Identification and functional characterization of human CD4(+)CD25(+) T cells with regulatory properties isolated from peripheral blood

Host CD25+CD4+Foxp3+ regulatory T cells primed by anti-CD137 mAbs inhibit graft-versus-host disease

CD25(+)CD4(+)Foxp3(+) regulatory T cells (Tregs) play a pivotal role in the maintenance of self-tolerance and regulation of immune responses. Previous studies have demonstrated that CD137 signals can promote proliferation and survival of Tregs in vitro. Here, we show that in vivo CD137-induced expansion of Tregs in naive mice was dependent upon IL-2 secreted by memory T cells. Tregs primed by anti-CD137 mAbs had a higher immunosuppressive capacity. Preconditioning with anti-CD137 mAbs significantly inhibited graft-versus-host disease (GVHD) in the C57BL/6 → (C57BL/6 × DBA/2) F1 acute GVHD model. In this disease model, a high proportion of host Tregs remained long-term in the recipient spleen, whereas donor hematopoietic cells replaced other host bone marrow-derived cells. Transient depletion of Tregs before transfer of donor cells completely abrogated the inhibitory effect of anti-CD137 mAbs on GVHD. In addition, adoptive transfer of anti-CD137-primed Tregs ameliorated GVHD. Our results demonstrate that it is possible to enhance the survival and/or the immunosuppressive activity of host Tregs in nonmyeloablative GVHD, and that 1 way of accomplishing this is through the prophylactic use of anti-CD137 mAbs in nonmyeloablative GVHD.

Ex vivo expansion of human Tregs specific for alloantigens presented directly or indirectly

Adoptive transfer of regulatory T cells (Tregs) prevents GVHD in experimental animals. Because antigen activation drives Treg function, we measured the frequency, growth requirements, and function of alloantigen-specific (allospecific) Tregs from human blood. When alloantigen was presented directly, the precursor frequency of allo-specific Tregs in normal individuals was 1.02% (95% confidence interval [95% CI]: 0.65-1.59) and non-Tregs 1.56% (95% CI: 0.94-2.55). When alloantigen was presented indirectly, the frequency of specific Tregs was approximately 100-fold less. Purified Tregs were expanded with APCs, rapamycin, IL-2, and IL-15. In 12 days, allo-specific Tregs expanded 793-fold (95% CI: 480-1107), with duplication approximately every 24 hours. Purified allo-specific Tregs suppressed responses to specific alloantigen selectively and were approximately 100-fold more potent than polyspecific Tregs and nonexpanded Tregs. Allo-specific Tregs maintained high expression of Foxp3, Bcl-2, lymphoid homing receptor CD62L, and chemokine receptor CCR7, predicting sustained function and migration to lymphoid tissues in vivo. Allo-specific Tregs produced TGF-β and IL-10 and expressed more cytoplasmic CTLA-4 compared with non-Tregs. These data provide a platform for the selective expansion of Tregs against major and possibly minor histocompatibility antigens and predict the feasibility of adoptive immunotherapy trials using Tregs with indirect allo-recognition for preventing GVHD while sparing GVL effects.

Mechanism of T cell exhaustion in a chronic environment

T cell exhaustion develops under conditions of antigen-persistence caused by infection with various chronic pathogens, such as human immunodeficiency virus (HIV) and mycobacterium tuberculosis (TB), or by the development of cancer. T cell exhaustion is characterized by stepwise and progressive loss of T cell function, which is probably the main reason for the failed immunological control of chronic pathogens and cancers. Recent observations have detailed some of the intrinsic and extrinsic factors that influence the severity of T cell exhaustion. Duration and magnitude of antigenic activation of T cells might be associated with up-regulation of inhibitory receptors, which is a major intrinsic factor of T cell exhaustion. Extrinsic factors might include the production of suppressive cytokines, T cell priming by either non-professional antigen-presenting cells (APCs) or tolerogenic dendritic cells (DCs), and alteration of regulatory T (Treg) cells. Further investigation of the cellular and molecular processes behind the development of T cell exhaustion can reveal therapeutic targets and strategies for the treatment of chronic infections and cancers. Here, we report the properties and the mechanisms of T cell exhaustion in a chronic environment.

Targeting human inducible regulatory T cells (Tr1) in patients with cancer: blocking of adenosine-prostaglandin E₂ cooperation

INTRODUCTION

Emerging data suggest that human inducible regulatory T cells (Tr1) produce adenosine and prostaglandin E(2) and that these factors cooperate in mediating immune suppression.

AREAS COVERED

Human Tr1 present in human tumors or blood of cancer patients express ectonucleotidases, CD39 and/or CD73, hydrolyze ATP to adenosine and are COX-2 positive. Expression of CD39 and/or CD73 on human tumors favors expansion and suppressor functions of Tr1. Adenosine and PGE(2) signal via adenosine 2A receptor (A(2A)R) and prostaglandin E(2) receptor 2 (EP(2)R) expressed on effector T (Teff) cells, suppressing their anti-tumor functions by a common mechanism involving upregulation of cytosolic cAMP levels and protein kinase A (PKA) type I activation. The frequency and activity of circulating CD4(+)CD39(+) and CD4(+)COX-2(+) Treg subsets increase in advanced disease and also following oncologic therapies.

EXPERT OPINION

Pharmacologic blocking of adenosine-PGE(2) collaboration provides a clinically-feasible strategy for disarming of Treg. Used in conjunction with conventional anti-cancer drugs or immune interventions, pharmacologic inhibitors could improve outcome of oncologic therapies.

Specific inflammatory microenvironments in the zones of the fetal membranes at term delivery

OBJECTIVE

The purpose of this study was to examine the histologic and immunologic differences between fetal membrane zones after membrane rupture at term delivery.

STUDY DESIGN

Fetal membrane explants from postrupture zones (periplacental, middle, rupture) were obtained from women following spontaneous vaginal delivery at term (n = 5). Tissues for histology, protein extracts, and RNA were isolated.

RESULTS

The collagen distribution decreased and the leukocyte density increased from the periplacental zone to the rupture zone. T cells were mainly present in the rupture zone and granulocytes in the middle zone. CXCL10, CXCR1, ICAM-1, -2, PSEL, tumor necrosis factor alpha, and matrix metalloproteinase-9 levels were higher in the middle zone than in the rupture zone and periplacental zone (P < .021). Interleukin-1beta and CXCL8 levels were higher in the rupture zone than in the middle zone and periplacental zone (P = .018 and P < .0001).

CONCLUSION

During labor specific immunologic microenvironments are created in the zones of the fetal membrane that may be involved in their rupture at the end of gestation.

