Reduction Of Tregs Research Articles

Oocyte donation pregnancies with high fetal-maternal immunogenetic dissimilarity show alterations in the maternal peripheral immunoregulatory response

Oocyte donation (OD) pregnancies result in increased fetal-maternal immunogenetic dissimilarity due to paternal and donor-derived genes. Higher fetal-maternal HLA mismatches are correlated with preeclampsia. Therefore, this study explored the maternal immune response, focusing on regulatory T cells (Tregs), during low versus high allogeneic pregnancies, and healthy versus preeclamptic OD pregnancies. Ten healthy and five preeclamptic OD pregnancies were included. Maternal peripheral blood was collected at different stages of pregnancy. Fetal-maternal HLA mismatches were determined, and immunophenotyping of peripheral blood mononuclear cells was conducted using a 22-colour spectral flow cytometry panel. Cytokines and hormones were detected in maternal plasma using ELISA and Luminex assays. The findings show similarities, but also distinct differences between low and high allogeneic healthy OD pregnancies. Early high allogeneic OD pregnancy showed reduction in Tregs, and CD8+ T cells, alongside lower percentage of effector/memory Tregs expressing PD-1 and Helios. Additionally, high allogeneic OD pregnancies showed increased IL-6 and progesterone in the first trimester. These variations suggest a different mode of immune regulation in early high allogeneic OD pregnancies, possibly to maintain healthy pregnancy. Further comparative analyses revealed reduced CD45RO+CTLA-4+ Tregs and increased latent TGF-β1 and -β2 levels in early preeclamptic compared to healthy OD pregnancy. Late-stage preeclamptic OD pregnancies exhibited higher frequencies of CD45RO+TIGIT+ Tregs and higher levels of TNFα, indicating both a regulatory and pro-inflammatory environment. Overall, this study sheds light on the course of various immunoregulatory key players in OD pregnancy, and expands knowledge on maternal tolerance in this particular type of pregnancy.

Role of serum cd4+, cd25+, and foxp3+ cells’ segmental and nonsegmental vitiligo

Background Vitiligo is an autoimmune skin disease presented with depigmented macules and patches. Vitiligo has an impact on the quality of life. The etiopathogenesis of vitiligo is multifactorial, including genetic, immune dysregulation, and oxidative stress mechanisms. Lately, several researches have underlined the pivotal function of regulatory T cells (Tregs) in the vitiligo pathogenesis with lack of data regarding their role in segmental vitiligo (SV). Objective To investigate the role of Tregs in SV and nonsegmental vitiligo (NSV) pathogenesis and its correlation with disease activity and severity. Patients and methods This case–control study included 20 cases with NSV and 10 cases with SV in addition to 10 healthy volunteers. Vitiligo Area Scoring Index and Vitiligo Disease Activity scores were estimated for vitiligo cases and all the included participants were assessed for the percentage of serum CD4+, CD25+, and FOXP3+ T cells using flow cytometry staining buffer. Results There was significant reduction of the peripheral Tregs in NSV cases in comparison with healthy participants and negative correlation with their percentage to disease activity. On the other hand, there was insignificant difference between the percentage of peripheral Tregs in SV cases and healthy participants. Also, there was insignificant correlation between peripheral Tregs and both severity and activity of the disease among SV cases. Conclusion NSV cases showed significant reduction of the peripheral Tregs and negative correlation with disease activity, indicating the importance of Tregs in the etiopathogenesis of NSV and hence future targeting therapy. On the other hand, in SV cases, there was insignificant reduction of peripheral Tregs and insignificant correlation between their percentage and both severity and activity indicating mosaic etiopathogenesis.

Predictive and pharmacodynamic biomarkers for combination therapy in stage III-IV melanoma: A Simon phase II trial (NCT03999749).

222 Background: The evaluation of biomarkers that predict response and immune-related adverse events (irAEs) is crucial for optimizing melanoma treatment with Immune checkpoint inhibitors (ICIs). We report predictive and pharmacodynamic biomarkers for response and irAEs using high-dimensional flow cytometry in a phase II trial combining nivolumab (3 mg/kg), ipilimumab (1 mg/ml), and the IL-6 receptor inhibitor tocilizumab (4 mg/kg) in unresectable/advanced melanoma patients. Methods: We analyzed serum and blood from melanoma patients at baseline, weeks 7 and 37, categorized them by irAE severity and clinical response. Patients were categorized based on the severity of irAEs (grades 3-5) (TOX), the absence of toxicity or grades 1-2 irAE (NT), clinical benefit (CB), and non-clinical benefit (NCB). Immune monitoring regimen included ELISA for IL-6, gp130, IL-23, osteopontin, and Luminex oncological panel (LXSAHM-22). We employed multi-parametric flow cytometry panels to examine myeloid cells, cytotoxic T cells, and checkpoint protein expression on immune cells. We processed ~1 million PBMCs per sample using various antibodies, with data acquisition performed via Sony’s ID7000 cytometer. The data underwent quality control, normalization PBMCs per patient, concatenation, dimensionality reduction, and clustering in FlowJo. Results: Among the 70 patients administered treatment, we observed a best overall response rate of 57%. Grade 3-5 irAEs occurred in 22% of patients by week 24. Patients manifesting irAEs exhibited notably higher baseline Th17 cell counts (NT=181±18 vs. Tox=311±49, p<0.01) and CD26+ Naive CD4 T-cell populations (NT=5838±801 vs. Tox=9632±1343, p<0.04), suggesting their potential role as predictive markers for toxicity. Additionally, in vitro investigations led us to identify CD26 co-stimulation as a preliminary step in TH17 cell differentiation. Key pharmacodynamic markers included a significant elevation in Treg cells (NCB=1286±71 vs. CB=1492±95, p=0.02) and reduction in serum gp130 levels (NCB=104±5 vs. CB=83±5 ng/ml, p<0.01) at week 7 in addition to IL-6 (NCB=7.5±1.5 vs. CB=4.6±1.1 pg/ml, p<0.01) and osteopontin (NCB=95±15 vs. CB=25±3 ng/ml, p<0.01) by week 37 when compared to baseline. Conclusions: Our findings suggest that Th17 cells can serve as a toxicity biomarker for combination therapy with ipilimumab, nivolumab and tocilizumab. Circulating Treg cells and serum osteopontin have emerged as promising pharmacodynamic biomarkers. Clinical trial information: NCT03999749 .

