Co-inhibitory Pathways Research Articles

Personalized neoantigen vaccines as early intervention in untreated patients with lymphoplasmacytic lymphoma: a non-randomized phase 1 trial

Lymphoplasmacytic lymphoma (LPL) is an incurable low-grade lymphoma with no standard therapy. Nine asymptomatic patients treated with a first-in-human, neoantigen DNA vaccine experienced no dose limiting toxicities (primary endpoint, NCT01209871). All patients achieve stable disease or better, with one minor response, and median time to progression of 72+ months. Post-vaccine single-cell transcriptomics reveal dichotomous antitumor responses, with reduced tumor B-cells (tracked by unique B cell receptor) and their survival pathways, but no change in clonal plasma cells. Downregulation of human leukocyte antigen (HLA) class II molecules and paradoxical upregulation of insulin-like growth factor (IGF) by the latter suggest resistance mechanisms. Vaccine therapy activates and expands bone marrow T-cell clonotypes, and functional neoantigen-specific responses (secondary endpoint), but not co-inhibitory pathways or Treg, and reduces protumoral signaling by myeloid cells, suggesting favorable perturbation of the tumor immune microenvironment. Future strategies may require combinations of vaccines with agents targeting plasma cell subpopulations, or blockade of IGF-1 signaling or myeloid cell checkpoints.

Advances and clinical applications of immune checkpoint inhibitors in hematological malignancies.

Immune checkpoints are differentially expressed on various immune cells to regulate immune responses in tumor microenvironment. Tumor cells can activate the immune checkpoint pathway to establish an immunosuppressive tumor microenvironment and inhibit the anti-tumor immune response, which may lead to tumor progression by evading immune surveillance. Interrupting co-inhibitory signaling pathways with immune checkpoint inhibitors (ICIs) could reinvigorate the anti-tumor immune response and promote immune-mediated eradication of tumor cells. As a milestone in tumor treatment, ICIs have been firstly used in solid tumors and subsequently expanded to hematological malignancies, which are in their infancy. Currently, immune checkpoints have been investigated as promising biomarkers and therapeutic targets in hematological malignancies, and novel immune checkpoints, such as signal regulatory protein α (SIRPα) and tumor necrosis factor-alpha-inducible protein 8-like 2 (TIPE2), are constantly being discovered. Numerous ICIs have received clinical approval for clinical application in the treatment of hematological malignancies, especially when used in combination with other strategies, including oncolytic viruses (OVs), neoantigen vaccines, bispecific antibodies (bsAb), bio-nanomaterials, tumor vaccines, and cytokine-induced killer (CIK) cells. Moreover, the proportion of individuals with hematological malignancies benefiting from ICIs remains lower than expected due to multiple mechanisms of drug resistance and immune-related adverse events (irAEs). Close monitoring and appropriate intervention are needed to mitigate irAEs while using ICIs. This review provided a comprehensive overview of immune checkpoints on different immune cells, the latest advances of ICIs and highlighted the clinical applications of immune checkpoints in hematological malignancies, including biomarkers, targets, combination of ICIs with other therapies, mechanisms of resistance to ICIs, and irAEs, which can provide novel insight into the future exploration of ICIs in tumor treatment.

Role of co‑inhibitory molecules in the treatment of psoriasis (Review).

Psoriasis is a common chronic inflammatory skin disease characterized by abnormal activation and infiltration of T-cells and excessive proliferation of keratinocytes (KCs). Its pathogenesis is complex and frequently accompanied by the imbalance of T-cell subpopulations, contributing to its development and further exacerbation. Therefore, the immune system, especially T-cells, is mainly involved in the pathogenesis of psoriasis. While T-cell activation not only requires the first recognition of T-cell receptor and major histocompatibility complex peptide, co-stimulatory and co-inhibitory pathways are reported to promote or dampen T-cell responses through a variety of mechanisms. In recent years, immuno-related agents have been applied in the treatment of numerous clinical diseases, including psoriasis, and are starting to show promising and potential therapy prospects in autoimmune skin diseases. The present review outlined the role of co-inhibitory molecules in the pathogenesis of psoriasis and their application in the treatment of psoriasis.

Blocking the CTLA-4 and PD-1 pathways during pulmonary paracoccidioidomycosis improves immunity, reduces disease severity, and increases the survival of infected mice.

Immune checkpoint pathways, i.e., coinhibitory pathways expressed as feedback following immune activation, are crucial for controlling an excessive immune response. Cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death protein-1 (PD-1) are the central classical checkpoint inhibitory (CPI) molecules used for the control of neoplasms and some infectious diseases, including some fungal infections. As the immunosuppression of severe paracoccidioidomycosis (PCM), a chronic granulomatous fungal disease, was shown to be associated with the expression of coinhibitory molecules, we hypothesized that the inhibition of CTLA-4 and PD-1 could have a beneficial effect on pulmonary PCM. To this end, C57BL/6 mice were infected with Paracoccidioides brasiliensis yeasts and treated with monoclonal antibodies (mAbs) α-CTLA-4, α-PD-1, control IgG, or PBS. We verified that blockade of CTLA-4 and PD-1 reduced the fungal load in the lungs and fungal dissemination to the liver and spleen and decreased the size of pulmonary lesions, resulting in increased survival of mice. Compared with PBS-treated infected mice, significantly increased levels of many pro- and anti-inflammatory cytokines were observed in the lungs of α-CTLA-4-treated mice, but a drastic reduction in the liver was observed following PD-1 blockade. In the lungs of α-CPI and IgG-treated mice, there were no changes in the frequency of inflammatory leukocytes, but a significant reduction in the total number of these cells was observed. Compared with PBS-treated controls, α-CPI- and IgG-treated mice exhibited reduced pulmonary infiltration of several myeloid cell subpopulations and decreased expression of costimulatory molecules. In addition, a decreased number of CD4+ and CD8+ T cells but sustained numbers of Th1, Th2, and Th17 T cells were detected. An expressive reduction in several Treg subpopulations and their maturation and suppressive molecules, in addition to reduced numbers of Treg, TCD4+, and TCD8+ cells expressing costimulatory and coinhibitory molecules of immunity, were also detected. The novel cellular and humoral profiles established in the lungs of α-CTLA-4 and α-PD-1-treated mice but not in control IgG-treated mice were more efficient at controlling fungal growth and dissemination without causing increased tissue pathology due to excessive inflammation. This is the first study demonstrating the efficacy of CPI blockade in the treatment of pulmonary PCM, and further studies combining the use of immunotherapy with antifungal drugs are encouraged.