Efficient peripheral construction of functional human regulatory CD4(+)CD25(high)Foxp3(+) T cells in NOD/SCID mice grafted with fetal human thymus/liver tissues and CD34(+) cells

Regulatory T cells, especially CD4(+)CD25(+) regulatory T cells are critical regulators of immune tolerance in humans and mice. Mice with humanized immunity have been developed by various transplantation strategies of human tissues or cells related to immunity, which are being extensively applied in biomedical research. However, it is unclear whether human CD4(+)CD25(+) regulatory T cells can normally develop in human thymic grafts and efficiently populate in the periphery in NOD/SCID mouse recipients. In human thymic grafts, high percentage of mature human CD4(+)CD25(high) regulatory T cells was detected. Human CD4(+)CD25(+) regulatory T cells maturing in fetal human thymus grafts could subsequently output to the periphery of NOD/SCID mouse recipients. Importantly, these cells exhibited Foxp3(+)CD45RO(+)CTLA4(+)CD127(-) phenotype, similarly to those in healthy individuals. In addition, human CD4(+)CD25(+) regulatory T cells maturing in human thymic grafts suppressed proliferative response of CD4(+)CD25(-) T cells to allogeneic antigens, though the peripheral CD4(+)CD25(+) regulatory T cells in fetal human thymus-grafted NOD/SCID mice showed somewhat decreased immunosuppressive ability compared with normal CD4(+)CD25(+) regulatory T cells. Thus, this humanized animal model is suitable for examining development and function of human CD4(+)CD25(+) regulatory T cells in vivo.

The ratio of Th-17 to Treg cells is associated with survival of patients with acute-on-chronic hepatitis B liver failure

Both T-helper 17 cells (Th-17) and CD4(+)CD25(+) regulatory T cells (Tregs) play important roles in the pathogenesis of hepatitis B virus (HBV) infection. Recent studies have suggested that Th-17 and Treg cells are increased in patients with chronic hepatitis B (CHB). This study further characterizes Th-17 and Treg cells in the blood of HBV-associated acute-on-chronic liver failure (ACLF) patients, and aids our understanding of how the two subsets of CD4(+) T cells affect each other and contribute to survival. Blood samples were obtained from 30 patients with HBV-associated ACLF, 30 patients with CHB, and 30 normal controls (NC). The frequencies of Th-17 and Treg cells were determined by intracellular cytokine staining analysis. To observe the suppressive function of Tregs, purified CD4(+)CD25(+) Tregs from peripheral blood mononuclear cells (PBMCs) were co-cultured with CD4(+)CD25(-) T cells for 48 h, and then IFN-γ and IL-17A from the supernatants were measured by ELISA. We found that both Th-17 and FoxP3(+) Treg cells were increased in ACLF patients. IL-17A secretion by CD4(+) T cells was not regulated by Treg cells, even though Tregs exhibited significant inhibition of IFN-γ production. Most importantly, the ratio of Th-17 to Treg cells was associated inversely with the survival of ACLF patients. These findings provide new information regarding the pathogenesis of HBV-associated ACLF, and the ratio of Th-17 to Tregs may represent a potential prognostic marker for the disease.

IL-1β promotes TGF-β1 and IL-2 dependent Foxp3 expression in regulatory T cells

Earlier, we have shown that GM-CSF-exposed CD8α− DCs that express low levels of pro-inflammatory cytokines IL-12 and IL-1β can induce Foxp3+ Tregs leading to suppression of autoimmunity. Here, we examined the differential effects of IL-12 and IL-1β on Foxp3 expression in T cells when activated in the presence and absence of DCs. Exogenous IL-12 abolished, but IL-1β enhanced, the ability of GM-CSF-exposed tolerogenic DCs to promote Foxp3 expression. Pre-exposure of DCs to IL-1β and IL-12 had only a modest effect on Foxp3− expressing T cells; however, T cells activated in the absence of DCs but in the presence of IL-1β or IL-12 showed highly significant increase and decrease in Foxp3+ T cell frequencies respectively suggesting direct effects of these cytokines on T cells and a role for IL-1β in promoting Foxp3 expression. Importantly, purified CD4+CD25+ cells showed a significantly higher ability to maintain Foxp3 expression when activated in the presence of IL-1β. Further analyses showed that the ability of IL-1β to maintain Foxp3 expression in CD25+ T cells was dependent on TGF-β1 and IL-2 expression in Foxp3+Tregs and CD25− effectors T cells respectively. Exposure of CD4+CD25+ T cells to IL-1β enhanced their ability to suppress effector T cell response in vitro and ongoing experimental autoimmune thyroidits in vivo. These results show that IL-1β can help enhance/maintain Tregs, which may play an important role in maintaining peripheral tolerance during inflammation to prevent and/or suppress autoimmunity.

Prognostic role of FOXP3+ regulatory T cells infiltrating human carcinomas: the paradox of colorectal cancer

The accumulation of regulatory T cells (Tregs) at high density in various human carcinomas is generally associated with a poor prognosis, as expected from their capacity to inhibit antitumor immunity. Surprisingly, in patients bearing colorectal carcinoma (CRC), high regulatory T-cell infiltration is associated with a favorable prognosis, as shown by the analysis of seven clinical studies. To explain this paradox, we emphasize a putative role of the dense microbiological flora present in the large intestine with a trend toward translocation through the tumor. This microbiological hazard requires a T-cell-mediated inflammatory anti-microbial response that involves Th17 cells and can thereby promote cancer growth. This Th17-cell-dependent proinflammatory and tumor-enhancing response can be attenuated by Tregs, thus constituting a possible explanation for their favorable role in CRC prognosis. The link between a high density of FOXP3-positive cells in CRC immune infiltrates and favorable prognosis should lead us to consider tumor infiltrating Tregs as allies to be respected, rather than enemies to be destroyed during trials of CRC treatment.

Specific immunotherapy and turning off the T cell: how does it work?

OBJECTIVE

To examine T-regulatory (Treg) cell functions in allergic immune responses and their roles during allergen specific immunotherapy based on recent developments and current understanding of immune regulation.

DATA SOURCES

PubMed search of English-language articles regarding Treg cells and allergen specific immunotherapy.

STUDY SELECTION

Articles on the subject matter were selected and reviewed.

RESULTS

Allergen specific immunotherapy is the ultimate treatment modality targeting the immunopathogenic mechanisms of allergic disorders. A diminished allergen-specific T-cell proliferation and suppressed secretion of T(H)1- and T(H)2-type cytokines are the characteristic hallmarks. In addition, Treg cells inhibit the development of allergen-specific T(H)2 and T(H)1 cell responses and therefore exert key roles in healthy immune response to allergens. Treg cells potently suppress IgE production and directly or indirectly control the activity of effector cells of allergic inflammation, such as eosinophils, basophils, and mast cells.

CONCLUSION

As advancements in the field of allergen specific immunotherapy ensue, they may provide novel progression of more rational and safer approaches for the prevention and treatment of allergic disorders. Currently, the Treg cell field is an open research area to increase our understanding in mechanisms of peripheral tolerance to allergens.

