs probably characterized by a large amount of tumor neoantigens resulting in a marked infiltration of lymphocytes and PD-L1 upregulation also in NCs.

Materials and Methods

Sixty-three colorectal cancer specimens from a cohort of 61 patients were retrospectively reviewed. Thirty-seven MSS and 26 MSI-H CRCs enrolled in this study. Immunohistochemical staining to PD-L1 was performed by using MAb E1L3N.

Conclusions

Our study calls attention to the importance to assess PD-L1 expression in tumor microenvironment also evaluating type and density of infiltrating immune cells to better stratify CRCs with different immunological patterns.

Evaluation of programmed cell death protein 1 (PD-1) expression as a prognostic biomarker in patients with clear cell renal cell carcinoma

Programmed cell death protein 1 (PD-1) immune checkpoint inhibitors have shown activity in patients with advanced renal cell carcinoma (RCC). However, the role of PD-1 expression in tumor-infiltrating lymphocytes (TILs) as a biomarker for poor outcome is not clear. In this study, we evaluated the prognostic value of TIL PD-1 expression in patients with clear cell RCC (ccRCC). 82 patients who underwent nephrectomy for localized or metastatic ccRCC and followed up for at least four years were searched from our database and retrospectively enrolled. Their fixed primary tumor specimens were stained with anti-PD-1 (NAT105). The specimens were classified as negative or positive for PD-1 expression, and the positive specimens were further scored in 10% increments. 37 (45.12%) patients were negative (<1% stained), 26 (31.71%) patients were low (<10 and 10%), and 19 (23.17%) patients were high (20-50%) for PD-1 expression. The prognostic value of TIL PD-1 expression was evaluated by univariate Cox proportional hazards regression on overall and recurrence-free survivals. Higher TIL PD-1 expression was not associated with increased risk of death (P = 0.336) or with increased risk of recurrence (P = 0.572). Higher primary tumor stage was associated with increased risk of recurrence (P = 0.003), and higher Fuhrman nuclear grade was associated with increased risk of death (P <0.001) and with increased risk of recurrence (P <0.001). Our study shows that TIL PD-1 expression by immunohistochemistry (IHC) does not correlate with poor clinical outcome in patients with ccRCC and is inferior to established prognosticating tools.

Cancer immunotherapy-induced endocrinopathies: Clinical behavior and therapeutic approach

Cancer immunotherapy has proven to be effective in a wide variety of tumors. The use of immune checkpoint blocking monoclonal antibodies has become a standard treatment regimen in some of them as advanced melanoma. However, given the mechanism of action, its use may be associated with immune-related adverse events that may complicate the clinical course and prognosis of patients. Among these are autoimmune endocrine adverse effects, such as hypophysitis, hypo and hyperthyroidism, and adrenal insufficiency. This review focuses on the most relevant and new aspects related to the incidence, clinical presentation, diagnosis and treatment of these adverse effects associated with different types of immune checkpoint inhibitors in cancer immunotherapy.

The role of macrophage phenotype in regulating the response to radiation therapy

Increasing experimental and clinical evidence has revealed a critical role for myeloid cells in the development and progression of cancer. The ability of monocytes and macrophages to regulate inflammation allows them to manipulate the tumor microenvironment to support the growth and development of malignant cells. Recent studies have shown that macrophages can exist in several functional states depending on the microenvironment they encounter in the tissue. These functional phenotypes influence not only the genesis and propagation of tumors, but also the efficacy of cancer therapies, particularly radiation. Early classification of the macrophage phenotypes, or "polarization states," identified 2 major states, M1 and M2, that have cytotoxic and wound repair capacity, respectively. In the context of tumors, classically activated or M1 macrophages driven by interferon-gamma support antitumor immunity while alternatively activated or M2 macrophages generated in part from interleukin-4 exposure hinder antitumor immunity by suppressing cytotoxic responses against a tumor. In this review, we discuss the role that the functional phenotype of a macrophage population plays in tumor development. We will then focus specifically on how macrophages and myeloid cells regulate the tumor response to radiation therapy.

Histopathological and genotypic characterization of metastatic colorectal carcinoma with PD-L1 (CD274)-expression: Possible roles of tumour micro environmental factors for CD274 expression

Aberrant PD-L1 (CD274) expression has been described in different types of tumour and linked to tumour aggressiveness and a poor prognosis. In primary colorectal carcinomas (CRCs), CD274 expression was reported to be associated with mismatch repair (MMR)-deficiency, BRAF mutation, and "stem-like" immunophenotype defined by down-regulation of homeobox protein CDX2 and membranous expression of activated leukocyte cell adhesion molecule (ALCAM). However, the immunophenotype and genotype of CD274-positive metastatic CRC have not been extensively analysed. In this study, 189 CRC metastases were evaluated immunohistochemically for CD274, MMR proteins, CDX2, and ALCAM expression. Immunostaining for CD4, CD8, and FOXP3 was also performed to characterize tumour-associated immune cells. In addition, 34 arbitrarily selected lesions were genotyped using Sanger- and next-generation sequencing. Univariate analyses showed no clear association between CD274 expression and clinicopathological parameters including MMR-deficiency or "stem-like" immunophenotype after adjustment for multiple testing. Comparison of the clinicopathological profiles of CD274-positive primary and metastatic tumours revealed in the latter younger age of occurrence (60.9 ± 13.3 versus 72.6 ± 13.1 years, p = 0.001), cytoplasm-dominant CD274 expression (p < 0.001), infrequent MMR-deficiency (p < 0.001), and common KRAS mutations (54%, p < 0.001). In five cultured colon cancer cell lines, CD274 was expressed and modulated after exogenous exposure to IFNγ and TGF-β1. Thus, CD274 regulation mechanisms might include tumour micro environmental factors. Based on significantly different characteristics in CD274-positive metastatic and primary CRCs, evaluation of metastases should also be considered when planning immune checkpoint inhibitor therapy.

Isolated Adrenocorticotropic Hormone Deficiency Caused by Nivolumab in a Patient with Metastatic Lung Cancer

Nivolumab has promising efficacy for treating various advanced malignant tumors, although it has been reported to induce a wide range of autoimmune adverse effects. We herein report the case of a patient with metastatic lung adenocarcinoma who developed adrenal insufficiency after 12 cycles of nivolumab treatment. Endocrine test results supported a diagnosis of isolated adrenocorticotropic hormone deficiency due to hypophysitis, and replacement therapy using hydrocortisone has been successful. Although hypophysitis is a rare immune-related adverse event that is associated with nivolumab therapy, clinical awareness is essential, as this condition can be life-threatening and requires prompt treatment.

Current prospects of type II interferon γ signaling and autoimmunity

Interferon γ (IFNγ) is a pleiotropic protein secreted by immune cells. IFNγ signals through the IFNγ receptor, a protein complex that mediates downstream signaling events. Studies into IFNγ signaling have provided insight into the general concepts of receptor signaling, receptor internalization, regulation of distinct signaling pathways, and transcriptional regulation. Although IFNγ is the central mediator of the adaptive immune response to pathogens, it has been shown to be involved in several non-infectious physiological processes. This review will provide an introduction into IFNγ signaling biology and the functional roles of IFNγ in the autoimmune response.

