Human gingiva‐derived mesenchymal stem cells alleviate inflammatory bowel disease via IL‐10 signalling‐dependent modulation of immune cells

Current evidence indicates that inflammatory bowel disease (IBD) is caused primarily by impaired mucosal immunity, resulting in an imbalance between epithelial barrier function and tissue inflammation. Human gingiva‐derived mesenchymal stem cells (GMSCs) exhibit immunomodulatory and anti‐inflammatory effects in a variety of immunity‐ and inflammation‐associated diseases. However, the role of GMSCs in treating IBD has not been elucidated. Our study, therefore, examined the therapeutic effect and mechanism of GMSCs in a murine colitis model of IBD. Our results indicate that the infusion of GMSCs significantly prolonged survival and relieved symptoms. Phenotype analyses showed that the frequencies of NK1.1⁺ and CD11b⁺ cells, as well as CD4 T cells in the spleen, were suppressed in GMSC‐treated mice compared with the PBS‐ or fibroblast‐treated control groups. Additionally, GMSC treatment markedly increased the numbers of interleukin (IL)‐10⁺ regulatory T cells, reduced the secretion of pro‐inflammatory cytokines, and increased production of anti‐inflammatory cytokines. A mechanistic study revealed that anti‐IL‐10R antibody abolished the protective effect of GMSCs compared with mice treated with anti‐IgG antibody. Thus, our results indicate that GMSCs play a critical role in alleviating colitis by modulating inflammatory immune cells via IL‐10 signalling.     

Inhibition of cardiac allograft rejection in mice using interleukin‐35‐modified mesenchymal stem cells

Interleukin‐35 (IL‐35) is a cytokine recently discovered to play a potent immunosuppressive role by intensifying the functions of regulatory T cells and inhibiting the proliferation and functions of T helper 1 and T helper 17 cells. Mesenchymal stem cells (MSCs) have recently emerged as promising candidates for cell‐based immune therapy, and our previous study showed that IL‐35 gene modification can effectively enhance the therapeutic effect of MSCs in vitro. In this study, we isolated adipose tissue‐derived MSCs in vitro and infected them with lentiviral vectors overexpressing the IL‐35 gene, thereby creating IL‐35‐MSCs. Subsequently, IL‐35‐MSCs were then injected into mice of the allogeneic heterotopic abdominal heart transplant model to determine their effect on allograft rejection. The results showed that IL‐35‐MSCs could continuously secrete IL‐35 in vivo and in vitro, successfully alleviate allograft rejection and prolong graft survival. In addition, compared to MSCs, IL‐35‐MSCs showed a stronger immunosuppressive ability and further reduced the percentage of Th17 cells, increased the proportion of CD4⁺ Foxp3⁺ T cells, and regulated Th1/Th2 balance in heart transplant mice. These findings suggest that IL‐35‐MSCs have more advantages than MSCs in inhibiting graft rejection and may thus provide a new approach for inducing immune tolerance during transplantation.     

The influence of bone marrow‐ and synovium‐derived mesenchymal stromal cells from osteoarthritis patients on regulatory T cells in co‐culture

There is increasing evidence that inflammation in the synovium plays a major role in the progression of osteoarthritis (OA). However, the immunogenic properties of mesenchymal stromal cells (MSCs), which are considered to regulate immunity in various diseases, remain largely unknown in OA. The purpose of this study was to determine the influence of MSCs from OA patients on regulatory T cells (T_regs) in an allogeneic co‐culture model. Bone marrow (BM) and synovial membrane (SM) were harvested from hip joints of OA patients and co‐cultured with lymphocytes enriched in CD4⁺CD25⁺CD127^– regulatory T cells (T_reg⁺LC) from healthy donors. T_reg proportions and MSC markers were assessed by flow cytometry. Cytokine levels were assessed after 2 and 5 days of co‐cultivation. Additionally, T_reg⁺LC cultures were analysed in the presence of interleukin (IL)‐6 and MSC‐supernatant complemented medium. B‐MSCs and S‐MSCs were able to retain the T_reg proportion compared to lymphocyte monocultures. T cell–MSC co‐cultures showed a significant increase of IL‐6 compared to MSC cultures. S‐MSCs produced higher amounts of IL‐6 compared to B‐MSCs, both in single and T cell co‐cultures. The effect of retaining the T_reg percentage could be reproduced partially by IL‐6 addition to the medium, but could only be observed fully when using MSC culture supernatants. Our data demonstrate that retaining the T_reg phenotype in MSC–T cell co‐cultures can be mediated by MSC derived from OA patients. IL‐6 plays an important role in mediating these processes. To our knowledge, this study is the first describing the interaction of MSCs from OA patients and T_regs in an allogeneic co‐culture model.     