Early Intervention and Favorable Biologic Effects of Personalized Neoantigen Vaccines on the Tumor Immune Microenvironment in Smoldering Waldenstrom Macroglobulinemia

Lymphoplasmacytic lymphoma (LPL) is an incurable low-grade B-cell lymphoma, characterized by the presence of clonal tumor cells infiltrating the bone marrow. Despite a cumulative risk of progression, there is no approved therapy for patients in the asymptomatic phase. We conducted a first-in-human clinical trial of a novel individualized therapeutic DNA idiotype neoantigen vaccine as an early intervention in nine patients with untreated asymptomatic LPL. The vaccine platform encoded the autologous LPL-derived Ig single chain variable fragment fused to human chemokine CCL20 (macrophage inflammatory protein-3, MIP-3a), which was designed to trigger T-cell immunity by targeting delivery of the expressed fusion protein to antigen presenting cells. The vaccine was well tolerated with no dose limiting toxicities. One patient achieved a minor response, and all remaining patients experienced stable disease, with median time to disease progression of 61+ months, which compares favorably to median time to progression of 3.9 years in published series. Direct interrogation of the tumor microenvironment by single-cell transcriptome analysis revealed explanations for lack of more robust objective clinical responses. Comparing paired pre- and post- vaccine bone marrow samples, we observed a striking dichotomous pattern of significantly reduced numbers of clonal tumor cells, identified by their unique BCR sequences, and downregulation of genes involved in signaling pathways critical for B-cell survival among the mature B cells subpopulation post-vaccine in the majority of patients, but no change in clonally related plasma cell-like clusters of any patient (Figure 1). Downregulation of HLA molecule expression suggested intrinsic resistance by tumor plasma cell subpopulations and cell-cell interaction analyses predicted paradoxical upregulation of IGF signaling post vaccine by plasma cell, but not mature B-cell subpopulations, suggesting a potential mechanism of acquired resistance. Vaccine therapy induced dynamic changes in bone marrow T-cells, including upregulation of signaling pathways involved in T-cell activation, expansion of T-cell clonotypes (Figure 2), increased T-cell clonal diversity, and functional tumor idiotype-specific cytokine production, with little change in co-inhibitory pathways or Treg. Vaccine therapy also globally altered cell-cell communication networks across various bone marrow cell types. CellChat analysis inferred significant downregulation of signaling pathways post-vaccine that likely directly promote growth of LPL cells, such as APRIL and IL-6 which are known to promote B- or plasma cell survival. Other pathways were reduced post-vaccine, such as RESISTIN, which has a known role in supporting proliferation of solid cancers. A role for RESISTIN in supporting LPL has not been previously inferred, but it has been reported to induce multidrug resistance in multiple myeloma. Bioinformatic analysis also identified a predominant role for myeloid cells in the tumor microenvironment as a source of vaccine-induced, downregulated pro-tumoral signaling to LPL cells. The pathways affected were primarily associated with monocytic, rather than granulocytic or dendritic cell subpopulations, particularly non-classical CD14 -CD16 + monocytes, and to a lesser extent classical CD14 +CD16 - monocytes . Recent reports indicate that an increased pro-inflammatory myeloid signature is an early step in the development of LPL and in monoclonal gammopathy of undetermined significance. Taken together, these results suggest that this prototype neoantigen vaccine favorably perturbed the tumor immune microenvironment, resulting in reduction of clonal tumor mature B-cell, but not plasma cell subpopulations. Future functional studies of the pathways affected are needed to confirm mechanisms of resistance elucidated and to design combination strategies to circumvent them. Such strategies could include adding IFN gamma or epigenetic drugs, designed to increase HLA molecule expression on plasma cell-like LPL subpopulations and combining neoantigen vaccines with agents that specifically target plasma cells or pathways known to promote their growth, such as IGF-1 receptor inhibitors. Finally, our data suggest that combinations of these vaccines with myeloid cell checkpoint blockade may be worthwhile.

Cd70 Deficiency Impairs CD4 + and CD8 + T-Cell Immune Surveillance in Bcl6-Driven Diffuse Large B-Cell Lymphomas

