Percutaneous Delivery of Hederacoside C-Loaded Nanoliposome Gel Alleviates Psoriasiform Skin Inflammation through the CCL17/Treg Axis.

Psoriasis is a chronic, recurrent, and inflammatory skin disease. Topical agents, which can avoid the adverse effects of systemic treatment, are the first-choice therapy for patients with mild-to-moderate psoriasis. Hederacoside C (HSC) with anti-inflammatory properties has been used to treat some inflammatory diseases. We speculated that HSC might also be effective for psoriasis treatment. However, topical application of HSC for psoriasis treatment is challenging because of its low water solubility and poor skin permeability. Therefore, it is important to effectively deliver HSC percutaneously using certain biomaterials. Here we constructed a hydroxypropyl-ß-cyclodextrin-coated liposome gel formulation for the loading and percutaneously delivering of HSC, referred to as HSC-Lipo@gel. The characterization, stability, release properties, and mechanical or transdermal features of the HSC-Lipo@gel were evaluated. Its therapeutic potential was also demonstrated using mouse models of IMQ-induced psoriasis. We found that HSC-Lipo@gel effectively improved the skin permeability of HSC with the property of good stability and sustained release. Importantly, HSC-Lipo@gel showed higher efficacy than HSC@gel without liposomes in alleviating psoriatic skin lesions. It attenuated epidermal hyperplasia and suppressed expression of IL-17A, TNF-α, IL-6, and IL-23 in lesional skin. Interestingly, HSC-Lipo@gel reduced the expression of CC chemokine ligand 17 (CCL17), but not CCL22, in the skin. Especially, HSC-Lipo@gel inhibited CCL17 expression by skin dendritic cells while increasing regulatory T cells (Tregs) in both skin and draining lymph nodes of psoriatic mice. Administration of CCL17 resulted in severe skin lesions and reduced CD4+FoxP3+ Tregs in psoriatic mice previously treated with HSC-Lipo@gel. Finally, HSC or HSC-Lipo also suppressed the CCL17 production by dendritic cells in vitro. Therefore, HSC-Lipo@gel alleviated psoriasiform skin inflammation by increasing cutaneous Tregs via downregulation of the expression of CCL17, but not CCL22. Thus, HSC-Lipo@gel may be a stable, highly permeable, and effective system for topical treatment of psoriasis.

Re-establishing immune tolerance in multiple sclerosis: focusing on novel mechanisms of mesenchymal stem cell regulation of Th17/Treg balance.

The T-helper 17 (Th17) cell and regulatory T cell (Treg) axis plays a crucial role in the development of multiple sclerosis (MS), which is regarded as an immune imbalance between pro-inflammatory cytokines and the maintenance of immune tolerance. Mesenchymal stem cell (MSC)-mediated therapies have received increasing attention in MS research. In MS and its animal model experimental autoimmune encephalomyelitis, MSC injection was shown to alter the differentiation of CD4+T cells. This alteration occurred by inducing anergy and reduction in the number of Th17 cells, stimulating the polarization of antigen-specific Treg to reverse the imbalance of the Th17/Treg axis, reducing the inflammatory cascade response and demyelination, and restoring an overall state of immune tolerance. In this review, we summarize the mechanisms by which MSCs regulate the balance between Th17 cells and Tregs, including extracellular vesicles, mitochondrial transfer, metabolic reprogramming, and autophagy. We aimed to identify new targets for MS treatment using cellular therapy by analyzing MSC-mediated Th17-to-Treg polarization.

Prognosis comparison between hepatocellular carcinoma patients with microvascular invasion who received hepatectomy alone and those who underwent early PA-TACE: a retrospective cohort study.

