Regulatory T Cells: Regulation of Identity and Function

Granzyme B May Act as an Effector Molecule to Control the Inflammatory Process in COPD

Chronic obstructive pulmonary disease (COPD) is caused by smoking, but only a small proportion of smokers have disease severe enough to develop COPD. COPD is not always progressive. The question then arises as to what explains the different trajectories of COPD. The role of autoimmunity and regulatory T (Treg) cells in the pathogenesis of COPD is increasingly being recognized. Nine published studies on Treg cells in the lung tissue or bronchoalveolar lavage fluid have shown that smokers with COPD have fewer Treg cells than smokers without COPD or nonsmokers. Three studies showed a positive correlation between Treg cell count and FEV1%, suggesting an important role for Treg cells in COPD progression. Treg cells can regulate immunological responses via the granzyme B (GzmB) pathway. Immunohistochemical staining for GzmB in surgically resected lungs with centrilobular emphysema showed that the relationship between the amount of GzmB+ cells and FEV1% was comparable to that between Treg cell count and FEV1% in the COPD lung, suggesting that GzmB could be a functional marker for Treg cells. The volume fraction of GzmB+  cells in the small airways, the number of alveolar GzmB+ cells, and GzmB expression measured by enzyme-linked immunosorbent assay in the lung tissue of smokers were significantly correlated with FEV1%. These results suggest that the GzmB content in lung tissue may determine the progression of COPD by acting as an effector molecule to control inflammatory process. Interventions to augment GzmB-producing immunosuppressive cells in the early stages of COPD could help prevent or delay COPD progression.

Sequential immunotherapy: towards cures for autoimmunity

Despite major progress in the treatment of autoimmune diseases in the past two decades, most therapies do not cure disease and can be associated with increased risk of infection through broad suppression of the immune system. However, advances in understanding the causes of autoimmune disease and clinical data from novel therapeutic modalities such as chimeric antigen receptor T cell therapies provide evidence that it may be possible to re-establish immune homeostasis and, potentially, prolong remission or even cure autoimmune diseases. Here, we propose a 'sequential immunotherapy' framework for immune system modulation to help achieve this ambitious goal. This framework encompasses three steps: controlling inflammation; resetting the immune system through elimination of pathogenic immune memory cells; and promoting and maintaining immune homeostasis via immune regulatory agents and tissue repair. We discuss existing drugs and those in development for each of the three steps. We also highlight the importance of causal human biology in identifying and prioritizing novel immunotherapeutic strategies as well as informing their application in specific patient subsets, enabling precision medicine approaches that have the potential to transform clinical care.

Regulatory T Cell Dysfunction in Autoimmune Diseases

Regulatory T cells (Tregs), a suppressive subpopulation of T cells, are potent mediators of peripheral tolerance, responsible for immune homeostasis. Many autoimmune diseases exhibit disruptions in Treg function or quantity, resulting in an imbalance between protective and pathogenic immune cells. Selective expansion or manipulation of Tregs is a promising therapeutic approach for autoimmune diseases. However, the extensive diversity of Treg subpopulations and the multiple approaches used for Treg identification leads to high complexity, making it difficult to develop a successful treatment capable of modulating Tregs. In this review, we describe the suppressive mechanisms, subpopulations, classification, and identification methodology for Tregs, and their role in the pathogenesis of autoimmune diseases.

Guardians and Mediators of Metastasis: Exploring T Lymphocytes, Myeloid-Derived Suppressor Cells, and Tumor-Associated Macrophages in the Breast Cancer Microenvironment

Breast cancers (BCs) are solid tumors composed of heterogeneous tissues consisting of cancer cells and an ever-changing tumor microenvironment (TME). The TME includes, among other non-cancer cell types, immune cells influencing the immune context of cancer tissues. In particular, the cross talk of immune cells and their interactions with cancer cells dramatically influence BC dissemination, immunoediting, and the outcomes of cancer therapies. Tumor-infiltrating lymphocytes (TILs), tumor-associated macrophages (TAMs), and myeloid-derived suppressor cells (MDSCs) represent prominent immune cell populations of breast TMEs, and they have important roles in cancer immunoescape and dissemination. Therefore, in this article we review the features of TILs, TAMs, and MDSCs in BCs. Moreover, we highlight the mechanisms by which these immune cells remodel the immune TME and lead to breast cancer metastasis.

Defining Human Regulatory T Cells beyond FOXP3: The Need to Combine Phenotype with Function

Regulatory T cells (Tregs) are essential to maintain immune homeostasis by promoting self-tolerance. Reduced Treg numbers or functionality can lead to a loss of tolerance, increasing the risk of developing autoimmune diseases. An overwhelming variety of human Tregs has been described, based on either specific phenotype, tissue compartment, or pathological condition, yet the bulk of the literature only addresses CD25-positive and CD127-negative cells, coined by naturally occurring Tregs (nTregs), most of which express the transcription factor Forkhead box protein 3 (FOXP3). While the discovery of FOXP3 was seminal to understanding the origin and biology of nTregs, there is evidence in humans that not all T cells expressing FOXP3 are regulatory, and that not all Tregs express FOXP3. Namely, the activation of human T cells induces the transient expression of FOXP3, irrespective of whether they are regulatory or inflammatory effectors, while some induced T cells that may be broadly defined as Tregs (e.g., Tr1 cells) typically lack demethylation and do not express FOXP3. Furthermore, it is unknown whether and how many nTregs exist without FOXP3 expression. Several other candidate regulatory molecules, such as GITR, Lag-3, GARP, GPA33, Helios, and Neuropilin, have been identified but subsequently discarded as Treg-specific markers. Multiparametric analyses have uncovered a plethora of Treg phenotypes, and neither single markers nor combinations thereof can define all and only Tregs. To date, only the functional capacity to inhibit immune responses defines a Treg and distinguishes Tregs from inflammatory T cells (Teffs) in humans. This review revisits current knowledge of the Treg universe with respect to their heterogeneity in phenotype and function. We propose that it is unavoidable to characterize human Tregs by their phenotype in combination with their function, since phenotype alone does not unambiguously define Tregs. There is an unmet need to align the expression of specific markers or combinations thereof with a particular suppressive function to coin functional Treg entities and categorize Treg diversity.

Toll-like receptor 4 (TLR4) deficiency impedes Toxoplasma gondii excreted-secreted antigens (ESA)-induced abortion

INTRODUCTION

Toxoplasma gondii is an opportunistic intracellular parasite that is a major pathogenic factor in miscarriage, especially when it occurs early in pregnancy. We have previously demonstrated that the regulation of forkhead box transcription factor (Foxp3) is associated with abortion in early pregnancy caused by excretory-secretory antigen (ESA) of strain China 1. We aimed to reveal the underlying mechanism of miscarriage caused by ESA.

METHODS

A TLR4-/- pregnant mouse model was successfully constructed. Pregnant mice at gestational day 5 (G5) were injected with ESA. All animals were sacrificed on G13, pregnancy outcomes were observed, and abortion rates were calculated. Placental status observed by Hematoxylin-eosin staining; gene expression was measured by IHC; flow cytometry analysis was used to determine the number and function of regulatory T cells. In EL4 cells, real-time PCR and Western blot were used to evaluate gene expression and cytokines assay.

RESULTS

In vivo studies revealed that ESA injection caused 83% abortion in pregnant mice but only 35% abortion in TLR4-/- pregnant mice. In addition, ESA attenuated the number and function of regulatory T cells, further suppressed Foxp3, FOXO1 levels, and upregulated CD127 expression. TLR4-/- mice partially reversed this inhibitory effect on regulatory T cells. Furthermore, in vitro studies revealed that ESA inhibited TLR4/NF-κB signaling pathway expression and that TLR4 agonists significantly restored the ESA-induced decrease in Foxp3.

DISCUSSION

These findings suggest that ESA suppresses Foxp3 expression by blocking TLR4/NF-κB signaling, resulting in miscarriage. More importantly, the results indicated that miscarriage caused by ESA is TLR4 dependent.