High-throughput and high-dimensional single-cell analysis of antigen-specific CD4+ T cells in COVID-19 and influenza

Abstract This study aims to elucidate the tissue-specific dynamics of antigen-specific CD4+ T cells in response to SARS-CoV-2 and influenza. We have developed TetTCRII-SeqHD, a novel high-throughput, high-dimensional single-cell analysis platform that utilizes barcoded tetramers for antigen-specific TCR sequencing. It enables simultaneous profiling of CD4+ T cells' antigen specificities, TCR sequences, gene and surface-protein expression in human tissues. Using this technology, we have profiled >50,000 SARS-CoV-2-specific CD4+ T cells from lung, lung-associated lymph node, spleen, and blood. Our results show distinct TCR repertoires and responses of CD4+ T cells in COVID-19 and influenza. Tissue-isolated CD4+ T cells display overlapping core signatures, yet distinct tissue cues influence their phenotype, pointing to site-specific functions. In COVID-19, unique transcriptional profiles of CD4+ T cells is characterized by a pronounced cytotoxic signature and a reduction in Treg, in contrast to flu-specific cells. We also observed that tissue context influences the Treg TCR repertoire, with clonal diversity tending to be more restricted in lung tissues compared to the spleen. This study provides a comprehensive understanding of CD4+ T cell heterogeneity and function in tissues during viral infections. The novel TetTCRII-SeqHD platform presents an advancement in analyzing tissue-localized immune responses, offering potential implications for future immune research and vaccine strategies.

Abstract 2909: ST101, a clinical CEBPβ antagonist peptide, promotes an immune-active tumor microenvironment by multiple cellular mechanisms

Abstract CCAAT/Enhancer Binding Protein β (C/EBPβ) is a transcription factor that is an established driver of cellular transformation in several cancer types with poor prognosis, including glioblastoma (GBM), triple negative breast cancer (TNBC) and non-small cell lung cancer (NSCLC). These cancers’ growth is often supported by an immunosuppressive (IS) tumor microenvironment (TME), characterized by high expression of TAMs, MDSCs, Tregs, and in the case of GBM, IS microglia. In addition to its cell-autonomous role of promoting survival and proliferation in cancer cells, C/EBPβ is also critical for IS M2 macrophage polarization, while its role in other TME populations is less understood. ST101 is a peptide antagonist of C/EBPβ that is being evaluated in a Phase 2 clinical study in patients with recurrent and newly diagnosed glioblastoma (NCT04478279). Here we explored the impact of ST101 on IS TME cell populations and on activation of cytotoxic T-cells in macrophage co-culture systems. ST101 increased the M1:M2 ratio up to 40-fold in hPBMC-derived macrophages cultured under conditions that typically drive M2 polarization. Further, ST101 promoted M2 repolarization to the M1 cell type, demonstrating that C/EBPβ is required for maintenance of the M2 program. When added to co-cultures of T cells with M2 macrophages, ST101 induced a 3-4-fold increase in intracellular IFN-γ staining indicating enhanced T cell activation. Notably, in M1 cultures ST101 further enhanced expression of the immune activity marker CD80 and T cell activation. Similar to its effect on M2 repolarization, ST101 induced activation of iPs-derived IS human microglia cultures toward an M1-like program. ST101 also impacted IS cell populations in vivo, as demonstrated in an orthotopic TNBC model in which ST101 exposure was associated with a reduction of the TAM fraction, increased intratumoral M1/M2 ratios, reduction of Tregs, increase of CD8:Treg fraction, and enhanced activity in combination with anti-PD-1. Similar observations were observed in clinical samples, where following ST101 exposure a significant decrease in expression of factors involved in M2 polarization, including CD209, SIGLEC5, and IL-24, and T cell suppression, including FoxP3 and inhibitory KIR proteins, were observed. Gene expression analysis suggests that ST101 induced a decrease in the intratumoral Treg:TIL ratio, indicating a shift towards a more immune-active TME. Overall, these results provide novel evidence for the contribution of C/EBPβ to the expression of multiple IS cancer-associated cell types and support the use of ST101 to antagonize C/EBPβ and promote an immune-active TME. Further, these data provide rational for evaluating the clinical impact of ST101 in combinations with immune checkpoint inhibitors. Citation Format: Claudio Scuoppo, Julia Diehl, Ricardo Ramirez, Mark Koester, Erin Gallagher, Siok Leong, Jerel Gonzales, Karen Mendelson, Zach Mattes, Lila Ghamsari, Gene Merutka, Abi Vainstein-Haras, Barry J. Kappel, Jim A. Rotolo. ST101, a clinical CEBPβ antagonist peptide, promotes an immune-active tumor microenvironment by multiple cellular mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2909.