Exogenous interleukin‐33 targets myeloid‐derived suppressor cells and generates periphery‐induced Foxp3+ regulatory T cells in skin‐transplanted mice

Interleukin-33 (IL-33) has been a focus of study because of its variety of functions shaping CD4⁺ T-cell biology. In the present work, we evaluated the modulatory effect of IL-33 on suppressor cells in an in vivo transplantation model. C57BL/6 wild-type mice were grafted with syngeneic or allogeneic skin transplants and treated with exogenous IL-33 daily. After 10 days of treatment, we analysed draining lymph node cellularity and found in allogeneic animals an increment in myeloid-derived suppressor cells, which co-express MHC-II, and become enriched upon IL-33 treatment. In line with this observation, inducible nitric oxide synthase and arginase 1 expression were also increased in allogeneic animals upon IL-33 administration. In addition, IL-33 treatment up-regulated the number of Foxp3⁺ regulatory T (Treg) cells in the allogeneic group, complementing the healthier integrity of the allografts and the increased allograft survival. Moreover, we demonstrate that IL-33 promotes CD4⁺ T-cell expansion and conversion of CD4⁺ Foxp3⁻ T cells into CD4⁺ Foxp3⁺ Treg cells in the periphery. Lastly, the cytokine pattern of ex vivo-stimulated draining lymph nodes indicates that IL-33 dampens interferon-γ and IL-17 production, stimulating IL-10 secretion. Altogether, our work complements previous studies on the immune-modulatory activity of IL-33, showing that this cytokine affects myeloid-derived suppressor cells at the cell number and gene expression levels. More importantly, our research demonstrates for the first time that IL-33 allows for in vivo Foxp3⁺ Treg cell conversion and favours an anti-inflammatory or tolerogenic state by skewing cytokine production. Therefore, our data suggest a potential use of IL-33 to prevent allograft rejection, bringing new therapeutics to the transplantation field.     

T follicular regulatory (Tfr) cells: Dissecting the complexity of Tfr‐cell compartments

Germinal centers (GC) have been known as key anatomic structures in humoral immunity, where isotype switching and affinity maturation occur. As a consequence, elucidation of GC regulation has potential implications for the understanding of autoantibody‐mediated diseases. It is now accepted that different regulatory mechanisms coexist, including the action of a specialized population of Foxp3⁺ regulatory T cells with unique access to the B‐cell follicle: the T follicular regulatory (Tfr) cells. Tfr cells develop through a multistep process requiring migration through different compartments of lymphoid tissues. This review discusses the ontogeny and physiology of Tfr cells, their distribution within distinct anatomic compartments, and their function. A greater understanding of Tfr biology and GC regulation is likely to lead to better stratification of patients with autoantibody‐mediated diseases, and to the identification of novel therapeutic targets.     

