Erythroderma is challenging to diagnose. The aim of this single-centre retrospective study was to identify factors that can be used to improve the diagnosis of erythroderma. Among 91 patients with erythroderma, 21 were diagnosed with eczema, 17 with psoriasis, 20 with drug-induced erythroderma, 13 with erythrodermic mycosis fungoides and 20 with Sézary syndrome. Nail alterations, ear involvement, and severe scaling were significantly associated with psoriasis (p = 0.044). Fever and hypereosinophilia were associated with drug-induced erythroderma. Expression of programmed cell death protein 1 was observed in all skin biopsies. However, with Sézary syndrome, programmed cell death protein 1 expression was significantly higher than with other aetiologies. A programmed cell death protein 1 hormone receptor score (H-score) >50 was associated with Sézary syndrome (p < 0.001, sensitivity 75%, specificity 92%) as well as CXCL13 expression (p < 0.044). CD7 loss was more frequent with erythrodermic mycosis fungoides and Sézary syndrome (p = 0.022). This study reports the importance of programmed cell death protein 1 expression for the differential diagnosis of Sézary syndrome and other aetiologies, including erythrodermic mycosis fungoides.

Humanized mice developing functional human T cells endogenously and capable of recognizing cognate human leukocyte antigen-matched tumors are emerging as relevant models for studying human immuno-oncology in vivo. Herein, mice transplanted with human CD34+ stem cells and bearing endogenously developed human T cells for >15 weeks were infected with an oncogenic recombinant Epstein-Barr virus (EBV), encoding enhanced firefly luciferase and green fluorescent protein. EBV-firefly luciferase was detectable 1 week after infection by noninvasive optical imaging in the spleen, from where it spread rapidly and systemically. EBV infection resulted into a pronounced immunologic skewing regarding the expansion of CD8+ T cells in the blood outnumbering the CD4+ T and CD19+ B cells. Furthermore, within 10 weeks of infections, mice developing EBV-induced tumors had significantly higher absolute numbers of CD8+ T cells in lymphatic tissues than mice controlling tumor development. Tumor outgrowth was paralleled by an up-regulation of the programmed cell death receptor 1 on CD8+ and CD4+ T cells, indicative for T-cell dysfunction. Histopathological examinations and in situ hybridizations for EBV in tumors, spleen, liver, and kidney revealed foci of EBV-infected cells in perivascular regions in close association with programmed cell death receptor 1-positive infiltrating lymphocytes. The strong spatiotemporal correlation between tumor development and the T-cell dysfunctional status seen in this viral oncogenesis humanized model replicates observations obtained in the clinical setting.

Death-associated protein kinase (DAPk) and DAPk-related protein kinase (DRP)-1 proteins are Ca+2/calmodulin-regulated Ser/Thr death kinases whose precise roles in programmed cell death are still mostly unknown. In this study, we dissected the subcellular events in which these kinases are involved during cell death. Expression of each of these DAPk subfamily members in their activated forms triggered two major cytoplasmic events: membrane blebbing, characteristic of several types of cell death, and extensive autophagy, which is typical of autophagic (type II) programmed cell death. These two different cellular outcomes were totally independent of caspase activity. It was also found that dominant negative mutants of DAPk or DRP-1 reduced membrane blebbing during the p55/tumor necrosis factor receptor 1-induced type I apoptosis but did not prevent nuclear fragmentation. In addition, expression of the dominant negative mutant of DRP-1 or of DAPk antisense mRNA reduced autophagy induced by antiestrogens, amino acid starvation, or administration of interferon-gamma. Thus, both endogenous DAPk and DRP-1 possess rate-limiting functions in these two distinct cytoplasmic events. Finally, immunogold staining showed that DRP-1 is localized inside the autophagic vesicles, suggesting a direct involvement of this kinase in the process of autophagy.

The key role of an inhibitory receptor, Programmed Death-1, has been evaluated in 273 patients with autoimmune myasthenia gravis. At the genetic level, SNP's genotyping showed no significant association to the disease. Gene expressions in patients were not different from that in controls. Interestingly, at the cell-surface protein level, there were significant elevated levels of PD-1 on T cells and its ligand PD-L1 on monocytes in the patients compared to controls. However, we could not demonstrate any secreted soluble forms of PD-1 among the patients and controls. Thus, our study shows PD-1 might have a natural regulatory property behind MG.