High frequencies of CD62L⁺ naive regulatory T cells in allografts are associated with a low risk of acute graft-versus-host disease following unmanipulated allogeneic haematopoietic stem cell transplantation

Regulatory T cells (T(regs) ) play a key role in the prevention of acute graft-versus-host disease (aGVHD). To investigate the association between T(reg) subsets and aGVHD, we prospectively analysed T cell subsets in the allografts of 35 patients undergoing myeloablative unmanipulated haematopoietic stem cell transplantation. Multivariate analysis found that patients infused with less than 0·29 × 10(6) /kg of CD4(+) CD25(high) CD45RA(+) CD62L(+) T cells during transplantation exhibited an increased incidence of II-IV aGVHD [hazard ratio (HR) = 0·000, 95% CI = 0·000-0·106, P = 0·013]. Next, we compared the reconstitution characteristics of T cell subsets between haploidentical haematopoietic stem cell transplantation (HSCT) and sibling HSCT by collecting peripheral blood samples at regular intervals (days 30, 60 and 90) after transplantation. No significant differences were observed in the reconstitution of conventional T cells between haploidentical HSCT and sibling identical HSCT. However, total counts of recovered naiveT(regs) and CD62L(+) naive T(regs) from haploidentical HSCT were significantly lower compared to sibling identical HSCT; P-values were 0·045 and 0·021, respectively. Although total counts of conventional T cells in aGVHD patients reached similar levels compared to non-aGVHD patients before day 60 post-HSCT, total counts of naive T(regs) and CD62L(+) naive T(regs) in aGVHD patients did not reach similar levels to non-aGVHD patients until 90 days post-HSCT. Taken together, our findings demonstrate that a large population of CD62L(+) naive T(regs) in allografts reduces the incidence of aGVHD. Further, development of aGVHD is related closely to the delayed reconstitution of the naive T(reg) population.

Immunomodulatory effects of cyclophosphamide and implementations for vaccine design

Drug repositioning refers to the utilization of a known compound in a novel indication underscoring a new mode of action that predicts innovative therapeutic options. Since 1959, alkylating agents, such as the lead compound cyclophosphamide (CTX), have always been conceived, at high dosages, as potent cytotoxic and lymphoablative drugs, indispensable for dose intensity and immunosuppressive regimen in the oncological and internal medicine armamentarium. However, more recent work highlighted the immunostimulatory and/or antiangiogenic effects of low dosing CTX (also called "metronomic CTX") opening up novel indications in the field of cancer immunotherapy. CTX markedly influences dendritic cell homeostasis and promotes IFN type I secretion, contributing to the induction of antitumor cytotoxic T lymphocytes and/or the proliferation of adoptively transferred T cells, to the polarization of CD4(+) T cells into TH1 and/or TH17 lymphocytes eventually affecting the Treg/Teffector ratio in favor of tumor regression. Moreover, CTX has intrinsic "pro-immunogenic" activities on tumor cells, inducing the hallmarks of immunogenic cell death on a variety of tumor types. Fifty years after its Food and Drug Administration approval, CTX remains a safe and affordable compound endowed with multifaceted properties and plethora of clinical indications. Here we review its immunomodulatory effects and advocate why low dosing CTX could be successfully combined to new-generation cancer vaccines.

Human FoxP3+ regulatory T cells in systemic autoimmune diseases

Since the characterization of CD4(+)CD25(+) regulatory T (Treg) cells in mice, significant progress has been made in the definitions of the phenotype and the function of human Treg cells in health and in pathological conditions. Recent advances in the field leading to a better molecular definition of Treg subsets in humans and the description of the dynamics of differentiation of Treg cells should bring new insights in the understanding of human chronic systemic autoimmune diseases. How Treg cells are compromised in these diseases is a challenging issue because the elucidation of the mechanisms leading to such anomaly might lead to promising novel therapeutic approaches.

The role of regulatory T cells in atopic dermatitis

Regulatory T (T(reg)) cells play a pivotal role in immune suppression and are integral to the control of allergic responses. The chronic inflammatory skin condition atopic dermatitis (AD) is severest in patients who are sensitized to allergens from diverse sources including foods, pollens and animal danders, as well as skin-colonizing organisms. These individuals typically present with eczematous skin eruptions in early childhood, and evolution of the disease is thought to reflect an underlying dysregulated T-cell response to allergens that manifests as a Th2 response. Studying T(reg) cells in the context of AD from infancy into adulthood could yield insight into their role in disease pathogenesis and reveal new strategies for exploiting these cells for therapeutic purposes. Such studies are challenging in humans owing to the heterogeneous nature of T(reg) cells, lack of a reliable surface marker, and the paucity of knowledge surrounding the emergence of specialized T cells in early life. Moreover, the blurred distinction between activated effector T cells and T(reg) cells further complicates studies in the context of inflammatory disorders such as AD. There is emerging evidence to suggest that T(reg) cells can convert to Th2 cells and that this pathway is bidirectional. This phenomenon may be a double-edged sword with important implications not only for subverting T(reg) cells in disease, but also for potential treatments designed to amplify these cells in order to suppress the allergic inflammatory cascade in AD.

Successful generation of primary virus-specific and anti-tumor T-cell responses from the naive donor T-cell repertoire is determined by the balance between antigen-specific precursor T cells and regulatory T cells

BACKGROUND

One of the major challenges in allogeneic stem cell transplantation is to find a balance between the harmful induction of graft-versus-host disease and the beneficial graft-versus-leukemia and pathogen-specific immune responses. Adoptive transfer of in-vitro generated donor T cells with specific anti-leukemic or pathogen-specific activity may be effective. However, in many cases this requires the in-vitro priming and expansion of antigen-specific precursor T cells from the naïve donor T-cell repertoire.

DESIGN AND METHODS

Antigen-specific CD8 T cells were generated by co-culture of CD45RO-depleted, regulatory T cell-depleted donor peripheral blood mononuclear cells with autologous peptide-loaded dendritic cells, followed by two re-stimulations with peptide-loaded autologous monocytes. Responding T cells were isolated based on CD137 expression and further purified using peptide/major histocompatibility complex tetramers.

RESULTS

Using this method we were able to reproducibly generate functionally high avidity T cells directed against multiple viral antigens and minor histocompatibility antigens from the naïve T-cell repertoire of seronegative, minor histocompatibility antigen-negative donors. Furthermore, we demonstrated that reduction of the regulatory T-cell frequency by depletion of CD45RO(+) responder cells resulted in improved priming and expansion of antigen-specific precursor T cells.

CONCLUSIONS

In conclusion, we present a robust method for the in-vitro induction and isolation of antigen-specific T cells from the naïve repertoire. We demonstrate that the likelihood of successful generation of primary immune responses is determined by a delicate balance between the numbers of antigen-specific precursor T cells and the numbers and activation state of regulatory T cells locally at the site of priming of the immune response.