Anti‐CD25 monoclonal antibody Fc variants differentially impact regulatory T cells and immune homeostasis

Interleukin‐2 (IL‐2) is a critical regulator of immune homeostasis through its non‐redundant role in regulatory T (Treg) cell biology. There is major interest in therapeutic modulation of the IL‐2 pathway to promote immune activation in the context of tumour immunotherapy or to enhance immune suppression in the context of transplantation, autoimmunity and inflammatory diseases. Antibody‐mediated targeting of the high‐affinity IL‐2 receptor α chain (IL‐2Rα or CD25) offers a direct mechanism to target IL‐2 biology and is being actively explored in the clinic. In mouse models, the rat anti‐mouse CD25 clone PC61 has been used extensively to investigate the biology of IL‐2 and Treg cells; however, there has been controversy and conflicting data on the exact in vivo mechanistic function of PC61. Engineering antibodies to alter Fc/Fc receptor interactions can significantly alter their in vivo function. In this study, we re‐engineered the heavy chain constant region of an anti‐CD25 monoclonal antibody to generate variants with highly divergent Fc effector function. Using these anti‐CD25 Fc variants in multiple mouse models, we investigated the in vivo impact of CD25 blockade versus depletion of CD25⁺ Treg cells on immune homeostasis. We report that immune homeostasis can be maintained during CD25 blockade but aberrant T‐cell activation prevails when CD25⁺ Treg cells are actively depleted. These results clarify the impact of PC61 on Treg cell biology and reveal an important distinction between CD25 blockade and depletion of CD25⁺ Treg cells. These findings should inform therapeutic manipulation of the IL‐2 pathway by targeting the high‐affinity IL‐2R.     

Interleukin‐21 (IL‐21) synergizes with IL‐2 to enhance T‐cell receptor‐induced human T‐cell proliferation and counteracts IL‐2/transforming growth factor‐β‐induced regulatory T‐cell development

Interleukin‐2 (IL‐2) is a mainstay for current immunotherapeutic protocols but its usefulness in patients is reduced by severe toxicities and because IL‐2 facilitates regulatory T (Treg) cell development. IL‐21 is a type I cytokine acting as a potent T‐cell co‐mitogen but less efficient than IL‐2 in sustaining T‐cell proliferation. Using various in vitro models for T‐cell receptor (TCR)‐dependent human T‐cell proliferation, we found that IL‐21 synergized with IL‐2 to make CD4⁺ and CD8⁺ T cells attain a level of expansion that was impossible to obtain with IL‐2 alone. Synergy was mostly evident in naive CD4⁺ cells. IL‐2 and tumour‐released transforming growth factor‐β (TGF‐β) are the main environmental cues that cooperate in Treg cell induction in tumour patients. Interleukin‐21 hampered Treg cell expansion induced by IL‐2/TGF‐β combination in naive CD4⁺ cells by facilitating non‐Treg over Treg cell proliferation from the early phases of cell activation. Conversely, IL‐21 did not modulate the conversion of naive activated CD4⁺ cells into Treg cells in the absence of cell division. Treg cell reduction was related to persistent activation of Stat3, a negative regulator of Treg cells associated with down‐modulation of IL‐2/TGF‐β‐induced phosphorylation of Smad2/3, a positive regulator of Treg cells. In contrast to previous studies, IL‐21 was completely ineffective in counteracting the suppressive activity of Treg cells on naive and memory, CD4⁺ and CD8⁺ T cells. Present data provide proof‐of‐concept for evaluating a combinatorial approach that would reduce the IL‐2 needed to sustain T‐cell proliferation efficiently, thereby reducing toxicity and controlling a tolerizing mechanism responsible for the contraction of the T‐cell response.     

Histone methylation mediates plasticity of human FOXP3+ regulatory T cells by modulating signature gene expressions