A chimeric antigen receptor (CAR) is a type of fusion protein that comprises an antigen-recognition domain and signaling domains. In the present study, a programmed death-ligand 1 (PD-L1)-specific CAR, comprised of a single-chain variable fragment (scFv) derived from a monoclonal antibody, co-stimulatory domains of cluster of differentiation (CD) 28 and 4-1BB and a T-cell-activation domain derived from CD3ζ, was designed. The construction was cloned and packaged into the lentiviral vector pLVX. Flow cytometry confirmed that peripheral blood mononuclear cells were efficiently transduced and that the CAR was successfully expressed on T cells. The cytotoxicity of transduced T cells was detected using PD-L1-positive NCI-H358 bronchioalveolar carcinoma cells and A549 lung adenocarcinoma cells (with a low expression of PD-L1, only in the A549 cells). The results demonstrated mild cytotoxicity at an effector-to-target ratio of 10:1. An ELISA revealed a significant increase in the level of interferon-γ released from T cells transduced with scFv-28Bz when the cells were co-cultured with PD-L1-positive NCI-H358 cells, while interkeukin-2 and tumor necrosis factor-α levels remained unchanged. These data indicated a potential method for the treatment of solid tumors.

Hyperglycemia impairs immune response; however, it remains unknown whether the anti-tumor effects of anti-programmed cell death-1 antibody (PD-1-Ab) treatment are changed in hyperglycemic conditions. We analyzed the effect of PD-1-Ab on tumor growth in streptozotocin-induced diabetic mice (STZ-mice) subcutaneously inoculated with MC38 (a colon carcinoma cell line). Furthermore, we assessed the expression of chemokines by polymerase chain reaction (PCR) array in tumor-draining lymph nodes (dLNs) of these mice and MC38 cells cultured in different glucose concentrations. The suppressive effect of PD-1-Ab on tumor growth was attenuated. This was accompanied by fewer tumor-infiltrating CD8+ T cells, and STZ-mice had fewer tumor-infiltrating CD11c+ dendritic cells (DCs) than normoglycemic mice. mRNA expression levels of CXCL9, a chemokine recruiting CD8+ T cells, were lower in dLNs of STZ-mice than in normoglycemic mice after PD-1-Ab treatment, and its protein was expressed in DCs. In MC38 cells cultured with 25 mM glucose, mRNA expression of CCL7, a chemokine recruiting DCs, was decreased compared to cells cultured with 5 mM glucose. These results suggest that the STZ-induced hyperglycemia impairs the effect of PD-1-Ab treatment on MC38 tumor growth, and is accompanied by reduced infiltration of DCs and CD8+ T cells and decreased expression of CCL7 and CXCL9.

JS-001 is the first monoclonal antibody (mAb) against programmed cell death protein-1 (PD-1) approved by the China Food and Drug Administration (CFDA) into the clinical trails. To date, however, no pre-clinical pharmacological and pharmacokinetic (PK) data are available. In this study, we investigated the efficacy of JS-001 and conducted a preclinical PK study, including the monitoring of anti-drug antibodies (ADAs). We found that JS-001 specifically bound to PD-1 antigen with an EC50 of 21 nmol/L, and competently blocked the binding of PD-1 antigen to PD-L1 and PD-L2 with IC50 of 3.0 and 3.1 nmol/L, respectively. Furthermore, JS-001 displayed distinct species cross-reactivity: it could bind to the PD-1 antigen on the peripheral blood mononuclear cells (PBMCs) of humans and cynomolgus monkeys, but not to those of mice and woodchucks; the Kd values for the interaction between JS-001 and PD-1 antigens on CD8+ T cells of human and cynomolgus monkey were 2.1 nmol/L and 1.2 nmol/L, respectively. In vitro, treatment with JS-001 (0.01-10 μg/mL) dose-dependently stimulated human T cell proliferation, as well as IFN-γ and TNF-α secretion. In HBsAg-vaccinated cynomolgus monkeys, the expression of PD-1+/CD4+ and PD-1+/CD8+ was significantly elevated, intramuscular injection of JS-001 (1 and 10 mg/kg) resulted in dramatic decreases in PD-1+/CD4+ and PD-1+/CD8+ expression in a dose-dependent manner, which was supported by PD-1 receptor occupancy (RO) results. In the PK study, 18 cynomolgus monkeys treated with single, ascending doses of 1, 10, and 75 mg/kg, and another 6 cynomolgus monkeys received 10 mg/kg successive administration. The plasma clearance of JS-001 followed a linear PK profile with single administration in the 1 and 10 mg/kg groups and a non-linear PK profile in the 75 mg/kg group. In the successive 10 mg/kg administration group, no drug accumulation was observed. But the AUC from the last exposure was lower than that of the first administration, which was probably due to the production of ADAs, as demonstrated in immunogenicity study. These non-clinical data are encouraging and provide a basis for the efficacy and safety of JS-001 in clinical trials.

