transforming-growth-factor-beta and Lymphopenia

Lymphopenia is strongly associated with autoimmune diseases. The molecular mechanisms that link both phenomena are still unclear, but certain key pathways have been described. Central tolerance is as important as peripheral. In the earlier, epithelial and dendritic cells play a crucial role in the selection of clones. In the latter, regulatory T cells (Tregs) rise as inductors of anergy in order to prevent the development of autoimmune pathology. In lymphopenic conditions, T cells develop the process of lymphopenia-induced proliferation (LIP). A complex interaction between the major histocompatibility complex (MHC) and the T cell receptor (TCR) makes this process possible. Furthermore, IL-7 can act synergistically or in an independent manner to promote LIP. A lack of Transforming Growth Factor-β (TGF-β) was recently described as the second hit needed to develop autoimmunity in a lymphopenic microenvironment, given its actions in Tregs and its interaction with CTLA-4. Regarding autoimmune clinical scenarios, lymphopenia is related to both, systemic and organ-specific diseases. Thus, the molecular study of such patients has been limited and needs to be widened to the pathways shown here to be involved in the development of lymphopenia and autoimmunity.

Topics: Animals; Autoimmune Diseases; Autoimmunity; Clonal Selection, Antigen-Mediated; CTLA-4 Antigen; Homeostasis; Humans; Immune Tolerance; Interleukin-7; Lymphopenia; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

We investigated a prognostic impact of radiotherapy-induced lymphopenia (RIL) in breast cancer patients treated with breast-conservative surgery (BCS). We included 531 breast cancer patients who were treated with BCS and adjuvant radiotherapy. None of these received (neo)adjuvant chemotherapy. Pre- and post- absolute lymphocyte counts (ALC) were reviewed before and after radiotherapy. The primary endpoint was to evaluate recurrence-free survival (RFS) according to the pre-to-post ALC ratio. Binary logistic regression model was used to identify risk factors for RIL. Either continuous or categorical (> 2.4) pre-to-post ALC ratio was associated with RFS. In 531 patients receiving whole breast irradiation (WBI) and regional nodal irradiation (RNI), RFS was significantly reduced in the patients with high pre-to-post ALC ration (> 2.4). In multivariable analysis, low pre-to-post post ALC ratio was significantly related to decreased RFS in the multivariable analysis (HR 2.293, 95% CIs 1.110-4.735, P = 0.025). In 452 patients treated with WBI alone, high pre-to-post ALC ratio was still significantly associated with decreased RFS in the multivariable analysis (HR 2.708, 95% CIs 1.016-7.218, P = 0.046). In binary logistic regression analysis, RNI was only significant risk factor for clinically meaningful RIL. Our findings show that a markedly decrease in ALC during radiotherapy has a negative prognostic impact.

Topics: Breast Neoplasms; Female; Humans; Lymphocyte Count; Lymphopenia; Prognosis; Radiation Oncology; Transforming Growth Factor beta

TGF-β is widely held to be critical for the maintenance and function of regulatory T (T(reg)) cells and thus peripheral tolerance. This is highlighted by constitutive ablation of TGF-β receptor (TR) during thymic development in mice, which leads to a lethal autoimmune syndrome. Here we describe that TGF-β-driven peripheral tolerance is not regulated by TGF-β signalling on mature CD4⁺ T cells. Inducible TR2 ablation specifically on CD4⁺ T cells did not result in a lethal autoinflammation. Transfer of these TR2-deficient CD4⁺ T cells to lymphopenic recipients resulted in colitis, but not overt autoimmunity. In contrast, thymic ablation of TR2 in combination with lymphopenia led to lethal multi-organ inflammation. Interestingly, deletion of TR2 on mature CD4⁺ T cells does not result in the collapse of the T(reg) cell population as observed in constitutive models. Instead, a pronounced enlargement of both regulatory and effector memory T cell pools was observed. This expansion is cell-intrinsic and seems to be caused by increased T cell receptor sensitivity independently of common gamma chain-dependent cytokine signals. The expression of Foxp3 and other regulatory T cells markers was not dependent on TGF-β signalling and the TR2-deficient T(reg) cells retained their suppressive function both in vitro and in vivo. In summary, absence of TGF-β signalling on mature CD4⁺ T cells is not responsible for breakdown of peripheral tolerance, but rather controls homeostasis of mature T cells in adult mice.