Background: Postoperative adjuvant transcatheter arterial chemoembolization (PA-TACE) can achieve longer overall survival (OS) and disease-free survival (DFS) in hepatocellular carcinoma (HCC) patients with microvascular invasion (MVI). We investigated whether this treatment strategy could benefit these patients by mediating the dysfunctional immunological status. Therefore, a retrospective cohort study was conducted to investigate the effect of early PA-TACE in HCC patients with MVI by measuring the levels of T helper cell 17 (Th17) and regulatory T cell (Treg). Methods: This study retrospectively included 472 patients with HCC undergoing hepatectomy between December 2015 and December 2018, and 115 patients with MVI confirmed by postoperative pathology were enrolled and divided into two groups of TACE group and non-TACE group according to whether TACE was performed. HCC patients with MVI. The proportion of Treg and Th17 cells in peripheral blood was measured one day before and four weeks after TACE. All patients in the two groups were followed up until death or until the study ended in December 2023. The rates of OS and progression-free survival (PFS) in patients with MVI were compared between those who received hepatectomy alone and those who underwent early PA-TACE. Results: Among 115 HCC patients with MVI from 472 patients, the study enrolled 51 patients with PA-TACE into the TACE group and 42 patients without TACE into the non-TACE group. There were no statistical differences in baseline data between the two groups (all P>0.05). The frequency of Treg among CD4+ T cells in HCC patients with PA-TACE was significantly lower than baseline (7.34%±3.61% vs. 5.82%±2.76%, P<0.001), and the frequency of Th17 among CD4+ T cells in these patients was significantly higher than baseline (0.49%±0.28% vs. 0.50%±0.25%, P<0.001). Among all the patients, the median OS was 61.8 months. The OS rate and PFS rate at 12, 36, and 60 months in the TACE group were significantly higher than those in the non-TACE group (all P<0.05). Conclusions: PA-TACE may have roles in improving survival outcomes, and restoring immune homeostasis in HCC patients with MVI after hepatectomy.

Targeting tumor-infiltrating CCR8+ regulatory T cells induces antitumor immunity through functional restoration of CD4+ Tconvs and CD8+ T cells in colorectal cancer.

BACKGROUND: Chemokine (C-C motif) receptor 8 (CCR8) is a chemokine receptor selectively expressed on tumor-infiltrating regulatory T cells (Tregs). Strong immunosuppression mediated by CCR8+ Tregs observed in breast and lung malignancies suggest for their functional significance in cancer therapy. To date, detailed characterization of tumor-infiltrating CCR8+ Tregs cells in colorectal cancer (CRC) is limited. METHODS: To study the presence and functional involvement of CCR8+ Tregs in CRC, we analyzed the proportions of CCR8-expressing T cells in different T cell subsets in tumor and adjacent normal tissues and peripheral blood mononuclear cells (PBMCs) from CRC patients by Flow cytometry. Also, we compared the distribution of CCR8+ T cells in malignant tissues and peripheral lymphoid organs from a subcutaneous CRC murine model. Bioinformatic analysis was performed to address the significance of CCR8 expression levels in CRC prognosis, immune regulatory gene expression profiles and potential molecular mechanisms associated with CCR8+ Tregs in CRC tumors. Further, we administrated an anti-CCR8 monoclonal antibody to CT26 tumor-bearing mice and examined the antitumor activity of CCR8-targeted therapy both in vivo and in an ex vivo confirmative model. RESULTS: Here, we showed that Tregs was predominantly presented in the tumors of CRC patients (13.4 ± 5.8, p < 0.0001) and the CRC subcutaneous murine model (35.0 ± 2.6, p < 0.0001). CCR8 was found to be preferentially expressed on these tumor-infiltrating Tregs (CRC patients: 63.6 ± 16.0, p < 0.0001; CRC murine model: 65.3 ± 9.5, p < 0.0001), which correlated with poor survival. We found that majority of the CCR8+ Tregs expressed activation markers and exhibited strong suppressive functions. Treatment with anti-CCR8 antibody hampered the growth of subcutaneous CRC tumor through effectively restoring the anti-tumor immunity of CD4+ conventional T cells (CD4+ Tconvs) and CD8+ T cells, which was confirmed in the ex vivo examinations. CONCLUSIONS: Collectively, these findings illustrate the importance of CCR8+ Tregs for an immunosuppressive microenvironment in CRC tumors by functional inhibition of CD4+ Tconvs and CD8+ T cells, and suggest for the applicable value of CCR8-targeted therapy for CRC.