All creatures great and small: regulatory T cells in mice, humans, dogs and other domestic animal species

Abnormalities of peripheral tolerance are thought to contribute to the pathogenesis of a number of inflammatory, autoimmune and neoplastic diseases of both humans and animals. Furthermore, the induction of allograft tolerance is the 'holy grail' of clinical transplantation. Of the various mechanisms underlying peripheral tolerance, regulatory T cells (Tregs) have risen to particular prominence. Various Treg subsets have been characterised, including naturally occurring cells that develop along a regulatory lineage in the thymus and induced cells that arise in the periphery from conventional T cell precursors. The transcription factor Forkhead box (Foxp3) serves a crucial role in stabilising the Treg transcriptome and is a faithful marker of peripheral Tregs in the mouse, though its expression is somewhat more promiscuous in man. Regulatory T cells display a wide spectrum of suppressive and cytotoxic mechanisms and may convert to specific T helper cell subsets in response to appropriate inflammatory cues. Although knowledge of Tregs in domestic animal species is still in its infancy, a growing body of literature is accumulating in the dog, cat, pig, cow, sheep and horse. We highlight our own and other studies of Tregs in the dog, an important veterinary species and a model for a number of human diseases. The ethos of 'One Health, One Medicine' is anticipated to accelerate efforts to close the knowledge gap between domestic animal and mainstream species in this field. We predict that the prodigious pace of research into Tregs will continue unabated for years to come, fuelled by the exciting therapeutic potential of these cells.

CTLA-4 blockade following relapse of malignancy after allogeneic stem cell transplantation is associated with T cell activation but not with increased levels of T regulatory cells

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a key negative regulator of T cell activation and proliferation. Ipilimumab is a human monoclonal antibody that specifically blocks the binding of CTLA-4 to its ligand. To test the hypothesis that blockade of CTLA-4 by ipilimumab could augment graft-versus-malignancy (GVM) effects without a significant impact on graft-versus-host disease (GVHD), we conducted a phase I clinical trial of ipilimumab infusion in patients with relapsed malignancy following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Here, we report the analysis of peripheral blood T lymphocyte reconstitution, T regulatory cell (Treg) expression, and T cell activation markers after a single dose of ipilimumab in 29 patients. Peripheral blood samples were collected from all patients before and after ipilimumab infusion. Lymphocyte immunophenotyes, including levels of CD4(+)CD25(high) cells and T cell activation markers, were analyzed in all cases. Levels of CD4(+)CD25(high)Foxp3(+) cells and intracellular CTLA-4 in CD4(+) T cells also were evaluated in the last 11 cases. We found lower baseline levels of CD4(+) and CD45RO(+) T cells in patients compared with normal controls. More than 50% of the patients had abnormally low lymphocyte counts (CD4 or/and CD8 T cells), and some had no circulating B lymphocytes. The percentages of both CD4(+)CD25(high) and CD4(+)CD25(high)Foxp3(+) T cells were significantly higher in patients before ipilimumab infusion than in healthy donors. Twenty of 29 patients exhibited an elevated level of CD4(+)CD25(low) activated T cells at baseline, compared with only 3 of 26 healthy donors. Both CD4(+) and CD8(+) T lymphocyte counts were significantly increased after ipilimumab infusion. There was no consistent change in absolute lymphocyte count or in the number of T cells expressing the activation marker CD69. However, increases in CD4(+)CD25(low) T cells were seen in 20 of 29 patients and increases in CD4(+)HLA-DR(+) T cells were seen in the last 10 patients in the first 60 days after ipilimumab infusion. Although the percentages of both CD4(+)CD25(high) and CD4(+)CD25(high)Foxp3(+) T cells decreased significantly during the observation period, the absolute cell counts did not change. Intracellular CTLA-4 expression in CD4(+)CD25(lo/-) T cells increased significantly after ipilimumab infusion. We conclude that CTLA-4 blockade by a single infusion of ipilimumab increased CD4(+) and CD4(+)HLA-DR(+) T lymphocyte counts and intracellular CTLA-4 expression at the highest dose level. There was no significant change in Treg cell numbers after ipilimumab infusion. These data demonstrate that significant changes in T cell populations occur on exposure to a single dose of ipilimumab. Further studies with multiple doses are needed to explore this phenomenon further and to correlate changes in lymphocyte subpopulations with clinical events.

Yoghurt consumption regulates the immune cells implicated in acute intestinal inflammation and prevents the recurrence of the inflammatory process in a mouse model

Crohn's disease and ulcerative colitis, two forms of inflammatory bowel disease, are important problems in industrialized countries. The complete etiology of these two diseases is still unknown but likely involves genetic, environmental, and immunological factors. The aim of the present work was to determine whether the anti-inflammatory effects reported for yoghurt in acute trinitrobenzene sulfonic acid-induced intestinal inflammation in mice also could prevent or attenuate the recurrent intestinal inflammation, thus maintaining remission. The innate response also was evaluated through participation of Toll-like receptors (TLRs) and the analysis of T-cell populations to determine the effects of yoghurt in an acute inflammatory bowel disease model. Yoghurt exerted a beneficial effect on acute intestinal inflammation by regulating T-cell expansion and modulating the expression of TLRs, with decrease of TLR4(+) and increase of TLR9(+) cells. The anti-inflammatory effect of yoghurt also was demonstrated in a recurrent inflammation model. Yoghurt administration during the remission phase prevented the recurrence of inflammation without producing undesirable side effects. The yoghurt effect may be mediated by increased interleukin 10 production and changes in intestinal microbiota.

Intrinsic and extrinsic control of peripheral T-cell tolerance by costimulatory molecules of the CD28/ B7 family

Positive and negative costimulation by members of the CD28 family is critical for the development of productive immune responses against foreign pathogens and their proper termination to prevent inflammation-induced tissue damage. In addition, costimulatory signals are critical for the establishment and maintenance of peripheral tolerance. This paradigm has been established in many animal models and has led to the development of immunotherapies targeting costimulation pathways for the treatment of cancer, autoimmune disease, and allograft rejection. During the last decade, the complexity of the biology of costimulatory pathways has greatly increased due to the realization that costimulation does not affect only effector T cells but also influences regulatory T cells and antigen-presenting cells. Thus, costimulation controls T-cell tolerance through both intrinsic and extrinsic pathways. In this review, we discuss the influence of costimulation on intrinsic and extrinsic pathways of peripheral tolerance, with emphasis on members of the CD28 family, CD28, cytotoxic T-lymphocyte antigen-4 (CTLA-4), and programmed death-1 (PD-1), as well as the downstream cytokine interleukin-1 (IL-2).