Anti-tumor immune responses to lymphoid malignancies are modulated by co-stimulatory and co-inhibitory pathways. Our group previously characterized the recurrent genetic alterations in primary diffuse large B-cell lymphomas (DLBCL) and identified frequent inactivating mutations or copy loss of the CD70 co-stimulatory ligand in these tumors. CD70 co-stimulation of CD27 + T cells induces antigen-dependent T-cell expansion and immune surveillance of normal and malignant B cells. Given the frequent combination of CD70 and BCL6 alterations in our human DLBCL series, we investigated the consequences of CD70deficiency ( Cd70 -/-) in a murine model of BCL6-driven lymphomagenesis ( Bcl6 tg/+). Cd70 -/-; Bcl6 tg/+ animals developed predominantly splenic DLBCLs with earlier onset and increased penetrance when compared to Bcl6 tg/+ mice (p<.01). Hence, to elucidate potential differences in T-cell mediated anti-tumor responses in Cd70 -/-; Bcl6 tg/+ versus Bcl6 tg/+ mice (and wild-type (WT) and Cd70 -/- animals) and to characterize the concurrent processes of B-cell transformation and immune evasion over time, we performed single-cell RNA sequencing of splenic cell suspensions from animals euthanized for symptoms and additional asymptomatic mice at pre-determined timepoints (6, 14 and 18 months). We applied unsupervised clustering and defined the major B- and T-cell types based on canonical lineage markers. Additionally, we reconstructed the splenic T-cell receptor (TCR) and B-cell receptor (BCR) sequences with the TRUST4 algorithm to assess their diversity and clonal expansion. TRUST4 analyses revealed clonally expanded B cells that were primarily found in specific clusters. These clusters also had an increased number of aberrant cells identified with an orthogonal approach that detects copy number alterations, InferCNV. Certain of these clusters were more abundant in aged asymptomatic Bcl6 tg/+ and Cd70 -/-; Bcl6 tg/+ animals than in symptomatic mice. Aberrant cells in these clusters had a memory-like IgM + phenotype ( Nt5e, Zeb2, Cd38, Cd44, Itgb1) and included two discrete populations: 1) previously described age-associated/autoimmune-like cells ( Tbx21, Cd11c, Cd11b) and 2) newly appreciated atypical memory cells . Additional clusters that were predominantly found in symptomatic animals included aberrant cells with increased expression of cycling genes and downregulation of lineage-defining markers and MHC II (p<.001). We interpret the aberrant memory-like B-cells in asymptomatic Cd70 -/-; Bcl6 tg/+ and Bcl6 tg/+ animals to be precursors of the ones detected in symptomatic mice. Importantly, malignant clonal expansion and splenomegaly occurred at earlier timepoints and to a greater extent in Cd70 -/-; Bcl6 tg/+ than Bcl6 tg/+ mice (p<.01). To further characterize potential anti-tumor immune responses, we examined splenic CD8 + and CD4 + T-cell subsets in tumor-bearing cohorts ( Bcl6 tg/+ and Cd70 -/-; Bcl6 tg/+) and control animals (WT and Cd70 -/-). In the tumor-bearing cohorts, we detected selective expansion of CD8 + cytotoxic T cells (CTLs) with a spectrum of activation and exhaustion markers. CD8 + CTL expansion was significantly greater in Bcl6 tg/+ mice than Cd70 -/-; Bcl6 tg/+ animals. We also identified selective expansion of a major CD4 + CTL compartment ( GzmB, Prf1, Eomes) in the tumor-bearing cohorts that persisted significantly longer in Bcl6 tg/+ than Cd70 -/-; Bcl6 tg/+ mice. In the tumor-bearing cohorts at 18 months, there was significantly greater clonal expansion of CD4 + CTLs, in comparison to CD8 + CTLs, highlighting the likely importance of this understudied cytotoxic CD4 + T-cell subset. In this regard, the downregulation of MHC II on the malignant B cells of symptomatic mice likely favored CD4 + CTL immune escape and accelerated the development of overt lymphoma. Taken together, our data indicate that genetic perturbation of CD70/CD27 co-stimulation limits the development of an effective T-cell mediated immune response to Bcl6 tg/+-driven DLBCL and highlights the unanticipated role of CD4 + CTLs and MHC II down-regulation in the attempted development and subsequent loss of an anti-tumor immune response. Additionally, we identified previously unappreciated precursor populations of murine DLBCL that warrant further investigation in human tumors.

Blinatumomab in Combination with Immune Checkpoint Inhibitors (ICIs) of PD-1 and CTLA-4 in Adult Patients with Relapsed/Refractory (R/R) CD19 Positive B-Cell Acute Lymphoblastic Leukemia (ALL): Results of a Phase I Study

Background: Blinatumomab (blina) improves outcomes in R/R CD19+ ALL compared to chemotherapy. However, the overall response rate to blina was 44%, and median overall survival (OS) is just 7.7 mos (Kantarjian. NEJM. 2017). Preclinical studies show increased PD-L1 expression on leukemic blasts potentially contributes to relapse after blina. The addition of PD-1 +/- CTLA-4 blockade to blina leads to increased in vitro T cell proliferation and enhanced cytotoxicity (Feucht. Oncotarget 2016). Thus, blockade of co-inhibitory pathways may enhance blina efficacy in vivo. We describe results of a multi-center phase I study combining blina with immune checkpoint inhibitors (ICIs) targeting PD-1 (nivolumab) +/- CTLA-4 (ipilimumab). Methods: In a dose-escalation study, we evaluated the safety, tolerability, and preliminary efficacy of blina with nivolumab (nivo) +/- ipilimumab (ipi) using a 3+3 design. Pts ³16 years-old with R/R CD19+ B-ALL or mixed phenotype acute leukemia (MPAL) were eligible. Pts ³60 years could be untreated. Table 1 presents the dose escalation schema. Expansion cohorts of 6 pts were planned at the maximum tolerated dose (MTD) for blina + nivo AND blina + nivo + ipi. Pts received up to 5 cycles of blina and 1 year of ICIs. Pts removed from the study during the blina lead-in (days 1-10) were replaced. Dose-limiting toxicities (DLTs) were defined as grade 3+ non-hematologic toxicities requiring the permanent discontinuation of treatment in the first 42 days. Primary endpoints were toxicities and MTD. Secondary endpoints included complete remission (CR), MRD-negativity at a sensitivity of 0.01%, duration of response and OS from treatment initiation. Results: Twenty-seven pts were enrolled to 3 dose levels (14 DLA1, 3 DLB1, and 10 DLB-1) from September 2017-December 2022. Six pts were replaced (4 prior to ICI dosing and 2 requiring subsequent therapy in the DLT window). The median age of enrolled pts was 55 (range 24-84), 14 were male (52%), and median baseline BM blasts were 60% (range 0.2-98%). Baseline characteristics are presented in Table 2. A single DLT (G4 infusion reaction and G3 hypotension) occurred among 6 pts at DLA1. Based on this safety and efficacy data, blina + nivo was expanded to include 6 additional pts without additional DLTs. There were 2 DLTs at DLB1 (G5 pneumonitis and G2 GVHD), which led to de-escalation to DLB-1, where there was 1 DLT (G3 delirium). Grade 2+ immune-related adverse events attributable to ICIs included pneumonitis (G2+G5), rash (G2+G3), transaminitis (G2+G3), colitis (G3), and hypothyroidism (G2). Grade 3+ adverse events attributable to blina included neutropenia (5-G4+3-G3), dysphasia (2-G3), weakness (G3), seizure (G4), and transaminitis (1-G4+4-G3). Among 22 pts evaluable for response, the CR rate was 68% (100% MRD-negative). Among 13 pts with >50% BM blasts at baseline, 62% achieved CR. Pts with B-myeloid MPAL (0/2) and a history of extramedullary disease (1/4) were less likely to respond. Nine responders subsequently relapsed including 3 with isolated extramedullary disease and 2 with CD19-negative disease. As shown in Figure 1, relapse-free survival (RFS) at 1 year was 27% (95% CI 10-46), while OS at 1 year was 63% (95% CI 38-79). Twelve pts underwent allogeneic blood or marrow transplant (alloBMT) following study treatment. At 1 year for alloBMT pts, RFS was 51% (95% CI 19-76) and OS was 61% (95% CI 26-83). Ongoing analyses of changes in T cell subpopulations, co-signaling molecule expression, and single cell RNA seq results will be presented. Conclusions: Combination therapy with blina and ICIs in R/R ALL is safe, feasible, and associated with a high MRD-negative response rate. Long-term survival was promising in comparison to prior results with blina monotherapy, especially following consolidation with alloBMT. A randomized trial of blina +/- nivolumab is needed to confirm the benefit of this combination.

