Immunotherapy using immune checkpoint inhibitors (ICIs) has become a prominent strategy for cancer treatment over the past ten years. However, the efficacy of ICIs remains limited, with certain cancers exhibiting resistance to these therapeutic approaches. Consequently, several immune checkpoint proteins are presently being thoroughly screened and assessed in both preclinical and clinical studies. Among these candidates, T cell immunoglobulin and mucin-domain containing-3 (TIM-3) is considered a promising target. TIM-3 exhibits multiple immunosuppressive effects on various types of immune cells. Given its differential expression levels at distinct stages of T cell dysfunction in the tumor microenvironment (TME), TIM-3, along with programmed cell death protein 1 (PD-1), serves as indicators of T cell exhaustion. Moreover, it is crucial to carefully evaluate the impact of TIM-3 and PD-1 expression in cancer cells on the efficacy of immunotherapy. To increase the effectiveness of anti-TIM-3 and anti-PD-1 therapies, it is proposed to combine the inhibition of TIM-3, PD-1, and programmed death-ligand 1 (PD-L1). The efficacy of TIM-3 inhibition in conjunction with PD-1/PD-L1 inhibitors is being evaluated in a number of ongoing clinical trials for patients with various cancers. This study systematically investigates the fundamental biology of TIM-3 and PD-1, as well as the detailed mechanisms through which TIM-3 and PD-1/PD-L1 axis contribute to cancer immune evasion. Additionally, this article provides a thorough analysis of ongoing clinical trials evaluating the synergistic effects of combining PD-1/PD-L1 and TIM-3 inhibitors in anti-cancer treatment, along with an overview of the current status of TIM-3 and PD-1 antibodies.

Tumor-draining lymph nodes (TDLNs) play a pivotal role in tumor growth and the immune response, activating immune cells such as CD8 + T cells and natural killer cells to combat tumors. However, tumors can subvert TDLNs to avoid immune attack. Initially, TDLNs stimulate a robust antitumor response, but as tumor evolve, they infiltrate with immunosuppressive cells that alter the TDLN environment and potentially promote metastasis. Immunotherapy, including immune checkpoint inhibitor (ICI), have emerged as a potential solution to this challenge by reconfiguring the TDLN environment to enhance immune responses and influence the immune status of the primary tumor. The integrity of the TDLNs is crucial for the efficacy of immunotherapy. Conventional surgery often removes TDLNs, but this may impede immune system function and the effectiveness of immunotherapy. It is therefore recommended that removal of TDLNs be considered after neoadjuvant treatment rather than before adjuvant treatment. Accurate identification of patients who require post-neoadjuvant TDLN removal and the determination of metastatic nodes is of paramount importance in tailoring treatment plans, optimizing of patient outcomes, and improving quality of life.

To investigate the impact of glucocorticoids (GCs) and anti-rheumatic drugs on lymphocyte activation gene-3 (LAG-3) and on programmed cell death-1 (PD-1) expression by synovial and peripheral cells ex vivo.

Synovial fluid mononuclear cells (SFMCs) from psoriatic arthritis (PsA, n = 26) and rheumatoid arthritis (RA, n = 13) patients, synovial fluid cells (SFCs) from osteoarthritis (OA, n = 5) patients and peripheral blood mononuclear cells (PBMCs) of healthy donors (n = 14) were co-cultured with GCs, glucocorticoid receptor antagonist RU486, methotrexate (MTX) and biologics. LAG-3 and PD-1 expression on immune subsets were analysed by flow cytometry.

GCs in PsA inhibited SFMC growth vs medium [2.3 (0.4) × 105vs 5.3 (0.7) × 105, respectively, P < 0.01] and markedly up-regulated CD14+LAG-3+ cells [11.7 (2.4)% vs 0.8 (0.3)%, P < 0.0001, respectively], but not CD3+LAG-3+ and CD14+PD-1+ cells. MTX had no effect on CD14+LAG-3+ cells [0.7 (0.3)%]. The TNF inhibitors infliximab (IFX) and etanercept, but not IL-12/23 inhibitor, up-regulated CD14+LAG-3+ cells vs medium [2.0 (0.6)% and 1.6 (0.4)% vs 0.5 (0.1)%, P < 0.03, respectively]. SFMC growth inhibition by GC in both PsA and RA correlated with CD14+LAG-3+ cell up-regulation (r = 0.53, P = 0.03). RU486 inhibited GC-induced CD14+LAG-3+ cells up-regulation in a dose-dependent manner compared with GC alone [5 µM 5.3 (1.2)% and 50 µM 1.3 (0.5)% vs 7.0 (1.4)%, P < 0.003], but had no significant effect on CD14+LAG-3+ cells co-cultured with IFX. GCs in healthy donors' PBMCs up-regulated the immune subsets CD3+LAG-3+, CD14+LAG-3+ and CD14+PD-1+ cells.

This study proposes a novel regulatory mechanism of GCs and of TNF inhibitors mediated by LAG-3 up-regulation in synovial cells and PBMCs. LAG-3 modulation may be a promising target for development of novel therapies for inflammatory arthritis.

Leishmania (Leishmania) infantum chagasi infections range from asymptomatic (AS) to severe visceral leishmaniasis (VL). One of the manifestations is an atypical non-ulcerated cutaneous leishmaniasis (NUCL), which occurs in some locations of Central America with few cases of VL. We conducted a transcriptomic analysis of cell-mediated immunity (CMI) on blood samples from NUCL, AS, VL patients from Amapala, Honduras, and healthy controls. RNA-seq revealed a similar perturbation of gene expression in NUCL and AS. Eight gene signatures of CMI were found in NUCL involved in CD8+ T lymphocyte infiltration, reactive oxygen species generation, PD-1 receptor ligand, inflammasome assembly, chemotaxis, complement receptor and suppressor immune cell infiltration. NUCL was distinguished from VL by its up-regulation of differently expressed genes (DEGs) related to T lymphocyte exhaustion, adhesion and transmigration of leukocytes, and down-regulation of oxidative stress genes. In contrast, VL exhibited up-regulated DEGs involved in antigen cross-presentation, and similar to VL from Brazil, down-regulated DEGs involved in innate immunity. Corroborating the transcriptome findings, both the Leishmanin skin test, and the immunopathology of NUCL skin lesion defined NUCL as a proinflammatory condition, intermediate between the AS and VL clinical outcomes. That condition may be the underlying element for the benign nature of the NUCL.