Abstract 4554: Novel combination therapy for treating proteasome inhibitor-resistant multiple myeloma

Abstract Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by osteolytic bone disease and immunosuppression. Proteasome inhibitors (PIs) have remarkably improved the survival of MM patients, but dose-limiting toxicities and the development of drug resistance limit their long-term utility. Elevated TGF-β levels in MM patient sera correlate with drug resistance, disease progression, metastasis and poor prognosis. Therefore, we evaluated the anti-MM therapeutic potential of a TGF-β type I receptor kinase inhibitor, Vactosertib. In vitro treatment of Vactosertib synergistically inhibited the growth of bortezomib (BTZ)-resistant MM cells in combination with either BTZ or ixazomib (IXZ) by suppressing TGF-β activation of Smad2/3 and expression of PSMB5, which encodes the proteasome 5 catalytic subunit targeted by PIs. Oral administration of Vactosertib as a single agent decreased MM progression and mortality of the mice bearing BTZ-resistant MM. Vactosertib alone also attenuated PSMB5 expression and proteasome activity, reduced the expansion of CD11b+Gr-1+ myeloid derived suppressor cells (MDSCs) in bone marrow (BM) tumor microenvironment (TME), and diminished the population of Foxp3+ regulatory T cells (Treg) in the spleen. Combination therapy of Vactosertib plus PI (BTZ or IXZ) exhibited a synergistic anti-myeloma effect when compared to either Vactosertib or PI alone by greatly prolonged survival and significant a reduction in both MDSCs and Tregs. Furthermore, therapy of BCMA+ CAR T cells in combination with Vactosertib exhibited a synergistic anti-tumor effect, compared to either CAR T cells or Vactosertib. Taken together, our data provide the rationale for clinical evaluation of Vactosertib in MM and demonstrate proof-of-concept that combination of Vactosertib and either PI or cell therapy may overcome drug resistance and enhance durable patient responses. Citation Format: Byung-Gyu Kim, Sung Hee Choi, Huong Nguyen, Fu-Sen Liang, Seong-Jin Kim, John Letterio, Alex Huang. Novel combination therapy for treating proteasome inhibitor-resistant multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4554.

Abstract 6860: Fluorescent tracking reveals that radiation therapy influences the migration and plasticity of Tregs within the tumor microenvironment

Abstract Radiation therapy (RT) has long been a cornerstone in cancer treatment, yet the mechanisms underlying its impact on the immune system remain incompletely understood. RT is recognized for its ability to induce DNA damage within cancer cells, leading to cancer cell death. For those cancer cells that do not die as a result of radiation, tumor infiltration by immune cells is closely associated with treatment outcomes. T cell infiltration is a dynamic process, with subsets taking up residence in the tumor while the majority recirculate through lymph nodes into the peripheral blood. T regulatory cells (Tregs) have been recognized as potent suppressors of anti-tumor immune responses, dampening immune-mediated clearance of cancer cells. While RT can initially contribute to an improved anti-tumor immune response, this beneficial effect is often counterbalanced by the presence of suppressive Tregs. Tregs can infiltrate the tumor microenvironment, ultimately impeding and overwhelming the immune response generated by RT. Our objective was to gain insights into the migratory patterns of Tregs to and from tumor sites and to elucidate how RT influences the dynamics of Treg recirculation. Utilizing the established photoconvertible Kaede mouse model we can track photoconverted cells following RT. Following photoconversion, photoconverted T cells were observable within the tumor and subsequently moved to the TdLN and on to other NdLN at later time points. In the TdLN of mice bearing MC38, Moc1, and Moc2 tumors, Tregs represented a significantly higher proportion of photoconverted cells compared to non-Treg CD4 or CD8 T cells. To validate their active departure from the tumor site, mice underwent FTY720 treatment, resulting in a reduction in both photoconverted Treg and non-Treg migration to the TdLN. When RT was administered to the tumor, there was a decrease in photoconverted Treg and non-Treg CD4 T cells within the TdLN, consistent with the expected cytotoxic effects on the irradiated tumor upstream. To focus on recruitment back from the TdLN, mice were analyzed after photoconversion of the TdLN. This revealed that a majority of TdLN Tregs exhibited a preference for relocating to the tumor, with only a minority migrating to the NdLN. The newly entered Tregs were analyzed in the tumor, at D1 and D3 post RT, and we found that these Tregs exhibited increased expression of CCR8, CD69, KLRG1 and Ly6C as compared to those in non-irradiated tumors, suggesting that these are recent entrants with limited suppressive capacity. These findings illuminate the intricate dynamics between RT, Tregs, and the use of site-specific photoconversion to track immune cell movement and changes over time to understand treatment responses. Our ongoing studies focus on the interplay between the Treg and the tumor environment that dictates the success of CD8 T cell mediated control of residual cancer cells following RT. Citation Format: David J. Friedman, Tiffany Blair, Gwen Kramer, Aanchal Preet Kaur, Jason Baird, Alejandro Alice, Megan Potuznik, Marka R. Crittenden, Michael J. Gough. Fluorescent tracking reveals that radiation therapy influences the migration and plasticity of Tregs within the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6860.