Clinical and molecular impact of concurrent thyroid autoimmune disease and thyroid cancer: From the bench to bedside.

The recent incorporation of immune checkpoint inhibitors targeting the PD-1 (programmed cell death receptor 1) and CTLA-4 (cytotoxic T lymphocyte antigen 4) pathways into the therapeutic armamentarium of cancer has increased the need to understand the correlation between the immune system, autoimmunity, and malignant neoplasms. Both autoimmune thyroid diseases and thyroid cancer are common clinical conditions. The molecular pathology of autoimmune thyroid diseases is characterized by the important impact of the PD-1/PD-L1 axis, an important inhibitory pathway involved in the regulation of T-cell responses. Insufficient inhibitory pathways may prone the thyroid tissue to a self-destructive immune response that leads to hypothyroidism. On the other hand, the PD-1/PD-L1 axis and other co-inhibitory pathways are the cornerstones of the immune escape mechanisms in thyroid cancer, which is a mechanism through which the immune response fails to recognize and eradicate thyroid tumor cells. This common mechanism raises the idea that thyroid autoimmunity and thyroid cancer may be opposite sides of the same coin, meaning that both conditions share similar molecular signatures. When associated with thyroid autoimmunity, thyroid cancer may have a less aggressive presentation, even though the molecular explanation of this clinical consequence is unclear. More studies are warranted to elucidate the molecular link between thyroid autoimmune disease and thyroid cancer. The prognostic impact that thyroid autoimmune disease, especially chronic lymphocytic thyroiditis, may exert on thyroid cancer raises important insights that can help physicians to better individualize the management of patients with thyroid cancer.

BTLA-derived peptides as inhibitors of BTLA/HVEM complex formation – design, synthesis and biological evaluation

Immune checkpoints can be divided into co-stimulatory and co-inhibitory molecules that regulate the activation and effector functions of T cells. The co-inhibitory pathways mediated by ICPs are used by cancer cells to escape from immune surveillance, and therefore the blockade of these receptor/ligand interactions is one of the strategies used in the treatment of cancer. The two main pathways currently under investigation are CTLA-4/CD80/CD86 and PD-1/PD-L1, and the monoclonal Abs targeting them have shown potent immunomodulatory effects and activity in clinical environments. Another interesting target in cancer treatment is the BTLA/HVEM complex. Binding of BTLA protein on T cells to HVEM on cancer cells leads to inhibition of T cell proliferation and cytokine production. In the presented work, we focused on blocking the HVEM protein using BTLA-derived peptides. Based on the crystal structure of the BTLA/HVEM complex and MM/GBSA analysis performed here, we designed and synthesized peptides, specifically fragments of BTLA protein. We subsequently checked the inhibitory capacities of these compounds using ELISA and a cellular reporter platform. Two of these peptides, namely BTLA(35−43) and BTLA(33−64)C58Abu displayed the most promising properties, and we therefore performed further studies to evaluate their affinity to HVEM protein, their stability in plasma and their effect on viability of human PBMCs. In addition, the 3D structure for the peptide BTLA(33−64)C58Abu was determined using NMR. Obtained data confirmed that the BTLA-derived peptides could be the basis for future drugs and their immunomodulatory potential merits further examination.