Topics: Animals; Autoimmunity; Cell Proliferation; Colitis; Gene Deletion; Homeostasis; Inflammation; Integrases; Lymphopenia; Mice; Mice, Inbred C57BL; NIH 3T3 Cells; Receptors, Antigen, T-Cell; Reproducibility of Results; Signal Transduction; T-Lymphocytes, Regulatory; Tamoxifen; Thymus Gland; Transforming Growth Factor beta

T cell-specific deletion of the receptor for transforming growth factor-β (TGF-β) mediated by Cre recombinase expressed early in T cell development leads to early-onset lethal autoimmune disease that cannot be controlled by regulatory T cells. However, when we deleted that receptor through the use of Cre driven by a promoter that is active much later in T cell development, adult mice in which most peripheral CD4(+) or CD8(+) T cells lacked the receptor for TGF-β showed no signs of autoimmunity. Because of their enhanced responses to weak stimulation of the T cell antigen receptor, when transferred into lymphopenic recipients, naive TGF-β-unresponsive T cells underwent much more proliferation and differentiation into effector cells and induced lymphoproliferative disease. We propose that TGF-β signaling controls the self-reactivity of peripheral T cells but that in the absence of TGF-β signals, an added trigger such as lymphopenia is needed to drive overt autoimmune disease.

Topics: Animals; Autoimmunity; Cell Proliferation; Cells, Cultured; Female; Leukocyte Common Antigens; Lymphocyte Activation; Lymphopenia; Lymphoproliferative Disorders; Male; Mice; Receptors, Antigen, T-Cell; Receptors, Transforming Growth Factor beta; Signal Transduction; T-Lymphocytes; Transforming Growth Factor beta

Topics: Animals; Autoimmunity; Cell Proliferation; Female; Lymphopenia; Male; Signal Transduction; T-Lymphocytes; Transforming Growth Factor beta

The pleiotropic cytokine TGF-β has been implicated in the regulation of numerous aspects of the immune response, including naïve T cell homeostasis. Previous studies found that impairing TGF-β responsiveness (through expression of a dominant-negative TGF-β RII [DNRII] transgene) leads to accumulation of memory phenotype CD8 T cells, and it was proposed that this resulted from enhanced IL-15 sensitivity. Here we show naïve DNRII CD8 T cells exhibit enhanced lymphopenia-driven proliferation and generation of "homeostatic" memory cells. However, this enhanced response occurred in the absence of IL-15 and, unexpectedly, even in the combined absence of IL-7 and IL-15, which were thought essential for CD8 T cell homeostatic expansion. DNRII transgenic CD8 T cells still require access to self Class I MHC for homeostatic proliferation, arguing against generalized dysregulation of homeostatic cues. These findings suggest TGF-β responsiveness is critical for enforcing sensitivity to homeostatic cytokines that limit maintenance and composition of the CD8 T cell pool. (154 words).

Topics: Animals; CD8-Positive T-Lymphocytes; Cell Proliferation; Genes, Dominant; Histocompatibility Antigens Class I; Homeostasis; Interleukin-15; Interleukin-7; Lymphocyte Depletion; Lymphopenia; Mice; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Transforming Growth Factor beta

Topics: Animals; Autoimmunity; Cell Proliferation; Female; Lymphopenia; Male; Signal Transduction; T-Lymphocytes; Transforming Growth Factor beta

Topics: Animals; Autoimmunity; Cell Proliferation; Female; Lymphopenia; Male; Signal Transduction; T-Lymphocytes; Transforming Growth Factor beta

Mitogen-activated protein kinases (MAPKs) are key mediators of the T cell receptor (TCR) signals but their roles in T helper (Th) cell differentiation are unclear. Here we showed that the MAPK kinase kinases MEKK2 (encoded by Map3k2) and MEKK3 (encoded by Map3k3) negatively regulated transforming growth factor-β (TGF-β)-mediated Th cell differentiation. Map3k2(-/-)Map3k3(Lck-Cre/-) mice showed an abnormal accumulation of regulatory T (Treg) and Th17 cells in the periphery, consistent with Map3k2(-/-)Map3k3(Lck-Cre/-) naive CD4(+) T cells' differentiation into Treg and Th17 cells with a higher frequency than wild-type (WT) cells after TGF-β stimulation in vitro. In addition, Map3k2(-/-)Map3k3(Lck-Cre/-) mice developed more severe experimental autoimmune encephalomyelitis. Map3k2(-/-)Map3k3(Lck-Cre/-) T cells exhibited impaired phosphorylation of SMAD2 and SMAD3 proteins at their linker regions, which negatively regulated the TGF-β responses in T cells. Thus, the crosstalk between TCR-induced MAPK and the TGF-β signaling pathways is important in regulating Th cell differentiation.