Increased Nasal Blimp1 + Treg Cells After Sublingual Immunotherapy Reflect the Efficacy of Treatment in Allergic Rhinitis.

Allergen-specific immunotherapy (AIT) plays a pivotal role in altering the immune status and tissue responses in allergic rhinitis (AR). This study focuses on the impact of sublingual immunotherapy (SLIT) involving dust mite drops, exploring the modulation of regulatory Tcells (Treg) and their specific marker, BLIMP1, in the nasal mucosa. Immune cells were isolated from nasal lavage fluid of patients with AR undergoing SLIT (n = 94). Treg cells were analyzed for BLIMP1 expression, and chemokine levels associated with Treg recruitment were assessed using Luminex assay. Patients were categorized on the basis of SLIT efficacy and followed for changes after discontinuation. SLIT induced a significant increase in nasal Treg cells (7.09 ± 2.59% vs. 0.75 ± 0.27%, P < 0.0001). BLIMP1 expression in Treg cells notably increased after SLIT (0.36 ± 0.22% to 16.86 ± 5.74%, P < 0.0001). Ineffective SLIT cases exhibited lower levels of nasal Treg and Blimp1 + Treg cells (both P < 0.0001). Receiver operating characteristic (ROC) analysis confirmed their potential as efficacy predictors (AUC = 0.908 and 0.968, respectively). SLIT discontinuation led to a significant reduction in Treg and Blimp1 + Treg cells (P < 0.001), emphasizing their maintenance during treatment. Pro-inflammatory cytokines decreased (P < 0.001), while CCL2 associated with Treg recruitment increased (P = 0.0015). Elevated nasal Blimp1 + Treg cells serve as a predictive biomarker for SLIT responsiveness in pediatric AR. Their influence on immunotherapy effectiveness contributes to a nuanced understanding of SLIT mechanisms, allowing for disease stratification and personalized treatment plans. This study offers scientific support for predicting SLIT efficacy, enhancing the prospects of improved treatment outcomes in AR.

Low-dose decitabine enhances the efficacy of viral cancer vaccines for immunotherapy

Cancer immunotherapy requires a specific antitumor CD8+ Tcell-driven immune response; however, upon genetic and epigenetic alterations of the antigen processing and presenting components, cancer cells escape the CD8+ Tcell recognition. As a result, poorly immunogenic tumors are refractory to conventional immunotherapy. In this context, the use of viral cancer vaccines in combination with hypomethylating agents represents a promising strategy to prevent cancer from escaping immune system recognition. In this study, we evaluated the sensitivity of melanoma (B16-expressing ovalbumin) and metastatic triple-negative breast cancer (4T1) cell lines to FDA-approved low-dose decitabine in combination with PeptiCRAd, an adenoviral anticancer vaccine. The two models showed different sensitivity to decitabine invitro and invivo when combined with PeptiCRAd. In particular, mice bearing syngeneic 4T1 cancer showed higher tumor growth control when receiving the combinatorial treatment compared to single controls in association with a higher expression of MHC class I on cancer cells and reduction in Tregs within the tumor microenvironment. Furthermore, remodeling of the CD8+ Tcell infiltration and cytotoxic activity toward cancer cells confirmed the effect of decitabine in enhancing anticancer vaccines in immunotherapy regimens.

Strengthening the Combinational Immunotherapy from Modulating the Tumor Inflammatory Environment via Hypoxia-Responsive Nanogels.

Despite the success of immuno-oncology in clinical settings, the therapeutic efficacy is lower than the expectation due to the immunosuppressive inflammatory tumor microenvironment (TME) and the lack of functional lymphocytes caused by exhaustion. To enhance the efficacy of immuno-oncotherapy, a synergistic strategy should be used that can effectively improve the inflammatory TME and increase the tumor infiltration of cytotoxic T lymphocytes (CTLs). Herein, a TME hypoxia-responsive nanogel (NG) is developed to enhance the delivery and penetration of diacerein and (-)-epigallocatechin gallate (EGCG) in tumors. After systemic administration, diacerein effectively improves the tumor immunosuppressive condition through a reduction of MDSCs and Tregs in TME, and induces tumor cell apoptosis via the inhibition of IL-6/STAT3 signal pathway, realizing a strong antitumor effect. Additionally, EGCG can effectively inhibit the expression of PD-L1, restoring the tumor-killing function of CTLs. The infiltration of CTLs increases at the tumor site with activation of systemic immunity after the combination of TIM3 blockade therapy, ultimately resulting in a strong antitumor immune response. This study provides valuable insights for future research on eliciting effective antitumor immunity by suppressing adverse tumor inflammation. The feasible strategy proposed in this work may solve the urgent clinical concerns of the dissatisfactory checkpoint-based immuno-oncotherapy.

CD4+ T-Cell Legumain Deficiency Attenuates Hypertensive Damage via Preservation of TRAF6.