Necroptosis, a regulated form of necrosis, has emerged as a novel therapeutic strategy that could enhance cancer immunotherapy. However, its role in tumorigenesis is still debated because recent studies have reported both anti- and pro-tumoral effects. Here, we aimed to systematically evaluate the associations between tumor necroptosis (mixed lineage kinase domain-like protein, MLKL; phosphorylated MLKL, pMLKL; and receptor-interacting protein kinase 1-receptor-interacting protein kinase 3, RIPK1-RIPK3 interaction) and tumor-infiltrating immune cells (CD8+ and FOXp3+ T cells and CD163+ M2 macrophages) and tumor PD-L1 by immunohistochemistry in 88 cholangiocarcinoma (CCA) patients who had undergone surgical resection. Their associations with clinicopathological characteristics, survival data, and prognosis were evaluated. MLKL was found to be an unfavorable prognostic factor (p-value = 0.023, HR = 2.070) and was inversely correlated with a clinically favorable immune cell signature (high CD8+/high FOXp3+/low CD163+). Both pMLKL and RIPK1-RIPK3 interaction were detected in CCA primary tissues. In contrast to MLKL, pMLKL status was significantly positively correlated with a favorable immune signature (high CD8+/high FOXp3+/low CD163+) and PD-L1 expression. Patients with high pMLKL-positive staining were significantly associated with an increased abundance of CD8+ T cell intratumoral infiltration (p-value = 0.006). Patients with high pMLKL and PD-L1 expressions had a longer overall survival (OS). The results from in vitro experiments showed that necroptosis activation in an RMCCA-1 human CCA cell line selectively promoted proinflammatory cytokine and chemokine expression. Jurkat T cells stimulated with necroptotic RMCCA-1-derived conditioned medium promoted PD-L1 expression in RMCCA-1. Our findings demonstrated the differential associations of necroptosis activation (pMLKL) and MLKL with a clinically favorable immune signature and survival rates and highlighted a novel therapeutic possibility for combining a necroptosis-based therapeutic approach with immune checkpoint inhibitors for more efficient treatment of CCA patients.

Programmed cell death 1 ligand (PD-L1) and its receptor (PD-1) are key molecules for immunoregulation and immunotherapy. PD-L1 binding PD-1 is an effective way to regulate T or B cell immunity in autoimmune diseases such as rheumatoid arthritis (RA). In our study, we overexpressed PD-L1 by constructing a recombinant of PD-L1-lentiviral vector, which was subsequently used to transfect mouse bone marrow mesenchymal stem cells (MBMMSCs) and significantly suppressed the development of collagen-induced arthritis (CIA) in DBA/1j mice. In addition, PD-L1-transfected MBMMSCs (PD-L1-MBMMSCs) ameliorated joint damage, reduced proinflammatory cytokine expression, and inhibited T and B cell activation. Furthermore, PD-L1-MBMMSCs decreased the number of dendritic cells and increased the numbers of regulatory T cells and regulatory B cells in joints of CIA mice. In conclusion, our results provided a potential therapeutic strategy for RA treatment with PD-L1-MBMMSC-targeted therapy.