Deubiquitinating enzymes: potential regulators of the tumor microenvironment and implications for immune evasion.

Ubiquitination and deubiquitination are important forms of posttranslational modification that govern protein homeostasis. Deubiquitinating enzymes (DUBs), a protein superfamily consisting of more than 100 members, deconjugate ubiquitin chains from client proteins to regulate cellular homeostasis. However, the dysregulation of DUBs is reportedly associated with several diseases, including cancer. The tumor microenvironment (TME) is a highly complex entity comprising diverse noncancerous cells (e.g., immune cells and stromal cells) and the extracellular matrix (ECM). Since TME heterogeneity is closely related to tumorigenesis and immune evasion, targeting TME components has recently been considered an attractive therapeutic strategy for restoring antitumor immunity. Emerging studies have revealed the involvement of DUBs in immune modulation within the TME, including the regulation of immune checkpoints and immunocyte infiltration and function, which renders DUBs promising for potent cancer immunotherapy. Nevertheless, the roles of DUBs in the crosstalk between tumors and their surrounding components have not been comprehensively reviewed. In this review, we discuss the involvement of DUBs in the dynamic interplay between tumors, immune cells, and stromal cells and illustrate how dysregulated DUBs facilitate immune evasion and promote tumor progression. We also summarize potential small molecules that target DUBs to alleviate immunosuppression and suppress tumorigenesis. Finally, we discuss the prospects and challenges regarding the targeting of DUBs in cancer immunotherapeutics and several urgent problems that warrant further investigation.

Treg-derived TGF-ß1 dampens cGAS-STING signaling to downregulate the expression of class I MHC complex in multiple myeloma.

Multiple myeloma (MM) progression involves diminished tumor antigen presentation and an immunosuppressive microenvironment, characterized by diminished expression of major histocompatibility complexes (MHC) class I molecule and elevated programmed death ligand 1 (PDL1) in MM cells, along with an enriched population of regulatory T cells (Tregs). To investigate Treg's influence on MM cells, we established a co-culture system using Tregs from MM patients and the MM cell lines (MM.1S and SK-MM-1) in vitro and assessed the effects of intervening in the relevant pathways connecting Tregs and MM cells in vivo. In vitro, Tregs induced transforming growth factor beta-1 (TGF-ß1) production, downregulated MHC I members, and increased PDL1 expression in MM cells. Treg-derived TGF-ß1 suppressed the cGAS-STING pathway, contributing to the loss of MHC I molecule expression and PDL1 upregulation. Correspondingly, neutralizing TGF-ß1 or activating the cGAS-STING pathway restored MHC I and PDL1 expression, effectively countering the pro-tumorigenic effect of Tregs on MM cells in vivo. These data elucidated how Tregs influence tumor antigen presentation and immunosuppressive signal in MM cells, potentially providing therapeutic strategies, such as neutralizing TGF-ß1 or activating the cGAS-STING pathway, to address the immune escape and immunosuppressive dynamics in MM.

Immunomodulation of Ethyl pyruvate on gestational diabetes mellitus in Mice; The impact on Th17/Treg balance.