T cells are central to the immune responses contributing to hypertension. LGMN (legumain) is highly expressed in T cells; however, its role in the pathogenesis of hypertension remains unclear. Peripheral blood samples were collected from patients with hypertension, and cluster of differentiation (CD)4+ T cells were sorted for gene expression and Western blotting analysis. TLGMNKO (T cell-specific LGMN-knockout) mice (Lgmnf/f/CD4Cre), regulatory T cell (Treg)-specific LGMN-knockout mice (Lgmnf/f/Foxp3YFP Cre), and RR-11a (LGMN inhibitor)-treated C57BL/6 mice were infused with Ang II (angiotensin II) or deoxycorticosterone acetate/salt to establish hypertensive animal models. Flow cytometry, 4-dimensional label-free proteomics, coimmunoprecipitation, Treg suppression, and in vivo Treg depletion or adoptive transfer were used to delineate the functional importance of T-cell LGMN in hypertension development. LGMN mRNA expression was increased in CD4+ T cells isolated from hypertensive patients and mice, was positively correlated with both systolic and diastolic blood pressure, and was negatively correlated with serum IL (interleukin)-10 levels. TLGMNKO mice exhibited reduced Ang II-induced or deoxycorticosterone acetate/salt-induced hypertension and target organ damage relative to wild-type (WT) mice. Genetic and pharmacological inhibition of LGMN blocked Ang II-induced or deoxycorticosterone acetate/salt-induced immunoinhibitory Treg reduction in the kidneys and blood. Anti-CD25 antibody depletion of Tregs abolished the protective effects against Ang II-induced hypertension in TLGMNKO mice, and LGMN deletion in Tregs prevented Ang II-induced hypertension in mice. Mechanistically, endogenous LGMN impaired Treg differentiation and function by directly interacting with and facilitating the degradation of TRAF6 (tumor necrosis factor receptor-associated factor 6) via chaperone-mediated autophagy, thereby inhibiting NF-κB (nuclear factor kappa B) activation. Adoptive transfer of LGMN-deficient Tregs reversed Ang II-induced hypertension, whereas depletion of TRAF6 in LGMN-deficient Tregs blocked the protective effects. LGMN deficiency in T cells prevents hypertension and its complications by promoting Treg differentiation and function. Specifically targeting LGMN in Tregs may be an innovative approach for hypertension treatment.

Iguratimod Regulates CD4+ T-Cell Homeostasis and Function By Restoring PINK1/Parkin-Mediated Mitophagy in Immune Thrombocytopenia

Introduction Immune thrombocytopenia (ITP), an acquired autoimmune disease, is characterized by immune-mediated platelet destruction and suppressed platelet production, resulting in isolated thrombocytopenia. Subpopulation imbalance and dysfunction of CD4+ T cells are involved in the pathogenesis of ITP. However, the exact mechanism of CD4+ T-cell abnormalities is not fully understood. Mitophagy, a process that eliminates damaged and dysfunctional mitochondria, has conventionally been considered the primary mechanism responsible for mitochondrial quality control. Mitophagy deficiency has been implicated in a series of inflammatory and autoimmune diseases, such as systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD) and rheumatoid arthritis (RA). However, whether it plays a role in ITP immune abnormalities and its specific mechanism remain unclear. Iguratimod is a small molecule compound that is widely used as a novel antirheumatic drug in the treatment of rheumatoid arthritis. Iguratimod inhibits the production of several inflammatory cytokines, including IL-1, IL-6, IL-8, and tumor necrosis factor (TNF), by enhancing mitophagy. Our previous clinical study demonstrated the efficacy of iguratimod in the treatment of ITP. This study aimed to explore whether iguratimod regulates CD4+ T-cell homeostasis and function by enhancing mitophagy in ITP. Methods BM CD4+ T cells were isolated from ITP patients and healthy donors. The subgroup of CD4+ T cells was analyzed by flow cytometry. ELISA was used to evaluate cytokine and chemokine levels in bone marrow plasma. Mitochondrial mass, morphology, quality and mitophagy were evaluated by flow cytometry, confocal microscopy, electron microscopy and western blotting. RNA sequencing and metabolomics were performed. Epigenetic state alteration was assessed by a transposase-accessible chromatin assay with high throughput sequencing (ATAC-seq). Iguratimod-treated BM-derived ITP-CD4+ T cells and an ITP active mouse model were used to explore its regulation of mitophagy and effects on T-cell homeostasis and function. Results Th1/Th2 imbalance and Treg reduction were observed in the bone marrow of ITP patients, consistent with a previous report. Flow cytometry and confocal microscopy revealed an increase in mitochondrial content and mtROS in CD4+ T cells but a decrease in mitochondrial membrane potential. Furthermore, electron microscopy revealed structural damage to mitochondria in ITP-CD4+ T cells. These data confirmed an accumulation of damaged mitochondria in ITP-CD4+ T cells. The expression levels of LC3II/LC3I, PINK1 and parkin decreased in CD4+ T cells, and the colocalization of mitochondria and lysosomes decreased, which suggested compromised PINK1/parkin-mediated mitophagy in ITP-CD4+ T cells. RNA-seq revealed transcriptional changes associated with mitochondrial function, mitophagy and metabolic pathways in ITP-CD4+ T cells. Moreover, metabolomics showed alterations in TCA cycle metabolites. Since epigenetic programs are regulated by metabolites, ATAC-seq was performed to obtain the epigenetic state. We found that ITP-CD4+ T cells altered chromatin accessibility in regions with T cell differentiation, transcription factors and T-cell function. After in vitro treatment with iguratimod, the Th1/Th2 imbalance was corrected, and the number of Tregs was restored. The content, morphology and membrane potential of mitochondria in ITP-CD4+ T cells were restored after iguratimod intervention. The expression level of PINK1 and parkin and the colocalization of mitochondria and lysosomes were increased, suggesting an improvement in mitophagy. In vivo, iguratimod accelerated platelet recovery in an ITP active mouse model. After treatment, the Th1/Th2 imbalance and the Treg number were restored, and the mitophagy of CD4+ T cells was corrected in the bone marrow of the ITP mouse model. Conclusion PINK1/Parkin-mediated mitophagy deficiency contributed to mitochondrial dysfunction and altered the metabolism of ITP-CD4+ T cells, which affected their differentiation and function by regulating the epigenetic state of immune response genes. Iguratimod could restore CD4+ T-cell subpopulations and treat ITP by enhancing mitophagy.