Correlating programmed death ligand 1 (PD-L1) expression, mismatch repair deficiency, and outcomes across tumor types: implications for immunotherapy

The identification of biomarkers associated with response to therapeutic agents is central to optimizing patient outcomes. Expression of the immune checkpoint proteins PD-1/L1, and DNA mismatch repair deficiency (dMMR) status may be predictive response biomarkers for immunotherapies, but their overlap requires further study. We prospectively conducted PD-L1 and MMR immunohistochemistry (IHC) on 430 consecutive patients with advanced gastrointestinal (GI) cancers, genitourinary (GU) cancers or rare cancers between June 2012 and March 2016. Overall 393/430 (91.4%) patients were evaluable for PD-L1 expression by IHC. The frequency of tumor PD-L1 positivity (PD-L1+) was 16.5% (65/393). Among anatomic tumor sites PD-L1+ was 28.6% in melanoma, 22.2% in GC, 20.9% in CRC, 12.5% in BTC, 7.1% in GU cancer, 6.7% in HCC, 0% in pancreatic cancer and 0% in sarcoma. Among the 394 evaluable for MLH1/MSH2 expression cases, 18 patients (4.5%) had dMMR tumors. The dMMR was most common in GC (7.1%) followed by 6.7% in HCC, 4.4% in CRC, and 2.7% in sarcoma. Of the 365 patients evaluable for both PD-L1 and MLH1/MSH2 expression, there was a significant association between the PD-L1 expression and MLH1/MSH2 loss (P = 0.01), but not with overall survival within tumor types. PD-L1 status and dMMR are overlapping putative response biomarkers in immunoncology. Clinical trials with biomarker enrichment restricted to PD-L1+ or dMMR may be inadequate to capture the subset of patients who may benefit from immune mediated therapies. More robust immunotherapy biomarkers and careful clinical trial design are warranted.

Expression of ALCAM (CD166) and PD-L1 (CD274) independently predicts shorter survival in malignant pleural mesothelioma

Diffuse malignant mesothelioma of the pleura is a highly aggressive tumor typically associated with short survival. ALCAM (CD166), a type I transmembrane protein, is a member of the immunoglobulin superfamily. In normal cells, ALCAM regulates physiological processes such as angiogenesis and immune response. In cancer, it is associated with neoplastic progression, including invasion, migration, and metastasis. Furthermore, ALCAM is considered one of the cancer stem cell markers such as ALDH1 (ALDH1A1) and SALL4. The PD-L1 (CD274)/PD-1 (PDCD1, CD279) pathway is crucial for the modulation of immune responses in normal cells. Nevertheless, pathologic activation of the PD-L1/PD-1 pathway participates in immune evasion by tumor cells. Many PD-L1-expressing tumor cells have been identified in different types of cancer, including malignant mesothelioma. In this study, 175 well-characterized primary diffuse pleural mesotheliomas, including the epithelioid (n = 148), biphasic (n = 15), and sarcomatoid (n = 12) histotypes, were evaluated immunohistochemically for cancer stem cell markers (ALCAM, ALDH1, and SALL4) and PD-L1 expression. Twenty-five percent of the mesotheliomas (43/175) expressed ALCAM, whereas ALDH1 and SALL4 positivity was seen in 1% to 2% of cases. Thirty-three percent of the analyzed tumors (57/175) contained PD-L1-positive cells. Overall survival was significantly decreased in the cohort of patients with ALCAM- or PD-L1-positive tumors (both P < .01). Furthermore, the multivariate Cox hazards regression analysis identified ALCAM and PD-L1 (both P < 0.01) as potential independent risk factors. Thus, a combination of these 2 markers might be useful for prognostication and planning the treatment of patients with malignant pleural mesothelioma.

Comprehensive Immunohistochemical Study of Programmed Cell Death Ligand 1 (PD-L1): Analysis in 5536 Cases Revealed Consistent Expression in Trophoblastic Tumors

Programmed cell death 1/programmed cell death ligand (PD-1/PD-Ls) axis is crucial for the modulation of immune responses and self-tolerance. Also, aberrant PD-L1 expression on the tumor cells or tumor-associated inflammatory cells accelerates immune evasion of tumor cells. In the past decade, PD-1/PD-L immune checkpoint inhibitors were introduced to cancer treatment trials and, in some cases, showed significant anticancer effects. PD-L1 immunohistochemical staining is considered a potential predictor of clinical response to PD-1/PD-L immune checkpoint inhibitor treatment. However, immunohistochemical data on PD-L1 expression in different types of cancer especially rare entities remain incomplete. In this study, PD-L1 expression was immunohistochemically analyzed in 5536 tumors including germ cell, epithelial, mesenchymal, melanocytic/neuroectodermal, and lymphohematopoietic tumors, as well as in a set of human normal tissues including a fetus. Immunohistochemical analysis was performed with E1L3N rabbit monoclonal antibody and Leica Bond Max automation using multitumor blocks containing up to 70 tumor samples. PD-L1 was constitutively and strongly expressed in placental trophoblasts as well as choriocarcinomas and trophoblastic components of germ cell tumors. Also, the neoplastic cells of classical Hodgkin lymphoma, anaplastic large cell lymphoma, schwannoma, thymoma, and squamous cell carcinoma of various sites frequently expressed PD-L1. In gastrointestinal adenocarcinomas, PD-L1-expression was associated with EBER positivity and mismatch-repair deficiency. In addition, PD-L1 was variably expressed in non-neoplastic macrophages and dendritic cells. PD-L1 immunohistochemistry may have some role in the immunophenotypic differential diagnosis of tumors and pinpointing potential candidates for anti-PD-1/PD-L immune checkpoint therapy.

Tumor location impacts immune response in mouse models of colon cancer

Existing preclinical models of human colorectal cancer (CRC) that rely on syngeneic subcutaneous grafts are problematic, because of increasing evidence that the immune microenvironment in subcutaneous tissue is significantly different from the gastrointestinal tract. Similarly, existing orthotopic models that use a laparotomy for establishing grafts are also problematic, because the surgical procedure results in extensive inflammation, thereby creating a nonphysiologic tumor microenvironment. To facilitate the bench-to-bedside translation of CRC immunotherapy strategies, we developed a novel orthotopic model in mice that uses endoscopy-guided microinjection of syngeneic cancer cells. When we compared immune system infiltration, we found that tumors in the subcutaneous model had fewer T cells, B cells, and natural killer (NK) cells, but more immunosuppressive myeloid cells; in contrast, tumors in our orthotopic model had a higher number of tumor-infiltrating T cells, B cells, and NK cells, with fewer immunosuppressive myeloid cells. The number of immune-stimulating cytokines, such as interleukin (IL)-2, IL-6, interferon (IFN)-gamma, and granzyme B, was also higher in tumors in our model, as compared with the subcutaneous model. Those differences resulted in heightened sensitivity to immune checkpoint blockade therapy in our endoscopy-guided orthotopic CRC model. Our study indicates that tumor location affects immune response in CRC mouse models; choosing the appropriate preclinical model is important when testing immunotherapy in CRC.

Expression of immunoregulatory molecules PD-L1 and PD-1 in oral cancer and precancerous lesions: A cohort study of Japanese patients

OBJECTIVE

An association of the programmed cell death-1 (PD-1) and its ligand PD-L1 with various types of malignant tumors has been established. This study aimed to investigate the role of the PD-L1/PD-1 pathway in oral squamous cell carcinoma (OSCC) and oral epithelial precursor lesions (OEPL).