Gestational diabetes mellitus (GDM) is recognized as one of the most common diseases among pregnant women and inflammatory responses can be a major reason for its induction and development. T helper 17 (Th17)/regulatory T cells (Tregs) imbalance resulting in the increased levels of pro-inflammatory and decreased levels of anti-inflammatory cytokines has been showed as major mechanisms involved in the pathogenesis of GDM. There are various treatment options, but none of them are completely therapeutic. Ethyl pyruvate (EP) is a stable derivate of pyruvate that showed anti-oxidant and anti-inflammatory properties in an in-vivo and in-vitro models. To examine the therapeutic efficacy of EP in GDM, mice were mated and EP (100 mg/kg) was administered intraperitoneally to C57BL/6 mice. EP-treated mice exhibited improved symptoms of GDM by decreased blood glucose levels and body-weight and increased insulin levels and insulin sensitivity. Furthermore, EP could significantly attenuate the impairments to offspring, including birth size and birth weight. The inflammatory responses were also decreased by EP through regulating the production of Th17-related cytokines, such as interleukin (IL)- 17 and IL-21. The levels of other inflammatory cytokines were also inhibited, including IL-1ß, IL-6, and tumor necrosis factor (TNF)-α. In addition, it was found that EP increased the population of Tregs and Treg-related cytokines, IL-10 and transforming Growth Factor-ß TGF-ß, in GDM mice. In conclusion, EP could modulate GDM in mice and might be a potential therapeutic strategy candidate for the treatment of patients with GDM.

FOXP3 (in)stability and cancer immunotherapy.

Dysregulation of regulatory T cells (Tregs) is described in the context of inflammatory and autoimmune diseases, and cancer. Forkhead box P3 (FOXP3) is a transcription factor that its activity is an indicator of Treg identity. FOXP3 induces metabolic versatility in intra-tumoral Tregs, so that its deficiency mediates Treg instability or even gives rise to the acquisition of effector T cell phenotype. FOXP3 dysregulation and defectiveness occurs upon ubiquitination, methylation and presumably acetylation. Stimulators of PTEN, mammalian target of rapamycin complex 2 (mTORC2), and nucleus accumbens-associated protein-1 (NAC1), and inhibitors of B lymphocyte-induced maturation protein-1 (Blimp-1), Deltex1 (DTX1) and ubiquitin-specific peptidase 22 (USP22) are suggested to hamper FOXP3 stability, and to promote its downregulation and further Treg depletion. A point is that Treg subsets reveal different reliance on FOXP3, which indicates that not all Tregs are strictly dependent on FOXP3, and presumably Tregs with different origin rely on diverse regulators of FOXP3 stability. The focus of this review is over the current understanding toward FOXP3, its activity in Tregs and influence from different regulators within tumor microenvironment (TME). Implication of FOXP3 targeting in cancer immunotherapy is another focus of this paper.

Selective targeting or reprogramming of intra-tumoral Tregs.

Regulatory T cells (Tregs) are critical immunosuppressive cells that are frequently present in the tumor microenvironment of solid cancers and enable progression of tumors toward metastasis. The cells expand in response to tumor-associated antigens and are actively involved in bypassing immunotherapy with immune checkpoint inhibitors through integrating numerous environmental signals. A point here is that Tregs are clonally distinct in peripheral blood from tumor area. Currently, an effective and novel task in cancer immunotherapy is to selectively destabilize or deplete intra-tumoral Tregs in order to avoid systemic inflammatory events. Helios is a transcription factor expressed selectively by Tregs and promotes their stabilization, and Trps1 is a master regulator of intra-tumoral Tregs. Anti-CCR8 and the IL-2Rßγ agonist Bempegaldesleukin selectively target intra-tumoral Treg population, with the former approved to not elicit autoimmunity. Disarming Treg-related immunosuppression in tumors through diverting their reprogramming or promoting naïve T cell differentiation into cells with effector immune activating profile is another promising area of research in cancer immunotherapy. Blimp-1 inhibitors and glucocorticoid-induced TNFR-related protein agonists are example approaches that can be used for diverting Treg differentiation into Th1-like CD4+ T cells, thereby powering immunogenicity against cancer. Finally, selective target of intra-tumoral Tregs and their reprogramming into effector T cells is applicable using low-dose chemotherapy, and high-salt and high-tryptophan diet.