CD4⁺ FOXP3⁺ regulatory T (Treg) cells constitute a heterogeneous and plastic T-cell lineage that plays a pivotal role in maintaining immune homeostasis and immune tolerance. However, the fate of human Treg cells after loss of FOXP3 expression and the epigenetic mechanisms contributing to such a phenotype switch remain to be fully elucidated. In the current study, we demonstrate that human CD4⁺ CD25^high CD127^low/− Treg cells convert to two subpopulations with distinctive FOXP3⁺ and FOXP3⁻ phenotypes following in vitro culture with anti-CD3/CD28 and interleukin-2. Digital gene expression analysis showed that upon in vitro expansion, human Treg cells down-regulated Treg cell signature genes, such as FOXP3, CTLA4, ICOS, IKZF2 and LRRC32, but up-regulated a set of T helper lineage-associated genes, especially T helper type 2 (Th2)-associated, such as GATA3, GFI1 and IL13. Subsequent chromatin immunoprecipitation-sequencing of these subpopulations yielded genome-wide maps of their H3K4me3 and H3K27me3 profiles. Surprisingly, reprogramming of Treg cells was associated with differential histone modifications, as evidenced by decreased abundance of permissive H3K4me3 within the down-regulated Treg cell signature genes, such as FOXP3, CTLA4 and LRRC32 loci, and increased abundance of H3K4me3 within the Th2-associated genes, such as IL4 and IL5; however, the H3K27me3 modification profile was not significantly different between the two subpopulations. In conclusion, this study revealed that loss of FOXP3 expression from human Treg cells during in vitro expansion can induce reprogramming to a T helper cell phenotype with a gene expression signature dominated by Th2 lineage-associated genes, and that this cell type conversion may be mediated by histone methylation events.     

Embryonic stem cell‐derived haematopoietic progenitor cells down‐regulate the CD3 ξ chain on T cells,abrogating alloreactive T cells

Murine embryonic stem (ES) cell‐derived haematopoietic progenitor cells (HPCs) engraft and populate lymphoid organs. In vivo, HPCs engraft across MHC barriers protecting donor‐type allografts from rejection. However, the underlying phenomenon remains elusive. Here, we sought to determine the mechanism by which ES cell‐derived HPCs regulate alloreactive T cells. We used the 2C mouse, which expresses a transgenic T‐cell receptor against H2‐L^d to determine whether HPCs are deleted by cytotoxic T lymphocytes (CTLs). Previously, we reported that HPCs express MHC class I antigens poorly and do not express class II antigens. In vitro stimulated 2C CTLs failed to lyse H2‐L^d HPCs in a standard 4‐hr ⁵¹chromium release assay. Similarly, when the HPCs were tested in an ELISPOT assay measuring the release of interferon‐γ by CTLs, HPCs failed to induce CTL degranulation. In addition, mice that were injected with HPCs showed a marked decrease in T‐cell responses to alloantigen and CD3 stimulation, but showed a normal response to PMA/ionomycin, suggesting that HPCs impaired T‐cell signalling through the T‐cell receptor/CD3 complex. Here, we show that HPCs secrete arginase, an enzyme that scavenges l ‐arginine, leading to metabolites that down‐regulate CD3 ζ chain. Indeed an arginase inhibitor partially restored expression of the CD3 ζ chain, implicating arginase 1 in the down‐regulation of T cells. This previously unrecognized property of ES cell‐derived HPCs could positively enhance the engraftment of ES cell‐derived HPCs across MHC barriers by preventing rejection.     

Adipose‐tissue regulatory T cells: Critical players in adipose‐immune crosstalk

Obesity and type‐2 diabetes (T2D) are associated with metabolic defects and inflammatory processes in fat depots. FoxP3⁺ regulatory T cells (Tregs) control immune tolerance, and have an important role in controlling tissue‐specific inflammation. In this mini‐review we will discuss current insights into how cross‐talk between T cells and adipose tissue shapes the inflammatory environment in obesity‐associated metabolic diseases, focusing on the role of CD4⁺T cells and Tregs. We will also highlight potential opportunities for how the immunoregulatory properties of Tregs could be harnessed to control inflammation in obesity and T2D and emphasize the critical need for more research on humans to establish mechanisms that are conserved in both mice and humans.     