MATERIALS AND METHODS

We examined 106 OSCC and 79 OEPL specimens for PD-L1 and PD-1 expression by immunohistochemistry. The results were compared with clinicopathological features of OSCC patients.

RESULTS

In OSCC and OEPL specimens, PD-L1 expression was detected predominantly in epithelial or carcinoma cells, whereas PD-1 expression was found mainly in infiltrating or stromal lymphocytes. Seventy-two OSCC (67.9%) and 21 OEPL (26.6%) specimens were positive for PD-L1, and 73 OSCC (68.9%) and 23 OEPL (29.2%) specimens were positive for PD-1. PD-L1 and PD-1 expression levels were significantly different between OEPL and OSCC specimens (P < 0.001). There were significant positive correlations between PD-L1 and PD-1 expression in OEPL and OSCC specimens (P < 0.001). PD-L1 and PD-1 immunoreactivity was significantly associated with tumor size (P < 0.05). PD-L1 and PD-1 immunoreactivity in cases with advanced TNM staging was significantly higher than that in low staging cases (P < 0.01). There were significant correlations between PD-L1 and PD-1 expression in OSCC specimens and pathological variables such as stromal lymphocytic reaction (P < 0.05) and invasion depth (P < 0.01).

CONCLUSION

PD-L1 and PD-1 immunohistochemical status may be related to carcinogenesis, tumor progression, and prognosis in oral epithelial lesions. Agents targeting PD-1 and PD-L1 might be useful for OSCC treatment.

Neuronal IFN-beta-induced PI3K/Akt-FoxA1 signalling is essential for generation of FoxA1+Treg cells

Neurons reprogramme encephalitogenic T cells (T_enc) to regulatory T cells (T_regs), either FoxP3⁺T_regs or FoxA1⁺T_regs. We reported previously that neuronal ability to generate FoxA1⁺T_regs was central to preventing neuroinflammation in experimental autoimmune encephalomyelitis (EAE). Mice lacking interferon (IFN)-β were defective in generating FoxA1⁺T_regs in the brain. Here we show that lack of neuronal IFNβ signalling is associated with the absence of programme death ligand-1 (PDL1), which prevents their ability to reprogramme T_enc cells to FoxA1⁺T_regs. Passive transfer-EAE via IFNβ-competent T_enc cells to mice lacking IFNβ and active induced-EAE in mice lacking its receptor, IFNAR, in the brain (Nes^Cre:Ifnar^fl/fl) result in defective FoxA1⁺T_regs generation and aggravated neuroinflammation. IFNβ activates neuronal PI3K/Akt signalling and Akt binds to transcription factor FoxA1 that translocates to the nucleus and induces PDL1. Conversely, inhibition of PI3K/Akt, FoxA1 and PDL1 blocked neuronal ability to generate FoxA1⁺T_regs. We characterize molecular factors central for neuronal ability to reprogramme pathogenic T cells to FoxA1⁺T_regs preventing neuroinflammation.

A systems biology approach to investigating the influence of exercise and fitness on the composition of leukocytes in peripheral blood

BACKGROUND

Exercise immunology has become a growing field in the past 20 years, with an emphasis on understanding how different forms of exercise affect immune function. Mechanistic studies are beginning to shed light on how exercise may impair the development of cancer or be used to augment cancer treatment. The beneficial effects of exercise on the immune system may be exploited to improve patient responses to cancer immunotherapy.

METHODS

We investigated the effects of acute exercise on the composition of peripheral blood leukocytes over time in a male population of varying fitness. Subjects performed a brief maximal intensity cycling regimen and a longer less intense cycling regimen at separate visits. Leukocytes were measured by multi-parameter flow cytometry of more than 50 immunophenotypes for each collection sample.

RESULTS

We found a differential induction of leukocytosis dependent on exercise intensity and duration. Cytotoxic natural killer cells demonstrated the greatest increase (average of 5.6 fold) immediately post-maximal exercise whereas CD15⁺ granulocytes demonstrated the largest increase at 3 h post-maximal exercise (1.6 fold). The longer, less intense endurance exercise resulted in an attenuated leukocytosis. Induction of leukocytosis did not differ in our limited study of active (n = 10) and sedentary (n = 5) subjects to exercise although we found that in baseline samples, sedentary individuals had elevated percentages of CD45RO⁺ memory CD4⁺ T cells and elevated proportions of CD4⁺ T cells expressing the negative immune regulator programmed death-1 (PD-1). Finally, we identified several leukocytes whose presence correlated with obesity related fitness parameters.

CONCLUSIONS

Our data suggests that leukocytes subsets are differentially mobilized into the peripheral blood and dependent on the intensity and duration of exercise. Pre-existing compositional differences of leukocytes were associated with various fitness parameters.

Serum sPD-L1, Upregulated in Sepsis, May Reflect Disease Severity and Clinical Outcomes in Septic Patients

We aimed to find the correlation between serum sPD-L1 (soluble programmed cell death L-1 ligand) and sepsis. Totally 91 consecutive patients with sepsis were performed in a 15-bed medical intensive care unit (ICU) of the second affiliated hospital, Xi'an Jiaotong University in Xi'an, China, between February 2015 and May 2016. Healthy controls (HC) consisted of 29 healthy volunteer. Baseline demographic data were recorded. Blood samples were collected through an indwelling central venous or by peripheral venipuncture. Serum sPD-L1 and sPD-1 levels were determined with enzyme-linked immunosorbent assay kits (Elabscience Biotechnology Co. Ltd, Wuhan, China). SPSS19.0 software (SPSS Inc., Chicago, Illinois, USA) was used for statistical analysis. Kaplan-Meier survival analysis and Cox regression analysis were also performed. Serum sPD-L1 levels and sPD-1 levels were significantly increased in septic patients compared with HC (P = 0.000). Serum sPD-L1 levels were significantly increased in non-survivors compared with survivors (P < 0.05), but there was no statistically difference on serum sPD-1 levels between non-survivors and survivors (P > 0.05). Serum sPD-L1 levels were correlated with absolute lymphocyte (ALC), platelets and SOFA scores. Serum sPD-L1/sPD-1 levels were negatively correlated with ALC and platelets, and SOFA scores. The prognostic accuracy of the sPD-L1 level to predict 28-day mortality was similar to that of the APACHE-II scores and SOFA scores. Cox regression analysis showed that sPD-L1 was an independent prognostic factor. Serum sPD-L1 is upregulated in sepsis and may reflect disease severity and clinical outcomes in patients. Serum sPD-L1 may be an independent prognostic factor for sepsis.

PD-1 inhibitors increase the incidence and risk of pneumonitis in cancer patients in a dose-independent manner: a meta-analysis

Therapies that targeted PD-1 have shown remarkable rates of durable clinical responses in patients with various tumor types. However, the extent and knowledge of pulmonary toxicities associated with PD-1 blockade, mainly manifested as pneumonitis, remains obscure. In this study, a total of 6360 subjects from 16 phase II/III clinical trials were pooled for meta-analysis to evaluate the overall incidence and risk of PD-1 inhibitors-related pneumonitis in cancer patients. The incidence of pneumonitis during anti-PD-1 immunotherapy was 2.92% (95%CI: 2.18–3.90%) for all-grade and 1.53% (95%CI: 1.15–2.04%) for high-grade pneumonitis. Compared with routine chemotherapy, PD-1 inhibitors were associated with a significant increased risk of pneumonitis. Moreover, among the types of tumor treated with PD-1 inhibitors, the melanoma patients have the lowest incidence of pneumonitis, while the non-small cell lung cancer (NSCLC) and renal cell carcinoma (RCC) patients have the highest. Furthermore, no significant differences were detected in the incidences of all- and high-grade pneumonitis between high-dose and low-dose groups of PD-1 inhibitors. In conclusion, PD-1 inhibitors were probably associated with an increased risk of pneumonitis in a dose-independent manner, compared with routine chemotherapeutic agents. The frequency and severity of treatment-mediated pneumonitis was quite different in patients with various tumor types.