#5611 ASSOCIATION BETWEEN LOSS OF IMMUNE CHECKPOINT PROGRAMMED CELL DEATH PROTEIN 1 AND ACTIVE ANCA-ASSOCIATED RENAL VASCULITIS

Abstract Background and Aims Immune checkpoint inhibitors (ICIs) have made an important contribution on the survival of patients with certain cancers. ICIs interrupt co-inhibitory signalling pathways mediated by programmed cell death protein 1 (PD-1), programmed cell death protein-ligand 1 (PD-L1), and cytotoxic T lymphocyte-associated antigen (CTLA-4) that result in the elimination of cancer cells by stimulating the immune system. Immune-related adverse events have also been described and attributed to an enhanced immune system activation. Recent observations have suggested dysregulation of immune checkpoints in active antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Therefore, we here aimed to analyze abundance of immune checkpoint molecules PD-1/PD-L1 and its implications in ANCA-associated renal vasculitis. Method We here analyzed intrarenal PD-1 and PD-L1 by immunostaining in a total number of 15 kidney biopsies with ANCA-associated renal vasculitis in correlation with glomerular and tubulointer-stitial lesions. For independent validation, publicly available datasets were analyzed for PD-1 expression (encoded by PDCD1). Results We here observed a predominant tubulointerstitial expression of PD-1 that is decreased in ANCA-associated renal vasculitis. Moreover, loss of tubulointerstitial PD-1 correlated with active ANCA-associated renal vasculitis. Consistent to the observed association with active glomerular and tubulointerstitial lesions, we identified that interstitial PD-1 correlated with tubular and/or glomerular PD-L1 positivity. Finally, PD-1 was associated with decreased local synthesis of complement factor B. Interestingly, we did not observe a correlation between PD-1 and complement C5 or its C5a receptor. Combined with our observations, this may implicate a link between im-paired PD-1/PD-L1 signalling, complement factor B, and active ANCA-associated renal vasculitis. Conclusion These findings could be of relevance because experimental data have already been described that PD-1 agonism can be used therapeutically to attenuate autoimmunity in multiple disease models. Furthermore, targeted therapy against complement C5/C5a receptor and factor B are both available and currently evolving in the treatment of AAV. Therefore, this pilot study expands our current knowledge and describes a potential interplay between immune checkpoints and the alternative complement pathway in active ANCA-associated renal vasculitis.

A Predictive Disease Risk Model for Ankylosing Spondylitis: Based on Integrated Bioinformatic Analysis and Identification of Potential Biomarkers Most Related to Immunity.

The pathogenesis of ankylosing spondylitis (AS) is still not clear, and immune-related genes have not been systematically explored in AS. The purpose of this paper was to identify the potential early biomarkers most related to immunity in AS and develop a predictive disease risk model with bioinformatic methods and the Gene Expression Omnibus database (GEO) to improve diagnostic and therapeutic efficiency. To identify differentially expressed genes and create a gene coexpression network between AS and healthy samples, we downloaded the AS-related datasets GSE25101 and GSE73754 from the GEO database and employed weighted gene coexpression network analysis (WGCNA). We used the GSVA, GSEABase, limma, ggpubr, and reshape2 packages to score immune data and investigated the links between immune cells and immunological functions by using single-sample gene set enrichment analysis (ssGSEA). The value of the core gene set and constructed model for early AS diagnosis was investigated by using receiver operating characteristic (ROC) curve analysis. Biological function and immune score analyses identified central genes related to immunity, key immune cells, key related pathways, gene modules, and the coexpression network in AS. Granulysin (GNLY), Granulysin (GZMK), CX3CR1, IL2RB, dysferlin (DYSF), and S100A12 may participate in AS development through NK cells, CD8+ T cells, Th1 cells, and other immune cells and represent potential biomarkers for the early diagnosis of AS occurrence and progression. Furthermore, the T cell coinhibitory pathway may be involved in AS pathogenesis. The AS disease risk model constructed based on immune-related genes can guide clinical diagnosis and treatment and may help in the development of personalized immunotherapy.

Abstract 6374: The role of myeloid cell-expressed PVRL2 in high-grade serous ovarian cancer

Abstract Ovarian cancer (OC) is the fifth leading cause of cancer death in women in the United States. Standard of care (surgical resection and platinum-based chemotherapy) has limited survival benefit for patients with advanced disease. Since 3 of every 4 patients are diagnosed with stage III-IV disease, novel therapeutic approaches are needed to improve survival. In trials with PD1/PD-L1 blockers, patients with OC had modest responses, highlighting an unmet need for effective immunotherapies. Our group has shown the PVRL2-PVRIG node in the DNAM-1 axis suppresses CD8 T cell effector function in syngeneic tumors as well as patient-derived ovarian tumors. This study aims to determine the requirement of tumor- vs myeloid cell-derived PVRL2 for driving immune suppression in OC. Taqman qPCR was conducted for PVRL2, PVR and PD-L1 mRNA expressions of classically activated (M1), and alternatively activated (M2) macrophages from wild-type and PVRL2−/− mice. In our syngeneic OC model, ID8-Vegf-Defb29 (50,000 cells/ovary) were surgically implanted in the ovarian bursa and monitored for disease progression. These studies were performed in (1) PVRL2−/− mice vs. wild type mice and (2) PVRL2−/− → Wild-type vs. wild-type → wild-type bone marrow chimeras. PVRL2−/- ID8-Vegf-Defb29 clones were generated by CRISPR-Cas9, validated for absence of off-target edits by whole exome sequencing and implanted in wild-type and PVRL2−/− mice. Multiplex immunofluorescence (mIF) of PanCK/CD8-CD68-PVRL2/PVR was performed on archived HGSOC tissue from patients treated at Johns Hopkins Hospital. CITE-seq was performed on viable TILs from 6 treatment-naïve and 4 neoadjuvant chemotherapy-treated patients. PVR transcripts were elevated in PVRL2−/− M1 (3.77-fold, p=0.04) and M2 (2.61-fold, p=0.003) macrophages compared to wild type. The expression of PD-L1 was increased in M2 macrophages of PVRL2-/- mice compared to wild-type mice (Mean ratio: 2.28, p=0.04). PVRL2−/− mice and PVRL2 bone marrow chimeras had significantly improved survival compared to their respective control cohorts. Tumors derived from PVRL2−/− ID8-Vegf-Defb29 clones grew slowly in PVRL2−/− mice compared to wild-type mice. PVRL2 and PVR were highly expressed in human HGSOC, and the prognosis was worse for patients with high PVRL2 expression. In mIF, PVRL2 was expressed not only on tumor cells but also on CD68-positive cells. In CITE-seq, PVRL2 and PVR were strongly expressed in macrophage and dendritic cell clusters. The enhanced expression of PVR and PD-L1 in PVRL2−/− M1 and M2 macrophages suggests compensatory activation of co-inhibitory signaling pathways. PVRL2 deficiency selectively in hematopoietically-reconstituted immune cells (primarily myeloid cells) and not in tumor cells conferred a significant survival benefit in our syngeneic OC model. Taken together, blockade of the PVRL2-PVRIG axis in conjunction with PD-1/L1 inhibition may be an effective modality in OC. Citation Format: Kosuke Murakami, Hirofumi Ando, Michele Doucet, William Huang, Sudipto Ganguly. The role of myeloid cell-expressed PVRL2 in high-grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6374.