Regulation of Treg cells by cytokine signaling and co-stimulatory molecules

CD4+CD25+Foxp3+ regulatory T cells (Tregs), a vital component of the immune system, are responsible for maintaining immune homeostasis and preventing excessive immune responses. This review explores the signaling pathways of the cytokines that regulate Treg cells, including transforming growth factor beta (TGF-β), interleukin (IL)-2, IL-10, and IL-35, which foster the differentiation and enhance the immunosuppressive capabilities of Tregs. It also examines how, conversely, signals mediated by IL-6 and tumor necrosis factor -alpha (TNF-α) can undermine Treg suppressive functions or even drive their reprogramming into effector T cells. The B7 family comprises indispensable co-stimulators for T cell activation. Among its members, this review focuses on the capacity of CTLA-4 and PD-1 to regulate the differentiation, function, and survival of Tregs. As Tregs play an essential role in maintaining immune homeostasis, their dysfunction contributes to the pathogenesis of autoimmune diseases. This review delves into the potential of employing Treg-based immunotherapy for the treatment of autoimmune diseases, transplant rejection, and cancer. By shedding light on these topics, this article aims to enhance our understanding of the regulation of Tregs by cytokines and their therapeutic potential for various pathological conditions.

Antibody-Suppressor CXCR5+CD8+ T Cells Are More Potent Regulators of Humoral Alloimmunity after Kidney Transplant in Mice Compared to CD4+ Regulatory T Cells

Adoptive cell therapy (ACT), especially with CD4+ regulatory T cells (CD4+ Tregs), is an emerging therapeutic strategy to minimize immunosuppression and promote long-term allograft acceptance, although much research remains to realize its potential. In this study, we investigated the potency of novel Ab-suppressor CXCR5+CD8+ T cells (CD8+ TAb-supp) in comparison with conventional CD25highFoxp3+CD4+ Tregs for suppression of humoral alloimmunity in a murine kidney transplant (KTx) model of Ab-mediated rejection (AMR). We examined quantity of peripheral blood, splenic and graft-infiltrating CD8+ TAb-supp, and CD4+ Tregs in KTx recipients and found that high alloantibody-producing CCR5 knockout KTx recipients have significantly fewer post-transplant peripheral blood and splenic CD8+ TAb-supp, as well as fewer splenic and graft-infiltrating CD4+ Tregs compared with wild-type KTx recipients. ACT with alloprimed CXCR5+CD8+ T cells reduced alloantibody titer, splenic alloprimed germinal center (GC) B cell quantity, and improved AMR histology in CCR5 knockout KTx recipients. ACT with alloprimed CD4+ Treg cells improved AMR histology without significantly inhibiting alloantibody production or the quantity of splenic alloprimed GC B cells. Studies with TCR transgenic mice confirmed Ag specificity of CD8+ TAb-supp-mediated effector function. In wild-type recipients, CD8 depletion significantly increased alloantibody titer, GC B cells, and severity of AMR pathology compared with isotype-treated controls. Anti-CD25 mAb treatment also resulted in increased but less pronounced effect on alloantibody titer, quantity of GC B cells, and AMR pathology than CD8 depletion. To our knowledge, this is the first report that CD8+ TAb-supp cells are more potent regulators of humoral alloimmunity than CD4+ Treg cells.

FOXP3: A Player of Immunogenetic Architecture in Lung Cancer

The transcription factor forkhead box protein 3 (FOXP3) is considered to be a prominent component of the immune system expressed in regulatory T cells (Tregs). Tregs are immunosuppressive cells that regulate immune homeostasis and self-tolerance. FOXP3 was originally thought to be a Tregs-specific molecule, but recent studies have pinpointed that FOXP3 is expressed in a diversity of benign tumors and carcinomas. The vast majority of the data have shown that FOXP3 is correlated with an unfavorable prognosis, although there are some reports indicating the opposite function of this molecule. Here, we review recent progress in understanding the FOXP3 role in the immunogenetic architecture of lung cancer, which is the leading cause of cancer-related death. We discuss the prognostic significance of tumor FOXP3 expression, tumor-infiltrating FOXP3-lymphocytes, tumor FOXP3 in tumor microenvironments and the potential of FOXP3-targeted therapy.

Immunotherapy and the ovarian cancer microenvironment: Exploring potential strategies for enhanced treatment efficacy

Despite progress in cancer immunotherapy, ovarian cancer (OC) prognosis continues to be disappointing. Recent studies have shed light on how not just tumour cells, but also the complex tumour microenvironment, contribute to this unfavourable outcome of OC immunotherapy. The complexities of the immune microenvironment categorize OC as a 'cold tumour'. Nonetheless, understanding the precise mechanisms through which the microenvironment influences the effectiveness of OC immunotherapy remains an ongoing scientific endeavour. This review primarily aims to dissect the inherent characteristics and behaviours of diverse cells within the immune microenvironment, along with an exploration into its reprogramming and metabolic changes. It is expected that these insights will elucidate the operational dynamics of the immune microenvironment in OC and lay a theoretical groundwork for improving the efficacy of immunotherapy in OC management.

Bispecific antibodies tethering innate receptors induce human tolerant-dendritic cells and regulatory T cells

There is an urgent need for alternative therapies targeting human dendritic cells (DCs) that could reverse inflammatory syndromes in many autoimmune and inflammatory diseases and organ transplantations. Here, we describe a bispecific antibody (bsAb) strategy tethering two pathogen-recognition receptors at the surface of human DCs. This cross-linking switches DCs into a tolerant profile able to induce regulatory T-cell differentiation. The bsAbs, not parental Abs, induced interleukin 10 and transforming growth factor β1 secretion in monocyte-derived DCs and human peripheral blood mononuclear cells. In addition, they induced interleukin 10 secretion by synovial fluid cells in rheumatoid arthritis and gout patients. This concept of bsAb-induced tethering of surface pathogen-recognition receptors switching cell properties opens a new therapeutic avenue for controlling inflammation and restoring immune tolerance.

Probiotic Limosilactobacillus reuteri DSM 17938 Changes Foxp3 Deficiency-Induced Dyslipidemia and Chronic Hepatitis in Mice

The probiotic Limosilactobacillus reuteri DSM 17938 produces anti-inflammatory effects in scurfy (SF) mice, a model characterized by immune dysregulation, polyendocrinopathy, enteropathy, and X-linked inheritance (called IPEX syndrome in humans), caused by regulatory T cell (Treg) deficiency and is due to a Foxp3 gene mutation. Considering the pivotal role of lipids in autoimmune inflammatory processes, we investigated alterations in the relative abundance of lipid profiles in SF mice (± treatment with DSM 17938) compared to normal WT mice. We also examined the correlation between plasma lipids and gut microbiota and circulating inflammatory markers. We noted a significant upregulation of plasma lipids associated with autoimmune disease in SF mice, many of which were downregulated by DSM 17938. The upregulated lipids in SF mice demonstrated a significant correlation with gut bacteria known to be implicated in the pathogenesis of various autoimmune diseases. Chronic hepatitis in SF livers responded to DSM 17938 treatment with a reduction in hepatic inflammation. Altered gene expression associated with lipid metabolism and the positive correlation between lipids and inflammatory cytokines together suggest that autoimmunity leads to dyslipidemia with impaired fatty acid oxidation in SF mice. Probiotics are presumed to contribute to the reduction of lipids by reducing inflammatory pathways.

Immunomodulatory effect of vitamin D supplementation on Behçet's disease patients: effect on nitric oxide and Th17/Treg cytokines production

INTRODUCTION

In the last decade, an immuno-modulatory effect of vitamin D supplementation have emerged as a potential therapeutic approach for some inflammatory and autoimmune diseases. As previously reported, vitamin D deficiency was strongly linked to several diseases as Behçet's disease (BD). BD is a chronic systemic inflammatory disorder with autoimmunity, genetic and environmental factors involvement. The aim of our current study is to set up a new therapeutic strategy in BD, combining conventional therapy and vitamin D supplementation.

MATERIALS AND METHODS

Blood samples were collected from active and inactive BD patients and healthy controls (HC) to evaluate 25(OH) vitamin D levels using an electrochemiluminescence method. All deficient and insufficient vitamin D BD patients' were supplemented with vitamin D3 (CHOLECALCIFEROL, 200 000 UI/1 ml). In this context, NO, IL-17A and IL-10 levels were evaluated in patients and HC in vivo and ex vivo using Griess and ELISA methods respectively.

RESULTS

Before supplementation, we noted with interest that BD patients had vitamin D deficiency, associated with elevated in vivo and ex vivo NO and IL-17A levels compared to HC. Conversely, low IL-10 levels were observed in the same BD patients in comparison to HC. Interestingly, restored vitamin D status in supplemented BD patients was related to the decreased NO levels. In the same way, the IL-10/IL-17A ratio was improved.