Clinicopathologic profile, immunophenotype, and genotype of CD274 (PD-L1)-positive colorectal carcinomas

The CD274 (PD-L1)/PDCD1 (PD-1) pathway is crucial for the modulation of immune responses and self-tolerance. Aberrantly expressed CD274 allows tumor cells to evade host immune system and is considered to be a mechanism of adaptive immune resistance. Inhibition of the CD274/PDCD1 immune checkpoint offers a promising new therapeutic strategy. Although CD274-expressing tumor cells have been identified in different types of tumors including colorectal cancer, clinicopathologic profile of these CD274-positive tumors has not been extensively studied. In this study, 454 primary colorectal carcinomas were analyzed histologically and immunohistochemically for CD274, mismatch repair (MMR) proteins, intestinal differentiation marker (CDX2), and stem cell markers (ALCAM, ALDH1A1, and SALL4). CD274-positive colorectal carcinomas (54/454 (12%)) usually (83%) involved the right or transverse colon with poorly differentiated and solid/medullary histology. On the basis of multivariate logistic regression analysis, CD274 positivity was significantly associated with poorly differentiated histotype (OR: 3.32; 95% CI: 1.46-7.51; P=0.004), MMR deficiency (OR: 10.0; 95% CI: 4.66-21.5; P<0.001), and 'stem-like' immunophenotype defined by the loss or weak expression of CDX2 and ALCAM-positivity (OR: 5.51; 95% CI: 1.66-18.3; P=0.005). Mutation analysis of 66 arbitrary selected colorectal carcinomas revealed that CD274-positive tumors usually (88%) carried the BRAF V600E mutation. Thus, colorectal carcinomas defined by CD274 positivity displayed features associated with tumors arising via the serrated neoplasia pathway. Moreover, colorectal carcinomas characterized by lack of CDX2 and prominent expression of ALCAM frequently (71%) showed CD274 positivity. This might suggest association of CD274 expression with 'stem-like' phenotype. Further evaluation of a larger cohort or experimental analyses would be needed to confirm this notion.

Immunoinhibitory checkpoint deficiency in medium and large vessel vasculitis

Giant cell arteritis (GCA) causes autoimmune inflammation of the aorta and its large branches, resulting in aortic arch syndrome, blindness, and stroke. CD4⁺ T cells and macrophages form organized granulomatous lesions in the walls of affected arteries, destroy the tunica media, and induce ischemic organ damage through rapid intimal hyperplasia and luminal occlusion. Pathogenic mechanisms remain insufficiently understood; specifically, it is unknown whether the unopposed activation of the immune system is because of deficiency of immunoinhibitory checkpoints. Transcriptome analysis of GCA-affected temporal arteries revealed low expression of the coinhibitory ligand programmed death ligand-1 (PD-L1) concurrent with enrichment of the programmed death-1 (PD-1) receptor. Tissue-residing and ex vivo-generated dendritic cells (DC) from GCA patients were PD-L1^lo, whereas the majority of vasculitic T cells expressed PD-1, suggesting inefficiency of the immunoprotective PD-1/PD-L1 immune checkpoint. DC-PD-L1 expression correlated inversely with clinical disease activity. In human artery-SCID chimeras, PD-1 blockade exacerbated vascular inflammation, enriched for PD-1⁺ effector T cells, and amplified tissue production of multiple T-cell effector cytokines, including IFN-γ, IL-17, and IL-21. Arteries infiltrated by PD-1⁺ effector T cells developed microvascular neoangiogenesis as well as hyperplasia of the intimal layer, implicating T cells in the maladaptive behavior of vessel wall endogenous cells. Thus, in GCA, a breakdown of the tissue-protective PD1/PD-L1 checkpoint unleashes vasculitic immunity and regulates the pathogenic remodeling of the inflamed arterial wall.

Checkpoint Proteins in Pediatric Brain and Extracranial Solid Tumors: Opportunities for Immunotherapy

Pediatric brain and extracranial solid tumors are a diverse group of malignancies that represent almost half of all pediatric cancers. Standard therapy includes various combinations of surgery, cytotoxic chemotherapy, and radiation, which can be very harmful to a developing child, and survivors carry a substantial burden of long-term morbidities. Although these therapies have improved survival rates for children with solid tumors, outcomes still remain extremely poor for subsets of patients. Recently, immunosuppressive checkpoint molecules that negatively regulate immune cell function have been described. When found on malignant cells or in the tumor microenvironment, they contribute to immune evasion and tumor escape. Agents designed to inhibit these proteins have demonstrated significant efficacy in human adult solid tumor studies. However, there is limited research focusing on immune checkpoint molecules and inhibitors in pediatric solid tumors. In this review, we examine the current knowledge on immune checkpoint proteins with an emphasis on cytotoxic T lymphocyte antigen-4 (CTLA-4); programmed cell death protein-1 (PD-1) and programmed death-ligand 1 (PD-L1); OX-2 membrane glycoprotein (CD200); and indoleamine 2,3-dioxygenase (IDO). We review T-cell signaling, the mechanisms of action of these checkpoint molecules, pediatric preclinical studies on checkpoint proteins and checkpoint blockade, pediatric checkpoint inhibitor clinical trials conducted to date, and future immunotherapy opportunities for childhood cancers. Clin Cancer Res; 23(2); 342-50. ©2016 AACR.

Current Status of Immunotherapy Treatments for Pancreatic Cancer

Pancreatic cancer (PC) is a lethal disease representing the seventh most frequent cause of death from cancer worldwide. Resistance of pancreatic tumors to current treatments leads to disappointing survival rates, and more specific and effective therapies are urgently needed. In recent years, immunotherapy has been proposed as a promising approach to the treatment of PC, and encouraging results have been published by various preclinical and clinical studies. This review provides an overview of the latest developments in the immunotherapeutic treatment of PC and summarizes the most recent and important clinical trials.

Nivolumab-induced hypophysitis in a patient with advanced malignant melanoma

The anti-programmed cell death-1 monoclonal antibody (mab), nivolumab has recently been approved for the treatment of unresectable or metastatic malignant melanoma and non-small-cell lung cancers in Japan. Ipilimumab, an anti-cytotoxic T lymphocyte antigen-4 mab for malignant melanoma that was approved earlier than nivolumab in Western countries, is known to frequently cause endocrine immune-related adverse events such as hypophysitis and thyroid dysfunction. We herein report a patient with advanced melanoma who appeared to develop hypophysitis as a consequence of the inhibition of PD-1 by nivolumab. One week after the 6^th administration of nivolumab, the patient developed progressive fatigue and appetite loss. Laboratory data on admission for the 7^th administration of nivolumab showed eosinophilia and hyponatremia. Since ACTH and cortisol levels were low, nivolumab was discontinued and a large dose of hydrocortisone (100 mg/d) was promptly administered intravenously. A magnetic resonance imaging scan revealed the mild enlargement of the anterior pituitary gland and thickening of the stalk with homogenous contrast. A detailed assessment of anterior pituitary functions with hypothalamic hormone challenges showed that hormonal secretions other than ACTH and TSH were normal. With a replacement dose of hydrocortisone (20 mg/d), the 7^th administration of nivolumab was completed without exacerbating the patient's general condition. The present report provides the first detailed endocrinological presentation of nivolumab-induced hypophysitis showing the enlargement of the pituitary gland and stalk in a malignant melanoma patient in Japan. Oncologists and endocrinologists need to be familiar with potentially life-threatening hypophysitis induced by immune-checkpoint inhibitors.