Proteasomes generate antigenic peptides presented on cell surfaces-a process that, in neuroglia, is highly responsive to external stimuli. However, the function of the self-antigens presented by CNS parenchymal cells remains unclear. Here, we report that the fidelity of neuroglial self-antigens is crucial to suppress encephalitogenic T cell responses by elevating regulatory T (Treg) cell populations. We demonstrate that loss of the proteasome adaptor protein Ecm29 alters the efficacy and accuracy of antigen generation. Inducible oligodendroglia- or microglia-conditional Ecm29 knockout mice exhibit higher susceptibility to experimental autoimmune encephalomyelitis (EAE) than control counterparts do, coincident with reduced Treg cell populations in the spinal cord. Immunopeptidome profiling identifies self-antigens that modulate myelin-reactive T cell responses. Intraspinal adeno-associated virus (AAV)/Olig001-mediated expression of the self-antigen NDUFA1p ameliorates EAE and expands NDUFA1p-recognizing CD103+CD8+CD122+ Treg cells. Thus, Ecm29/proteasome-controlled, neuroglia-derived self-antigens modulate CNS immune tolerance.

The development of nanobodies targeting Programmed Cell Death Protein-1 (PD-1) offers a promising approach in cancer immunotherapy. This study aims to design and characterize a PD-1-specific nanobody using an integrated computational and experimental approach.

An in silico design strategy was employed, involving Complementarity-Determining Region (CDR) grafting to construct the nanobody sequence. The three-dimensional structure of the nanobody was predicted using AlphaFold2, and molecular docking simulations via ClusPro were conducted to evaluate binding interactions with PD-1. Physicochemical properties, including stability and solubility, were analyzed using web-based tools, while molecular dynamics (MD) simulations assessed stability under physiological conditions. The nanobody was produced and purified using Ni-NTA chromatography, and experimental validation was performed through Western blotting, ELISA, and dot blot analysis.

Computational findings demonstrated favorable binding interactions, stability, and physicochemical properties of the nanobody. Experimental results confirmed the nanobody's specific binding affinity to PD-1, with ELISA and dot blot analyses providing evidence of robust interaction.

This study highlights the potential of combining computational and experimental approaches for engineering nanobodies. The engineered PD-1 nanobody exhibits promising characteristics, making it a strong candidate for further testing in cancer immunotherapy applications.

Mechanistic understanding of the inhibitory immunoreceptor PD-1 is largely based on mouse models, but human and mouse PD-1 share only 59.6% amino acid identity. Here, we found that human PD-1 is more inhibitory than mouse PD-1, owing to stronger interactions with the ligands PD-L1 and PD-L2 and more efficient recruitment of the effector phosphatase Shp2. In a mouse melanoma model with adoptively transferred T cells, humanization of a PD-1 intracellular domain disrupted the antitumor activity of CD8+ T cells and increased the magnitude of anti-PD-1 response. We identified a motif highly conserved across vertebrate PD-1 orthologs, absent in rodents, as a key determinant for differential Shp2 recruitment. Evolutionary analysis suggested that PD-1 underwent a rodent lineage-specific functional attenuation during evolution. Together, our study uncovers species-specific features of the PD-1 pathway, with implications for PD-1 evolution and differential anti-PD-(L)1 responses in mouse models and human patients.

Advances in understanding of AA have led to the first approved therapies for this disease, and in the past two years, there have been three medicines approved for the treatment of severe alopecia areata. There are numerous clinical trials of novel therapeutics underway across the spectrum of AA.

Thyroid eye disease (TED) primarily occurs in hyperthyroid patients, sometimes resulting in poor visual prognosis. Although other autoimmune diseases have been reported to be associated with serum programmed cell death 1 (PD-1), the relationship with TED remains unknown. This study investigated the relationship between TED and immune checkpoint molecules.

Serum immune checkpoint molecules were measured in TED and control patient blood samples. In TED patients, blood samples were compared before and 6 months after steroid pulse treatment. Cytometry analysis was additionally performed in TED and control patients to compare the expression of (PD-1) of T cells.

Serum concentrations of PD-1 in TED and control patients were 163.49 ± 79.01 (pg/mL) and 123.58 ± 46.61 (pg/mL) (P = 0.03). Serum PD-L1 concentration in TED was 157.89 ± 55.34 (pg/mL), while 152.58 ± 22.70 (pg/mL) in control patients (P = 0.92). For flow cytometry analysis, the mean fluorescence intensity (MFI) ratio of PD-1 in Foxp3high CD45RA- of the CD4+ T cells and CD127-CD25high of the CD4+ T cells were higher in TED versus control patients (P = 0.04, P = 0.02). There was also a higher percentage of PD-1 expressions on CD4+ T cells and Foxp3high CD45- T cells in TED patients versus that for control patients (P < 0.001, P = 0.003).

PD-1 expression of CD4+Foxp3+ regulatory T cells appear to be associated with TED pathogenesis before and after treatment. Regulatory T cells expressed PD-1 have possibilities of clinical activity and autoimmune pathology of TED.

Mechanistic understanding of the immune checkpoint receptor PD1 is largely based on mouse models, but human and mouse PD1 orthologs exhibit only 59.6% identity in amino acid sequences. Here we show that human PD1 is more inhibitory than mouse PD1 due to stronger interactions with the ligands PDL1 and PDL2 and with the effector phosphatase Shp2. A novel motif highly conserved among PD1 orthologs in vertebrates except in rodents is primarily responsible for the differential Shp2 recruitment. Evolutionary analysis suggested that rodent PD1 orthologs uniquely underwent functional relaxation, particularly during the K-Pg boundary. Humanization of the PD1 intracellular domain disrupted the anti-tumor activity of mouse T cells while increasing the magnitude of anti-PD1 response. Together, our study uncovers species-specific features of the PD1 pathway, with implications to PD1 evolution and differential anti-PD(L)1 responses in mouse models and human patients.