T cell co-stimulatory and co-inhibitory pathways in atopic dermatitis.

The use of immune checkpoint inhibitors (ICIs) targeting the T cell inhibitory pathways has revolutionized cancer treatment. However, ICIs might induce progressive atopic dermatitis (AD) by affecting T cell reactivation. The critical role of T cells in AD pathogenesis is widely known. T cell co-signaling pathways regulate T cell activation, where co-signaling molecules are essential for determining the magnitude of the T cell response to antigens. Given the increasing use of ICIs in cancer treatment, a timely overview of the role of T cell co-signaling molecules in AD is required. In this review, we emphasize the importance of these molecules involved in AD pathogenesis. We also discuss the potential of targeting T cell co-signaling pathways to treat AD and present the unresolved issues and existing limitations. A better understanding of the T cell co-signaling pathways would aid investigation of the mechanism, prognosis evaluation, and treatment of AD.

Association between Loss of Immune Checkpoint Programmed Cell Death Protein 1 and Active ANCA-Associated Renal Vasculitis.

Immune checkpoint inhibitors (ICIs) have made an important contribution to the survival of patients with certain cancers. ICIs interrupt co-inhibitory signaling pathways mediated by programmed cell death protein 1 (PD-1), programmed cell death protein ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated antigen (CTLA-4) that result in the elimination of cancer cells by stimulating the immune system. However, immune-related adverse events have also been described and attributed to an enhanced immune system activation. Recent observations have suggested a dysregulation of immune checkpoints in active antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We here analyzed intrarenal PD-1 and PD-L1 by immunostaining in a total of 15 kidney biopsies with ANCA-associated renal vasculitis in correlation with glomerular and tubulointerstitial lesions. For independent validation, publicly available datasets were analyzed for PD-1 expression (encoded by PDCD1). We here observed a predominant tubulointerstitial expression of PD-1 that is decreased in ANCA-associated renal vasculitis. Moreover, loss of tubulointerstitial PD-1 correlated with active ANCA-associated renal vasculitis. Consistent with the observed association with active glomerular and tubulointerstitial lesions, we identified that interstitial PD-1 correlated with tubular and/or glomerular PD-L1 positivity. Finally, PD-1 was associated with decreased local synthesis of complement factor B. Interestingly, we did not observe a correlation between PD-1 and complement C5 or its C5a receptor. Combined with our observations, this may implicate a link between impaired PD-1/PD-L1 signaling, complement factor B and active ANCA-associated renal vasculitis. These findings could be of relevance because experimental data have already described that PD-1 agonism can be used therapeutically to attenuate autoimmunity in multiple disease models. Furthermore, targeted therapy against a complement C5/C5a receptor and factor B are both available and currently evolving in the treatment of AAV. Therefore, this pilot study expands our current knowledge and describes a potential interplay between immune checkpoints and the alternative complement pathway in active ANCA-associated renal vasculitis.

Cancer cell intrinsic TIM-3 induces glioblastoma progression

Glioblastoma (GBM) is identified to share common signal pathways between glioma and immune cells. Here, we find that Tcell immunoglobulin domain and mucin domain protein 3 (TIM-3) is one of the most common co-inhibitory immune checkpoints in GBM shared by tumor and non-tumor cells. Glioma cell-intrinsic TIM-3 is involved in not only regulating malignant behaviors of glioma cells but also inducing macrophage migration and transition to anti-inflammatory/pro-tumorigenic phenotype by a TIM-3/interleukin 6 (IL6) signal. In mechanism, as one of the major regulators of IL6, TIM-3 regulates its expression through activating NF-κB. Blocking this feedback loop by Tocilizumab, an IL6R inhibitor, inhibited the above effects and repressed the tumorigenicity of GBM invivo. Our work identifies glioma cell-intrinsic functions of TIM-3/IL6 signal mediating the crosstalk feedback loop between glioma cells and tumor-associated macrophages (TAMs). Blocking this feedback loop may provide a novel therapeutic strategy for GBM.