Topics: Animals; Bone Marrow Transplantation; Cell Differentiation; Enzyme Activation; Forkhead Transcription Factors; Lymphocyte Count; Lymphopenia; MAP Kinase Kinase Kinase 2; MAP Kinase Kinase Kinase 3; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Phosphorylation; Protein Processing, Post-Translational; Protein Structure, Tertiary; Receptors, Antigen, T-Cell; Smad2 Protein; Smad3 Protein; Specific Pathogen-Free Organisms; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory; Th17 Cells; Transforming Growth Factor beta

Acute lymphopenia-induced homeostatic proliferation (HP) of T cells promotes antitumor immunity, but the mechanism is unclear. We hypothesized that this is due to a lack of inhibitory signals that allows activation of T cells with low affinity for self-antigens. Tumors resist immunity in part by expressing inhibitory molecules such as PD-1 ligand 1 (PD-L1), B7-H4, and TGF-beta. In irradiated mice undergoing HP, we found that T cells displayed a severe deficit in the activation-induced expression of inhibitory molecules PD-1 and CTLA-4, and TGF-beta1-induced expression of Foxp3. HP T cells were also less suppressed by B7-H4/Ig and, unlike control T cells, failed to produce IL-10 in response to this molecule. This deficiency in regulation was reversed as normal T-cell numbers were restored. We conclude that T cells are weakly regulated by inhibitory molecules during the acute phase of HP, which could explain their increased effectiveness in cancer immunotherapy.

Topics: Animals; Antigens, CD; Antigens, Differentiation; Autoantigens; B7-1 Antigen; Cell Proliferation; CTLA-4 Antigen; Forkhead Transcription Factors; Homeostasis; Lymphopenia; Mice; Programmed Cell Death 1 Receptor; T-Lymphocytes; Transforming Growth Factor beta; V-Set Domain-Containing T-Cell Activation Inhibitor 1

Interleukin-23 (IL-23) is an inflammatory cytokine that plays a key role in the pathogenesis of several autoimmune and inflammatory diseases. It orchestrates innate and T cell-mediated inflammatory pathways and can promote T helper 17 (Th17) cell responses. Utilizing a T cell transfer model, we showed that IL-23-dependent colitis did not require IL-17 secretion by T cells. Furthermore, IL-23-independent intestinal inflammation could develop if immunosuppressive pathways were reduced. The frequency of naive T cell-derived Foxp3+ cells in the colon increased in the absence of IL-23, indicating a role for IL-23 in controlling regulatory T cell induction. Foxp3-deficient T cells induced colitis when transferred into recipients lacking IL-23p19, showing that IL-23 was not essential for intestinal inflammation in the absence of Foxp3. Taken together, our data indicate that overriding immunosuppressive pathways is an important function of IL-23 in the intestine and could influence not only Th17 cell activity but also other types of immune responses.

Topics: Adoptive Transfer; Animals; Colitis; Forkhead Transcription Factors; Immune Tolerance; Inflammation Mediators; Interleukin-10; Interleukin-23; Lymphopenia; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

We previously demonstrated prolonged, profound CD4+ T-lymphopenia in rheumatoid arthritis (RA) patients following lymphocyte-depleting therapy. Poor reconstitution could result either from reduced de novo T-cell production through the thymus or from poor peripheral expansion of residual T-cells. Interleukin-7 (IL-7) is known to stimulate the thymus to produce new T-cells and to allow circulating mature T-cells to expand, thereby playing a critical role in T-cell homeostasis. In the present study we demonstrated reduced levels of circulating IL-7 in a cross-section of RA patients. IL-7 production by bone marrow stromal cell cultures was also compromised in RA. To investigate whether such an IL-7 deficiency could account for the prolonged lymphopenia observed in RA following therapeutic lymphodepletion, we compared RA patients and patients with solid cancers treated with high-dose chemotherapy and autologous progenitor cell rescue. Chemotherapy rendered all patients similarly lymphopenic, but this was sustained in RA patients at 12 months, as compared with the reconstitution that occurred in cancer patients by 3-4 months. Both cohorts produced naive T-cells containing T-cell receptor excision circles. The main distinguishing feature between the groups was a failure to expand peripheral T-cells in RA, particularly memory cells during the first 3 months after treatment. Most importantly, there was no increase in serum IL-7 levels in RA, as compared with a fourfold rise in non-RA control individuals at the time of lymphopenia. Our data therefore suggest that RA patients are relatively IL-7 deficient and that this deficiency is likely to be an important contributing factor to poor early T-cell reconstitution in RA following therapeutic lymphodepletion. Furthermore, in RA patients with stable, well controlled disease, IL-7 levels were positively correlated with the T-cell receptor excision circle content of CD4+ T-cells, demonstrating a direct effect of IL-7 on thymic activity in this cohort.