CONCLUSIONS

Collectively, our data suggest that vitamin D supplementation in combination with conventional treatments has a beneficial effect and could constitute a good therapeutic candidate for alleviating inflammatory responses during Behçet disease.

Regulatory T-cell dysfunctions are associated with increase in tumor necrosis factor α in autoimmune hemolytic anemia and participate in Th17 polarization

Warm autoimmune hemolytic anemia (wAIHA) is a rare acquired autoimmune disease mediated by antibodies targeting red blood cells. The involvement of CD4 T-helper cells has been scarcely explored, with most findings extrapolated from animal models. Here, we performed quantification of both effector T lymphocytes (Teff) and regulatory T cells (Treg), associated with functional and transcriptomic analyses of Treg in human wAIHA. We observed a shift of Teff toward a Th17 polarization concordant with an increase in serum interleukin-17 concentration that correlates with red blood cell destruction parameters, namely lactate dehydrogenase and bilirubin levels. A decrease in circulating Treg, notably effector Treg, associated with a functional deficiency, as represented by their decrease capability to inhibit Teff proliferation, were also observed. Treg deficiency was associated with a reduced expression of Foxp3, the master transcription factor known to maintain the Treg phenotype stability and suppressive functions. Transcriptomic profiling of Treg revealed activation of the tumor necrosis facto (TNF)-α pathway, which was linked to increased serum TNF-α concentrations that were twice as high as in controls. Treg transcriptomic profiling also suggested that post-translational mechanisms possibly accounted for Foxp3 downregulation and Treg dysfunctions. Since TNF-α participates in the rupture of immune tolerance during wAIHA, its inhibition could be of interest. To this end, the effects of fostamatinib, a SYK inhibitor, were investigated in vitro, and we showed that besides the inhibition of erythrocyte phagocytosis by monocytes, fostamatinib is also able to dampen TNF-α production, thus appearing as a promising multitargeting therapy in wAIHA (clinicaltrials gov. Identifier: NCT02158195).

Molecular mechanism of lncRNAs in pathogenesis and diagnosis of auto-immune diseases, with a special focus on lncRNA-based therapeutic approaches

Autoimmune diseases are a diverse set of conditions defined by organ damage due to abnormal innate and acquired immune system responses. The pathophysiology of autoimmune disorders is exceedingly intricate and has yet to be fully understood. The study of long non-coding RNAs (lncRNAs), non-protein-coding RNAs with at least 200 nucleotides in length, has gained significant attention due to the completion of the human genome project and the advancement of high-throughput genomic approaches. Recent research has demonstrated how lncRNA alters disease development to different degrees. Although lncRNA research has made significant progress in cancer and generative disorders, autoimmune illnesses are a relatively new research area. Moreover, lncRNAs play crucial functions in differentiating various immune cells, and their potential relationships with autoimmune diseases have received growing attention. Because of the importance of Th17/Treg axis in auto-immune disease development, in this review, we discuss various molecular mechanisms by which lncRNAs regulate the differentiation of Th17/Treg cells. Also, we reviewed recent findings regarding the several approaches in the application of lncRNAs in the diagnosis and treatment of human autoimmune diseases, as well as current challenges in lncRNA-based therapeutic approaches to auto-immune diseases.

Regulatory TR3-56 Cells in the Complex Panorama of Immune Activation and Regulation

The interplay between immune activation and immune regulation is a fundamental aspect of the functional harmony of the immune system. This delicate balance is essential to triggering correct and effective immune responses against pathogens while preventing excessive inflammation and the immunopathogenic mechanisms of autoimmunity. The knowledge of all the mechanisms involved in immune regulation is not yet definitive, and, probably, the overall picture is much broader than what has been described in the scientific literature so far. Given the plasticity of the immune system and the diversity of organisms, it is highly probable that numerous other cells and molecules are still to be ascribed to the immune regulation process. Here, we report a general overview of how immune activation and regulation interact, based on the involvement of molecules and cells specifically dedicated to these processes. In addition, we discuss the role of TR3-56 lymphocytes as a new cellular candidate in the immune regulation landscape.

Insights into the Tumor Microenvironment-Components, Functions and Therapeutics

Similarly to our healthy organs, the tumor tissue also constitutes an ecosystem. This implies that stromal cells acquire an altered phenotype in tandem with tumor cells, thereby promoting tumor survival. Cancer cells are fueled by abnormal blood vessels, allowing them to develop and proliferate. Tumor-associated fibroblasts adapt their cytokine and chemokine production to the needs of tumor cells and alter the peritumoral stroma by generating more collagen, thereby stiffening the matrix; these processes promote epithelial-mesenchymal transition and tumor cell invasion. Chronic inflammation and the mobilization of pro-tumorigenic inflammatory cells further facilitate tumor expansion. All of these events can impede the effective administration of tumor treatment; so, the successful inhibition of tumorous matrix remodeling could further enhance the success of antitumor therapy. Over the last decade, significant progress has been made with the introduction of novel immunotherapy that targets the inhibitory mechanisms of T cell activation. However, extensive research is also being conducted on the stromal components and other cell types of the tumor microenvironment (TME) that may serve as potential therapeutic targets.

Deciphering the immune landscape of head and neck squamous cell carcinoma: A single-cell transcriptomic analysis of regulatory T cell responses to PD-1 blockade therapy

Immunotherapy is changing the Head and Neck Squamous Cell Carcinoma (HNSCC) landscape and improving outcomes for patients with recurrent or metastatic HNSCC. A deeper understanding of the tumor microenvironment (TME) is required in light of the limitations of patients' responses to immunotherapy. Here, we aimed to examine how Nivolumab affects infiltrating Tregs in the HNSCC TME. We used single-cell RNA sequencing data from eight tissues isolated from four HNSCC donors before and after Nivolumab treatment. Interestingly, the study found that Treg counts and suppressive activity increased following Nivolumab therapy. We also discovered that changes in the CD44-SSP1 axis, NKG2C/D-HLA-E axis, and KRAS signaling may have contributed to the increase in Treg numbers. Furthermore, our study suggests that decreasing the activity of the KRAS and Notch signaling pathways, and increasing FOXP3, CTLA-4, LAG-3, and GZMA expression, may be mechanisms that enhance the killing and suppressive capacity of Tregs. Additionally, the result of pseudo-temporal analysis of the HNSCC TME indicated that after Nivolumab therapy, the expression of certain inhibitory immune checkpoints including TIGIT, ENTPD1, and CD276 and LY9, were decreased in Tregs, while LAG-3 showed an increased expression level. The study also found that Tregs had a dense communication network with cluster two, and that certain ligand-receptor pairs, including SPP1/CD44, HLA-E/KLRC2, HLA-E/KLRK1, ANXA1/FPR3, and CXCL9/FCGR2A, had notable changes after the therapy. These changes in gene expression and cell interactions may have implications for the role of Tregs in the TME and in response to Nivolumab therapy.

Mitochondrial-regulated Tregs: potential therapeutic targets for autoimmune diseases of the central nervous system

Regulatory T cells (Tregs) can eliminate autoreactive lymphocytes, induce self-tolerance, and suppress the inflammatory response. Mitochondria, as the energy factories of cells, are essential for regulating the survival, differentiation, and function of Tregs. Studies have shown that patients with autoimmune diseases of the central nervous system, such as multiple sclerosis, neuromyelitis optica spectrum disorder, and autoimmune encephalitis, have aberrant Tregs and mitochondrial damage. However, the role of mitochondrial-regulated Tregs in autoimmune diseases of the central nervous system remains inconclusive. Therefore, this study reviews the mitochondrial regulation of Tregs in autoimmune diseases of the central nervous system and investigates the possible mitochondrial therapeutic targets.