Lower frequency of CD62L(high) and higher frequency of TNFR2(+) Tregs are associated with inflammatory conditions in type 1 diabetic patients

Diabetes type 1 is a chronic autoimmune disease in which insulin-producing cells are gradually destroyed by autoreactive T cells. Human regulatory cells play important role in controlling autoimmunity, and their qualitative or quantitative dysfunctions may result in ineffective suppression of autoreactive T cells. CD62L is a surface molecule that plays role in homing capabilities of Tregs, and only cells with high expression of CD62L have high suppressive potential. Tregs are also characterized by the constant expression of TNFR2. The frequency of Tregs carrying TNFR2 is higher in inflammatory conditions. We investigated blood regulatory T cells with CD62L expression and regulatory T cells expressing TNFR2 in type 1 diabetic patients. We found differences in these populations when comparing to healthy individuals. We propose that these may be associated with inflammatory conditions that are present in patients with type 1 diabetes. The lower percentage of Tregs and Treg CD62L(high) may contribute to ineffective suppression of proinflammatory cytokines production during type 1 diabetes.

Ulcerative colitis: immune function, tissue fibrosis and current therapeutic considerations

BACKGROUND

Ulcerative colitis (UC) is a complex disease in which the interaction of genetic, environmental and microbial factors drives chronic intestinal inflammation that finally leads to extensive tissue fibrosis.

DISCUSSION

The present review discusses the current knowledge on genetic susceptibility, especially of the IL-12/IL-23 pathway, the pathophysiologic role of the involved cytokines (e.g. IL-13, IL-23, TGFβ1) and immune cells (e.g. T cells, epithelial cells, fibroblasts) in UC followed by an overview on actual therapeutic considerations. These future therapies will target selectively the involved cell types by blocking their activation and its downstream signalling, by inhibiting their migration to the inflamed site and by anti-cytokine strategies. This may avoid-when initiated in time-the perpetuation of the inflammatory mechanisms thus preventing fibrosis. With respect to animal models that have guided the most productive efforts for understanding human inflammatory bowel disease, these will be shortly discussed in the respective context.

Ulcerative colitis: immune function, tissue fibrosis and current therapeutic considerations

BACKGROUND

Ulcerative colitis (UC) is a complex disease in which the interaction of genetic, environmental and microbial factors drives chronic intestinal inflammation that finally leads to extensive tissue fibrosis.

DISCUSSION

The present review discusses the current knowledge on genetic susceptibility, especially of the IL-12/IL-23 pathway, the pathophysiologic role of the involved cytokines (e.g. IL-13, IL-23, TGFβ1) and immune cells (e.g. T cells, epithelial cells, fibroblasts) in UC followed by an overview on actual therapeutic considerations. These future therapies will target selectively the involved cell types by blocking their activation and its downstream signalling, by inhibiting their migration to the inflamed site and by anti-cytokine strategies. This may avoid-when initiated in time-the perpetuation of the inflammatory mechanisms thus preventing fibrosis. With respect to animal models that have guided the most productive efforts for understanding human inflammatory bowel disease, these will be shortly discussed in the respective context.

Immune recovery after cyclophosphamide treatment in multiple myeloma: implication for maintenance immunotherapy

Multiple myeloma (MM) is a progressive B-lineage neoplasia characterized by clonal proliferation of malignant plasma cells. Increased numbers of regulatory T cells (Tregs) were determined in mouse models and in patients with MM, which correlated with disease burden. Thus, it became rational to target Tregs for treating MM. The effects of common chemotherapeutic drugs on Tregs are reviewed with a focus on cyclophosphamide (CYC). Studies indicated that selective depletion of Tregs may be accomplished following the administration of a low-dose CYC. We report that continuous nonfrequent administrations of CYC at low doses block the renewal of Tregs in MM-affected mice and enable the restoration of an efficient immune response against the tumor cells, thereby leading to prolonged survival and prevention of disease recurrence. Hence, distinctive time-schedule injections of low-dose CYC are beneficial for breaking immune tolerance against MM tumor cells.

At the crossroads between tolerance and aggression: Revisiting the "layered immune system" hypothesis

"We do not grow absolutely, chronologically. We grow sometimes in one dimension, and not in another; unevenly. We grow partially. We are relative. We are mature in one realm, childish in another. The past, present and future mingle and pull us backward, forward, or fix us in the present. We are made up of layers, cells, constellations."-Anaïs NinIt has long been recognized that the developing immune system exhibits certain peculiarities when compared to the adult immune system. Nonetheless, many still regard the fetal immune system as simply being an immature version of the adult immune system. Here we discuss historical evidence as well as recent findings, which suggest that the human immune system may develop in distinct layers with specific functions at different stages of development.

The correlation between tumor-infiltrating Foxp3+ regulatory T cells and cyclooxygenase-2 expression and their association with recurrence in resected head and neck cancers

The aim of this study was to investigate the correlation between tumor-infiltrating CD4+ CD25(high) Foxp3+ naturally occurring regulatory T cells (Foxp3+ nTregs) and cyclooxygenase-2 (COX-2) expression and their association with local recurrence in resected head and neck cancers. Intratumoral COX-2 and Foxp3+ nTregs expressions were retrospectively assessed using immunohistochemistry. Associations between the clinicopathological characteristics and either intratumoral COX-2 expression or number of Foxp3+ nTregs were tested using the Chi-square test. The correlation between the number of Foxp3+ nTregs and COX-2 expression was tested using Spearman's rank correlation test. Associations between recurrence-free survival (RFS) and either intratumoral COX-2 expression or number of Foxp3+ nTregs were calculated using the Kaplan-Meier method, and factors that may influence the RFS were analyzed by Cox regression. The five-year RFS for all patients was 35.09%. Patient clinicopathological characteristics had no relationship with intratumoral COX-2 expression or the number of Foxp3+ nTregs. However, a positive correlation between intratumoral COX-2 expression and the number of Foxp3+ nTregs was observed (P < 0.001). The RFS of patients with elevated COX-2 expression was significantly worse than that of patients without intratumoral COX-2 expression (P = 0.0228). The RFS of patients with tumors containing >6 Foxp3+ cells was significantly worse than that of patients with tumors containing ≤6 Foxp3+ cells (P = 0.0020). However, by Cox regression analysis, the RFS of all patients was not influenced by intratumoral COX-2 expression (P = 0.100) or the number of Foxp3+ nTregs (P = 0.071). Tumor-infiltrating CD4+ CD25(high) Foxp3+ nTregs were positively correlated with intratumoral COX-2 expression and were associated with a worse RFS in univariate analysis.

T(reg) cells: collection, processing, storage and clinical use

T regulatory cells are fundamental in the maintenance of immune homeostasis and self-tolerance. Experimental models suggest the existence of two functional types of T(reg) cells designated naturally occurring and induced. Interest in T(reg) cells increased with evidence from experimental mouse and human models demonstrating that the immunosuppressive potential of these cells can be utilized in the treatment of various pathological conditions. The existence of a subpopulation of suppressive T cells was the subject of significant controversy among immunologists for many years. T regulatory cells limit immune activation through a variety of direct and indirect interactions, many of which are yet to be determined. Fully understanding T(reg) cells biology will lead us to harnessing the capacity of these cells in order to develop strategies to prevent autoimmune disorders and tolerance to transplantation. Efficient isolation, expansion and cryopreservation strategies that comply with Good Manufacturing Practice (GMP) guidelines are prerequisites for the clinical application of human CD4+ CD25+ CD127(low) FOXP3+ regulatory T cells.