CD8+ CD122+ regulatory T cells contain clonally expanded cells with identical CDR3 sequences of the T‐cell receptor β‐chain

We identified CD8⁺ CD122⁺ regulatory T cells (CD8⁺ CD122⁺ Treg cells) and reported their importance in maintaining immune homeostasis. The absence of CD8⁺ CD122⁺ Treg cells has been shown to lead to severe systemic autoimmunity in several mouse models, including inflammatory bowel diseases and experimental autoimmune encephalomyelitis. The T‐cell receptors (TCRs) expressed on CD8⁺ CD122⁺ Treg cells recognize the target cells to be regulated. To aid in the identification of the target antigen(s) recognized by TCRs of CD8⁺ CD122⁺ Treg cells, we compared the TCR diversity of CD8⁺ CD122⁺ T cells with that of conventional, naive T cells in mice. We analysed the use of TCR‐Vβ in the interleukin 10‐producing population of CD8⁺ CD122⁺ T cells marked by high levels of CD49d expression, and found the significantly increased use of Vβ13 in these cells. Immunoscope analysis of the complementarity‐determining region 3 (CDR3) of the TCR β‐chain revealed remarkable skewing in a pair of Vβ regions, suggesting the existence of clonally expanded cells in CD8⁺ CD122⁺ T cells. Clonal expansion in Vβ13⁺ cells was confirmed by determining the DNA sequences of the CDR3s. The characteristic TCR found in this study is an important building block for further studies to identify the target antigen recognized by CD8⁺ CD122⁺ Treg cells.     

Prevention of acute liver allograft rejection by IL‐10‐engineered mesenchymal stem cells

Hepatic allograft rejection remains a challenging problem, with acute rejection episode as the major barrier for long‐term survival in liver transplant recipients. To explore a strategy to prevent allograft rejection, we hypothesized that mesenchymal stem cells (MSCs) genetically engineered with interleukin‐10 (IL‐10) could produce beneficial effects on orthotopic liver transplantation (OLT) in the experimental rat model. Syngeneic MSCs transduced with IL‐10 were delivered via the right jugular vein 30 min post‐orthotopic transplantation in the rat model. To evaluate liver morphology and measure cytokine concentration, the blood and liver samples from each animal group were collected at different time‐points (3, 5 and 7 days) post‐transplantation. The mean survival time of the rats treated with MSCs–IL‐10 was shown to be much longer than those treated with saline. According to Banff scheme grading, the saline group scores increased significantly compared with those in the MSCs–IL‐10 group. Retinoid acid receptor‐related orphan receptor gamma t (RORγt) expression was more increased in the saline group compared to those in the MSCs–IL‐10 group in a time‐dependent manner; forkhead box protein 3 (FoxP3) expression also decreased significantly in the saline group compared with those in the MSCs–IL‐10 group in a time‐dependent manner. The expression of cytokines [IL‐17, IL‐23, IL‐6, interferon (IFN)‐γ and tumour necrosis factor (TNF)‐α] in the saline groups increased significantly compared with the time‐point‐matched MSCs–IL‐10 group, whereas cytokine expression of (IL‐10, TGF‐β1) was deceased markedly compared to that in the MSCs–IL‐10 group. These results suggest a potential role for IL‐10‐engineered MSC therapy to overcome clinical liver transplantation rejection.     

CTLA‐4 expressed by FOXP3+ regulatory T cells prevents inflammatory tissue attack and not T‐cell priming in arthritis

Cytotoxic T‐lymphocyte antigen 4 (CTLA‐4) ‐mediated regulation of already tolerized autoreactive T cells is critical for understanding autoimmune responses. Although defects in CTLA‐4 contribute to abnormal FOXP3⁺ regulatory T (Treg) cell function in rheumatoid arthritis, its role in autoreactive T cells remains elusive. We studied immunity towards the dominant collagen type II (CII) T‐cell epitope in collagen‐induced arthritis both in the heterologous setting and in the autologous setting where CII is mutated at position E266D in mouse cartilage. CTLA‐4 regulated all stages of arthritis, including the chronic phase, and affected the priming of autologous but not heterologous CII‐reactive T cells. CTLA‐4 expression by both conventional T (Tconv) cells and Treg cells was required but while Tconv cell expression was needed to control the priming of naive autoreactive T cells, CTLA‐4 on Treg cells prevented the inflammatory tissue attack. This identifies a cell‐type‐specific time window when CTLA‐4‐mediated tolerance is most powerful, which has important implications for clinical therapy with immune modulatory drugs.     