Human HLA-DR+CD27+ regulatory T cells show enhanced antigen-specific suppressive function

Regulatory T cells (Tregs) have potential for the treatment of autoimmune diseases and graft rejection. Antigen specificity and functional stability are considered critical for their therapeutic efficacy. In this study, expansion of human Tregs in the presence of porcine PBMCs (xenoantigen-expanded Tregs, Xn-Treg) allowed the selection of a distinct Treg subset, coexpressing the activation/memory surface markers HLA-DR and CD27 with enhanced proportion of FOXP3+Helios+ Tregs. Compared with their unsorted and HLA-DR+CD27+ double-positive (DP) cell-depleted Xn-Treg counterparts, HLA-DR+CD27+ DP-enriched Xn-Tregs expressed upregulated Treg function markers CD95 and ICOS with enhanced suppression of xenogeneic but not polyclonal mixed lymphocyte reaction. They also had less Treg-specific demethylation in the region of FOXP3 and were more resistant to conversion to effector cells under inflammatory conditions. Adoptive transfer of porcine islet recipient NOD/SCID IL2 receptor γ-/- mice with HLA-DR+CD27+ DP-enriched Xn-Tregs in a humanized mouse model inhibited porcine islet graft rejection mediated by 25-fold more human effector cells. The prolonged graft survival was associated with enhanced accumulation of FOXP3+ Tregs and upregulated expression of Treg functional genes, IL10 and cytotoxic T lymphocyte antigen 4, but downregulated expression of effector Th1, Th2, and Th17 cytokine genes, within surviving grafts. Collectively, human HLA-DR+CD27+ DP-enriched Xn-Tregs expressed a specific regulatory signature that enabled identification and isolation of antigen-specific and functionally stable Tregs with potential as a Treg-based therapy.

Crucial Role of Foxp3 Gene Expression and Mutation in Systemic Lupus Erythematosus, Inferred from Computational and Experimental Approaches

The impaired suppressive function of regulatory T cells is well-understood in systemic lupus erythematosus. This is likely due to changes in Foxp3 expression that are crucial for regulatory T-cell stability and function. There are a few reports on the correlation between the Foxp3 altered expression level and single-nucleotide polymorphisms within the Foxp3 locus. Moreover, some studies showed the importance of Foxp3 expression in the same diseases. Therefore, to explore the possible effects of single-nucleotide polymorphisms, here, we evaluated the association of IVS9+459/rs2280883 (T>C) and -2383/rs3761549 (C>T) Foxp3 polymorphisms with systemic lupus erythematosus. Moreover, through machine-learning and deep-learning methods, we assessed the connection of the expression level of the gene with the disease. Single-nucleotide polymorphisms of Foxp3 (IVS9+459/rs2280883 (T>C) and -2383/rs3761549 (C>T)) were, respectively, genotyped using allele-specific PCR and direct sequencing and polymerase chain reaction-restriction fragment length polymorphism, in 199 systemic lupus erythematosus patients and 206 healthy age- and sex-matched controls. The Statistical Package for the Social Sciences version 19 and Fisher's exact and chi-square tests were used to analyze the data. Moreover, six machine-learning models and two sequential deep-learning models were designed to classify patients from normal people in the E-MTAB-11191 dataset through the expression level of Foxp3 and its correlated genes. The allele and genotype frequencies of both polymorphisms in question were found to be significantly associated with an increased risk of systemic lupus erythematosus. Furthermore, both of the two single-nucleotide polymorphisms were associated with some systemic-lupus-erythematosus-related risk factors. Three SVM models and the logistic regression model showed an 81% accuracy in classification problems. In addition, the first deep-learning model showed an 83% and 89% accuracy for the training and validation data, respectively, while the second model had an 85% and 79% accuracy for the training and validation datasets. In this study, we are prompted to represent the predisposing loci for systemic lupus erythematosus pathogenesis and strived to provide evidence-based support to the application of machine learning for the identification of systemic lupus erythematosus. It is predicted that the recruiting of machine-learning algorithms with the simultaneous measurement of the applied single nucleotide polymorphisms will increased the diagnostic accuracy of systemic lupus erythematosus, which will be very helpful in providing sufficient predictive value about individual subjects with systemic lupus erythematosus.

Tumor microenvironment diversity and plasticity in cancer multidrug resistance

Multidrug resistance (MDR) poses a significant obstacle to effective cancer treatment, and the tumor microenvironment (TME) is crucial for MDR development and reversal. The TME plays an active role in promoting MDR through several pathways. However, a promising therapeutic approach for battling MDR involves targeting specific elements within the TME. Therefore, this comprehensive review elaborates on the research developments regarding the dual role of the TME in promoting and reversing MDR in cancer. Understanding the complex role of the TME in promoting and reversing MDR is essential to developing effective cancer therapies. Utilizing the adaptability of the TME by targeting novel TME-specific factors, utilizing combination therapies, and employing innovative treatment strategies can potentially combat MDR and achieve personalized treatment outcomes for patients with cancer.

Lower vitamin D levels are associated with the pathogenesis of inflammatory bowel diseases

Vitamin D plays a role in regulating immune homeostasis, inflammation and has an impact on the pathogenesis of inflammatory bowel diseases (IBD). IBD has a multifactorial pathogenesis primarily associated with immune dysregulation, dysbiosis, structurally altered intestinal mucosa, and genetic factors. The immunomodulatory function of this vitamin is linked to its control over innate and adaptive immunity, facilitated through its nuclear vitamin D receptor, leading to the inhibition of nuclear factor kappa-B. This study aimed to investigate serum vitamin D levels in patients with IBD compared to healthy individuals and to evaluate the relationship between vitamin D and inflammatory markers. Cross-sectional study. The study included 106 participants divided into 2 groups: patients with IBD (92), and healthy controls (14). The diagnosis of IBD was based on clinical, laboratory, fecal, endoscopic, and histological findings, following the European guidelines for diagnosis and follow-up ECCO-ESGAR guidelines for diagnostic assessment of IBD from 2019. Serum vitamin D levels were measured along with laboratory tests, imaging, and endoscopic examinations. IBD activity was evaluated using the Montreal classification and clinical and endoscopic indices. Data analysis involved calculating the mean, minimum, and maximum values, standard deviation, and Pearson coefficient. The level of statistical significance for this study was set at P < .05. The study found a prevalence of vitamin D deficiency in 32.6% of patients with IBD, while 66.3% had insufficiency, as compared with healthy individuals. The mean levels of vitamin D in UC and CD were 16 ± 8.6 ng/mL, whereas in the control healthy group, they were 26 ± 9.73 ng/mL. A statistically significant reverse correlation was observed between lower vitamin D levels and higher levels of the inflammatory markers. The study concluded that IBD patients exhibit lower levels of vitamin D, which is associated with inflammation and may contribute to the pathogenesis of the disease.

Extracellular Vesicles from Immune Cells: A Biomedical Perspective

Research on the role of extracellular vesicles (sEV) in physiology has demonstrated their undoubted importance in processes such as the transportation of molecules with significance for cell metabolism, cell communication, and the regulation of mechanisms such as cell differentiation, inflammation, and immunity. Although the role of EVs in the immune response is actively investigated, there is little literature revising, in a comprehensive manner, the role of small EVs produced by immune cells. Here, we present a review of studies reporting the release of sEV by different types of leukocytes and the implications of such observations on cellular homeostasis. We also discuss the function of immune cell-derived sEV and their relationship with pathological states, highlighting their potential application in the biomedical field.

Pathogenesis of chronic rhinosinusitis with nasal polyp and a prominent T2 endotype

Chronic rhinosinusitis is a heterogenous and multifactorial disease, characterized by persistent inflammation of the nose and paranasal sinuses, which causes nasal obstruction, nasal discharge, facial pain, and smell disturbance. Chronic rhinosinusitis is divided into two phenotypes: chronic rhinosinusitis with nasal polyp and chronic rhinosinusitis without nasal polyp. Nasal polyps can be associated with many inflammatory cells including eosinophil cells, neutrophil cells, plasma cells, and lymphocytes. T2 endotype is characterized by the type-2 immune response and nasal polyps are associated with eosinophilic dominant infiltration. In contrast, in the T1 and T3 endotypes, chronic rhinosinusitis can be associated with neutrophilic dominant infiltration. In addition, there are mixed types of inflammation with different proportions of eosinophils-neutrophils in chronic rhinosinusitis. In the T2 endotype, there is an increase in the production of Th2 cytokines, including interleukin-4, interleukin-5, and interleukin-13, high levels of immunoglobulin-E in polyp tissue, and eosinophilia. Stimulation of Th2 cells, type-2 innate lymphoid cells, epithelial cell damage, Staphylococcus aureus enterotoxins, and autoimmune antibodies have important roles in the enhancement of Th2 cytokines and pathogenesis of chronic rhinosinusitis with nasal polyp. Monoclonal antibodies target type-2 inflammation, decrease nasal polyp size, and improve the clinical symptoms of CRSwNP patients. The present review will focus on factors involved in the pathogenesis of chronic rhinosinusitis and its treatment.