The evolving role of mTOR inhibition in transplantation tolerance

The mammalian target of rapamycin (mTOR) plays a key role in the immune response. mTOR inhibitors suppress T cell activation and proliferation and are effective immunosuppressants. Today there is growing interest in their potential role in inducing tolerance after transplantation. mTOR inhibitors induce anergy in naïve T cells, promote the expansion of regulatory T cells, and inhibit the maturation of dendritic cells, thus promoting immunologic tolerance. Here we review the mechanisms by which mTOR inhibitors promote tolerance. We discuss the clinical relevance of these mechanisms and suggest how they might be used in the design of future protocols to induce tolerance.

Analysis of the transcriptional program of developing induced regulatory T cells

CD25+ regulatory T cells develop in the thymus (nTregs), but may also be generated in the periphery upon stimulation of naive CD4 T cells under appropriate conditions (iTregs). To gain insight into the mechanisms governing iTreg development, we performed longitudinal transcriptional profiling of CD25+ T cells during their differentiation from uncommitted naive CD4 T cells. Microarray analysis of mRNA from CD25+ iTregs early after stimulation revealed expression of genes involved in cell cycle progression and T cell activation, which largely overlapped with genes expressed in CD25+ effector T cells (Teffs) used as a control. Whereas expression of these genes remained elevated in Teffs, it declined gradually in developing iTregs, resulting in a more quiescent phenotype in mature iTregs. A similar pattern of kinetics was observed for biological processes and for intracellular pathways over-represented within the expressed genes. A maximum dichotomy of transcriptional activity between iTregs and Teffs was reached at late stages of their maturation. Of interest, members of the FoxO and FoxM1 transcription factor family pathways exhibited a reciprocal expression pattern in iTregs and Teffs, suggesting a role of these transcription factors in determining T cell fate.

Importance of IL-10 modulation by probiotic microorganisms in gastrointestinal inflammatory diseases

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms that are naturally present in many foods and possess a wide range of therapeutic properties. The aim of this paper is to present an overview of the current expanding knowledge of one of the mechanisms by which LAB and other probiotic microorganisms participate in the prevention and treatment of gastrointestinal inflammatory disease through their immune-modulating properties. A special emphasis will be placed on the critical role of the anti-inflammatory cytokine IL-10, and a brief overview of the uses of genetically engineered LAB that produce this important immune response mediator will also be discussed. Thus, this paper will demonstrate the critical role that IL-10 plays in gastrointestinal inflammatory diseases and how probiotics could be used in their treatment.

Human FoxP3(+)CD4(+) regulatory T cells: their knowns and unknowns

Human regulatory T cells (Tregs) expressing the transcription factor FoxP3 play indispensable roles for the maintenance of immunological self-tolerance and immune homeostasis. In this review, we discuss immunological characteristics of human FoxP3(+) Tregs and to what extent they are similar to or different from the murine counterparts. We also discuss important issues that remain to be addressed in the field to better understand the pathophysiology of autoimmune disease and to build solid basis for immunotherapies targeting FoxP3(+) Tregs.

Natural regulatory T cells in autoimmunity

The suppressive/immunomodulatory function of CD4(+)CD25(+)FOXP3(+) regulatory T (Treg) cells is crucial for the maintenance of immune homeostasis, which helps to prevent autoimmunity and reduce the inflammation induced by pathogens and environmental insults. This review summarizes the current knowledge on the types and mechanisms of action of Treg cells and their role in the immune tolerance to self-antigens, with a particular focus on naturally occurring Treg cells.

Human cord blood CD4+CD25hi regulatory T cells suppress prenatally acquired T cell responses to Plasmodium falciparum antigens

In malaria endemic regions, a fetus is often exposed in utero to Plasmodium falciparum blood-stage Ags. In some newborns, this can result in the induction of immune suppression. We have previously shown these modulated immune responses to persist postnatally, with a subsequent increase in a child's susceptibility to infection. To test the hypothesis that this immune suppression is partially mediated by malaria-specific regulatory T cells (T(regs)) in utero, cord blood mononuclear cells (CBMC) were obtained from 44 Kenyan newborns of women with and without malaria at delivery. CD4(+)CD25(lo) T cells and CD4(+)CD25(hi) FOXP3(+) cells (T(regs)) were enriched from CBMC. T(reg) frequency and HLA-DR expression on T(regs) were significantly greater for Kenyan as compared with North American CBMC (p < 0.01). CBMC/CD4(+) T cells cultured with P. falciparum blood-stage Ags induced production of IFN-γ, IL-13, IL-10, and/or IL-5 in 50% of samples. Partial depletion of CD25(hi) cells augmented the Ag-driven IFN-γ production in 69% of subjects with malaria-specific responses and revealed additional Ag-reactive lymphocytes in previously unresponsive individuals (n = 3). Addition of T(regs) to CD4(+)CD25(lo) cells suppressed spontaneous and malaria Ag-driven production of IFN-γ in a dose-dependent fashion, until production was completely inhibited in most subjects. In contrast, T(regs) only partially suppressed malaria-induced Th2 cytokines. IL-10 or TGF-β did not mediate this suppression. Thus, prenatal exposure to malaria blood-stage Ags induces T(regs) that primarily suppress Th1-type recall responses to P. falciparum blood-stage Ags. Persistence of these T(regs) postnatally could modify a child's susceptibility to malaria infection and disease.

In vitro Treg suppression assays

Determining the activity of a regulatory T-cell population in vitro is often the first step in analyzing its function. To obtain reliable and reproducible results, it is critical to follow the protocol that is most applicable to your experimental question. We have outlined below a basic in vitro suppression assay as well as a variety of alternative/additional protocols that can be utilized alone or in combination as desired.

Methods for in vitro generation of human type 1 regulatory T cells

Type 1 regulatory T (Tr1) cells are adaptive regulatory T cells that are induced in the periphery upon chronic exposure to antigen (Ag) in a tolerogenic environment containing interleukin (IL)-10. Tr1 cells are Ag-specific; they produce high levels of IL-10 and TGF-β in the absence of IL-4 and suppress T-cell responses via a cytokine-dependent mechanism. During the last decade, several protocols have been developed to generate Tr1 cell lines in vitro. In this chapter, we outline protocols to generate non-Ag- and Ag-specific Tr1 cell lines and assays used to characterize Tr1 cell phenotype and functions.