The Dance Between Tumor Molecular Biology and Antitumor Immune Response.

When the cyclin kinase 4/6 inhibitor abemaciclib was sequenced with PD-1 blockade in mostly immunologically "cold" murine models, enhanced immune-mediated antitumor effects-including increased lifespan, recruitment of CD8 cells to tumor, reduction of regulatory T-cell and immunosuppressive cytokines in tumor, increased tumor antigen presentation, and broadening of the T-cell receptor repertoire-were achieved in both cutaneous and brain metastases. See related article by Nayyar et al., p. 420.

Regulatory T Cells in the Pathogenesis of Graves' Disease.

Maintaining a delicate balance between the prompt immune response to pathogens and tolerance towards self-antigens and commensals is crucial for health. T regulatory (Treg) cells are pivotal in preserving self-tolerance, serving as negative regulators of inflammation through the secretion of anti-inflammatory cytokines, interleukin-2 neutralization, and direct suppression of effector T cells. Graves' disease (GD) is a thyroid-specific autoimmune disorder primarily attributed to the breakdown of tolerance to the thyroid-stimulating hormone receptor. Given the limitations of currently available GD treatments, identifying potential pathogenetic factors for pharmacological targeting is of paramount importance. Both functional impairment and frequency reduction of Tregs seem likely in GD pathogenesis. Genome-wide association studies in GD have identified polymorphisms of genes involved in Tregs' functions, such as CD25 (interleukin 2 receptor), and Forkhead box protein P3 (FOXP3). Clinical studies have reported both functional impairment and a reduction in Treg frequency or suppressive actions in GD, although their precise involvement remains a subject of debate. This review begins with an overview of Treg phenotype and functions, subsequently delves into the pathophysiology of GD and into the existing literature concerning the role of Tregs and the balance between Tregs and T helper 17 cells in GD, and finally explores the ongoing studies on target therapies for GD.

EZH2 Inhibitors Enhance CART Cell Quality, Efficacy, In Vivo Homing, Tumor Cell Binding and Killing of Fully Syngeneic Primary B Cell Lymphomas, As Well As Reprogramming Lymphoma Cells to a Highly Immunogenic and T Cell Adherent Phenotype

Although having efficacy in a subset of diffuse large B cell lymphoma (DLBCL) patients, cellular immunotherapies are currently administered without guidance as to whether the underlying biology or immunology are conducive to durable response. Moreover, mechanisms explaining CART resistance in DLBCLs remain largely unknown. One critical missing link to address these unmet needs are syngeneic animal models precisely reflecting the genetics and immunology of human DLBCLs. To overcome these hurdles, we developed a suite of genetically engineered mouse models (GEMM) faithfully recapitulating different types of DLBCL. A retrospective study showed that C3/EZB DLBCLs, featuring EZH2 mutations and BCL2 translocation, experienced inferior outcomes after CART therapy. We reported that Ezh2 mutations cause aberrant repression of genes required for productive immune synapses with T cells. We hypothesized that this phenotype limits CART cell activity in vivo, and that EZH2 inhibitors could overcome CART resistance. We generated EZB GEMMs with conditional expression of Ezh2 Y641F and BCL2 in germinal center (GC) B cells. These mice developed T cell depleted lymphomas, histologically similar to human C3/EZB DLBCLs. We generated several EZB cell lines from these mice, which recapitulated the epigenetic, transcriptional, histological, and immune microenvironment of EZB DLBCLs in humans when engrafted in immunocompetent recipients. Strikingly, treating EZB cells with EZH2 inhibitor tazemetostat (taz) ex vivo reprogrammed them to re-express the full spectrum of T cell engagement genes such as ICOSL, ITGB7, 4-1BBL, and OX40L and rendered them highly immunogenic. For example, mixing endogenous T cells with taz pre-treated EZB cells yielded markedly enhanced killing (p&amp;lt;0.001). Taz pre-treated EZB cells failed to engraft in syngeneic mice due to immunological rejection, but caused fatal DLBCL in Rag1-/- mice. EZB cell lines did not undergo proliferation arrest after taz ex vivo, but showed a significant reduction in tumor burden (p&amp;lt;0.05) when treated in vivo, along with a 3-fold increase in tumor CD4 and CD8 cells (p&amp;lt;0.05), and 50% reduction in Tregs (p&amp;lt;0.01). Taz also increased the proportion of naïve/memory CD8 and reduced effector CD8 cells. EZH2 inhibitors therefore mediate their effects at least in part through immunological mechanisms. We next examined whether taz had any deleterious effect on CART cells. Pre-treating donor mice with taz prior to harvesting T cells yielded significant increase in memory CD8 CART cells after transduction (p&amp;lt;0.05). Taz pre-treated CART cells displayed superior killing of EZB cells (p&amp;lt;0.001) and proliferative capacity ex vivo (p&amp;lt;0.001). Infusing taz pre-treated CART cells in EZB mice resulted in significantly reduced tumor burden in vivo (p&amp;lt;0.001) and reduction in PD1+CD38+ exhausted CD8 CART cells (p&amp;lt;0.001). On the other hand, pre-treatment of EZB cells (but not CART cells) with taz ex vivo enhanced CART cell killing by 3-fold (p&amp;lt;0.001). Administering CART cells in vivo in EZB mice after taz treatment significantly prolonged their survival (100% vs 30%, p&amp;lt;0.01) and was associated with significant reduction in tumor burden assessed by IVIS and post-mortem examination. Therefore, EZH2 inhibition enhances CART cell activity through direct effects on CART cells, in addition to making EZB immunogenic. Finally, to directly demonstrate the functional consequence of rendering EZB lymphomas immunogenic on CART performance in vivo, we performed intravital 2-photon imaging of popliteal lymph nodes using dTomato labeled CART cells and GFP+ EZB lymphomas. Remarkably, pre-treatment of EZB cells with taz, doubled the recruitment of CART cells into lymphomas (p&amp;lt;0.001) and significantly enhanced the CART to EZB lymphoma cell surface engagement index (strength and duration of binding, p&amp;lt;0.001). This was associated with increased killing, and CART-engaged lymphoma cells were observed to be ingested/engulfed or phagocyted by tumor resident macrophages. Collectively, EZH2 inhibitors yield a potent boost to CART mediated anti-lymphoma effects by enhancing CART cell functions and B cell immunogenicity, which would likely yield a significant clinical benefit for these patients where CART cells are less active. These results prompted us to initiate a clinical trial evaluating the safety and efficacy of this combination in B cell lymphomas (NCT05934838).