Positive PD-L1 Expression Predicts Worse Outcome in Cutaneous Angiosarcoma

Purpose

Programmed death-1 (PD-1) or programmed death ligand-1 (PD-L1) targeted therapies have shown promising survival outcomes in several human neoplasms. However, it is unclear whether the expression of PD-L1 can be correlated to any clinical and pathologic variables in patients with cutaneous angiosarcoma (CA). The aim of this study was to evaluate the clinicopathological significance of PD-L1 expression in CA patients.

Materials and Methods

Data from 52 patients with CA were retrospectively reviewed. PD-L1 expression, tumor proliferation determined by Ki-67 index, and immunohistochemical evaluation of tumor-infiltrating lymphocytes, CD4+ and CD8+, were used to determine correlation with clinicopathological variables.

Results

PD-L1 was positively expressed in 40% of all patients. PD-L1 expression was significantly associated with tumor cell proliferation. Multivariate analysis confirmed that high levels of CD8+ tumor-infiltrating lymphocytes were a significant predictor in patients with clinical stage I CA and the positive expression of PD-L1 was an independent prognostic factor in predicting worse outcome.

Conclusion

PD-L1 expression is a novel pathologic marker for predicting worse outcome in patients with CA.

Role of B7-H1 in gastrointestinal cancer

Immune evasion is a hallmark of cancer. Although cancer cells have been shown to be able to be recognized by T cells, host immune system fails to develop effective antitumor activity and tumor control. B7-H1, an immune inhibitory molecule, plays an important role in the immune evasion process. B7-H1 inhibits T cell immunity during immune priming and effector phases and is also implicated in intrinsic proliferation, apoptosis and migration of tumor cells. Targeting B7-H1 using blockade antibodies has generated immense antitumor activity in preclinical tumor models. Durable response for a variety of tumor types was also documented in clinical trials. Thus, B7-H1 targeted immune therapy offers a new line of tumor treatment. Gastrointestinal cancer is one of the leading causes of tumor morbidity. However, traditional therapy has not been able to effectively improve survival. This review will focus on the role of B7-H1 in immune evasion and the latest progression of the B7-H1 blockade immune therapy in gastrointestinal cancer.

Association of programmed death-1 polymorphisms with the risk and prognosis of esophageal squamous cell carcinoma

Programmed death-1 (PD-1) is an immunoinhibitory receptor belonging to the CD28 family. This study was designed to investigate the association of PD-1 rs36084323:A>G, rs2227981:C>T, rs2227982:C>T and rs10204525:A>G single nucleotide polymorphisms (SNPs) with the risk and prognosis of esophageal squamous cell carcinoma (ESCC) in a high-incidence population from Northern China. These four SNPs were genotyped by polymerase chain reaction ligase detection reaction (PCR-LDR) method in 584 ESCC patients and 585 healthy controls. The rs2227981:C>T SNP C/T genotype increased the risk of ESCC for the smokers (OR = 1.483, 95% CI = 1.018-2.160) and rs2227982:C>T SNP C/T genotype enhanced susceptibility to ESCC for the females (OR = 1.708, 95% CI = 1.056-2.762). For rs10204525:A>G SNP, A/A genotype was related to increased risk of ESCC (OR = 1.735, 95% CI = 1.086-2.771) overall. Among the 584 ESCC patients, the survival information of 204 ESCC patients was collected. The rs36084323:A>G SNP A/G genotype was associated with lower risk of death in ESCC patients with upper gastrointestinal cancer (UGIC) family history (HR = 0.339, 95%CI = 0.115-0.996). The rs2227982:C>T SNP C/T genotype was associated with lower risk of death in smoker ESCC patients and ESCC patients with UGIC family history (HR = 0.409 and 0.292, 95%CI = 0.194-0.863 and 0.101-0.847). PD-1 rs2227981:C>T, rs2227982:C>T and rs10204525:A>G SNPs might be used as predictive markers of the susceptibility to ESCC for the Han nationality in a high-incidence population from Northern China. PD-1 rs36084323:A>G and rs2227982:C>T SNPs were associated with the prognosis of the Han ESCC patients in this high-incidence region.

The association between PD-L1 and EGFR status and the prognostic value of PD-L1 in advanced non-small cell lung cancer patients treated with EGFR-TKIs

Backgrounds

Recent clinical trials have shown that immune-checkpoint blockade yields remarkable response in a subset of non–small cell lung cancer (NSCLC) patients. However, few studies directly focus on the association between epidermal growth factor receptor (EGFR) mutational status and programmed cell death-ligand 1 (PD-L1) expression. We examined whether PD-L1 is related to clinicopathologic factors and prognosis in patients with advanced NSCLC treated with EGFR-tyrosine kinase inhibitors (EGFR-TKIs).

Methods

One-hundred and seventy patients with advanced NSCLC were explored. Paraffin-embedded tumour sections were stained with PD-L1 antibody. EGFR mutation was examined by fluorescent quantitative polymerase chain reaction (PCR). The correlations between PD-L1 expression and EGFR status and survival parameters were analyzed.

Results

The overall frequency of PD-L1 over-expression was 65.9% (112/170). In lung adenocarcinoma, PD-L1 tended to be associated with mutant EGFR (PD-L1 overexpression in mutant and wild-type EGFR, 64/89 (71.9%) vs. 32/56 (57.1%), respectively; p=0.067). Subgroup analyses showed that high PD-L1 expression was associated with significantly shorter overall survival (OS) in EGFR wild-type patients (p=0.029) but not in EGFR mutant patients (p=0.932) treated with EGFR-TKIs. Even more, for EGFR mutant patients, higher expression of PD-L1 might only signal better outcome with TKIs.

Conclusions

High PD-L1 expression was likely to be associated with the presence of EGFR mutation in advanced lung adenocarcinoma. For EGFR wild-type patients, the PD-L1 over expression can be considered as a poor prognostic indicator of OS.

Pointed Progress in Second-Line Advanced Non-Small-Cell Lung Cancer: The Rapidly Evolving Field of Checkpoint Inhibition

PURPOSE

Non-small-cell lung cancer (NSCLC) is globally prevalent and associated with high rates of mortality. Immune checkpoint pathways are often exploited by tumors to evade immunity-mediated destruction, and checkpoint inhibitors can reactivate tumor-related immune responses. This review considers available clinical evidence for the use of checkpoint inhibitors in the treatment of second-line advanced NSCLC.

METHODS

Our systematic search revealed 20 clinical trials evaluating checkpoint inhibitors in the second-line setting, three of which were randomized trials comparing programmed cell death protein 1 and programmed death ligand 1 (PD-L1) inhibitors to docetaxel, the current standard of care in this setting.