Distinct cytokines balance the development of regulatory T cells and interleukin‐10‐producing regulatory B cells

Regulatory T cells have been well described and the factors regulating their development and function have been identified. Recently, a growing body of evidence has documented the existence of interleukin‐10 (IL‐10) ‐producing B cells, which are called regulatory B10 cells. These cells attenuate autoimmune, inflammatory and transplantation reactions, and the main mechanism of their inhibitory action is the production of IL‐10. We show that the production of IL‐10 by lipopolysaccharide‐stimulated B cells is significantly enhanced by IL‐12 and interferon‐γ and negatively regulated by IL‐21 and transforming growth factor‐β. In addition, exogenous IL‐10 also inhibits B‐cell proliferation and the expression of the IL‐10 gene in lipopolysaccharide‐stimulated B cells. The negative autoregulation of IL‐10 production is supported by the observation that the inclusion of anti‐IL‐10 receptor monoclonal antibody enhances IL‐10 production and the proliferation of activated B cells. The effects of cytokines on IL‐10 production by B10 cells did not correlate with their effects on B‐cell proliferation or on IL‐10 production by T cells or macrophages. The cytokine‐induced changes in IL‐10 production occurred on the level of IL‐10 gene expression, as confirmed by increased or decreased IL‐10 mRNA expression in the presence of a particular cytokine. The regulatory cytokines modulate the number of IL‐10‐producing cells rather than augmenting or decreasing the secretion of IL‐10 on a single‐cell level. Altogether these data show that the production of IL‐10 by B cells is under the strict regulatory control of cytokines and that individual cytokines differentially regulate the development and activity of regulatory T cells and IL‐10‐producing regulatory B cells.     

Co‐expression of TNFR2 and CD25 identifies more of the functional CD4+FOXP3+ regulatory T cells in human peripheral blood

Previously, we found that co‐expression of CD25 and TNFR2 identified the most suppressive subset of mouse Treg. In this study, we report that human peripheral blood (PB) FOXP3⁺ cells present in CD25^high, CD25^low and even CD25^– subsets of CD4⁺ cells expressed high levels of TNFR2. Consequently, TNFR2‐expressing CD4⁺CD25 ⁺ Treg included all of the FOXP3⁺ cells present in the CD4⁺CD25^high subset as well as a substantial proportion of the FOXP3⁺ cells present in the CD4⁺CD25^low subset. Flow cytometric analysis of PB identified five‐fold more Treg, determined by FOXP3 expression, in the CD4⁺CD25⁺TNFR2⁺ subset than in the CD4⁺CD25^high subset. In addition, similar levels of FOXP3⁺ cells were identified in both the CD4⁺CD25⁺TNFR2⁺ and CD4⁺CD25⁺CD127^low/? subsets. Furthermore, the CD4⁺CD25⁺TNFR2⁺ subset expressed high levels of CTLA‐4, CD45RO, CCR4 and low levels of CD45RA and CD127, a phenotype characteristic of Treg. Upon TCR stimulation, human PB CD4 ⁺ CD25 ⁺ TNFR2 ⁺ cells were anergic and markedly inhibited the proliferation and cytokine production of co‐cultured T‐responder cells. In contrast, CD4 ⁺ CD25 ⁺ TNFR2 ^– and CD4 ⁺ CD25 ^– TNFR2 ⁺ T cells did not show inhibitory activity. As some non‐Treg express TNFR2, the combination of CD25 and TNFR2 must be used to identify a larger population of human Treg, a population that may prove to be of diagnostic and therapeutic benefit in cancer and autoimmune diseases.     