Treg cell: Critical role of regulatory T-cells in depression

Depression is a highly prevalent disorder of the central nervous system. The neuropsychiatric symptoms of clinical depression are persistent and include fatigue, anorexia, weight loss, altered sleep patterns, hyperalgesia, melancholia, anxiety, and impaired social behaviours. Mounting evidences suggest that neuroinflammation triggers dysregulated cellular immunity and increases susceptibility to psychiatric diseases. Neuroimmune responses have transformed the clinical approach to depression because of their roles in its pathophysiology and their therapeutic potential. In particular, activated regulatory T (Treg) cells play an increasingly evident role in the inflammatory immune response. In this review, we summarized the available data and discussed in depth the fundamental roles of Tregs in the pathogenesis of depression, as well as the clinical therapeutic potential of Tregs. We aimed to provide recent information regarding the potential of Tregs as immune-modulating biologics for the treatment and prevention of long-term neuropsychiatric symptoms of depression.

CD4 Phenotypes Are Associated with Reduced Expansion of Tumor-Infiltrating Lymphocytes in Melanoma Patients Treated with Adoptive Cell Therapy

Tumor-infiltrating lymphocyte (TIL) adoptive cell therapy is effective in treating malignant melanoma, but its success relies on the adequate ex vivo expansion of TIL. To assess correlates of TIL expansion, CD4+ and CD8+ TIL were analyzed by RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing of acetylated histone 3. Patients were grouped into "TIL high" and "TIL low" based on division at the median number of TIL infused. Greater numbers of TIL infused correlated with longer overall survival, and increased frequencies of CD4+ cells infused were negatively correlated with the number of TIL infused. RNA-seq analysis of CD4+ TIL showed increases in Th2/Th17/regulatory T cell-related transcripts and pathways in the TIL-low group. Analysis of a public single-cell RNA-seq dataset validated findings that increased frequencies of CD4+ cells were negatively correlated with the number of TIL infused. TIL-low patients had significantly increased frequencies of CD4+ cells expressing ETS2 and OSM and trended toward increased expression of TNFRSF18.

Cell-targeted vaccines: implications for adaptive immunity

Recent advancements in immunology and chemistry have facilitated advancements in targeted vaccine technology. Targeting specific cell types, tissue locations, or receptors can allow for modulation of the adaptive immune response to vaccines. This review provides an overview of cellular targets of vaccines, suggests methods of targeting and downstream effects on immune responses, and summarizes general trends in the literature. Understanding the relationships between vaccine targets and subsequent adaptive immune responses is critical for effective vaccine design. This knowledge could facilitate design of more effective, disease-specialized vaccines.

Distribution and chemotactic mechanism of CD4+ T cells in traumatic tracheal stenosis

A systemic and local inflammatory immune imbalance is thought to be the cause of traumatic tracheal stenosis (TS). However, with CD4+ T lymphocytes being the predominant immune cells in TS, the mechanism of action and recruitment has not been described. In our research, using flow cytometry, ELISA, immunofluorescence, and Transwell chamber assays, the expression, distribution, and potential chemotactic function of CD4+ T cells in TS patients were examined before and after treatment. The results showed that the untreated group had significantly more CD4+ T cells and their secreted TGF-β1 than the treated group. Additionally, the untreated group's CD4+ T cells showed a significant rise in CCL22 and CCL1, as well as a larger proportion of CCR4 and CCR8. CD4+ T cells and CD68+ macrophages located in TS also expressed CCL1 and CCL22. In vitro, anti-CCL1 and anti-CCL22 can partially block the chemoattractant effect of TS bronchoalveolar lavage (BAL) on purified CD4+ T cells. The findings of this study indicated that TS contained unbalanced CD4 immune cells that were actively recruited locally by CCR4/CCL22 and CCR8/CCL1. As a result, it is anticipated that CD4 immune rebalancing can serve as a novel treatment for TS.

An open-label multiyear study of sargramostim-treated Parkinson's disease patients examining drug safety, tolerability, and immune biomarkers from limited case numbers

BACKGROUND

The clinical utility and safety of sargramostim has previously been reported in cancer, acute radiation syndrome, autoimmune disease, inflammatory conditions, and Alzheimer's disease. The safety, tolerability, and mechanisms of action in Parkinson's disease (PD) during extended use has not been evaluated.

METHODS

As a primary goal, safety and tolerability was assessed in five PD patients treated with sargramostim (Leukine®, granulocyte-macrophage colony-stimulating factor) for 33 months. Secondary goals included numbers of CD4+ T cells and monocytes and motor functions. Hematologic, metabolic, immune, and neurological evaluations were assessed during a 5-day on, 2-day off therapeutic regimen given at 3 μg/kg. After 2 years, drug use was discontinued for 3 months. This was then followed by an additional 6 months of treatment.

RESULTS

Sargramostim-associated adverse events included injection-site reactions, elevated total white cell counts, and bone pain. On drug, blood analyses and metabolic panels revealed no untoward side effects linked to long-term treatment. Unified Parkinson's Disease Rating Scale scores remained stable throughout the study while regulatory T cell number and function were increased. In the initial 6 months of treatment, transcriptomic and proteomic monocyte tests demonstrated autophagy and sirtuin signaling. This finding paralleled anti-inflammatory and antioxidant activities within both the adaptive and innate immune profile arms.

CONCLUSIONS

Taken together, the data affirmed long-term safety as well as immune and anti-inflammatory responses reflecting clinical stability in PD under the sargramostim treatment. Confirmation in larger patient populations is planned in a future phase II evaluation.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03790670, Date of Registration: 01/02/2019, URL: https://clinicaltrials.gov/ct2/show/NCT03790670?cond=leukine+parkinson%27s&draw=2&rank=2 .

Adaptive immunology of Cryptococcus neoformans infections-an update

The fungal genus Cryptococcus comprises a group of pathogens with considerable phenotypic and genotypic diversity that can lead to cryptococcosis in both healthy and immunocompromised individuals. With the emergence of the HIV pandemic, cryptococcosis, mainly meningoencephalitis, afflicts HIV-infected patients with severe dysfunction of T cells. It has also been reported in recipients of solid organ transplantation and in patients with autoimmune diseases who take immunosuppressive agents long-term, as well as in those with unidentified immunodeficiency. The clinical outcome of the disease is primarily determined by the immune response resulting from the interplay between the host immune system and the pathogen. Most human infections are caused by Cryptococcus neoformans, and nearly all immunological studies have focused on C. neoformans. This review provides an updated understanding of the role of adaptive immunity during infection with C. neoformans in human and animal models over the past half-decade.

Dysfunction of Foxp3+ Regulatory T Cells Induces Dysbiosis of Gut Microbiota via Aberrant Binding of Immunoglobulins to Microbes in the Intestinal Lumen

Foxp3⁺ regulatory T (Treg) cells prevent excessive immune responses against dietary antigens and commensal bacteria in the intestine. Moreover, Treg cells contribute to the establishment of a symbiotic relationship between the host and gut microbes, partly through immunoglobulin A. However, the mechanism by which Treg cell dysfunction disturbs the balanced intestinal microbiota remains unclear. In this study, we used Foxp3 conditional knockout mice to conditionally ablate the Foxp3 gene in adult mice and examine the relationship between Treg cells and intestinal bacterial communities. Deletion of Foxp3 reduced the relative abundance of Clostridia, suggesting that Treg cells have a role in maintaining Treg-inducing microbes. Additionally, the knockout increased the levels of fecal immunoglobulins and immunoglobulin-coated bacteria. This increase was due to immunoglobulin leakage into the gut lumen as a result of loss of mucosal integrity, which is dependent on the gut microbiota. Our findings suggest that Treg cell dysfunction leads to gut dysbiosis via aberrant antibody binding to the intestinal microbes.