Effect of Buzhong Yiqitang on Th17/Treg Immune Imbalance and Notch1 Signaling Pathway in AIT Mice / 中国实验方剂学杂志

ObjectiveTo explore the effect of Buzhong Yiqitang on the immune imbalance of helper T cell 17 （Th17）/regulatory T cell （Treg） and Notch1 signaling pathway in mice with autoimmune thyroiditis （AIT）. MethodA total of 60 8-week-old NOD.H-2h4 mice were randomly divided into the normal group， model group， western medicine group （selenium yeast tablet， 32.5 mg·kg-1）， and low-dose （4.78 g·kg-1·d-1）， middle-dose （9.56 g·kg-1·d-1）， and high-dose （19 g·kg-1·d-1） Buzhong Yiqitang groups， with 10 mice in each group. The normal group was fed with distilled water， and the other groups were fed with water containing 0.05% sodium iodide for eight weeks. After the animal model of AIT was formed spontaneously， the mice were killed under anesthesia after intragastric administration for eight weeks. Serum anti-thyroglobulin antibodies （TGAb）， thyroid-stimulating hormone （TSH）， free triiodothyronine （FT3）， and free thyroid hormone （FT4） were detected by enzyme-linked immunosorbent assay （ELISA）， and thyroid tissue changes were observed by hematoxylin-eosin （HE） staining. The mRNA and protein expressions of retinoid-related orphan receptor-γt （RORγt）， interleukin （IL）-17， forkhead box P3 （FoxP3）， IL-10， Notch1， and hair division-related enhancer 1 （Hes1） in thyroid tissue were detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot， respectively. ResultCompared with the normal group， the thyroid structure of the model group was severely damaged， and lymphocytes were infiltrated obviously. The levels of serum TGAb， FT3， and FT4 contents were significantly increased， and TSH content was significantly decreased （P<0.01）. The mRNA and protein expression levels of RORγt， IL-17， Notch1， and Hes1 were significantly increased， while those of FoxP3 and IL10 were significantly decreased in the model group （P<0.01）. Compared with the model group， thyroid structural damage and lymphocyte infiltration were improved in the treatment groups， and serum TGAb， FT3， and FT4 contents were significantly decreased. TSH content was increased， and mRNA and protein expression levels of RORγt， IL-17， Notch1， and Hes1 were decreased. mRNA and protein expression levels of FoxP3 and IL-10 were increased to different degrees （P<0.05， P<0.01）， and the middle-dose Buzhong Yiqitang group had the most significant intervention effect. ConclusionBuzhong Yiqitang can alleviate the thyroid structural damage in AIT mice， and its mechanism may be related to improving the abnormal differentiation of Th17/Treg immune cells and inhibiting the activation of the Notch1 signaling pathway.

Dual-Armed Oncolytic Myxoma Virus Encoding IFN-γ and CD47 Promotes Lymphocyte Infiltration and Tumor Suppression of Syngeneic Murine Melanoma.

Myxoma virus (MyxV) is a rabbit-specific poxvirus. However, its ability to selectively target tumor cells has established it as a safe and effective anticancer therapy. To strengthen its preclinical efficacy, transgenes that can prolong cancer cell infection and enhance anti-tumor effector functions are currently being investigated. We engineered MyxV armed with CD47, to turn on a 'do not eat me' signal within infected cells with actively replicating viruses, and with IFN-γ to further activate host immune anticancer responses. Tumor suppressive activities were significantly enhanced by the dual-armed MyxV_CD47/IFN-γ compared to parental MyxV or single-armed MyxV_CD47 or MyxV_IFN-γ. In addition, significant increases in IFN-γ+ CD8+T-cells and CD4+ T-cells populations within tumor-infiltrating lymphocytes (TIL) were observed after MyxV_CD47/IFN-γ treatment. Notably, all groups treated with MyxV showed a marked reduction in Foxp3+ CD4+ regulatory T-cells (Tregs) within TIL. We also show that MyxV infection induces PD-L1 up-regulation in cancer cells, and combinational treatment of MyxV with anti-mouse PD-L1 antibodies (αPD-L1) further controlled tumor burden and increased survival in the syngeneic melanoma model B16F10. Our data demonstrate that a CD47 and IFNγ dual-armed MyxV is an effective oncolytic viral immunotherapeutic. These findings strongly support further preclinical investigations to develop next-generation MyxV-based immunotherapy approaches.