RESULTS

A randomized phase II trial comparing the PD-L1 inhibitor atezolizumab to docetaxel did not demonstrate improved survival for atezolizumab in patients overall, although a trend toward improved survival with increased PD-L1 expression was apparent. Twin phase III trials showed significantly improved survival for the programmed cell death protein 1 inhibitor nivolumab compared with docetaxel in patients with both squamous and nonsquamous disease. PD-L1 expression correlated with improved survival in patients with nonsquamous disease, and patients with low levels of PD-L1 expression (< 10%) and those with EGFR mutations are unlikely to benefit. Checkpoint inhibitor therapy is generally well tolerated and associated with low rates of grade 3 or 4 adverse events compared with standard care.

CONCLUSION

Level 1 evidence exists to support the use of nivolumab as second-line treatment of patients with squamous advanced NSCLC, as well as in select patients with nonsquamous disease. Benefits remain unknown in patients with targetable driver mutations, and use of PD-L1 expression to guide therapy remains controversial. Results from ongoing randomized trials evaluating biomarkers and other checkpoint inhibitors will further our understanding of this rapidly evolving area of oncology.

Prognostic value of PD-L1 and PD-1 expression in pulmonary neuroendocrine tumors

PURPOSE

Programmed death 1 (PD-1) receptor and its ligand, programmed death ligand-1 (PD-L1), play critical roles in the immune invasion of various tumors. This study aimed to explore the clinical significance of PD-L1/PD-1 expression in the progression of pulmonary neuroendocrine tumors (PNETs).

METHODS

The expression of PD-L1 and PD-1 in 80 patients diagnosed with PNETs were investigated. Immunohistochemical analysis was performed on 80 formalin-fixed paraffin-embedded tissue specimens from PNETs and 20 corresponding cancer-adjacent tissue specimens.

RESULTS

Tissues from PNETs had higher levels of PD-L1 (58.8%) and PD-1 (51.3%) compared to the cancer-adjacent tissues (25% and 20%, respectively). Meanwhile, PD-L1 expression was associated with PD-1 expression (P=0.007). PD-L1 expression was significantly associated with histological type (P=0.014) and tumor stage (P=0.014). Univariate analyses showed that the overall survival time of PNETs patients was significantly associated with PD-L1 expression in cancer cells (P=0.003), PD-1 expression in tumor-infiltrating lymphocytes (P=0.001), tumor node metastasis stage (P<0.05), and distant metastasis (P<0.001). Additionally, multivariate analysis revealed that PD-L1 expression, PD1 expression, and distant metastasis of PNETs were independently associated with survival time. Moreover, Kaplan-Meier survival curves analysis revealed that patients with negative PD-L1 and PD-1 expression had better prognoses.

CONCLUSION

Data suggested that PD-L1 and PD-1 can be useful prognostic biomarkers for survival and can pave the way toward new immunotherapy regimens against PNETs through targeting the PD-L1/PD-1 pathway.

Expression of programmed death-1 ligand (PD-L1) in tumor-infiltrating lymphocytes is associated with favorable spinal chordoma prognosis

Aberrant expression of programmed death-1 (PD-1) receptor/PD-1 ligand (PD-L1) proteins alters human immunoresponse and promotes tumor development and progression. We assessed the expression status of PD-1 and PD-L1 in spinal chordoma tissue specimens and their association with clinicopathological characteristics of patients. Formalin-fixed paraffin-embedded tumor samples from 54 patients with spinal chordoma were collected for immunohistochemical analysis of PD-1 and PD-L1 expression. The association of the expression levels of PD-1 and PD-L1 with clinicopathological variables and survival data were statistically analyzed. Lymphocyte infiltrates were present in all 54 patient samples. Of 54 samples, 37 (68.5%) had both positive PD-1 and PD-L1 expression in tumor cell membrane. Moreover, 38 (70.4%) and 12 (22.2%) had positive PD-1 and PD-L1 expression in tumor-infiltrating lymphocytes (TILs), respectively. Tumors with positive PD-L1 expression were significantly associated with advanced stages of chordoma (p = 0.041) and TIL infiltration (p = 0.005), and had a borderline association with tumor grade (p = 0.051). However, positive tumor PD-L1 expression was not significantly associated with local recurrence-free survival (LRFS) or overall survival (OS). PD-1 expression in TILs was associated with poor LRFS (χ(2) = 10.051, p = 0.002, log-rank test). Multivariate analysis showed that PD-L1 expression only in TILs was an independent predictor for LRFS (HR = 0.298, 95% CI: 0.098-0.907, p = 0.033), and OS (HR = 0.188, 95% CI: 0.051-0.687, p = 0.011) in spinal chordoma patients. In conclusion, PD-L1 expression in TILs was an independent predictor for both LRFS and OS in spinal chordoma patients. Our findings suggest that the PD-1/PD-L1 pathway may be a novel therapeutic target for the immunotherapy of chordoma.

The associations between PD-1, CTLA-4 gene polymorphisms and susceptibility to ankylosing spondylitis: a meta-analysis and systemic review

Previous surveys had evaluated the effects of the PD-1, CTLA-4 gene polymorphisms on susceptibility to ankylosing spondylitis (AS), but the results remained controversial. To briefly examine these consequences, a comprehensive meta-analysis was conducted to estimate the relationships between PD-1 rs11568821, rs2227982, rs2227981, CTLA-4 +49 A/G and -318 C/T polymorphisms and AS risk. The available articles dated to December 2014 were searched in the PUBMED, MEDLINE and EMBASE databases. The data of the genotypes and/or alleles for the PD-1 rs11568821, rs2227982, rs2227981, CTLA-4 +49 A/G and -318 C/T polymorphisms in the AS and control subjects were extracted, and statistical analysis was conducted by STATA 11.2 software. Summary odds ratios (ORs) with their 95 % confidence intervals (95 % CIs) were calculated to determine the strength of associations with fixed-effects or random-effects models. A total of eight published studies were finally involved in this meta-analysis. Meta-analysis of PD-1 rs2227982 polymorphism under the T allele versus C allele (OR 1.744, 95 % CI 1.477-2.059, P < 0.0001), TT+TC versus CC (OR 2.292, 95 % CI 1.654-3.175, P < 0.0001), TT versus CC (OR 1.883, 95 % CI 1.299-2.729, P = 0.001) revealed a significant association with AS. Our meta-analysis demonstrated that the rs2227982 polymorphism in the PD-1 gene might contribute to AS susceptibility. However, further studies with large sample sizes and among different ethnicity populations should be required to confirm this association.

Association of PDCD1 polymorphism to systemic lupus erythematosus and rheumatoid arthritis susceptibility

OBJECTIVE

This study aims to analyze the relationship of programmed cell death 1 (PDCD1) gene polymorphism (PD1.3G/A - rs11568821) with features of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) in a Southern Brazilian population.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed in 95 SLE and 87 RA patients and 128 control group individuals from Santa Catarina, Southern Brazil. The Hardy-Weinberg equilibrium (HWE) test, and odds ratio (OR) were analyzed, considering CI 95% and p≤0.05.

RESULTS

The PD1.3A allele frequencies were 0.095 (SLE), 0.115 (RA) and 0.078 (controls). The genotypes of the control group were in HWE, while those of SLE and RA patients were not. However, we found no association between PD1.3 polymorphism and the SLE or RA susceptibility, nor clinical or epidemiological data.