Despite advances in understanding systemic lupus erythematosus (SLE), many challenges remain in unraveling the precise mechanisms behind the disease's development and progression. Recent evidence has questioned the role of programmed cell death protein 1 (PD-1) in suppressing autoreactive CD4+ T cells during autoimmune responses. Research has investigated the potential impacts of PD-1 on various CD4+ T-cell subpopulations, including T follicular helper (Tfh) cells, circulating Tfh (cTfh) cells, and T peripheral helper (Tph) cells, all of which exhibit substantial PD-1 expression and are closely related to several autoimmune disorders, including SLE. This review highlights the complex role of PD-1 in autoimmunity and emphasizes the imperative for further research to elucidate its functions during autoreactive T-cell responses. Additionally, we address the potential of PD-1 and its ligands as possible therapeutic targets in SLE.

PD-1 has a noteworthy function in developing acute myeloid leukemia (AML). The expression of PD-1 on effector T cells is regulated at the protein level depending on the interactions between cells. The objective of the study was to evaluate the PD-1 concentration levels and the polymorphism genetic variants (rs36084323 G/A) in Iraqi Arab patients with AML. Sanger's DNA sequencing was used, and the assessments were done by enzyme-linked immunosorbent assay and PD-1 gene polymorphism SNP rs36084323 G/A. The frequency of rs36084323 was significantly different between AML and control, with a lower risk for AML seen in patients with GA genotype (odds ratio; 95% confidence interval: 0.53; 0.32-0.87). PD-1 elevated AML compared to control (213.1 pg/mL vs. 178.8 pg/mL). in AML patients, there is upregulation in PD-1, which indicates that PD-1 is a possible biomarker for AML. PD-1 rs36084323 G/A may have a role in AML risk.

PD-1 (programmed Death-1) immune checkpoint inhibitors have provided significant benefits to tumor patients. However, a considerable proportion of the patients develop immune-related adverse events (irAEs), of which cutaneous irAEs (cirAEs, e.g., psoriasis) occur relatively early. This review provides an overview of the current progress in psoriasis de novo or exacerbation by PD-1 checkpoint inhibitors. It not only describes the relevant influencing factors but also theoretically analyzes the immunological mechanisms that lead to the onset or exacerbation of psoriasis. Finally, the authors present guidelines for the treatment of psoriasis de novo or exacerbation by PD-1 checkpoint inhibitors. The review is intended to assist dermatologists in the early recognition and effective individualized management of such cirAE, which is helpful to continue or adjust the tumor-targeted immunotherapy on the basis of ensuring the quality of life of tumor patients.

Thymic negative selection of the T cell receptor (TCR) repertoire is essential for establishing self-tolerance and acquired allograft tolerance following organ transplantation. However, it is unclear whether and how peripheral clonal deletion of alloreactive T cells induces transplantation tolerance. Here, we establish that programmed cell death protein 1 (PD-1) is a hallmark of alloreactive T cells and is associated with clonal expansion after alloantigen encounter. Moreover, we found that diphtheria toxin receptor (DTR)-mediated ablation of PD-1+ cells reshaped the TCR repertoire through peripheral clonal deletion of alloreactive T cells and promoted tolerance in mouse transplantation models. In addition, by using PD-1-specific depleting antibodies, we found that antibody-mediated depletion of PD-1+ cells prevented heart transplant rejection and the development of experimental autoimmune encephalomyelitis (EAE) in humanized PD-1 mice. Thus, these data suggest that PD-1 is an attractive target for peripheral clonal deletion and induction of immune tolerance.

The landscape of cancer treatment has undergone a significant transformation with the introduction of Immune Checkpoint Inhibitors (ICIs). Patients undergoing these treatments often report prolonged clinical and radiological responses, albeit with a potential risk of developing immune-related adverse events (irAEs). Here, we reviewed and discussed the mechanisms of action of ICIs and their pivotal role in regulating the immune system to enhance the anti-tumor immune response. We scrutinized the intricate pathogenic mechanisms responsible for irAEs, arising from the evasion of self-tolerance checkpoints due to drug-induced immune modulation. We also summarized the main clinical manifestations due to irAEs categorized by organ types, detailing their incidence and associated risk factors. The occurrence of irAEs is more frequent when ICIs are combined; with neurological, cardiovascular, hematological, and rheumatic irAEs more commonly linked to PD1/PD-L1 inhibitors and cutaneous and gastrointestinal irAEs more prevalent with CTLA4 inhibitors. Due to the often-nonspecific signs and symptoms, the diagnosis of irAEs (especially for those rare ones) can be challenging. The differential with primary autoimmune disorders becomes sometimes intricate, given the clinical and pathophysiological similarities. In conclusion, considering the escalating use of ICIs, this area of research necessitates additional clinical studies and practical insights, especially the development of biomarkers for predicting immune toxicities. In addition, there is a need for heightened education for both clinicians and patients to enhance understanding and awareness.

Immune checkpoint inhibitors (ICIs) are reshaping the prognosis of many cancers, but often cause immune-related adverse events (irAEs). Among neurological irAEs, myositis is the most frequently reported. Our aim is to describe clinical and non-clinical characteristics, treatment and outcome of all irMyositis (skeletal limb-girdle and/or ocular myositis) and irMyocarditis cases in our reference center.

We retrospectively enrolled all irMyositis/irMyocarditis patients seen between 2018 and 2022. We reviewed demographics, clinical characteristics, biological, neurophysiological, imaging workup, treatment and outcome.

We included 14 consecutive patients. The most frequent treatments were pembrolizumab (35%) or ipilimumab-nivolumab combination (35%). Limb-girdle, ocular (non-fluctuating palpebral ptosis and/or diplopia with or without ophthalmoparesis) and cardiac phenotypes were equally distributed, overlapping in 40% of cases. Ocular involvement was frequently misdiagnosed; review of brain MRIs disclosed initially missed signs of skeletal myositis in one patient and ocular myositis in 3. Seven patients had other co-existing irAEs. When performed, myography showed a myogenic pattern. CK was elevated in 8/15 patients, troponin-T in 12/12 and troponin-I in 7/9 tested patients. ICI were discontinued in all cases, with further immunosuppressive treatment in nine patients. In most cases, neurological and cardiological outcome was good at last follow-up.

Myositis is a potentially severe irAE. Despite its heterogeneous presentation, some highly suggestive clinical symptoms, such as ocular involvement, or radiological signs should raise physicians' attention to avoid misdiagnosis. We thus recommend a multidisciplinary assessment (including complete neuromuscular evaluation) even in case of isolated myocarditis. Our series underlines the importance of an early diagnosis, since suspension of ICI and adequate treatment are usually associated with good functional outcome.