In this study, we investigated the in vivo metastasis suppression effects of the platelet-derived growth factor receptor inhibitor dasatinib, which targets cancer-associated fibroblasts (CAFs), in combination with an anti-programmed cell death-1 (PD-1) antibody. We classified clinical CRC cases as inflamed, excluded, or desert using immunohistochemical analysis and evaluated the tumor stroma. The excluded type was the most common, and cases with high-volume stroma in the primary lesions also had a high stromal volume in the liver metastatic lesions. Liver-metastasis mouse models with different stromal volumes were established and treatment-induced changes in the tumor immune microenvironment were evaluated. The anti-PD-1 antibody alone exhibited a therapeutic effect for the liver metastases with low stromal volumes but not for the liver metastases with high stromal volumes. In contrast, antitumor effects were observed with anti-PD-1 antibody/dasatinib combination therapy even in the liver metastases with high stromal volumes. Combination therapy reduced the stromal volume, promoted immune cell infiltration, induced antitumor cytotoxic T-cell responses, activated antitumor immunity, and promoted tumor regression. These results suggest that CAFs play an important role in the immune evasion of CRC and that anti-PD-1 antibody/dasatinib combination therapy has potential as a treatment option for patients with metastatic CRC for whom immunotherapy alone is ineffective.

T cell activation represents a double-edged sword in atherogenesis, as it promotes both pro-inflammatory T cell activation and atheroprotective Foxp3(+) regulatory T cell (Treg) responses. Here, we investigated the role of the co-inhibitory receptor programmed cell death-1 (PD-1) in T cell activation and CD4(+) T cell polarization towards pro-atherogenic or atheroprotective responses in mice. Mice deficient for both low density lipoprotein receptor and PD-1 (Ldlr(-/-)Pd1(-/-)) displayed striking increases in systemic CD4(+) and CD8(+) T cell activation after 9 weeks of high fat diet feeding, associated with an expansion of both pro-atherogenic IFNγ-secreting T helper 1 cells and atheroprotective Foxp3+ Tregs. Importantly, PD-1 deficiency did not affect Treg suppressive function in vitro. Notably, PD-1 deficiency exacerbated atherosclerotic lesion growth and entailed a massive infiltration of T cells in atherosclerotic lesions. In addition, aggravated hypercholesterolemia was observed in Ldlr(-/-)Pd1(-/-) mice. In conclusion, we here demonstrate that although disruption of PD-1 signaling enhances both pro- and anti-atherogenic T cell responses in Ldlr(-/-) mice, pro-inflammatory T cell activation prevails and enhances dyslipidemia, vascular inflammation and atherosclerosis.

Despite the recent development of immunotherapies that target programmed death-1 (PD-1) or programmed death ligand-1 (PD-L1) in non-small cell lung cancer (NSCLC) treatment, these therapies are less effective in NSCLC patients with epidermal growth factor receptor (EGFR) mutations. However, the molecular mechanisms underlying this lower efficacy of immunotherapies in EGFR mutant lung cancers are still unclear. In this study, we analyzed PD-L1 protein expression in lung cancer cell lines with EGFR mutations prior to and after acquisition of resistance to EGFR tyrosine kinase inhibitors (TKIs). We found that parental lung cancer cell lines harboring EGFR mutations showed negative (PC9 and H3255 cells) and positive (HCC827 cells) staining for PD-L1 by immunohistochemistry. Comparing PD-L1 expression between EGFR-TKI resistant cell lines and their parental cells, we found that increased phosphorylation of EGFR was related to increased expression of PD-L1. Increased phosphorylation of EGFR was accompanied by the T790M secondary mutation. Acquired resistance cells with MET amplification or EGFR loss both showed decreased phosphorylation of EGFR and decreased PD-L1 expression. Our results indicate that lung cancer cell lines with EGFR mutations (parental cells) do not harbor high PD-L1 protein expression. In addition, EGFR phosphorylation affects PD-L1 expression after acquisition of resistance to EGFR-TKIs.

Programmed cell death 1 (PD-1) is a key cell-surface receptor of CD28 superfamily that triggers inhibitory pathways to attenuate T-cell responses and promote T-cell tolerance. As a crucial role in tumor immunity, PD-1 has been a focus of studies in anti-cancer therapy. It has been approved that tumors could exploit PD-1-dependent immune suppression for immune evasion. Considering the wide use of glucocorticoids (GCs) in anti-cancer therapy and their immunosuppressive effects, we explored whether GCs could influence the expression of PD-1.