Attenuated IL-2 muteins leverage the TCR signal to enhance regulatory T cell homeostasis and response in vivo.

Interleukin-2 (IL-2), along with T-cell receptor (TCR) signaling, are required to control regulatory T cell (Treg) homeostasis and function in vivo. Due to the heightened sensitivity to IL-2, Tregs retain the ability to respond to low-dose or attenuated forms of IL-2, as currently being developed for clinical use to treat inflammatory diseases. While attenuated IL-2 increases Treg selectivity, the question remains as to whether a weakened IL-2 signal sufficiently enhances Treg suppressive function(s) toward disease modification. To understand this question, we characterized the in vivo activity and transcriptomic profiles of two different attenuated IL-2 muteins in comparison with wildtype (WT) IL-2. Our study showed that, in addition to favoring Tregs, the attenuated muteins induced disproportionately robust effects on Treg activation and conversion to effector Treg (eTreg) phenotype. Our data furthermore suggested that Tregs activated by attenuated IL-2 muteins showed reduced dependence on TCR signal, at least in part due to the enhanced ability of IL-2 muteins to amplify the TCR signal in vivo. These results point to a new paradigm wherein IL-2 influences Tregs' sensitivity to antigenic signal, and that the combination effect may be leveraged for therapeutic use of attenuated IL-2 muteins.

CD25 targeting with the afucosylated human IgG1 antibody RG6292 eliminates regulatory T cells and CD25+ blasts in acute myeloid leukemia.

Background: Acute Myeloid leukemia is a heterogeneous disease that requires novel targeted treatment options tailored to the patients' specific microenvironment and blast phenotype. Methods: We characterized bone marrow and/or blood samples of 37 AML patients and healthy donors by high dimensional flow cytometry and RNA sequencing using computational analysis. In addition, we performed ex vivo ADCC assays using allogeneic NK cells isolated from healthy donors and AML patient material to test the cytotoxic potential of CD25 Mab (also referred to as RG6292 and RO7296682) or isotype control antibody on regulatory T cells and CD25+ AML cells. Results: Bone marrow composition, in particular the abundance of regulatory T cells and CD25 expressing AML cells, correlated strongly with that of the blood in patients with time-matched samples. In addition, we observed a strong enrichment in the prevalence of CD25 expressing AML cells in patients bearing a FLT3-ITD mutation or treated with a hypomethylating agent in combination with venetoclax. We adopted a patient-centric approach to study AML clusters with CD25 expression and found it most highly expressed on immature phenotypes. Ex vivo treatment of primary AML patient samples with CD25 Mab, a human CD25 specific glycoengineered IgG1 antibody led to the specific killing of two different cell types, CD25+ AML cells and regulatory T cells, by allogeneic Natural Killer cells. Conclusion: The in-depth characterization of patient samples by proteomic and genomic analyses supported the identification of a patient population that may benefit most by harnessing CD25 Mab's dual mode of action. In this pre-selected patient population, CD25 Mab could lead to the specific depletion of regulatory T cells, in addition to leukemic stem cells and progenitor-like AML cells that are responsible for disease progression or relapse.

People with Primary Progressive Multiple Sclerosis Have a Lower Number of Central Memory T Cells and HLA-DR+ Tregs.