Checkpoint inhibitors, such as PD1 inhibitors, represent an important pillar in the therapy of advanced malignancies of the head and neck region. The most relevant complications are immune-related adverse effects (irAEs), which represent an immense burden for patients. Currently, no sufficient stratification measures are available to identify patients at increased risk of irAEs. The aim of this retrospective study was to examine whether demographic, histopathological, clinical, or laboratory values at the start of CPI therapy represent a risk factor for the later occurrence of autoimmune complications.

Data from 35 patients between 2018 and 2021 who received therapy with nivolumab or pembrolizumab for head and neck malignancy were analyzed and assessed for any associations with the subsequent occurrence of irAEs.

IrAE developed in 37% of patients, with pneumonitis being the most common form (14%). Pneumonitis was found in patients with an average significantly lower T-stage of primary tumors. An increase in basophilic leukocytes was found in patients with dermatitis later in the course. When thyroiditis developed later, the patients had a higher CPS score and lower monocyte levels.

Even though individual laboratory values at the beginning of therapy might show a statistical association with the later occurrence of irAEs, neither demographic, histopathological, nor laboratory chemistry values seem to be able to generate a sound and reliable risk profile for this type of complication. Therefore, patients need to be educated and sensitized to irAEs, and regular screening for irAEs should be carried out.

Cutaneous squamous cell carcinomas (SCCs) are a major complication of some subtypes of epidermolysis bullosa (EB), with high morbidity and mortality rates and unmet therapeutic needs. The high rate of endogenous mutations and the fibrotic stroma are considered to contribute to the pathogenesis. Patients with dystrophic EB (DEB) and Kindler EB (KEB) have the highest propensity for developing SCCs. Another patient group that develops high-risk SCCs is immunosuppressed (IS) patients, especially after organ transplantation. Herein, we interrogate whether immune checkpoint proteins and immunosuppressive enzymes are dysregulated in EB-associated SCCs as an immune resistance mechanism and compare the expression patterns with those in SCCs from IS patients, who frequently develop high-risk tumors and sporadic SCCs, and immunocompetent (IC) individuals. The expression of indoleamine 2,3-dioxygenase (IDO), programmed cell death protein-1 (PD-1), programmed cell death ligand-1 (PD-L1), T cell immunoglobulin and mucin-domain-containing protein-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), and inflammatory infiltrates (CD4, CD8, and CD68) was assessed via immunohistochemistry and semi-quantitative analysis in 30 DEB-SCCs, 22 KEB-SCCs, 106 IS-SCCs, and 100 sporadic IC-SCCs. DEB-SCCs expressed significantly higher levels of IDO and PD-L1 in tumor cells and PD-1 in the tumor microenvironment (TME) compared with SCCs from IC and IS individuals. The number of CD4-positive T cells per mm2 was significantly lower in DEB-SCCs compared with IC-SCCs. KEB-SCCs showed the lowest expression of the exhaustion markers TIM-3 and LAG-3 compared with all other groups. These findings identify IDO, PD-1, and PD-L1 to be increased in EB-SCCs and candidate targets for combinatory treatments, especially in DEB-SCCs.

Highly self-reactive T cells are censored from the repertoire by both central and peripheral tolerance mechanisms upon receipt of high-affinity TCR signals. Clonal deletion is considered a major driver of central tolerance; however, other mechanisms such as induction of regulatory T cells and functional impairment have been described. An understanding of the interplay between these different central tolerance mechanisms is still lacking. We previously showed that impaired clonal deletion to a model tissue-restricted Ag did not compromise tolerance. In this study, we determined that murine T cells that failed clonal deletion were rendered functionally impaired in the thymus. Programmed cell death protein 1 (PD-1) was induced in the thymus and was required to establish cell-intrinsic tolerance to tissue-restricted Ag in CD8+ thymocytes independently of clonal deletion. In bone marrow chimeras, tolerance was not observed in PD-L1-deficient recipients, but tolerance was largely maintained following adoptive transfer of tolerant thymocytes or T cells to PD-L1-deficient recipients. However, CRISPR-mediated ablation of PD-1 in tolerant T cells resulted in broken tolerance, suggesting different PD-1 signaling requirements for establishing versus maintaining tolerance. Finally, we showed that chronic exposure to high-affinity Ag supported the long-term maintenance of tolerance. Taken together, our study identifies a critical role for PD-1 in establishing central tolerance in autoreactive T cells that escape clonal deletion. It also sheds light on potential mechanisms of action of anti-PD-1 pathway immune checkpoint blockade and the development of immune-related adverse events.

Relationship between surface antigen differentiation cluster 274 (CD274) gene polymorphism and systemic lupus erythematosus (SLE) risk is limited. This study aims to discuss whether in a Chinese Han population, CD274 gene polymorphisms may relate to SLE susceptibility.

Three hundred and ten SLE patients and 390 healthy controls were included in this case-control study. Using the Kompetitive Allele-Specific PCR (KASP) approach, five single nucleotide polymorphisms (SNPs), including rs2890658, rs4143815, rs822339, rs2282055, and rs2297137, were genotyped for CD274 gene polymorphisms. Correlation between the polymorphisms and clinical, laboratory features in SLE patients were discussed.

Frequency of C allele was substantially lower in SLE patients than in healthy controls (p = .015), and CC genotype was significantly negatively related to developing SLE at locus rs4143815 (p = .013). At locus rs822339, frequency of GA genotype was higher than that of the healthy controls (p = .006). At locus rs2282055, frequency of GG genotype was lower than that of healthy controls (p = .024). According to subgroup analysis, the CD274 gene polymorphisms rs2890658, rs4143815, rs822339, rs2282055, and rs2297137 were partly linked to some clinical symptoms of SLE patients, such as Complement 4 (C4), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR).

CD274 gene polymorphisms may be susceptible to SLE in the Chinese Han people.