脐血来源间充质干细胞可抑制异体T细胞的反应

目的 研究脐血间充质干细胞(HUCB-MSCs)对异体T细胞的抑制作用.方法 体外培养HUCB-MSCs,流式细胞术测表面标记;取正常人外周血,免疫磁珠分离CＤ３+T细胞,将分离的CD3+T与HUCB-MSCs 1:1混合培养5d,PHA刺激或不刺激,采用3H-TdR掺入法观察T细胞增殖,ELISA方法检测细胞因子,流...     

Critical stoichiometric ratio of CD4+ CD25+ FoxP3+ regulatory T cells and CD4+ CD25− responder T cells influence immunosuppression in patients with B‐cell acute lymphoblastic leukaemia

Regulatory T (Treg) cells act to suppress activation of the immune system and thereby maintain immunological homeostasis and tolerance to self-antigens. The frequency and suppressing activity of Treg cells in general are high in different malignancies. We wanted to identify the role and regulation of CD4⁺ CD25⁺ FoxP3⁺ Treg cells in B-cell acute lymphoblastic leukaemia (B-ALL). We have included patients at diagnosis (n = 54), patients in clinical remission (n = 32) and normal healthy individuals (n = 35). These diagnosed patients demonstrated a lower number of CD4⁺ CD25⁺ cells co-expressing a higher level of FoxP3, interleukin-10, transforming growth factor-β and CD152/CTLA-4 than the normal population. Treg cells from patients showed a higher suppressive capability on CD4⁺ CD25⁻ responder T (Tresp) cells than normal. The frequency and immunosuppressive potential of CD4⁺ CD25⁺ FoxP3⁺ Treg cells became high with the progression of malignancy in B-ALL. Relative distribution of Tresp and Treg cells was only ˜5 : 1 in B-ALL but ˜35 : 1 in normal healthy individuals, further confirming the elevated immunosuppression in patients. A co-culture study at these definite ex vivo ratios, indicated that Treg cells from B-ALL patients exhibited higher immunosuppression than Treg cells from normal healthy individuals. After chemotherapy using the MCP841 protocol, the frequency of CD4⁺ CD25⁺ cells was gradually enhanced with the reduction of FoxP3, interleukin-10 positivity corresponded with disease presentation, indicating reduced immunosuppression. Taken together, our study indicated that the CD4⁺ CD25⁺ FoxP3⁺ Treg cells played an important role in immunosuppression, resulting in a positive disease-correlation in these patients. To the best of our knowledge, this is the first detailed report on the frequency, regulation and functionality of Treg cells in B-ALL.     

Effect of interleukin‐6 receptor blockade on the balance between regulatory T cells and T helper type 17 cells in rheumatoid arthritis patients

A new paradigm has emerged relating the pathogenesis of rheumatoid arthritis (RA), focused on the balance between T helper type 17 cells and regulatory T cells (T_regs). In humans, both subpopulations depend on transforming growth factor (TGF)‐β for their induction, but in the presence of inflammatory cytokines, such as interleukin (IL)‐6, the generation of Th17 is favoured. Tocilizumab is a therapeutic antibody targeting the IL‐6 receptor (IL‐6R), which has demonstrated encouraging results in RA. The aim of this study was to evaluate the effect of tocilizumab on Th1 cells, Th17 cells, IL‐17 and interferon (IFN)‐γ double secretors Th17/Th1 cells, and T_regs in RA patients. Eight RA patients received tocilizumab monthly for 24 weeks and blood samples were obtained every 8 weeks to study T cell populations by flow cytometry. The frequency of Th17 cells, Th1 cells and Th17/Th1 cells was evaluated in peripheral blood mononuclear cells (PBMCs) activated in vitro with a polyclonal stimulus. T_regs were identified by their expression of forkhead box protein 3 (FoxP3) and CD25 by direct staining of PBMCs. Although no changes were detected in the frequency of Th1 or Th17 cells, the percentages of peripheral T_regs increased after therapy. In addition, the infrequent Th17/Th1 subpopulation showed a significant increment in tocilizumab‐treated patients. In conclusion, tocilizumab was able to skew the balance between Th17 cells and T_regs towards a more protective status, which may contribute to the clinical improvement observed in RA patients.