The importance of circulating immune cells to primary progressive multiple sclerosis (PPMS) pathophysiology is still controversial because most immunotherapies were shown to be ineffective in treating people with PPMS (pwPPMS). Yet, although controversial, data exist describing peripheral immune system alterations in pwPPMS. This study aims to investigate which alterations might be present in pwPPMS free of disease-modifying drugs (DMD) in comparison to age- and sex-matched healthy controls. A multicentric cross-sectional study was performed using 23 pwPPMS and 23 healthy controls. The phenotype of conventional CD4+ and CD8+ T cells, regulatory T cells (Tregs), B cells, natural killer (NK) T cells and NK cells was assessed. Lower numbers of central memory CD4+ and CD8+ T cells and activated HLA-DR+ Tregs were observed in pwPPMS. Regarding NK and NKT cells, pwPPMS presented higher percentages of CD56dimCD57+ NK cells expressing NKp46 and of NKT cells expressing KIR2DL2/3 and NKp30. Higher disease severity scores and an increasing time since diagnosis was correlated with lower numbers of inhibitory NK cells subsets. Our findings contribute to reinforcing the hypotheses that alterations in peripheral immune cells are present in pwPPMS and that changes in NK cell populations are the strongest correlate of disease severity.

Viral, genetic, and immune factors in the oncogenesis of adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) is a malignancy of mature CD4 + T cells induced by human T-cell leukemia virus type I (HTLV-1). HTLV-1 maintains life-long infection in the human host by clonal proliferation of infected cells and cell-to-cell spread of the virus. Two viral genes, tax and HTLV-1 bZIP factor (HBZ), promote expansion of infected cells through the important roles they play in acceleration of cell proliferation and protection from cell death. Long-term survival of infected clones in vivo causes genetic mutations and aberrant epigenetic changes to accumulate in host genes, resulting in the emergence of an ATL clone. Recent advances in sequencing technology have revealed the broad picture of genetic and transcriptional abnormalities in ATL cells. ATL cells have hyper-proliferative and anti-apoptotic signatures like those observed in other malignancies, but also notably have traits related to immune evasion. ATL cells exhibit a regulatory T-cell-like immuno-phenotype due to both the function of HBZ and mutation of several host genes, such as CCR4 and CIC. These findings suggest that immune evasion is a critical step in the oncogenesis of ATL, and thus novel therapies that activate anti-ATL/HTLV-1 immunity may be effective in the treatment and prevention of ATL.

Advances in application of regulatory T cells in transplant immune tolerance: from basic to clinical research / 器官移植

Regulatory T cells (Treg) are important inhibitory immune cells to establish immune tolerance, which play a pivotal role in regulating excessive immune response and autoimmune diseases of the host. Previous studies related to transplant immune tolerance have confirmed that increasing the number of Treg in vivo or enhancing the function of Treg serve as a therapeutic strategy to induce transplant immune tolerance. At present, Treg-based induction methods for transplant immune tolerance include adoptive infusion of Treg, in vivo amplification of Treg and utilization of antigen-specific Treg. In this article, the characteristics and mechanism of Treg, the latest research progress on basic experiments and clinical practice of Treg related to transplant immune tolerance at home and abroad were reviewed, and future challenges and development of Treg therapy were prospected, aiming to unravel the significance and application prospect of Treg in transplant immune tolerance, explore the advantages and limitations of Treg therapeutic strategies, and provide reference and evidence for subsequent research in this field.

Regulatory T Cell as Predictor of Intramyocardial Hemorrhage in STEMI Patients after Primary PCI.