Galectin-3 as a Marker for Increased Thrombogenicity in COVID-19

Galectin-3 is a beta-galactoside-binding lectin involved in inflammation and lung fibrosis and postulated to enhance thrombosis. In COVID-19, it is considered to be a prognostic marker of severity. The aim of this study was to evaluate whether galectin-3 is associated with thrombogenicity in COVID-19. Patients with moderate-to-severe COVID-19 (COVpos; n = 55) and patients with acute respiratory diseases, but without COVID-19 (COVneg; n = 35), were included in the study. We measured the amount of galectin-3, as well as other platelet and coagulation markers, and correlated galectin-3 levels with these markers of thrombogenicity and with the SOFA Score values. We found that galectin-3 levels, as well as von Willebrand Factor (vWF), antithrombin and tissue plasminogen activator levels, were higher in the COVpos than they were in the COVneg cohort. Galectin-3 correlated positively with vWF, antithrombin and D-dimer in the COVpos cohort, but not in the COVneg cohort. Moreover, galactin-3 correlated also with clinical disease severity, as measured by the SOFA Score. In patients with acute respiratory diseases, galectin-3 can be considered as a marker not only for disease severity, but also for increased hypercoagulability. Whether galectin-3 might be a useful therapeutic target in COVID-19 needs to be assessed in future studies.

IKK1 aggravates ischemia-reperfusion kidney injury by promoting the differentiation of effector T cells

Ischemia-reperfusion injury (IRI) is one of the major causes of acute kidney injury (AKI), and experimental work has revealed detailed insight into the inflammatory response in the kidney. T cells and NFκB pathway play an important role in IRI. Therefore, we examined the regulatory role and mechanisms of IkappaB kinase 1 (IKK1) in CD4⁺T lymphocytes in an experimental model of IRI. IRI was induced in CD4cre and CD4IKK1Δ mice. Compared to control mice, conditional deficiency of IKK1 in CD4⁺T lymphocyte significantly decreased serum creatinine, blood urea nitrogen (BUN) level, and renal tubular injury score. Mechanistically, lack in IKK1 in CD4⁺T lymphocytes reduced the ability of CD4 lymphocytes to differentiate into Th1/Th17 cells. Similar to IKK1 gene ablation, pharmacological inhibition of IKK also protected mice from IRI. Together, lymphocyte IKK1 plays a pivotal role in IRI by promoting T cells differentiation into Th1/Th17 and targeting lymphocyte IKK1 may be a novel therapeutic strategy for IRI.

Stratified distribution of Th17 and Treg cells in patients with multi-stage rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a typical, progressive autoimmune disease. Its occurrence and development are associated with dysregulation of T and B cell numbers. However, the specific immune characteristics of different RA courses remain incompletely defined. Here, we describe the peripheral blood lymphocyte subsets, particularly CD4 + T subsets, of different RA courses with a focus on early RA (Ea-RA).

METHODS

In all, 131 patients with Ea-RA, 117 with advanced RA (Ad-RA), and 109 with treated RA (Tr-RA) were enrolled. We collected general clinical data. Whole blood samples obtained from the patients and 97 healthy controls (HCs) were analysed via flow cytometry.

RESULTS

Decreased absolute NK cell numbers and increased CD4/CD8 T cell ratios were observed in different RA groups, including Ea-RA, compared to healthy controls. In Ea-RA patients, the Th17 and Treg cell numbers were similar to those in HCs. We performed k-means clustering based on the profiles of Th17 and Treg cells for patients with multi-stage of RA. We identified three patient types: type A characterised by relatively low Treg and Th17 cell numbers, type B with moderate levels of Treg cells and levels of Th17 cells similar to that of type C patients, and type C with high levels of Treg cells and levels of Th17 cells similar to that of type B patients.

CONCLUSION

The immune characteristics of Ea-RA patients differ from those of HCs; an immune system disorder is apparent although no differences in Th17 and Treg levels were evident between Ea-RA patients and HCs. We found distributional heterogeneities of Th17 and Treg cells in patients with multi-stage of RA. Stratified management based on such heterogeneity may serve as a useful novel immunotherapy allowing of early intervention.

The Role of Oxidative Stress in Vitiligo: An Update on Its Pathogenesis and Therapeutic Implications

Vitiligo is an autoimmune skin disorder caused by dysfunctional pigment-producing melanocytes which are attacked by immune cells. Oxidative stress is considered to play a crucial role in activating consequent autoimmune responses related to vitiligo. Melanin synthesis by melanocytes is the main intracellular stressor, producing reactive oxygen species (ROS). Under normal physiological conditions, the antioxidative nuclear factor erythroid 2-related factor 2 (Nrf2) pathway functions as a crucial mediator for cells to resist oxidative stress. In pathological situations, such as with antioxidant defects or under inflammation, ROS accumulate and cause cell damage. Herein, we summarize events at the cellular level under excessive ROS in vitiligo and highlight exposure to melanocyte-specific antigens that trigger immune responses. Such responses lead to functional impairment and the death of melanocytes, which sequentially increase melanocyte cytotoxicity through both innate and adaptive immunity. This report provides new perspectives and advances our understanding of interrelationships between oxidative stress and autoimmunity in the pathogenesis of vitiligo. We describe progress with targeted antioxidant therapy, with the aim of providing potential therapeutic approaches.

The potential for treg-enhancing therapies in nervous system pathologies

While inflammation may not be the cause of disease, it is well known that it contributes to disease pathogenesis across a multitude of peripheral and central nervous system disorders. Chronic and overactive inflammation due to an effector T-cell-mediated aberrant immune response ultimately leads to tissue damage and neuronal cell death. To counteract peripheral and neuroinflammatory responses, research is being focused on regulatory T cell enhancement as a therapeutic target. Regulatory T cells are an immunosuppressive subpopulation of CD4+ T helper cells essential for maintaining immune homeostasis. The cells play pivotal roles in suppressing immune responses to maintain immune tolerance. In so doing, they control T cell proliferation and pro-inflammatory cytokine production curtailing autoimmunity and inflammation. For nervous system pathologies, Treg are known to affect the onset and tempo of neural injuries. To this end, we review recent findings supporting Treg's role in disease, as well as serving as a therapeutic agent in multiple sclerosis, myasthenia gravis, Guillain-Barre syndrome, Parkinson's and Alzheimer's diseases, and amyotrophic lateral sclerosis. An ever-broader role for Treg in the control of neurologic disease has been shown for traumatic brain injury, stroke, neurotrophic pain, epilepsy, and psychiatric disorders. To such ends, this review serves to examine the role played by Tregs in nervous system diseases with a focus on harnessing their functional therapeutic role(s).

Differential regulatory T cell signature after recovery from mild COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is characterized by a range of symptoms in which host immune response have been associated with disease progression. However, the putative role of regulatory T cells (Tregs) in determining COVID-19 outcomes has not been thoroughly investigated. Here, we compared peripheral Tregs between volunteers not previously infected with SARS-CoV-2 (healthy control [HC]) and volunteers who recovered from mild (Mild Recovered) and severe (Severe Recovered) COVID-19. Peripheral blood mononuclear cells (PBMC) were stimulated with SARS-CoV-2 synthetic peptides (Pool Spike CoV-2 and Pool CoV-2) or staphylococcal enterotoxin B (SEB). Results of a multicolor flow cytometric assay showed higher Treg frequency and expression of IL-10, IL-17, perforin, granzyme B, PD-1, and CD39/CD73 co-expression in Treg among the PBMC from the Mild Recovered group than in the Severe Recovered or HC groups for certain SARS-CoV-2 related stimulus. Moreover, Mild Recovered unstimulated samples presented a higher Tregs frequency and expression of IL-10 and granzyme B than did that of HC. Compared with Pool CoV-2 stimuli, Pool Spike CoV-2 reduced IL-10 expression and improved PD-1 expression in Tregs from volunteers in the Mild Recovered group. Interestingly, Pool Spike CoV-2 elicited a decrease in Treg IL-17+ frequency in the Severe Recovered group. In HC, the expression of latency-associated peptide (LAP) and cytotoxic granule co-expression by Tregs was higher in Pool CoV-2 stimulated samples. While Pool Spike CoV-2 stimulation reduced the frequency of IL-10+ and CTLA-4+ Tregs in PBMC from volunteers in the Mild Recovered group who had not experienced certain symptoms, higher levels of perforin and perforin+granzyme B+ co-expression by Tregs were found in the Mild Recovered group in volunteers who had experienced dyspnea. Finally, we found differential expression of CD39 and CD73 among volunteers in the Mild Recovered group between those who had and had not experienced musculoskeletal pain. Collectively, our study suggests that changes in the immunosuppressive repertoire of Tregs can influence the development of a distinct COVID-19 clinical profile, revealing that a possible modulation of Tregs exists among volunteers of the Mild Recovered group between those who did and did not develop certain symptoms, leading to mild disease.