CONCLUSION

There was no significant association between PD1.3 polymorphism and SLE or RA susceptibility in this Southern Brazilian population.

Relationship between expression of PD-L1 and PD-L2 on esophageal squamous cell carcinoma and the antitumor effects of CD8⁺ T cells

The programmed death-1 (PD-1)/programmed death-ligands (PD-Ls) signal pathway has been implicated as a potential immune escape mechanism in several human cancers. However, the studies of PD‑1/PD‑Ls pathway in esophageal squamous cell carcinoma (ECSS) are not yet sufficient. The current study investigated the expression of PD‑L1, PD‑L2 and PD‑1 in ESCC tissues. The correlations between the expression of these proteins and clinical histopathological parameters were analyzed. Then the stable transfected Ec109 cell lines overexpressing PD‑L1/PD‑L2 were established by plasmid transfection successfully. Ec109 and CD8+ T cells were co‑cultured to analyze the effects of PD‑1/PD‑Ls signal pathway on the function of CD8+ T cells including proliferation, apoptosis and interferon‑γ production. We found that PD‑L1-positive patients had significantly poorer prognosis than the negative patients, while their prognosis was not related to PD‑L2 expression. The count of PD‑1+ TILs (tumor‑infiltrating lymphocytes) was negatively correlated with both PD‑L1 and PD‑L2 expression. In functional studies, we found that PD‑1/PD‑Ls signal pathway was able to downregulate the function of CD8+ T lymphocyte and its function could be restored by blocking the signal pathway. This indicates that PD‑1/PD‑Ls may prevent effective antitumor immunity, which provides important evidence to delineate the cellular immune deficiency mechanism in ESCC. Therefore, PD-1/PD-Ls are predicted to become novel targets for ESCC immunotherapy.

Targeting immune checkpoints in melanoma: an update

Different treatment modalities encompassed under the term 'immunotherapy' have led to major breakthroughs in the treatment of melanoma. Immune checkpoint-blocking antibodies targeting CTLA-4 and PD-1 result in significant activity and prolonged survival in patients with advanced melanoma and are currently available for clinical use. Studies addressing novel immune checkpoint blocking antibodies, combined approaches and predictive/prognostic biomarkers are expected to broaden the applicability and efficacy of this approach. In this article, we will review clinically meaningful aspects of immune checkpoint blockade, promising strategies under development and the challenges faced in a continuous search to improve the outcomes of patients affected by this disease.

CD152 and PD-1 down-regulation on CD8 T cells is associated with human acute liver allograft rejection

PURPOSE

To investigate CD152 and PD-1 expression on T lymphocytes and the function of CD152- and PD-1-positive CD8 T cells in human acute liver allograft rejection.

MATERIALS AND METHODS

Sixty-three patients undergoing liver transplantation were enrolled in this study, including 26 cases with acute allograft rejection (Gr-AR) and 37 cases with stable allograft liver function (Gr-SF). The expression of CD152 and PD-1 on T lymphocytes and the expression of granzyme and perforin on CD152- and PD-1-positive CD8 T cells in peripheral blood were analyzed using flow cytometry.

RESULTS

The peripheral CD4/CD8 ratio in Gr-AR was significantly lower than that in Gr-SF (P < .01). The expression of CD152 and PD-1 on CD8 and CD4 T cells was significantly lower in Gr-AR than in Gr-SF (all P < .01). The expression of granzyme B and perforin was significantly higher in Gr-AR than in Gr-SF (P < .01).

CONCLUSIONS

Down-regulation of the expression of negative costimulatory molecules such as CD152 and PD-1 on CD8 T cells may be associated with human acute liver allograft rejection.

Clinicopathologic analysis of programmed cell death-1 and programmed cell death-ligand 1 and 2 expressions in pulmonary adenocarcinoma: comparison with histology and driver oncogenic alteration status

Immunotherapies targeting the programmed cell death-1/programmed cell death-ligand 1 pathway have emerged as promising therapeutic strategies for lung cancer. However, the expression pattern and prognostic implications of programmed cell death-ligand 1 and 2 and programmed cell death-1 in comparison with the histology and genetic alterations in pulmonary adenocarcinomas remains unclear and thus were addressed here. Programmed cell death-ligand 1 and 2 expression in tumor cells and the quantities of programmed cell death-1(+) and CD8(+) tumor-infiltrating lymphocytes were immunohistochemically evaluated in 497 resected pulmonary adenocarcinomas and analyzed according to clinicopathological and genetic statuses. Programmed cell death-ligand 1 and 2 expression were observed in 59% and 64% of pulmonary adenocarcinomas, respectively, and showed a strong positive correlation with each other (P < 0.001). Programmed cell death-ligand 1 expression was higher in nodal metastasis cases (P = 0.006), smokers (P = 0.056), poorly differentiated tumors and histologic subtypes of solid and micropapillary patterns (P < 0.001). There was no significant difference in programmed cell death-ligand 1 and 2 expression according to EGFR mutation status. However, programmed cell death-ligand 1 expression was correlated with ALK translocation (P =0.054) and expression of EGFR and MET (P < 0.001). Meanwhile, programmed cell death-ligand 2 expression was correlated with ALK translocation (P = 0.052), and expression of MET (P < 0.001) and ERBB2 (P = 0.013). The numbers of CD8(+) and programmed cell death-1(+) lymphocytes were higher in smokers (P = 0.012 and 0.016) and MET-expressing adenocarcinomas (P < 0.001). Patients expressing programmed cell death-ligand 1 and/or high ratios of programmed cell death-1(+)/CD8(+) lymphocytes showed shorter disease-free survival (P = 0.001). Our study demonstrated that programmed cell death-ligand 1 and 2 expression varied with histology, EGFR, ALK, MET, and ERBB2 statuses, and activation of the programmed cell death-1/programmed cell death-ligand 1 pathway may be a poor prognostic factor in pulmonary adenocarcinomas.

The PD-1/B7-H1 pathway modulates the natural killer cells versus mouse glioma stem cells

PURPOSE

Glioblastoma multiforme (GBM) is the most malignant primary type of brain tumor in adults. There has been increased focus on the immunotherapies to treat GBM patients, the therapeutic value of natural killer (NK) cells is still unknown. Programmed death-1 (PD-1) is a major immunological checkpoint that can negatively regulate the T-cell-mediated immune response. We tested the combination of the inhibiting the PD-1/B7H1 pathway with a NK-cell mediated immune response in an orthotopic mouse model of GBM.

METHODS AND MATERIALS

Mouse glioma stem cells (GL261GSCs) and mouse NK cells were isolated and identified. A lactate dehydrogenase (LDH) assay was perfomed to detect the cytotoxicity of NK cells against GL261GSCs. GL261GSCs were intracranially implanted into mice, and the mice were stratified into 3 treatment groups: 1) control, 2) NK cells treatment, and 3) PD-1 inhibited NK cells treatment group. Overall survival was quantified, and animal magnetic resonance imaging (MRI) was performed to determine tumor growth. The brains were harvested after the mice were euthanized, and immunohistochemistry against CD45 and PCNA was performed.