Background: Intramyocardial hemorrhage (IMH) is a result of ischemia-reperfusion injury in ST-segment elevation myocardial infarction (STEMI) after primary percutaneous coronary intervention (PPCI). Despite patients with IMH show poorer prognoses, studies investigating predictors of IMH occurrence are scarce. This study firstly investigated the effectiveness of regulatory T cell (Treg), peak value of Creatine Kinase MB (pCKMB), high-sensitivity C-reactive protein (hsCRP), and left ventricular end-systolic diameter (LVESD) as predictors for IMH. Methods: In 182 STEMI patients received PPCI, predictors of IMH were analyzed by logistic regression analysis. The predictive ability of risk factors for IMH were determined by receiver operating characteristic curves, net reclassification improvement (NRI), integrated discrimination improvement (IDI) and C-index. Results: Overall, 80 patients (44.0%) developed IMH. All 4 biomarkers were independent predictors of IMH [odds ratio [OR] (95% confidence interval [CI]): 0.350 (0.202-0.606) for Treg, 1.004 (1.001-1.006) for pCKMB, 1.060 (1.022-1.100) for hsCRP, and 3.329 (1.346-8.236) for LVESD]. After propensity score matching (PSM), the biomarkers significantly predicted IMH with areas under the curve of 0.750 for Treg, 0.721 for pCKMB, 0.656 for hsCRP, 0.633 for LVESD, and 0.821 for the integrated 4-marker panel. The addition of integrated 4-marker panel to a baseline risk model had an incremental effect on the predictive value for IMH [NRI: 0.197 (0.039 to 0.356); IDI: 0.200 (0.142 to 0.259); C-index: 0.806 (0.744 to 0.869), all p < 0.05]. Conclusions: Treg individually or in combination with pCKMB, hsCRP, and LVESD can effectively predict the existence of IMH in STEMI patients received PPCI. Clinical Trial Registration: NCT03939338.

Cellular immune states in SARS-CoV-2-induced disease.

The general immune state plays important roles against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Cells of the immune system are encountering rapid changes during the acute phase of SARS-CoV-2-induced disease. Reduced fraction of functional CD8+ T cells, disrupted cross-talking between CD8+ T cells with dendritic cells (DCs), and impaired immunological T-cell memory, along with the higher presence of hyperactive neutrophils, high expansion of myeloid-derived suppressor cells (MDSCs) and non-classical monocytes, and attenuated cytotoxic capacity of natural killer (NK) cells, are all indicative of low efficient immunity against viral surge within the body. Immune state and responses from pro- or anti-inflammatory cells of the immune system to SARS-CoV-2 are discussed in this review. We also suggest some strategies to enhance the power of immune system against SARS-CoV-2-induced disease.

Regulation of hematopoietic and leukemia stem cells by regulatory T cells.

Adult bone marrow (BM) hematopoietic stem cells (HSCs) are maintained in a quiescent state and sustain the continuous production of all types of blood cells. HSCs reside in a specialized microenvironment the so-called HSC niche, which equally promotes HSC self-renewal and differentiation to ensure the integrity of the HSC pool throughout life and to replenish hematopoietic cells after acute injury, infection or anemia. The processes of HSC self-renewal and differentiation are tightly controlled and are in great part regulated through cellular interactions with classical (e.g. mesenchymal stromal cells) and non-classical niche cells (e.g. immune cells). In myeloid leukemia, some of these regulatory mechanisms that evolved to maintain HSCs, to protect them from exhaustion and immune destruction and to minimize the risk of malignant transformation are hijacked/disrupted by leukemia stem cells (LSCs), the malignant counterpart of HSCs, to promote disease progression as well as resistance to therapy and immune control. CD4+ regulatory T cells (Tregs) are substantially enriched in the BM compared to other secondary lymphoid organs and are crucially involved in the establishment of an immune privileged niche to maintain HSC quiescence and to protect HSC integrity. In leukemia, Tregs frequencies in the BM even increase. Studies in mice and humans identified the accumulation of Tregs as a major immune-regulatory mechanism. As cure of leukemia implies the elimination of LSCs, the understanding of these immune-regulatory processes may be of particular importance for the development of future treatments of leukemia as targeting major immune escape mechanisms which revolutionized the treatment of solid tumors such as the blockade of the inhibitory checkpoint receptor programmed cell death protein 1 (PD-1) seems less efficacious in the treatment of leukemia. This review will summarize recent findings on the mechanisms by which Tregs regulate stem cells and adaptive immune cells in the BM during homeostasis and in leukemia.