The influence of regulatory T cells and diurnal hormone rhythms on T helper cell activity

Symptoms of diseases such as rheumatoid arthritis, which is T helper 1 (Th1) dependent, and asthma, which is T helper 2 (Th2) dependent, are influenced by diurnal rhythms and natural regulatory T cells (nTreg). However, the mechanisms responsible for the diurnal rhythm of disease activity have not been identified and it is unclear whether nTreg activity is diurnal rhythm-dependent. We therefore investigated whether a 24-hr diurnal cycle affected the ability of various helper T-cell populations to generate immunomodulatory and pro-inflammatory cytokines, as well as its suppression by nTreg cells. Using a within-subject crossover design, sleep versus continuous wakefulness was compared over a 24-hr period in healthy young volunteers under defined environmental conditions. Venous blood was drawn periodically every 5 hr and the function of T cells was explored in vitro. We demonstrated that interleukin (IL)-2, interferon-γ (IFN-γ), tumour necrosis factor-α (TNF-α) and IL-10 secretion by naïve CD4(+) T cells follows a diurnal rhythm. Furthermore, multiple regression analysis, as well as subsequent in vitro experiments, suggested that serum levels of cortisol and prolactin are part of the underlying mechanism. Additionally, we observed that nTreg suppressed the secretion of IFN-γ, IL-2 and TNF-α, but not the secretion of IL-4, IL-6, IL-10 and IL-17A. However, the abrogation of IL-2 release was reversed upon inhibiting CD25 on nTreg. Highly purified nTreg secreted IL-6, IL-10 and IL-17A, but not IL-2, IL-4, IFN-γ or TNF-α. Taken together, our results demonstrate that hormones and nTreg modulate the diurnal rhythm of T helper cell activity.

Human regulatory T cells in autoimmune diseases

Human regulatory T cells (Tregs) play a critical role in preventing autoimmunity, and their failure contributes to autoimmune diseases. In recent years, our understanding of human Tregs has been greatly enhanced by improvements in the definition and isolation of pure human Tregs, as well as by the discovery of phenotypically and functionally distinct human Treg subsets. This progress has also yielded a better understanding of the mechanisms of human Treg suppression and the role of human Tregs in autoimmune diseases. An unexpected discovery is that human Tregs have considerable plasticity that allows them to produce the pro-inflammatory cytokine IL-17 under certain conditions. These recent advances highlight the importance of studying the roles of both mouse and human Tregs in autoimmunity.

Critical role of transcription factor PU.1 in the expression of CD80 and CD86 on dendritic cells

In this study, we investigated the role of a transcription factor, PU.1, in the regulation of CD80 and CD86 expression in dendritic cells (DCs). A chromatin immunoprecipitation assay revealed that PU.1 is constitutively bound to the CD80 and CD86 promoters in bone marrow-derived DCs. In addition, co-expression of PU.1 resulted in the transactivation of the CD80 and CD86 promoters in a reporter assay. The binding of PU.1 to cis-enhancing regions was confirmed by electromobility gel-shift assay. As expected, inhibition of PU.1 expression by short interfering RNA (siRNA) in bone marrow-derived DCs resulted in marked down-regulation of CD80 and CD86 expression. Moreover, overexpression of PU.1 in murine bone marrow-derived lineage-negative cells induced the expression of CD80 and CD86 in the absence of monocyte/DC-related growth factors and/or cytokines. Based on these results, we conclude that PU.1 is a critical factor for the expression of CD80 and CD86. We also found that subcutaneous injection of PU.1 siRNA or topical application of a cream-emulsified PU.1 siRNA efficiently inhibited murine contact hypersensitivity. Our results suggest that PU.1 is a potential target for the treatment of immune-related diseases.

Transcriptional regulation of Foxp3 in regulatory T cells

Regulatory T (Treg) cells constitute a unique T-cell lineage that plays a pivotal role in the maintenance of the peripheral tolerance. The transcription factor Foxp3 (Forkhead box P3) was identified as a master regulator for the development and function of Treg cells. It is well defined that Foxp3 expression is critical to program CD4+CD25+ Treg cell development and function; however, the molecular mechanisms that are involved in the regulation of the Foxp3 expression remain unclear. Recent studies have showed an indication that this process is influenced by a number of transcription factors. In this review, we summarize the current knowledge of how Foxp3 expression is controlled at molecular level by focusing on these factors.

GM-CSF-induced, bone-marrow-derived dendritic cells can expand natural Tregs and induce adaptive Tregs by different mechanisms

In our earlier work, we had shown that GM-CSF treatment of CBA/J mice can suppress ongoing thyroiditis by inducing tolerogenic CD8α(-) DCs, which helped expand and/or induce CD4(+)Foxp3(+) Tregs. To identify the primary cell type that was affected by the GM-CSF treatment and understand the mechanism by which Tregs were induced, we compared the effect of GM-CSF on matured spDCs and BMDC precursors in vitro. Matured spDCs exposed to GM-CSF ex vivo induced only a modest increase in the percentage of Foxp3-expressing T cells in cocultures. In contrast, BM cells, when cultured in the presence of GM-CSF, gave rise to a population of CD11c(+)CD11b(Hi)CD8α(-) DCs (BMDCs), which were able to expand Foxp3(+) Tregs upon coculture with CD4(+) T cells. This contact-dependent expansion occurred in the absence of TCR stimulation and was abrogated by OX40L blockage. Additionally, the BMDCs secreted high levels of TGF-β, which was required and sufficient for adaptive differentiation of T cells to Foxp3(+) Tregs, only upon TCR stimulation. These results strongly suggest that the BMDCs differentiated by GM-CSF can expand nTregs and induce adaptive Tregs through different mechanisms.

T regulatory cells in cord blood--FOXP3 demethylation as reliable quantitative marker

Background

Regulatory T-cells (Tregs), characterized as CD4+CD25^hi T-cells expressing FOXP3, play a crucial role in controlling healthy immune development during early immune maturation. Recently, FOXP3 demethylation was suggested to be a novel marker for natural Tregs in adults. In cord blood, the role and function of Tregs and its demethylation is poorly understood. We assessed FOXP3 demethylation in cord blood in relation to previously used Treg markers such as CD4⁺CD25^hi, FOXP3 mRNA, protein expression, and suppressive Treg function.

Methodology

Cord blood mononuclear cells (CBMC) were isolated from 70 healthy neonates, stimulated for 3 days with the microbial stimulus lipid A (LpA), and allergen Dermatophagoides pteronyssinus (Derp1). Tregs (CD4+CD25^hi, intracellular, mRNA FOXP3 expression, isolated cells), DNA methylation of the FOXP3-locus and suppressive Treg function were assessed.