PD-1/PD-L1 immune checkpoint blockade for cancer therapy showed promising results in clinical studies. Further endeavors are required to enhance patient stratification, as, at present, only a small portion of patients with PD-L1-positive tumors (as determined by PD-L1 targeted immunohistochemistry; IHC) benefit from anti-PD-1/PD-L1 immunotherapy. This can be explained by the heterogeneity of tumor lesions and the intrinsic limitation of multiple biopsies. Consequently, non-invasive in vivo quantification of PD-L1 on tumors and metastases throughout the entire body using positron emission tomography (PET) imaging holds the potential to augment patient stratification. Within the scope of this work, six new small molecules were synthesized by following a ligand-based drug design approach supported by computational docking utilizing lead structures based on the (2-methyl-[1,1'-biphenyl]-3-yl)methanol scaffold and evaluated in vitro for potential future use as PD-L1 PET tracers. The results demonstrated binding affinities in the nanomolar to micromolar range for lead structures and newly prepared molecules, respectively. Carbon-11 labeling was successfully and selectively established and optimized with very good radiochemical conversions of up to 57%. The obtained insights into the significance of polar intermolecular interactions, along with the successful radiosyntheses, could contribute substantially to the future development of small-molecule PD-L1 PET tracers.

Immune checkpoint inhibitors targeting programmed cell death 1 (PD-1) or its ligand (PD-L1) have been shown to be effective in treating patients with a variety of cancers. Biomarker studies have found positive associations between clinical response rates and PD-L1 expression on tumor cells, as well as the presence of tumor infiltrating lymphocytes (TILs). It is currently unknown whether tumors associated with neurofibromatosis types 1 and 2 (NF1 and NF2) express PD-L1. We performed immunohistochemistry for PD-L1 (clones SP142 and E1L3N), CD3, CD20, CD8, and CD68 in NF1-related tumors (ten dermal and six plexiform neurofibromas) and NF2-related tumors (ten meningiomas and ten schwannomas) using archival formalin-fixed paraffin-embedded tissues. Expression of PD-L1 was considered positive in cases with > 5% membranous staining of tumor cells, in accordance with previously published biomarker studies. PD-L1 expression in tumor cells (using the SP142 and E1L3N clones, respectively) was assessed as positive in plexiform neurofibromas (6/6 and 5/6) dermal neurofibromas (8/10 and 6/10), schwannomas (7/10 and 10/10), and meningiomas (4/10 and 2/10). Sparse to moderate presence of CD68, CD3, or CD8 positive TILs was found in 36 (100%) of tumor specimens. Our findings indicate that adaptive resistance to cell-mediated immunity may play a major role in the tumor immune microenvironment of NF1 and NF2-associated tumors. Expression of PD-L1 on tumor cells and the presence of TILs suggest that these tumors might be responsive to immunotherapy with immune checkpoint inhibitors, which should be explored in clinical trials for NF patients.

One of the important interactions in controlling the human immune system is the reaction between checkpoint proteins such as programmed cell death-1 (PD-1) and its ligand, PD-L1. These are negative immunoregulatory molecules that promote immune evasion of tumor cells. PD-L1 expression is an immune-mediated mechanism used by various malignant cells in order to down-regulate the immune system. Checkpoint inhibitors (CPIs) are a new class of anti-cancer agents that stimulate immune cells to elicit an antitumor response by blocking the ligand and receptor interactions. Nanobody (Nb) as a new type of antibody fragment, has some potential as CPI.