COVID-19 patients display changes in lymphocyte subsets with a higher frequency of dysfunctional CD8lo T cells associated with disease severity.

This work examines cellular immunity against SARS-CoV-2 in patients from Córdoba, Argentina, during two major waves characterized by different circulating viral variants and different social behavior. Using flow cytometry, we evaluated the main lymphocyte populations of peripheral blood from hospitalized patients with moderate and severe COVID-19 disease. Our results show disturbances in the cellular immune compartment, as previously reported in different cohorts worldwide. We observed an increased frequency of B cells and a significant decrease in the frequency of CD3+ T cells in COVID-19 patients compared to healthy donors (HD). We also found a reduction in Tregs, which was more pronounced in severe patients. During the first wave, the frequency of GZMB, CD107a, CD39, and PD-1-expressing conventional CD4+ T (T conv) cells was significantly higher in moderate and severe patients than in HD. During the second wave, only the GZMB+ T conv cells of moderate and severe patients increased significantly. In addition, these patients showed a decreased frequency in IL-2-producing T conv cells. Interestingly, we identified two subsets of circulating CD8+ T cells with low and high CD8 surface expression in both HD and COVID-19 patients. While the percentages of CD8hi and CD8lo T cells within the CD8+ population in HD are similar, a significant increase was observed in CD8lo T cell frequency in COVID-19 patients. CD8lo T cell populations from HD as well as from SARS-CoV-2 infected patients exhibited lower frequencies of the effector cytokine-producing cells, TNF, IL-2, and IFN-γ, than CD8hi T cells. Interestingly, the frequency of CD8lo T cells increased with disease severity, suggesting that this parameter could be a potential marker for disease progression. Indeed, the CD8hi/CD8lo index helped to significantly improve the patient's clinical stratification and disease outcome prediction. Our data support the addition of, at least, a CD8hi/CD8lo index into the panel of biomarkers commonly used in clinical labs, since its determination may be a useful tool with impact on the therapeutic management of the patients.

The kinetics of mTORC1 activation associates with FOXP3 expression pattern of CD4+ T cells and outcome of steroid-sensitive minimal change disease.

Minimal change disease (MCD) usually responds to glucocorticoids (GCs) but relapses in most cases. Relapse pathogenesis after complete remission (CR) remains unclear. We hypothesized that FOXP3+ T regulatory cell (Treg) dysregulation may drive early relapses (ER). In this study, a cohort of 23 MCD patients were treated with a conventional GC regimen for the initial onset of nephrotic syndrome. Upon GC withdrawal, seven patients suffered from ER, while 16 patients sustained remission (SR) during the 12-month follow-up. Patients with ER had reduced FOXP3+ Treg proportions compared with healthy controls. Treg reduction, accompanied by IL-10 impairment, was ascribed to a proportional decline of FOXP3medium rather than FOXP3high cells. GC-induced CR was marked by a rise in the proportions of FOXP3+ and FOXP3medium cells compared to baseline levels. These increases declined in patients with ER. The expression level of phosphorylated ribosomal protein S6 was used to track the dynamic shifts in mTORC1 activity within CD4+ T cells of MCD patients at various stages of treatment. Baseline mTORC1 activity was inversely correlated with FOXP3+ and FOXP3medium Treg proportion. The mTORC1 activity in CD4+ T cells served as a reliable indicator for ER and demonstrated improved performance when paired with FOXP3 expression. Mechanically, targeting mTORC1 intervention by siRNAs sufficiently altered the conversion pattern of CD4+ T cell to FOXP3+ Treg. Taken together, the activity of mTORC1 in CD4+ T cells can act as a credible predictor for ER in MCD, especially when combined with FOXP3 expression, and may offer a potential therapeutic avenue for the treatment of podocytopathies.