Principal Findings

Demethylation of FOXP3 in whole blood was specific for isolated CD4+CD25^hi Tregs. Demethylation of FOXP3 was positively correlated with unstimulated and LpA-stimulated FOXP3 mRNA-expression (p≤0.05), and CD4⁺CD25^hi T-cells (p≤0.03). Importantly, increased FOXP3 demethylation correlated with more efficient suppressive capacity of Tregs (r = 0.72, p = 0.005). Furthermore, FOXP3 demethylation was positively correlated with Th2 cytokines (IL-5, IL-13) following LpA-stimulation (p = 0.006/0.04), with Th2 and IL-17 following Derp1+LpA-stimulations (p≤0.009), but not Th1 cytokines (IFN-γ).

Conclusions

FOXP3 demethylation reliable quantifies Tregs in cord blood. FOXP3 demethylation corresponds well with the suppressive potential of Tregs. The resulting strict correlation with functionally suppressive Tregs and the relative ease of measurement render it into a valuable novel marker for large field studies assessing Tregs as qualitative marker indicative of functional activity.

The associations of circulating CD4+CD25high regulatory T cells and TGF-β with disease activity and clinical course in patients with adult-onset Still's disease

OBJECTIVE

To determine circulating levels of CD4(+)CD25(high) regulatory T (Treg) cells and transforming growth factor-β (TGF-β) in patients with adult-onset Still's disease (AOSD) and to examine the associations with disease activity and clinical course of this disease.

METHODS

The frequencies of circulating CD4(+)CD25(high) Treg cells in 52 active AOSD patients, 42 active systemic lupus erythematosus (SLE) patients, and 22 healthy controls (HCs) were determined using flow cytometry analysis. Levels of serum TGF-β and soluble interleukin-2 receptor (sIL-2R) were measured by enzyme-linked immunosorbent assay.

RESULTS

Significantly lower levels of circulating CD4(+)CD25(high) Treg cells and serum TGF-β were found in AOSD patients and SLE patients than those found in HCs. Levels of circulating CD4(+)CD25(high) Treg cells and TGF-β were inversely correlated with disease activity scores for AOSD patients and SLE patients. Circulating CD4(+)CD25(high) Treg cell frequencies were positively correlated with serum TGF-β levels for patients with both diseases. Levels of circulating CD4(+)CD25(high) Treg cells and TGF-β significantly increased, paralleling clinical remission and the decrease in levels of C-reactive protein and soluble interleukin-2 receptor after effective therapy in AOSD patients. AOSD patients with monocyclic course had significantly higher levels of circulating CD4(+)CD25(high) Treg cells and TGF-β compared to those with polycyclic and chronic articular course.

CONCLUSION

Diminished levels of circulating CD4(+)CD25(high) Treg cells and TGF-β, and inverse correlation with disease activity in patients with AOSD and SLE might be involved in the pathogenesis of both diseases. Increased levels of circulating CD4(+)CD25(high) Treg cells or TGF-β might be associated with a favorable clinical course in AOSD patients.

Multimodal therapy for liver cirrhosis patients with advanced hepatocellular carcinoma

PURPOSE

We have previously shown that continuous intra-arterial combination chemotherapy (IACC) might be more effective for advanced hepatocellular carcinoma (aHCC) in patients with HCV-related liver cirrhosis (C-LC) or alcoholic liver cirrhosis (A-LC) than in patients with HBV-related LC (B-LC). However, it is still unknown whether IACC actually improves the prognosis of aHCC patients with liver cirrhosis (LC), because it is difficult to perform a randomized controlled trial for patients with a poor prognosis. The aim of this study was to retrospectively assess the influence of IACC on the prognosis of aHCC.

METHODS

Fifty-eight adult Japanese patients who had aHCC and LC underwent repeated trans-arterial chemoembolization (TACE) without IACC between 1990 and 1997 at our hospital (group T), while 43 patients with aHCC and LC received IACC between 2000 and 2008 after undergoing several TACE sessions (group R). The Japan Integrated Staging score (JIS score) of each patient was ≥ 3 at the time of presentation, except for patients with tumor thrombi involving the first or subsequent portal vein branches or those with tumor invasion of the inferior vena cava. The same IACC regimen was repeated for as long as possible in group R.

RESULTS

In group T, 13 patients had B-LC, 37 patients had C-LC, and 8 patients had A-LC, while the respective numbers were 14, 21, and 8 in group R. The median survival time (MST) was 248 days for patients with C-LC in group T and 708 days for those in group R, while it was 253 days for patients with A-LC in group T and 593 days for those in group R. There were significant differences of survival between the two groups. However, MST was 369 days for patients with B-LC in group T and 782 days for those in group R, without a significant difference. In group R, a complete or partial response was achieved after 4 weeks of chemotherapy in 14.3% of patients with B-LC versus 42.9% of patients with C-LC and 37.5% of patients with A-LC.

CONCLUSIONS

In LC patients with a JIS score > 3 at diagnosis, multimodal therapy with IACC after TACE prolongs the MST of C-LC or A-LC patients compared with TACE alone, although it does not improve the MST of patients with B-LC.

Clinical significance of regulatory T cells and CD8+ effector populations in patients with human endometrial carcinoma

BACKGROUND

A study was carried out to determine the functional attributes of CD4(+) CD25(+) regulatory T cells in cancer progression by suppressing antitumor immunity.

METHODS

Triple-color flow cytometry was used to study the phenotype expression of CD4(+) CD25(+) regulatory T cells and CD8(+) T cells in the peripheral blood lymphocytes (PBLs) and tumor-infiltrating lymphocytes (TILs) of 57 cases of stage I to IV endometrial carcinoma. The expression of T cell subsets was correlated with clinical prognostic parameters.

RESULTS

The prevalence of CD4(+) CD25(+) T cells was significantly higher in the TILs than PBLs. The expression of CD4(+) CD25(+) regulatory T cells in cancer milieu correlated with the tumor grade, stage, and myometrium invasion. The expression of FOXP3 and GITR in CD4(+) CD25(+) regulatory T cells was lower in PBLs than TILs. Most tumor-infiltrating CD8(+) T cells were CD28(-) CD45RA(-) CD45RO(+) CCR7(-) , suggesting good terminal differentiation. Most of them had an activated role with CD69(+) CD103(+) CD152(+) . Functionally, both granzyme B and perforin were scarcely expressed in peripheral regulatory T cells but were highly expressed in peripheral regulatory T cells in the tumor microenvironment. In contrast, CD8(+) cytotoxic T cells derived from PBLs expressed both granzyme B and perforin, and at significantly higher levels than in TILs. Further functional assays demonstrated that Th1 cytokines and cytotoxic molecules can be synchronously up-regulated in CD8(+) cytotoxic T cells.

CONCLUSIONS

Regulatory T cells in the tumor microenvironment may abrogate CD8(+) T cell cytotoxicity in a granzyme B- and perforin-dependent conduit. Decreases in both Th1 cytokines and cytotoxic enzymes are relevant for regulatory T cell-mediated restraint of tumor clearance in vivo. Of clinical significance, the expression of regulatory T cells in TILs may mediate T cell immune repression within cancer milieu and thus greatly correlate with cancer progression.