Programmed death receptor ligand 1 (PD-L1), which belongs to the B7 family, is overexpressed in a variety of human cancer types and serves a crucial role in immune escape by malignant cells. Programmed death receptor 1 (PD-1) is a specific PD-L1 receptor. PD-1/PD-L1 signaling inhibits the antitumor effects of dendritic cell (DC) immunization for tumor treatment. The aim of the present study was to determine whether inhibiting PD-L1 may increase the immunologic anti-tumor effect of dendritic cells against pancreatic cancer. In the present study, PD-L1 levels in non-cancerous and malignant tissue samples were compared, and the impact of PD-L1 downregulation on human pancreatic cancer PaTu8988 cells was determined by lentivirus-based RNA interference and DC immunotherapy. PD-L1 expression in pancreatic specimens was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry. PaTu8988 cells expressing reduced levels of PD-L1 were generated by lentivirus-based knockdown to assess the mechanism by which the inhibition of PD-L1 signaling in DC immunization affects therapeutic outcomes in pancreatic cancer-bearing SCID-hu mice. PD-L1 levels were markedly elevated in pancreatic adenocarcinoma samples compared with in non-cancerous tissue. PD-L1 silencing in pancreatic adenocarcinoma cells resulted in improved treatment outcomes of DC immunization in vitro and in vivo compared with traditional DC immunization. PD-L1 silencing enhances the antitumor response of cytotoxic T cells by increasing interferon γ production in vitro. In vivo, this method prevented tumor growth and lung metastasis, and prolonged survival in the SCID-hu model. In conclusion, the results of the present study suggested that suppressing PD-L1 in malignant cells during DC immunization may be a useful tool for immunotherapy in pancreatic adenocarcinoma.

Agents targeting the programmed death ligand 1 (PD-L1)/programmed death receptor 1 immune checkpoint exhibited promising clinical outcomes in a variety of malignant tumors, including intrahepatic cholangiocarcinoma (ICC). However, the relationship between PD-L1 expression and CD8+ T-cell immune responses is not well defined in ICC.

RIPK1, RIPK3, ZBP1 and TRIF, the four mammalian proteins harboring RIP homotypic interaction motif (RHIM) domains, are key components of inflammatory signaling and programmed cell death. RHIM-domain protein activation is mediated by their oligomerization; however, mechanisms that promote a return to homeostasis remain unknown. Here we show that autophagy is critical for the turnover of all RHIM-domain proteins. Macrophages lacking the autophagy gene Atg16l1accumulated highly insoluble forms of RIPK1, RIPK3, TRIF and ZBP1. Defective autophagy enhanced necroptosis by Tumor necrosis factor (TNF) and Toll-like receptor (TLR) ligands. TNF-mediated necroptosis was mediated by RIPK1 kinase activity, whereas TLR3- or TLR4-mediated death was dependent on TRIF and RIPK3. Unexpectedly, combined deletion of Atg16l1 and Zbp1 accelerated LPS-mediated necroptosis and sepsis in mice. Thus, ZBP1 drives necroptosis in the absence of the RIPK1-RHIM, but suppresses this process when multiple RHIM-domain containing proteins accumulate. These findings identify autophagy as a central regulator of innate inflammation governed by RHIM-domain proteins.

Liver cancer is the sixth most common cancer worldwide with high morbidity and mortality. Programmed death ligand 1 (PD-L1) is a major ligand of programmed death 1 receptor (PD1), and PD1/PD-L1 checkpoint acts as a negative regulator of the immune system. Cancers evade the host's immune defense via PD-L1 expression. This study aimed to investigate the effects of tumor-related cytokines, interferon gamma (IFNγ), and tumor necrosis factor alpha (TNFα) on PD-L1 expression in human hepatocellular carcinoma cells, HepG2. Furthermore, as atorvastatin, a cholesterol-lowering agent, is documented for its immunomodulatory properties, its effect on PD-L1 expression was investigated. In this study, through real-time RT-PCR, Western blot, and immunocytochemistry methods, PD-L1 expression in both mRNA and protein levels was found to be synergistically upregulated in HepG2 by a combination of IFNγ and TNFα, and STAT1 activation was mainly responsible for that synergistic effect. Next, atorvastatin can inhibit the induction of PD-L1 by either IFNγ alone or IFNγ/TNFα combination treatment in HepG2 cells. In conclusion, in HepG2 cells, expression of PD-L1 was augmented by cytokines in the tumor microenvironment, and the effect of atorvastatin on tumor immune response through inhibition of PD-L1 induction should be taken into consideration in cancer patients who have been prescribed atorvastatin.