A novel therapeutic strategy for non-muscle invasive bladder cancer: OncoTherad® immunotherapy associated with platelet-rich plasma

Patients with non-muscle invasive bladder cancer (NMIBC) that are unresponsive to Bacillus Calmette-Guérin (BCG) have historically had limited treatment options. A new perspective is represented by OncoTherad® (MRB-CFI-1) immunotherapy, a nanostructured inorganic phosphate complex associated with glycosidic protein, developed by the University of Campinas in Brazil. Previous studies have shown that Platelet-Rich Plasma (PRP) also acts on immune activation and exerts antitumor effects. This study characterized the effects of the OncoTherad® associated with PRP in the treatment of NMIBC chemically induced in mice. When treated intravesically with PRP only, mice showed 28.6% of tumor progression inhibition rate; with OncoTherad® 85.7%; and with OncoTherad®+PRP 71.4%. Intravesical treatments led to distinct activation of Toll-like Receptors (TLRs) 2 and 4-mediated innate immune system in the interleukins (canonical) and interferons (non-canonical) signaling pathways. OncoTherad® isolated or associated with PRP upregulated TLR4 and its downstream cascade mediators as well as increased interleukins 6 (IL-6) and 1β (IL-1β), and interferon-γ (IFN-γ). In this way, the NMIBC microenvironment was modulated to a cytotoxic profile correlated with the IL-1β increase by stimulating immune pathways for IFN-γ production and consequent cytotoxic T lymphocytes (as CD8+ T-cells) activation and regulatory T-cells (Tregs) reduction. In addition, PRP did not trigger carcinogenic effects through the biomarkers evaluated. Considering the possibility of personalizing the treatment with the PRP use as well as the antitumor properties of OncoTherad®, we highlight this association as a potential new therapeutic strategy for NMIBC, mainly in cases of relapse and/or resistance to BCG.

S-531011, a Novel Anti-Human CCR8 Antibody, Induces Potent Antitumor Responses through Depletion of Tumor-Infiltrating CCR8-Expressing Regulatory T Cells.

Although regulatory T cells (Treg) are inhibitory immune cells that are essential for maintaining immune homeostasis, Tregs that infiltrate tumor tissue promote tumor growth by suppressing antitumor immunity. Selective reduction of tumor-infiltrating Tregs is, therefore, expected to activate antitumor immunity without affecting immune homeostasis. We previously reported that selective Treg depletion targeted by a C-C motif chemokine receptor 8 (CCR8) resulted in induction of strong antitumor immunity without any obvious autoimmunity in mouse models. Thus, herein, we developed a novel humanized anti-CCR8 monoclonal antibody, S-531011, aimed as a cancer immunotherapy strategy for patients with cancer. S-531011 exclusively recognized human CCR8 among all chemokine receptors and showed potent antibody-dependent cell-mediated cytotoxicity activity toward CCR8+ cells and neutralization activity against CCR8-mediated signaling. We observed that S-531011 reduced tumor-infiltrating CCR8+ Tregs and induced potent antitumor activity in a tumor-bearing human-CCR8 knock-in mouse model. Moreover, combination therapy with S-531011 and anti-mouse programmed cell death 1 (PD-1) antibody strongly suppressed tumor growth compared with anti-PD-1 antibody alone with no observable adverse effects. S-531011 also depleted human tumor-infiltrating Tregs, but not Tregs derived from human peripheral blood mononuclear cells. These results suggest that S-531011 is a promising drug for inducing antitumor immunity without severe side effects in the clinical setting.

Reduction in regulatory T cells in preterm newborns is associated with necrotizing enterocolitis

BackgroundDespite multifactorial pathogenesis, dysregulation of inflammatory immune response may play a crucial role in necrotizing enterocolitis (NEC). Regulatory T cells (Tregs) are involved in immune tolerance early in life. We aimed to investigate the predicting role of Tregs in developing NEC in neonates at high risk.MethodsWe studied six newborns with a diagnosis of NEC (cases) in comparison with 52 controls (without NEC). We further classified controls as neonates with feeding intolerance (FI) and neonates without it (FeedTol). The rate of female and male neonates (sex defined as a biological attribute) was similar. We analyzed the blood frequency of Tregs (not overall numbers) at three time points: 0–3 (T0), 7–10 (T1), and 27–30 (T2) days after birth by flow cytometry. Neonates’ sex was defined based on the inspection of external genitalia at birth.ResultsWe observed, at T0, a significantly lower frequency of Tregs in NEC cases (p < 0.001) compared with both FI (p < 0.01) and FeedTol controls (p < 0.01). Multivariate analysis reported that the occurrence of NEC was independently influenced by Treg frequency at birth (ß 2.98; p = 0.039).ConclusionTregs frequency and features in the peripheral blood of preterm neonates, early in life, may contribute to identifying neonates at high risk of developing NEC.ImpactRegulatory T cells may play a pivotal role in regulating the immune response in early life. Reduction of Tregs in early life could predispose preterm newborns to necrotizing enterocolitis.Early markers of necrotizing enterocolitis are still lacking. We demonstrated a predicting role of assessment of regulatory T cells in the diagnosis of this gastrointestinal emergency.Early identification of newborns at high risk of necrotizing enterocolitis through measurement of regulatory T cells may guide clinicians in the management of preterm newborns in order to reduce the development of this severe condition.