The current understanding of long COVID (LC) is still limited. This review highlights key findings regarding the role of gut microbiota, mitochondria, and the main pathophysiological aspects of LC revealed by clinical studies, related to the complex interplay between infection, intestinal dysbiosis, dysfunctional mitochondria, and systemic inflammation generated in a vicious circle, reflecting the molecular and cellular processes from the "leaky gut" to the "leaky electron transport chain (ETC)" into a quantum leap. The heterogeneity of LC has hindered progress in deciphering all the pathophysiological mechanisms, and therefore, the approach must be multidisciplinary, with a special focus not only on symptomatic management but also on addressing the underlying health problems of the patients. It is imperative to further assess and validate the effects of COVID-19 and LC on the gut microbiome and their relationship to infections with other viral agents or pathogens. Further studies are needed to better understand LC and expand the interdisciplinary points of view that are required to accurately diagnose and effectively treat this heterogeneous condition. Given the ability of SARS-CoV-2 to induce autoimmunity in susceptible patients, they should be monitored for symptoms of autoimmune disease after contracting the viral infection. One question remains open, namely, whether the various vaccines developed to end the pandemic will also induce autoimmunity. Recent data highlighted in this review have revealed that the persistence of SARS-CoV-2 and dysfunctional mitochondria in organs such as the heart and, to a lesser extent, the kidneys, liver, and lymph nodes, long after the organism has been able to clear the virus from the lungs, could be an explanation for LC.

It is unclear how the immune system initiates effective tissue repair responses without also simultaneously activating adaptive immune responses to self-antigens released by damaged or necrotic cells. We studied the role of repetitive adrenergic mediated stress on cardiac injury wild-type and programmed death-1-deficient (PD-1-/-) mice treated with 3 intraperitoneal low doses of isoproterenol followed by an intraperitoneal injection of high-dose ISO 7 days later (ISOprimed/ISOinjury). Repetitive adrenergic stress in ISOprimed/ISOinjury PD-1-/- mice resulted in a persistent dysregulated myocardial inflammatory response characterized by the expansion of autoreactive effector CD8+ T cells, increased cardiac hypertrophy, mild left ventricular dysfunction, and increased lethality when compared with ISOprimed/ISOinjury wild-type mice.

Alopecia areata (AA) is an autoimmune disease that has a complex underlying immunopathogenesis characterized by nonscarring hair loss ranging from small bald patches to complete loss of scalp, face, and/or body hair. Although the etiopathogenesis of AA has not yet been fully characterized, immune privilege collapse at the hair follicle (HF) followed by T-cell receptor recognition of exposed HF autoantigens by autoreactive cytotoxic CD8+ T cells is now understood to play a central role. Few treatment options are available, with the Janus kinase (JAK) 1/2 inhibitor baricitinib (2022) and the selective JAK3/tyrosine kinase expressed in hepatocellular carcinoma (TEC) inhibitor ritlecitinib (2023) being the only US Food and Drug Administration-approved systemic medications thus far for severe AA. Several other treatments are used off-label with limited efficacy and/or suboptimal safety and tolerability. With an increased understanding of the T-cell-mediated autoimmune and inflammatory pathogenesis of AA, additional therapeutic pathways beyond JAK inhibition are currently under investigation for the development of AA therapies. This narrative review presents a detailed overview about the role of T cells and T-cell-signaling pathways in the pathogenesis of AA, with a focus on those pathways targeted by drugs in clinical development for the treatment of AA. A detailed summary of new drugs targeting these pathways with expert commentary on future directions for AA drug development and the importance of targeting multiple T-cell-signaling pathways is also provided in this review.

T cells demonstrate high degree of complexity and broad range of functions, which distinguish them from other immune cells. Throughout their lifetime, T lymphocytes experience several functional states: quiescence, activation, proliferation, differentiation, performance of effector and regulatory functions, memory formation, and apoptosis. Metabolism supports all functions of T cells, providing lymphocytes with energy, biosynthetic substrates, and signaling molecules. Therefore, T cells usually restructure their metabolism as they transition from one functional state to another. Strong association between the metabolism and T cell functions implies that the immune response can be controlled by manipulating metabolic processes within T lymphocytes. This review aims to highlight the main metabolic adaptations necessary for the T cell function, as well as the recent progress in techniques to modulate metabolic features of lymphocytes.

γδ T cells have the unique ability to detect a wide range of tumors with low mutation burdens, making them attractive candidates for CAR-T-cell therapy. Unlike αβ T cells and other immune cells, γδ T cells are superior in MHC non-restriction, selective cell recruitment, and rapid activation. However, clinical trials have shown limited clinical benefits, and the adoptive transplantation of γδ T cells has often fallen short of expectations. We hypothesized that the limited effectiveness of γδ T cells in eradicating tumor cells may be attributed to the inhibitory tumor microenvironment induced by the suppressive PD-1/PD-L1 axis. Herein, we constructed novel armored γδ T cells capable of secreting humanized anti-PD-1 antibodies, referred to as "Lv-PD1-γδ T cells. Lv-PD1-γδ T cells showed improved proliferation and enhanced cytotoxicity against tumor cells, resulting in augmented therapeutic effects and survival benefits in ovarian tumor-bearing mice. These engineered cells demonstrated a prolonged in vivo survival of more than 29 days, without any potential for tumorigenicity in immunodeficient NOD/SCID/γ null mice. We also found that Lv-PD1-γδ T cells exhibited excellent tolerance and safety in humanized NOD/SCID/γ null mice. With attenuated or eliminated immunosuppression and maximized cytotoxicity efficacy by the local secretion of anti-PD1 antibodies in tumors, Lv-PD1-γδ T cells can serve as a promising "off-the-shelf" cell therapy against cancers.