S1213 Predictors of Hepatotoxicity in Patients Receiving Immune Checkpoint Inhibitors: A Large Population-Based Study

Introduction: Immune checkpoint inhibitors (ICPI) are monoclonal antibodies that interrupt co-inhibitory signaling pathways and promote immune-mediated eradication of cell tumors. ICPI has emerged in recent years as an efficacious treatment for advanced malignancies. Hepatotoxicity is an established adverse event associated with ICPI. The aim of this study is to determine the predictors of hepatotoxicity in patients receiving ICPI. Methods: We reviewed data from a large database (Explorys IBM) that aggregates health records from 26 large healthcare systems. We identified adults who received ICPI from 2011-2021. We excluded patients diagnosed with alcoholism, viral hepatitis, other drug induced liver injury & biliary disease. Of this cohort, we collected data on hepatocellular injury after the initiation of ICPI. Demographic information & data on potential risk factors were collected including malnutrition, chronic kidney disease (CKD), metabolic syndrome, non-alcoholic fatty liver disease (NAFLD), smoking, concomitant use of cytochrome P450-CYP2E1 inducers & use of ICPI combination. Univariable & multivariable logistic regression analyses were performed. Results: Out of 69 million adults in the database, 21060 received ICPI (0.03%) of whom 1780 had ICPI-induced hepatotoxicity (8.4%). Men received more ICPI than women (57.4% vs 42.5%). The majority who received ICPI were > 65 yr old (63.7%). Table summarizes the characteristics of patients received ICPI. In multivariable model, NAFLD & the use of ICPI combination were most associated with hepatotoxicity (OR 4.29 [ 95% CI: 4.15-4.43)] & (OR 4.30 [95% CI: 4.18-4.43]), respectively. These factors were closely followed by metabolic syndrome & malnutrition (OR 3.16 [95% CI: 3.10-3.22]) & (OR 3.07 [95% CI: 2.97-3.16]), respectively. Moreover, ICPI-induced hepatotoxicity was significantly associated with CKD (OR 2.46 [95% CI: 2.39-2.52]), smoking (OR 2.33 [95% CI: 2.28-2.38]), concomitant CYP2E1 inducers (OR 2.85 [95% CI: 2.77-2.93]), and to a lesser extent, with age >65 (OR 1.39 [95% CI: 1.33-1.44]). No significant association with gender was noted (OR 1.00 [95% CI: 0.93-1.07]), Figure. Conclusion: This large study shows that the highest predictors of ICPI-induced hepatotoxicity were underlying NAFLD & the use of ICPI combination. Other significant factors were age >65, metabolic syndrome, malnutrition, CKD, smoking, & concomitant use of CYP2E1 inducers. Further studies are needed to evaluate pathophysiology and molecular aspects of these relationships. Table 1. - Characteristics and conditions of patients in cohort ICPI ICPI + Hepatotoxicity Total 21060 1780 Number (Percentage) Number (Percentage) Age18-65>65 7630 (36.3%)13430 (63.7%) 630 (35.4%)1150 (64.6%) GenderFemaleMale 8960 (42.5%)12100 (57.4%) 760 (42.7%)1020 (57.3%) NAFLD 1530 (7.2%) 270 (15.1%) Malnutrition 6080 (28.8%) 770 (43.2%) Metabolic Syndrome 230 (1.09%) 50 (2.8%) CKD 5140 (24.4%) 550 (30.8%) Smoking 6400 (30.3%) 640 (35.9%) CYP2E1 inducers 2140 (10.1%) 330 (18.5%) Footnote: ICPI: Immune checkpoint inhibitor; NAFLD: Non-alcoholic fatty liver disease; CKD: Chronic Kidney disease. Figure 1.: Forest plot of predictors of ICPI-induced hepatotoxicity

Dual Costimulatory and Coinhibitory Targeting with a Hybrid Fusion Protein as an Immunomodulatory Therapy in Lupus Nephritis Mice Models.

Systemic lupus erythematosus is a complex autoimmune disorder mostly mediated by B-cells in which costimulatory signals are involved. This immune dysregulation can cause tissue damage and inflammation of the kidney, resulting in lupus nephritis and chronic renal failure. Given the previous experience reported with CTLA4-Ig as well as recent understanding of the PD-1 pathway in this setting, our group was encouraged to evaluate, in the NZBWF1 model, a human fusion recombinant protein (Hybri) with two domains: CTLA4, blocking the CD28—CD80 costimulatory pathway, and PD-L2, exacerbating the PD-1–PD-L2 coinhibitory pathway. After achieving good results in this model, we decided to validate the therapeutic effect of Hybri in the more severe MRL/lpr model of lupus nephritis. The intraperitoneal administration of Hybri prevented the progression of proteinuria and anti-dsDNA antibodies to levels like those of cyclophosphamide and reduced the histological score, infiltration of B-cells, T-cells, and macrophages and immune deposition in both lupus-prone models. Additionally, Hybri treatment produced changes in both inflammatory-related circulating cytokines and kidney gene expression. To summarize, both in vivo studies revealed that the Hybri effect on costimulatory-coinhibitory pathways may effectively mitigate lupus nephritis, with potential for use as a maintenance therapy.

Increased Expression of Multiple Co-Inhibitory Molecules on Malaria-Induced CD8+ T Cells Are Associated With Increased Function Instead of Exhaustion.

Activated cytotoxic CD8+ T cells can selectively kill target cells in an antigen-specific manner. However, their prolonged activation often has detrimental effects on tissue homeostasis and function. Indeed, overwhelming cytotoxic activity of CD8+ T cells can drive immunopathology, and therefore, the extent and duration of CD8+ T cell effector function needs to be tightly regulated. One way to regulate CD8+ T cell function is their suppression through engagement of co-inhibitory molecules to their cognate ligands (e.g., LAG-3, PD-1, TIM-3, TIGIT and CTLA-4). During chronic antigen exposure, the expression of co-inhibitory molecules is associated with a loss of T cell function, termed T cell exhaustion and blockade of co-inhibitory pathways often restores T cell function. We addressed the effect of co-inhibitory molecule expression on CD8+ T cell function during acute antigen exposure using experimental malaria. To this end, we infected OT-I mice with a transgenic P. berghei ANKA strain that expresses ovalbumin (PbTG), which enables the characterization of antigen-specific CD8+ T cell responses. We then compared antigen-specific CD8+ T cell populations expressing different levels of the co-inhibitory molecules. High expression of LAG-3 correlated with high expression of PD-1, TIGIT, TIM-3 and CTLA-4. Contrary to what has been described during chronic antigen exposure, antigen-specific CD8+ T cells with the highest expression of LAG-3 appeared to be fully functional during acute malaria. We evaluated this by measuring IFN-γ, Granzyme B and Perforin production and confirmed the results by employing a newly developed T cell cytotoxicity assay. We found that LAG-3high CD8+ T cells are more cytotoxic than LAG-3low or activated but LAG-3neg CD8+ T cells. In conclusion, our data imply that expression of co-inhibitory molecules in acute malaria is not necessarily associated with functional exhaustion but may be associated with an overwhelming T cell activation. Taken together, our findings shed new light on the induction of co-inhibitory molecules during acute T cell activation with ramifications for immunomodulatory therapies targeting these molecules in acute infectious diseases.