Low-dose interleukin-2 treatment increases the proportion of regulatory T cells in patients with rheumatic diseases: A meta-analysis

BACKGROUND

It is now accepted that immune tolerance disorders caused by inadequate Treg cell function or number are important factors in the development and progression of rheumatic diseases. There is increasing evidence that ld IL-2 treatment increases the proportion of Treg cells in patients' peripheral blood, but this conclusion is still controversial. Here, we performed a meta-analysis of reports documenting the proportion of Treg cells and the rate of adverse events in patients with rheumatic disease before and after the administration of ld IL-2 to better understand its effect and safety on Treg cells in the field of rheumatic diseases.

METHODS

We systematically searched PubMed, Embase, Scopus, Cochrane Library, and Web of science databases up to 15th November 2022 and identified studies that reported the proportion of peripheral blood Treg cells before and after ld IL-2 treatment in patients with rheumatic disease. Random-effects model was used to perform a meta-analysis of Treg cell proportions before and after ld IL-2 administration, and a meta-regression analysis was performed to explore heterogeneity. Inconsistency was evaluated using the I-squared index (I²), and publication bias was assessed by examining funnel plot asymmetry using the Egger tests.

RESULTS

Eighteen studies involving 1608 patients were included in the meta-analysis. The proportion of Treg cells in peripheral blood of these patients increased significantly after receiving ld IL-2 treatment [1.07 (95% CI 0.86,1.27), p < 0.001, I² = 67.3%]. Next, Meta-regression was performed for 5 variables including publish year, disease type, trail type and dosage and duration of the medication. The results suggest that these variables do not lead to high heterogeneity. (p = 0.698, 0.267, 0.502, 0.843, 0.560, respectively). And finally, statistical analysis showed no difference in adverse reactions between ld IL-2 group and control group in treatment [1.06 (95% CI 0.86,1.31), p = 0.586, I2 = 53.8%], which is unreliable because the data is so small.

CONCLUSIONS

Ld IL-2 does increase the proportion of peripheral blood Treg cells in patients with rheumatism, and single and cumulative doses must be considered when using ld IL-2. In addition, more studies on the safety of ld IL-2 are urgently needed.

Granzyme B in Autoimmune Skin Disease

Autoimmune diseases often present with cutaneous symptoms that contribute to dysfunction, disfigurement, and in many cases, reduced quality-of-life. Unfortunately, treatment options for many autoimmune skin diseases are limited. Local and systemic corticosteroids remain the current standard-of-care but are associated with significant adverse effects. Hence, there is an unmet need for novel therapies that block molecular drivers of disease in a local and/or targeted manner. Granzyme B (GzmB) is a serine protease with known cytotoxic activity and emerging extracellular functions, including the cleavage of cell-cell junctions, basement membranes, cell receptors, and other structural proteins. While minimal to absent in healthy skin, GzmB is markedly elevated in alopecia areata, interface dermatitis, pemphigoid disease, psoriasis, systemic sclerosis, and vitiligo. This review will discuss the role of GzmB in immunity, blistering, apoptosis, and barrier dysfunction in the context of autoimmune skin disease. GzmB plays a causal role in the development of pemphigoid disease and carries diagnostic and prognostic significance in cutaneous lupus erythematosus, vitiligo, and alopecia areata. Taken together, these data support GzmB as a promising therapeutic target for autoimmune skin diseases impacted by impaired barrier function, inflammation, and/or blistering.

Dihydroartemisinin imposes positive and negative regulation on Treg and plasma cells via direct interaction and activation of c-Fos

Dihydroartemisinin (DHA), a potent antimalarial drug, also exhibits distinct property in modulation on T_reg and B cells, which has been recognized for decades, but the underlying mechanisms remain understood. Herein we revealed that DHA could promote T_reg proliferation, meanwhile, suppress B cell expansion in germinal centers, and consequently decrease the number of circulating plasma cells and the content of serum immunoglobulins. Further, DHA-activated T_reg significantly mitigated lipopolysaccharide-induced and malaria-associated inflammation. All these scenarios were attributed to the upregulation of c-Fos expression by DHA and enhancement of its interaction with target genes in both T_reg and circulating plasma cells with bilateral cell fates. In T_reg, the c-Fos-DHA complex upregulated cell proliferation-associated genes and promoted cell expansion; whereas in plasma cells, it upregulated the apoptosis-related genes resulting in decreased circulating plasma cells. Thus, the bilateral immunoregulatory mechanism of DHA was elucidated and its application in the treatment of autoimmune diseases is further justified.

Profiling of Peripheral TRBV and CD4+CD25+ Treg in CHB Patients with HBeAg SC during TDF Treatment

Background

It is lacking that markers could predict the prognosis of chronic hepatitis B (CHB) subjects during antiviral treatment, and the related cellular immune mechanism is not fully evaluated.

Aim

To explore the comprehensive profile of T cell receptor β-chain (TRBV) and CD4+CD25+ regulatory T cell (Treg) in peripheral blood of CHB patients with HBeAg seroconverting (SC) during tenofovir disoproxil fumarate (TDF) treatment.

Methods

The frequency of CD4+CD25high+ Treg and number of skewed TRBV in 20 HBeAg positive patients were determined at baseline and following every 12 weeks during 96-week TDF treatment. The relationship among serum alanine aminotransferase (ALT) level, HBV DNA load, Treg frequency, and the number of skewed TRBV, respectively, was analyzed for CHB patients. Receiver operative characteristic curve was applied to analyze their diagnostic value for HBeAg SC.

Results

The number of skewed TRBV at week 48, Treg frequency at week 72, and ALT level at baseline could predict the HBeAg SC or non-SC in CHB patients during 96-week TDF treatment. Moreover, the positive correlation between ALT or HBV DNA and Treg levels or skewed TRBVs was significant in the SC group, but not in non-SC.

Conclusions

The predictive cutoff value of ALT for HBeAg SC was 178 U/L at baseline. Moreover, the ALT, Treg, and TRBV families would be associated with the prognosis and pathogenesis of CHB patients during TDF treatment.

FOXP3 regulatory T cells on prognosis of breast cancer

BACKGROUND

FOXP3 Tregs have been found in breast cancer patients, both humoral and tumor. Survival or prognosis of breast cancer patients seems to correlate with the increase and decrease in FOXP3 Treg.

OBJECTIVES

This review aims to provide insights regarding the FOXP3 Tregs involved and their mechanisms in breast cancer prognosis.

METHODS

The literature study method is used from primary and secondary libraries. The library search used online-based search instruments such as NCBI-PubMed, Google Scholar, and Elsevier. The data obtained were then arranged according to the framework, data on the relationship between FOXP3 Regulatory T Cells and breast cancer, and writing a journal review was carried out according to the given format. Regulators (Tregs) can inhibit anti-tumor immunity and promote tumor growth. Tregs also play a role in inhibiting cytotoxic T lymphocyte cells by inhibiting the release of granules from CD8+, where CD8+ is important in killing tumor cells. FOXP3 is a Treg-specific biomarker and plays an important role in the development and function of Tregs.

RESULTS

Studies on the presence of FOXP3+ Tregs in tumors have shown controversial results. Studies in some tumors reported the presence of FOXP3+, indicating a poor prognosis, whereas studies in other tumors found that FOXP3+ correlated with a good prognosis.

CONCLUSION

Regulatory T lymphocytes and TILs in invasive breast carcinoma are still not established. Therefore, further research on the Effect of FOXP3 expression of regulatory T lymphocytes on breast cancer is still important.

The Contrasting Seasonality Patterns of Some Cancer-Types and Herpes Zoster Can Be Explained by a Binary Classification of Immunological Reactions

A binary classification of the pathogenic immune reactions as anti-inflammatory high-Treg reactions or pro-inflammatory low-Treg reactions explains both the relatively low incidence rate of several types of cancer, and the relatively high incidence rate of herpes zoster cases diagnosed in the summer compared to cases diagnosed in the winter (in regions with temperate climate). This binary model also elucidates the longer survival of cancer patients diagnosed during the summer compared to these diagnosed in the winter. The three key elements of this explanation are: (a) the effect of sunlight on Treg production; (b) the evolvement of cancer from a low-Treg condition at early stage, to a high-Treg condition at advanced stage, and (c) the evolvement of herpes zoster from a high-Treg condition at pre-exudative stage to a low-Treg condition at acute exudative stage. A significant proportion of indolent tumors at the time of diagnosis (>20%) is a prerequisite for a beneficial effect of sunlight on cancer incidence rate and prognosis. This prerequisite restricts the beneficial effect of diagnosis during summer to certain types of cancer. Clinical implication: the prognosis of early stage tumors may be improved by a course of corticosteroid (or other immunosuppressant) treatment.