Checkpoint inhibitors such as PD-1/PD-L1 antibody therapeutics are a promising option for the treatment of multiple cancers. Due to the inherent limitations of antibodies, great efforts have been devoted to developing small-molecule PD-1/PD-L1 signaling pathway inhibitors. In this study we established a high-throughput AlphaLISA assay to discover small molecules with new skeletons that could block PD-1/PD-L1 interaction. We screened a small-molecule library of 4169 compounds including natural products, FDA approved drugs and other synthetic compounds. Among the 8 potential hits, we found that cisplatin, a first-line chemotherapeutic drug, reduced AlphaLISA signal with an EC50 of 8.3 ± 2.2 μM. Furthermore, we showed that cisplatin-DMSO adduct, but not semplice cisplatin, inhibited PD-1/PD-L1 interaction. Thus, we assessed several commercial platinum (II) compounds, and found that bis(benzonitrile) dichloroplatinum (II) disturbed PD-1/PD-L1 interaction (EC50 = 13.2 ± 3.5 μM). Its inhibitory activity on PD-1/PD-L1 interaction was confirmed in co-immunoprecipitation and PD-1/PD-L1 signaling pathway blockade bioassays. Surface plasmon resonance assay revealed that bis(benzonitrile) dichloroplatinum (II) bound to PD-1 (KD = 2.08 μM) but not PD-L1. In immune-competent wild-type mice but not in immunodeficient nude mice, bis(benzonitrile) dichloroplatinum (II) (7.5 mg/kg, i.p., every 3 days) significantly suppressed the growth of MC38 colorectal cancer xenografts with increasing tumor-infiltrating T cells. These data highlight that platinum compounds are potential immune checkpoint inhibitors for the treatment of cancers.

Blockade of the programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) immune checkpoint pathway is an efficient immunotherapeutic modality that provided significant advances in cancer treatment especially in solid tumors highly resistant to traditional therapy. Monoclonal antibodies (mAbs) and small-molecule inhibitors are the two main strategies used to block this axis with mAbs suffering from many limitations. Accordingly, the current alternative is the development of small-molecule PD-1/PD-L1 inhibitors. Here, we present a sequential virtual screening (VS) protocol involving pharmacophore screening followed by molecular docking for the discovery of novel PD-L1 inhibitors. The VS protocol resulted in the discovery of eight novel compounds. A 100 ns MD simulation showed two compounds, H4 and H6, exhibiting a stable binding mode at the PD-L1 dimer interface. Upon evaluation of their immunological activities, the two compounds induced higher cytokines levels (IL-2, IL-6, and INF-γ) relative to BMS-202, 72 h post treatment of PBMCs of HCC patients. Thus, the discovered hits represent potential leads for the development of novel classes targeting the PD-L1 receptor as anti-hepatocellular carcinoma agents.

T-cell exhaustion is a key stage in chronic infections since it limits immunopathology, but also hinders the elimination of pathogens. Exhausted T (Tex) cells encompass dynamic subsets, including progenitor cells that sustain long-term immunity through their memory/stem like properties, and terminally-differentiated cells, resembling the so-called Tex cells. The presence of Tex cells in chronic leishmaniasis has been reported in humans and murine models, yet their heterogeneity remains unexplored. Using flow cytometry, we identified Tex cells subtypes based on PD-1, CXCR5 and TIM-3 expressions in draining lymph nodes (dLNs) and lesion sites of C57BL/6 mice infected with L. mexicana at 30-, 60- and 90-days post-infection. We showed that infected mice developed a chronic infection characterized by non-healing lesions with a high parasite load and impaired Th1/Th2 cytokine production. Throughout the infection, PD-1+ cells were observed in dLNs, in addition to an enhanced expression of PD-1 in both CD4+ and CD8+ T lymphocytes. We demonstrated that CD4+ and CD8+ T cells were subdivided into PD-1+CXCR5+TIM-3- (CXCR5+), PD-1+CXCR5+TIM-3+ (CXCR5+TIM-3+), and PD-1+CXCR5-TIM-3+ (TIM-3+) subsets. CXCR5+ Tex cells were detected in dLNs during the whole course of the infection, whereas TIM-3+ cells were predominantly localized in the infection sites at day 90. CXCR5+TIM-3+ cells only increased at 30 and 60 days of infection in dLNs, whereas no increase was observed in the lesions. Phenotypic analysis revealed that CXCR5+ cells expressed significantly higher levels of CCR7 and lower levels of CX3CR1, PD-1, TIM-3, and CD39 compared to the TIM-3+ subset. CXCR5+TIM-3+ cells expressed the highest levels of all exhaustion-associated markers and of CX3CR1. In agreement with a less exhausted phenotype, the frequency of proliferating Ki-67 and IFN-γ expressing cells was significantly higher in the CXCR5+ subset within both CD4+ and CD8+ T cells compared to their respective TIM-3+ subsets, whereas CD8+CXCR5+TIM-3+ and CD8+TIM-3+ subsets showed an enhanced frequency of degranulating CD107a+ cells. In summary, we identified a novel, less-differentiated CXCR5+ Tex subset in experimental cutaneous leishmaniasis caused by L. mexicana. Targeting these cells through immune checkpoint inhibitors such as anti-PD-1 or anti PD-L1 might improve the current treatment for patients with the chronic forms of leishmaniasis.

Proline and serine-rich coiled-coil 1 (PSRC1) has been reported to function as an oncogene in several cancers by regulating mitosis, while there are few reports on the role of PSRC1 in lower-grade glioma (LGG). Thus, this study collected 22 samples and 1126 samples from our institution and several databases, respectively, to explore the function of PSRC1 in LGG. First, the analysis of clinical characteristics showed that PSRC1 was always highly expressed in more malignant clinical characteristics of LGG, such as higher WHO grade, recurrence type, and IDH wild type. Second, the prognosis analysis revealed that the high expression of PSRC1 was an independent risk factor contributing to the shorter overall survival of LGG patients. Third, the analysis of DNA methylation showed that the expression of PSRC1 was associated with its 8 DNA methylation sites, overall negatively regulated by its DNA methylation level in LGG. Fourth, the analysis of immune correlation revealed that the expression of PSRC1 was positively correlated with the infiltration of 6 immune cells and the expression of 4 well-known immune checkpoints in LGG, respectively. Finally, co-expression analysis and KEGG analysis showed the 10 genes most related to PSRC1 and the signaling pathways involved by PSRC1 in LGG, respectively, such as MAPK signaling pathway and focal adhesion. In conclusion, this study identified the pathogenic role of PSRC1 in the pathological progression of LGG, expanding the molecular understanding of PSRC1, and provided a biomarker and potential immunotherapeutic target for the treatment of LGG.