RESULTS

The mouse NK cells were identified as 90% CD3- NK1.1+CD335+ by flow cytometric analysis. In the LDH assay, the ratios of the damaged GL261GSCs, with the E:T ratios of 2.5:1, 5:1, and 10:1, were as follows: 1) non-inhibited group: 7.42%, 11.31%, and 15.1%, 2) B7H1 inhibited group: 14.75%, 18.25% and 29.1%, 3) PD-1 inhibited group: 15.53%, 19.21% and 29.93%, 4) double inhibited group: 33.24%, 42.86% and 54.91%. In the in vivo experiments, the mice in the PD-1 inhibited NK cells treatment group and IL-2-stimulated-NK cells treatment group displayed a slowest tumor growth (F = 308.5, P<0.01) and a slower tumor growth compared with control group (F = 118.9, P<0.01), respectively. The median survival of the mice in the three groups were as follows: 1) conrol group: 29 days, 2) NK cells treatment group: 35 days (P = 0.0012), 3) PD-1 inhibited NK cells treatment group: 44 days (P = 0.0024). Immunologic data of PCNA-positive cell ratios and CD45-positive cell ratios of the tumor specimens in the three groups were as follows: 1) control group: 65.72% (PCNA) and 0.92% (CD45), 2) NK treatment group: 27.66% (PCNA) and 13.46% (CD45), and 3) PD-1 inhibited NK cells treatment group: 13.66% (PCNA) and 23.66% (CD45) (P<0.001).

CONCLUSION

The results demonstrated that blockade of PD-1/B7H1 pathway could promote mouse NK cells to kill the GL261GSCs, and the PD-1-inhibited NK cells could be a feasible immune therapeutic approach against GBM.

Immunotherapy of melanoma

Melanoma is considered one of the immunogenic - if not the most immunogenic - malignancies. This is based on several observations.1.Spontaneous remissions occur occasionally.2.In about 5% of melanomas no primary tumour is found. The genetic aberrations of these tumours closely resemble those of cutaneous melanomas, and therefore are suggestive of spontaneous regressions of the primary tumours.3.Both primary tumours and metastases often have brisk lymphocytic infiltrates, a phenomenon that is correlated with better outcome.4.Studies of isolates of these tumour-infiltrating T lymphocytes have revealed that a proportion of these cells recognise melanoma antigens.5.Melanomas respond to immunotherapy. These observations have led to over 30 years of research on immunotherapy for melanoma; many of these efforts have failed, with only a few exceptions: interleukin-2 (IL-2) and to a lesser degree interferon-a (IFN-〈). Recently, new developments in immunotherapy have revolutionised this treatment modality. Anti-CTLA4 has received approval from the Food and Drugs Administration (FDA) and the European Medicines Agency (EMA) for the treatment of stage IV melanomas based on the improvement in overall survival in phase III trials, and more recently blockade of PD1/PDL1 interactions has shown objective clinical responses in a stage IV melanoma in early-phase clinical trials. In addition, several independent single-institution phase I/II trials using adoptive cell therapy have shown a consistently high response rate, including durable complete remissions in a substantial percentage of treated patients. Now, for the first time, immunotherapy has moved beyond the treatment of melanoma as both CTLA4 and PD1 blockade have been shown to induce objective responses in other tumour types as well. This chapter will discuss the mechanism of action, clinical efficacy and side effects of IL-2, the novel treatments consisting of the immune checkpoint blockade drugs anti-CTLA4 and anti-PD1 and adoptive cell therapy.

Association of PDCD1 polymorphism to Systemic Lupus Erythematosus and Rheumatoid Arthritis susceptibility

OBJECTIVE

This study aims to analyze the relationship of programmed cell death 1 (PDCD1) gene polymorphism (PD1.3G/A - rs11568821) with features of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) in a Southern Brazilian population.

METHODS

Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) was performed in 95 SLE and 87 RA patients and 128 control group individuals from Santa Catarina, Southern Brazil. The Hardy-Weinberg Equilibrium (HWE) test, and odds ratio (OR) were analyzed, considering CI 95% and p≤0.05.

RESULTS

The PD1.3A allele frequencies were 0.095 (SLE), 0.115 (RA) and 0.078 (controls). The genotypes of the control group were in HWE, while those of SLE and RA patients were not. However, we found no association between PD1.3 polymorphism and the SLE or RA susceptibility, nor clinical or epidemiological data.

CONCLUSION

There was no significant association between PD1.3 polymorphism and SLE or RA susceptibility in this Southern Brazilian population.

Clinicopathological and prognostic significance of programmed cell death ligand1 (PD-L1) expression in patients with non-small cell lung cancer: a meta-analysis

OBJECTIVE

Programmed cell death 1 (PD-1) and one of its ligands, PD-L1, are key immune checkpoint proteins. Evidences showed PD-L1 is an emerging biomarker for immunotherapy by anti-PD-1 and anti-PD-L1 antibody in non-small cell lung cancer (NSCLC). To investigate the association of PD-L1 protein expression with clinicopathological features and its impact on survival outcome, we conducted a meta-analysis.

METHODS

A comprehensive literature search of electronic databases (up to July 10, 2014) was performed. Correlation between PD-L1 expression and clinicopathological features and overall survival (OS) was analyzed by synthesizing the qualified data. Publication biases were examined.

RESULTS

A total of 1,550 NSCLC patients from 9 studies were included. The pooled odds ratios (ORs) indicated high PD-L1 expression was associated with poor tumor differentiation [OR =0.53, 95% confidence interval (CI): 0.39-0.72, P<0.0001]. Whereas, none of other clinicopathological characteristics [gender, smoking status, histological type, invasive depth of tumor, status of lymph node metastasis and tumor node metastasis (TNM) stage] were correlated with PD-L1 expression in current analysis. The combined hazard ratio (HR) for OS showed high expression of PD-L1 impaired the OS in NSCLC (HRpositive/negative =1.47, 95% CI: 1.19-1.83, P=0.0004).

CONCLUSIONS

Our meta-analysis indicated PD-L1 protein expression in NSCLC was not associated with common clinicopathological characteristics, except tumor differentiation. It was a poor prognostic biomarker for NSCLC. Further research should be performed to investigate the precise clinicopathological and prognostic significance of PD-L1 in NSCLC under uniform testing standard.

Relationship between programmed cell death-1 polymorphisms and clearance of hepatitis B virus

Programmed cell death-1 (PD-1) plays a critical role in regulating T-cell function during hepatitis B virus (HBV) infection. This study investigated the relationship between the polymorphisms of PD-1 gene and the susceptibility to HBV infection. Single nucleotide polymorphisms (SNPs) in PD-1 gene at positions +7146 G>A (guanine to adenine substitution) and +7209 C>T (cytosine to thymine substitution) were analysed using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in 220 subjects with chronic hepatitis B infection and 165 spontaneous clearance of HBV subjects. However, no statistically significant differences were found in the genotype distributions of the PD-1 +7146 G>A and PD-1 +7209 C>T polymorphisms among chronic hepatitis B and spontaneous clearance subjects. According to stratified analyses, borderline significance was observed between PD-1 +7146 GA genotype and risk of HBV chronicity in the subgroup of male gender (OR = 1.88, 95% 0.95-3.71; P = 0.07). Our findings demonstrate for the first time that the PD-1 +7146 G>A and PD-1 +7209 C>T polymorphisms have not been any major role in genetic susceptibility to chronicity of HBV infection, at least in the population studied here. Independent studies are needed to validate our findings in a larger series, as well as in patients of different ethnic origins.