FOXP3+ regulatory T cells and the immune escape in solid tumours

FOXP3+ regulatory T (Treg) cells play critical roles in establishing the immunosuppressive tumour microenvironment, which is achieved and dynamically maintained with the contribution of various stromal and immune cell subsets. However, the dynamics of non-lymphoid FOXP3+ Treg cells and the mutual regulation of Treg cells and other cell types in solid tumour microenvironment remains largely unclear. In this review, we summarize the latest findings on the dynamic connections and reciprocal regulations of non-lymphoid Treg cell subsets in accordance with well-established and new emerging hallmarks of cancer, especially on the immune escape of tumour cells in solid tumours. Our comprehension of the interplay between FOXP3+ Treg cells and key hallmarks of cancer may provide new insights into the development of next-generation engineered T cell-based immune treatments for solid tumours.

Crosstalk between dendritic cells and regulatory T cells: Protective effect and therapeutic potential in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system related to autoimmunity and is characterized by demyelination, neuroinflammation, and neurodegeneration. Cell therapies mediated by dendritic cells (DCs) and regulatory T cells (Tregs) have gradually become accumulating focusing in MS, and the protective crosstalk mechanisms between DCs and Tregs provide the basis for the efficacy of treatment regimens. In MS and its animal model experimental autoimmune encephalomyelitis, DCs communicate with Tregs to form immune synapses and complete a variety of complex interactions to counteract the unbalanced immune tolerance. Through different co-stimulatory/inhibitory molecules, cytokines, and metabolic enzymes, DCs regulate the proliferation, differentiation and function of Tregs. On the other hand, Tregs inhibit the mature state and antigen presentation ability of DCs, ultimately improving immune tolerance. In this review, we summarized the pivotal immune targets in the interaction between DCs and Tregs, and elucidated the protective mechanisms of DC-Treg cell crosstalk in MS, finally interpreted the complex cell interplay in the manner of inhibitory feedback loops to explore novel therapeutic directions for MS.

Low-dose IL-2 prevents murine chronic cardiac allograft rejection: Role for IL-2-induced T regulatory cells and exosomes with PD-L1 and CD73

To determine the effects and immunological mechanisms of low-dose interleukin-2 (IL-2) in a murine model of chronic cardiac allograft rejection (BALB/c to C57BL/6) after costimulatory blockade consisting of MR1 (250 μg/ip day 0) and CTLA4-Ig (200 μg/ip day 2), we administered low-dose IL-2 (2000 IU/day) starting on posttransplant day 14 for 3 weeks. T regulatory (Treg) cell infiltration of the grafts was determined by immunohistochemistry; circulating exosomes by western blot and aldehyde bead flow cytometry; antibodies to donor MHC by immunofluorescent staining of donor cells; and antibodies to cardiac self-antigens (myosin, vimentin) by ELISA. We demonstrated that costimulation blockade after allogeneic heart transplantation induced circulating exosomes containing cardiac self-antigens and antibodies to both donor MHC and self-antigens, leading to chronic rejection by day 45. Treatment with low-dose IL-2 prolonged allograft survival (>100 days), prevented chronic rejection, and induced splenic and graft-infiltrating CD4+ CD25+ Foxp3 Treg cells by day 45 and circulating exosomes (Foxp3+) with PD-L1 and CD73. MicroRNA 142, associated with the TGFβ pathway, was significantly downregulated in exosomes from IL-2-treated mice. In conclusion, low-dose IL-2 delays rejection in a murine model of chronic cardiac allograft rejection and also induces graft-infiltrating Tregs and circulating exosomes with immunoregulatory molecules.

Dynamically modeling the effective range of IL-2 dosage in the treatment of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease characterized by an overactive immune response to self-antigen. The overactivation of CD4⁺ Foxp3⁻ conventional T cells (Tcons) and the inactivation of CD4⁺ CD25⁺ Foxp3⁺ regulatory T cells (Tregs) play important roles in the progression of SLE. Clinical trials showed that low-dose interleukin-2 (IL-2) is effective in treating SLE. Here, we developed a mathematical model involving Tcons, Tregs, natural killer (NK) cells, and IL-2 to simulate the dynamic processes involved in the treatment of SLE. We found an effective range of IL-2 dosage defined by the Tcon/Treg ratio in SLE treatment, termed the IL-2 dosage therapeutic window (IDTW). Our results showed that high levels of self-antigen result in a narrow IDTW and high post-treatment Tcon/Treg ratio. Furthermore, we proposed a classification method based on the ratio of pre-treatment Treg to CD4⁺ T cells to predict the treatment outcome of SLE patients.

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Tcon/Treg ratio can be an indicator to define the IL-2 dosage therapeutic window in SLE treatment

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SLE patients with high levels of self-antigen are predicted to have a narrow IL-2 therapeutic window

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High-dose IL-2 should overactivate Tcons and increase the Tcon/Treg ratio in SLE patients

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SLE patients with lower pre-treatment Treg are more likely to benefit from IL-2 administration

Comprehensive insights into the function and molecular and pharmacological regulation of neuron-derived orphan receptor 1, an orphan receptor

Neuron-derived orphan receptor 1 (NOR1), also called nuclear receptor subfamily 4 group A member 3 (NR4A3), is a nuclear receptor belonging to the NR4A family. Since no endogenous ligand has been identified to date, NOR1 is also referred to as an orphan receptor. NOR1 is expressed in a variety of cells and tissues, including neurons, vascular smooth muscle cells, T lymphocytes, dendritic cells, tumor cells, heart, liver, and pancreas. Because NOR1 was first identified in apoptotic neurons, it is functionally associated with the regulation of cell migration and the growth of neuronal synapses. In-depth studies have shown that NOR1 can be edited by the immediate early gene and functions as a transcription factor. NOR1 has been shown to be rapidly induced by a number of stimulants including growth factors, fatty acids, and neurotransmitters. Elevated NOR1 levels may be involved in a number of pathophysiological processes. These include regulation of cellular apoptosis and regeneration, neuron formation, contextual fearing memory, inflammation, vascular smooth muscle proliferation, insulin secretion, and tumor development, whereby NOR1 mediates the pathogenesis of numerous diseases such as cerebral ischemia, depression, post-traumatic stress disorder, atherosclerosis, abdominal aortic aneurysm, cardiac hypertrophy, diabetes, osteoarthritis, rheumatoid arthritis, and cancer. However, to date, comprehensive insights into the function of NOR1 are not available in sources published online. In this review, we provide a brief overview of the function and molecular and pharmacological regulation of NOR1 in various pathological or physiological conditions to advance the development of NOR1 as a novel target for disease treatment.

A Systematic Review of Apoptosis in Correlation With Cancer: Should Apoptosis Be the Ultimate Target for Cancer Treatment?

Targeting apoptosis in cancer therapy has become increasingly popular, and there has been an increasing debate on whether apoptosis should be one of the main targets of therapy in cancer management. This study demonstrates the definition of apoptosis, the signaling pathways, and the pathogenesis behind it. We also show the correlation between apoptosis and cancer and how cancer can evade apoptosis to develop resistance to therapy. In addition, we illustrate the efficacy of adding pro-apoptotic therapy to conventional radio-chemotherapy cancer treatment.

A systematic review was conducted using PubMed, PubMed Central (PMC), and ResearchGate, including papers written in English, focusing on adult and geriatric populations, in literature reviews, systematic reviews, and randomized controlled trials published in the last 25 years with relevance to the question.

Based on the findings of this review, we conclude that apoptosis is a very sophisticated programmed cellular death with many signaling pathways. Its evasion should be considered one of the hallmarks of cancer and is responsible for multiple drug resistance (MDR) to cancer therapy. Targeting apoptosis seems promising, especially if combined with radio-chemotherapy.