Human programmed cell death protein 1 (PD-1) is a checkpoint protein involved in the regulation of immune response. Antibodies are widely used as inhibitors that block the immune checkpoint, preventing strong immune responses. Pembrolizumab is an FDA-approved IgG4 antibody with PD-1 inhibitory ability for the treatment of melanoma. In this study, we investigated the effect of Pembrolizumab on the conformational changes in PD-1 using extensive molecular modeling and simulation approaches. Our study revealed that during the 200 ns simulation, the average values of the solvent accessible surface area, the radius of gyration, and internal hydrogen bonds of PD-1 were 64.46 nm², 1.38 nm and 78, respectively, while these values of PD-1 in the PD-1/Pembrolizumab complex were 67.29 nm², 1.39 nm and 76, respectively. The RMSD value of PD-1 gradually increased until 80 ns and maintained its stable conformation at 0.32 nm after 80 ns, while this value of PD-1 in the PD-1/Pembrolizumab complex maintained an increasing trend during 200 ns. The interaction between PD-1 and Pembrolizumab led to a flexible but stable structure of PD-1. PD-1 rotated around the rotation axis of the C'D loop and gradually approached Pembrolizumab. The number of hydrogen bonds involved in the interactions on the C and C' strands increased from 4 at 100 ns to 7 at 200 ns. The strong affinity of Pembrolizumab for the C'D and FG loops of PD-1 disrupted the interactions between PD-1 and PD-L1. Inhibition of the interaction between PD-1 and PD-L1 increased the T cell activity, and is effective in controlling and curing cancer. Further experimental work can be performed to support this finding.

Programmed cell death protein 1 (PD-1) is a key receptor in the immune checkpoint pathway and has emerged to be a promising target for cancer therapy. PD-1 consists of an intracellular domain followed by a transmembrane domain that is connected to the extracellular domain by the stalk region. Although the PD-1 structure has been studied for more than two decades, the posttranslational modification of this protein has been incompletely characterized. In this study, we identified the previously undescribed modification sites of O-linked glycan on the stalk region of PD-1 protein using O-protease digestion coupling with intact mass analysis. The result indicates that T153, S157, S159, and T168 are modified by sialylated mucin-type O-glycan with core 1- and core 2-based structures. This study provides both information on potential novel modification sites on the PD-1 protein and an attractive method for identifying O-linked glycosylation using a specific enzyme and intact mass analysis.

Checkpoint inhibition (CPI) therapy and adoptive cell therapy with autologous tumor-infiltrating lymphocytes (TIL-based ACT) are the two most effective immunotherapies for the treatment of metastatic melanoma. While CPI has been the dominating therapy in the past decade, TIL-based ACT is beneficial for individuals even after progression on previous immunotherapies. Given that notable differences in response have been made when used as a subsequent treatment, we investigated how the qualities of TILs changed when the ex vivo microenvironment of intact tumor fragments were modulated with checkpoint inhibitors targeting programmed death receptor 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Initially, we show that unmodified TILs from CPI-resistant individuals can be produced, are overwhelmingly terminally differentiated, and are capable of responding to tumor. We then investigate these properties in ex vivo checkpoint modulated TILs finding that that they retain these qualities. Lastly, we confirmed the specificity of the TILs to the highest responding tumor antigens, and identified this reactivity resides largely in CD39+CD69+ terminally differentiated populations. Overall, we found that anti-PD-1 will alter the proliferative capacity while anti-CTLA4 will influence breadth of antigen specificity.

Peresolimab is a humanized IgG1 monoclonal antibody designed to stimulate the endogenous programmed cell death protein 1 (PD-1) inhibitory pathway. Stimulation of this pathway would be a novel approach to the treatment of patients with autoimmune or autoinflammatory diseases.

In this phase 2a, double-blind, randomized, placebo-controlled trial, we assigned, in a 2:1:1 ratio, adult patients with moderate-to-severe rheumatoid arthritis who had had an inadequate response to, a loss of response to, or unacceptable side effects with conventional synthetic disease-modifying antirheumatic drugs (DMARDs) or to biologic or targeted synthetic DMARDs to receive 700 mg of peresolimab, 300 mg of peresolimab, or placebo intravenously once every 4 weeks. The primary outcome was the change from baseline to week 12 in the Disease Activity Score for 28 joints based on the C-reactive protein level (DAS28-CRP). The DAS28-CRP ranges from 0 to 9.4, with higher scores indicating more severe disease. The primary comparison was between the 700-mg group and the placebo group. Secondary outcomes included the percentages of patients with American College of Rheumatology 20 (ACR20), ACR50, and ACR70 responses - defined as improvements from baseline of 20%, 50%, and 70% or more, respectively, in the numbers of tender and swollen joints and in at least three of five important domains - at week 12.

At week 12, the change from baseline in the DAS28-CRP was significantly greater in the 700-mg peresolimab group than in the placebo group (least-squares mean change [±SE], -2.09±0.18 vs. -0.99±0.26; difference in change, -1.09 [95% confidence interval, -1.73 to -0.46]; P<0.001). The results of the analyses of secondary outcomes favored the 700-mg dose over placebo with respect to the ACR20 response but not with respect to the ACR50 and ACR70 responses. Adverse events were similar in the peresolimab and placebo groups.

Peresolimab showed efficacy in a phase 2a trial in patients with rheumatoid arthritis. These results provide evidence that stimulation of the PD-1 receptor has potential efficacy in the treatment of rheumatoid arthritis. (Funded by Eli Lilly; ClinicalTrials.gov number, NCT04634253.).

Liver cancer, including hepatocellular carcinoma and intrahepatic cholangiocarcinoma, is increasing in incidence and mortality across the globe. An improved understanding of the complex tumor microenvironment has opened many therapeutic doors and led to the development of novel pharmaceuticals targeting cellular signaling pathways or immune checkpoints. These interventions have significantly improved tumor control rates and patient outcomes, both in clinical trials and in real-world practice. Interventional radiologists play an important role in the multidisciplinary team given their expertise in minimally invasive locoregional therapy, as the bulk of these tumors are usually in the liver. The aim of this review is to highlight the immunological therapeutic targets for primary liver cancers, the available immune-based approaches, and the contributions that interventional radiology can provide in the care of these patients.