The Multi-Kinase Inhibitor Lucitanib Enhances the Antitumor Activity of Coinhibitory and Costimulatory Immune Pathway Modulators in Syngeneic Models.

Lucitanib is a multi-tyrosine kinase inhibitor whose targets are associated with angiogenesis and other key cancer and immune pathways. Its antiangiogenic properties are understood, but lucitanib's immunomodulatory activity is heretofore unknown. Lucitanib exhibited such activity in vivo, increasing CD3 + , CD8 + , and CD4 + T cells and decreasing dendritic cells and monocyte-derived suppressor cells in mouse spleens. Depletion of CD8 + T cells from syngeneic MC38 colon tumor-bearing mice reduced the antitumor efficacy of lucitanib and revealed a CD8 + T-cell-dependent component of lucitanib's activity. The combination of lucitanib and costimulatory immune pathway agonists targeting 4-1BB, glucocorticoid-induced TNFR (GITR), inducible T-cell co-stimulator (ICOS), or OX40 exhibited enhanced antitumor activity compared with each single agent in immunocompetent tumor models. Lucitanib combined with blockade of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) or programmed cell death protein-1 (PD-1) coinhibitory immune pathways also showed enhanced antitumor activity over the single agents in multiple models. In CT26 tumors, lucitanib, alone or combined with anti-PD-1, reduced CD31 + vessels and depleted F4/80 + macrophages. Combination treatment also increased the number of intratumoral T cells. Gene expression in pathways associated with immune activity was upregulated by lucitanib in MC38 tumors and further potentiated by combination with anti-PD-1. Accordingly, lucitanib, alone or combined with anti-PD-1, increased intratumoral CD8 + T-cell abundance. Lucitanib's antitumor and pharmacodynamic activity, alone or combined with anti-PD-1, was not recapitulated by specific vascular endothelial growth factor receptor-2 (VEGFR2) inhibition. These data indicate that lucitanib can modulate vascular and immune components of the tumor microenvironment and cooperate with immunotherapy to enhance antitumor efficacy. They support the clinical development of lucitanib combined with immune pathway modulators to treat cancer.

A pilot study of ipilimumab and nivolumab in recurrent extensive-stage small cell lung cancer after platinum-based chemotherapy.

8583 Background: Immunotherapy has shown efficacy in the treatment of recurrent, extensive-stage small cell lung cancer (ES-SCLC). In the Checkmate 032 trial, ipilimumab and nivolumab combination therapy resulted in a 21% objective response rate in relapsed SCLC. At present, there are no biomarkers used in clinical practice to predict treatment responsiveness in SCLC. Ipilimumab and nivolumab act by blocking key co-inhibitory immune pathways of CTLA-4 and PD-1/PD-L1, respectively, leading to reinvigoration of anti-tumor cytotoxic T cell responses and a decrease in immune suppressive tumor infiltrating leukocytes. The ratio of intratumor Teff (CD8+) cells to Treg (CD4+/Foxp3+) cells (Teff/Treg) could be a more reliable biomarker than effector cell infiltration alone. Methods: In this open-label, single arm trial, we enrolled patients with ES-SCLC who previously received platinum-based chemotherapy; prior anti-PD-1 /PD-L1 therapy was allowed. Patients were treated with nivolumab 1 mg/kg and ipilimumab 3 mg/kg, for a total of 4 doses each and received nivolumab 480 mg beginning with cycle 5, every 4 weeks until progression, unacceptable toxicity or study discontinuation. On-study biopsies were performed prior to initiation of therapy and during week 4 for the biomarker primary objective—to correlate disease response with intratumor Teff/Treg changes. Secondary objectives include determining ORR, DOR, PFS, and OS. Results: Twenty-two patients (median age 63.5 [range 54-80] years, ECOG 0/1/2 [41%/50%/9%], sex M/F [45%/55%]) were enrolled and received treatment. Fourteen (64%) had paired biopsies while on treatment. Fifteen patients were evaluable per RECIST with an ORR of 13% (2/15, 2 partial responses [13%]) and DCR was 40% (6/15, 4 stable disease [27%]). Grade 3 treatment-related adverse events (TRAEs) occurred in 9/22 [40%]. Grade 4 TRAEs occurred in 2/22 [9%] (elevated lipase and elevated bilirubin) and Grade 5 TRAEs occurred in 1/22 patients (hepatic failure). Out of the 9 patients previously treated with anti- PD-1/PD-L1 therapy, 1 had a partial response and 2 had stable disease. Multiplexed quantitative immunofluorescence analysis revealed changes of both CD8+ effector T cells and Tregs in the tumor micro-environment associated with clinical benefit to immunotherapy. Conclusions: Combination immunotherapy with ipilimumab and nivolumab shows clinical efficacy in relapsed extensive-stage SCLC, including those previously treated with anti-PD-1/PDL-1 therapy. Obtaining paired biopsies was shown to be successful in this prospective trial to study the tumor microenvironment in SCLC tumors treated with checkpoint inhibitors. Early biomarker evaluation during week 4 shows local immunomodulatory effect of treatment and supports exploration as predictive biomarker in this population. Clinical trial information: 03670056.