Immune checkpoints are protein molecules expressed on the immune cell membrane, which regulate the immune system to kill tumor cells. As an essential immune checkpoint, overexpressed PD-1 on tumor cells could inhibit T-cell activation after being bonded to PD-1. Due to this inhibitory effect, T-cell proliferation and cytokine secretion are suppressed, leading to immune escape of tumor cells. Here, we established a high-throughput method based on cell function screening technology to screen drugs regulating PD-L1 expression in tumor cells at the transcriptional level. After two screening rounds, 12 compounds that enhanced PD-L1 transcription while seven weakened were sorted out among 1018 FDA-approved drugs. Finally, a tumor cell line was used to verify the upregulation of endogenous PD-L1 expression for a drug named "vorinostat," a histone deacetylation inhibitor, after the two rounds of optional selection. Therefore, our research provides another perspective for using "vorinostat" in treating tumors and offers a convenient method to detect the transcriptional expression of other intracellular proteins besides PD-L1.

Activation of PD-1 by anchoring it to Antigen Receptor (AR) components or associated co-receptors represents an attractive approach to treat autoimmune conditions. In this study, we provide evidence that CD48, a common lipid raft and Src kinase-associated coreceptor, induces significant Src kinase-dependent activation of PD-1 upon crosslinking, while CD71, a receptor excluded from these compartments, does not. Functionally, using bead-conjugated antibodies we demonstrate that CD48-dependent activation of PD-1 inhibits proliferation of AR-induced primary human T cells, and similarly, PD-1 activation using PD-1/CD48 bispecific antibodies inhibits IL-2, enhances IL-10 secretion, and reduces NFAT activation in primary human and Jurkat T cells, respectively. As a whole, CD48-dependent activation of PD-1 represents a novel mechanism to fine tune T cell activation, and by functionally anchoring PD-1 with receptors other than AR, this study provides a conceptual framework for rational development of novel therapies that activate inhibitory checkpoint receptors for treatment of immune-mediated diseases.

Periodontitis is a disease caused by infection and immunological imbalance, which often leads to the destruction of periodontal tissue. Programmed death protein 1 (PD-1) and its ligand: programmed death ligand 1 (PD-L1) are important "immune checkpoint" proteins that have a negative regulatory effect on T cells and are targets of immunotherapy. Studies have shown that the expression of PD-1 and PD-L1 in patients with periodontitis is higher than that in healthy individuals. The keystone pathogen Porphyromonas gingivalis (P. gingivalis) is believed to be the main factor driving the upregulation of PD-1/PD-L1. High expression of PD-1/PD-L1 can inhibit the inflammatory response and reduce the destruction of periodontal supporting tissues, but conversely, it can promote the "immune escape" of P. gingivalis, thus magnifying infections. In addition, the PD-1/PD-L1 pathway is also associated with various diseases, such as cancer and Alzheimer's disease. In this review, we discuss the influence and mechanism of the PD-1/PD-L1 pathway as a "double-edged sword" affecting the occurrence and development of periodontitis, as well as its function in periodontitis-related systemic disorders. The PD-1/PD-L1 pathway could be a new avenue for periodontal and its related systemic disorders therapy.

We identified 14 immune-related differentially Expressed Genes (DEGs) between COVID-19 patients and normal controls and the receiver operator characteristic curve results showed that they could be used to discriminate COVID-19 patients from healthy controls. Single-sample gene set enrichment analysis and CIBERSORT analysis displayed immune landscape of COVID-19 patients that the fraction of immune cells (like B cell subtypes and T cell subtypes) decreased distinctly in the first SARS-CoV-2 infection which may further weaken immunity of cancer patients and increasing inflammatory cells (Neutrophils and Macrophages) may further promote inflammatory response of cancer patients. Based on expression levels of 14 DEGs we found that first SARS-CoV-2 infection may accelerate progression of cancer patients by Kaplan-Meier survival, immune subtypes and tumor microenvironment analyses, and may weaken anti-PD-1 monoclonal antibody treatment effect of cancer patients by weighted gene co-expression network, tumor mutation burden and microsatellite instability analysis. The second SARS-CoV-2 infection was beneficial to control development of tumor seemingly, but it may be difficult for cancer patients to experience destroy successfully from first SARS-CoV-2 infection, let alone benefits from second SARS-CoV-2 infection. In addition, this study also emphasized significance of multi-factor analysis when analyzing impacts of SARS-CoV-2 infection on cancer patients.

Clear cell renal cell carcinoma (ccRCC) is one of the most common tumors in the world and affects human health seriously. PIMREG is a mitotic regulator which is essential to the metaphase-to-anaphase transition in cell cycle. Although PIMREG plays a crucial role in the malignant progression of tumors, there are few reports on its role in ccRCC.

The transcriptional expression profile and clinical data of PIMREG were downloaded from TCGA database and verified by qRT-PCR. Kaplan-Meier plotter was used to analyze the effect of PIMREG on overall survival (OS), disease specific survival (DSS) and progression-free interval (PFI) of patients with ccRCC. Univariable and multivariable Cox regression analysis were used to determine the independent prognostic factors of ccRCC. The effects of PIMREG on cell migration and invasion were detected by wound healing assay and transwell invasion assay, and CCK-8 assay, colony formation assay and cell cycle assay were used to detect the effect of PIMREG on cell proliferation. In addition, the changes in cell cycle related proteins were detected by western blot.

PIMREG was highly expressed in human ccRCC and was positively correlated with pathologic stage, TNM stage and histologic grade. In addition, patients with high expression of PIMREG had a poor prognosis. Univariable and multivariable Cox regression analysis identified that PIMREG was an independent prognostic factor of ccRCC. Additionally, PIMREG was also closely related to immune cell infiltration. Experiments in vitro identified that the knockdown of PIMREG could significantly inhibit the proliferation, migration and invasion abilities of ccRCC. The expression of cyclin D1, CDK4 and CDK6 was also significantly reduced after PIMREG knockdown.

PIMREG plays a vital role in the development of ccRCC and may become a potential therapeutic target in the future.

Dendritic cells (DCs), a kind of specialized immune cells, play key roles in antitumor immune response and promotion of innate and adaptive immune responses. Recently, many strategies have been developed to utilize DCs in cancer therapy, such as delivering antigens and adjuvants to DCs and using scaffold to recruit and activate DCs. Here we outline how different DC subsets influence antitumor immunity, summarize the FDA-approved vaccines and cancer vaccines under clinical trials, discuss the strategies for engineering DCs and noninvasive tracking of DCs to improve antitumor immunotherapy, and reveal the potential of artificial neural networks for the design of DC based vaccines.