Topics: Alemtuzumab; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibodies, Neoplasm; Arthritis, Rheumatoid; Autoimmune Diseases; Blood Specimen Collection; Bone Marrow; CD4-Positive T-Lymphocytes; Cells, Cultured; Cohort Studies; Combined Modality Therapy; Cytokines; Gene Rearrangement, T-Lymphocyte; Humans; Interleukin-6; Interleukin-7; Lymphocyte Depletion; Lymphopenia; Lymphopoiesis; Neoplasms; Oncostatin M; Peripheral Blood Stem Cell Transplantation; Stromal Cells; Thymus Gland; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

An ascitic lymphosarcoma (LS-A) of Swiss mice that regressed spontaneously on subcutaneous (s.c.) transplantation was investigated for the mechanism of its progressive growth and host mortality on intraperitoneal (i.p.) transplantation. In vitro studies indicated significant inhibition of LS-A proliferation seeded at higher cell density (>10(4)/ml). Culture supernatants of LS-A caused bi-modal growth effects, the early supernatants (24 h) caused stimulation and the late (72 h) supernatants inhibited LS-A proliferation. The 72-h supernatants also suppressed T and B cell response to mitogens in a dose-dependent manner. Pan anti-transforming growth factor-beta antibody abrogated the inhibitory effects of supernatants. The supernatants contained both latent as well as bio-active form of transforming growth factor-beta1 (TGF-beta1) as determined by ELISA. Mice bearing i.p. ascites tumor had elevated serum TGF-beta1, hemoglobulinemia, splenic lymphopenia, impaired response of the T cells to mitogen and reduced expression of transferrin receptor (CD71) on the bone marrow cells. However, mice which rejected s.c. transplants, did not show significant changes in these parameters. Our studies indicated profound influence of site of tumor growth on tumor progression and host immune system mediated by tumor-derived TGF-beta1. It is possible that human tumors which secrete TGF-beta1 may exhibit similar patho-physiological effects in the host depending on the anatomical site of the tumor.

Topics: Anemia; Animals; Antigens, CD; Antigens, Differentiation, B-Lymphocyte; Ascites; Cell Proliferation; Disease Progression; Hemoglobins; Humans; Injections, Intraperitoneal; Injections, Subcutaneous; Lymphoma, Non-Hodgkin; Lymphopenia; Male; Mice; Mitogens; Receptors, Transferrin; Sarcoma, Experimental; Spleen; T-Lymphocytes; Transforming Growth Factor beta; Transforming Growth Factor beta1; Tumor Cells, Cultured

During thymic T cell development, immature CD4+CD8+ double-positive (DP) thymocytes develop either into CD4+CD8- Th cells or CD4-CD8+ CTLs. Differentially expressed primary factors inducing the fate of these cell types are still poorly described. The transcription factor Runx3/AML-2 Runx, runt [corrected] dominant factor; AML, acute myeloid leukemia is expressed specifically during the development of CD8 single-positive (SP) thymocytes, where it silences CD4 expression. Deletion of murine Runx3 results in a reduction of CD8 SP T cells and concomitant accumulation of CD4+CD8+ T cells, which cannot down-regulate CD4 expression in the thymus and periphery. In this study we have investigated the role of Runx3 during thymocyte development and CD4 silencing and have identified integrin alpha(E)/CD103 on CD8 SP T cells as a new potential target gene of Runx3. We demonstrate that Runx3 is necessary not only to repress CD4, but also to induce CD103 expression during development of CD8 SP T cells. In addition, transgenic overexpression of Runx3 reduced CD4 expression during development of DP thymocytes, leading to a reduced number of CD4 SP thymocytes and an increased number of CD8 SP thymocytes. This reversal is not caused by redirection of specific MHC class II-restricted cells to the CD8 lineage. Overexpression of Runx3 also up-regulated CD103 expression on a subpopulation of CD4 SP T cells with characteristics of regulatory T cells. Thus, Runx3 is a main regulator of CD4 silencing and CD103 induction and thus contributes to the phenotype of CD8 SP T cells during thymocyte development.

Topics: Amino Acid Sequence; Animals; Antigens, CD; CD4 Antigens; CD4-CD8 Ratio; CD4-Positive T-Lymphocytes; CD8 Antigens; CD8-Positive T-Lymphocytes; Cell Differentiation; Cell Line, Tumor; Cell Lineage; Core Binding Factor Alpha 3 Subunit; Crosses, Genetic; DNA-Binding Proteins; Down-Regulation; Gene Silencing; Growth Inhibitors; Histocompatibility Antigens Class II; Integrin alpha Chains; Killer Cells, Natural; Lymphopenia; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Molecular Sequence Data; Thymoma; Thymus Gland; Transcription Factors; Transforming Growth Factor beta

CD4+ CD25+ regulatory T cells (T(Reg)) play a critical role in the control of autoimmunity. However, little is known about how T(Reg) suppress self-reactive T cells in vivo, thus limiting the development of T(Reg)-based therapy for treating autoimmune diseases. This is in large part due to the dependency on a state of lymphopenia to demonstrate T(Reg)-mediated suppression in vivo and the unknown Ag specificity of T(Reg) in most experimental models. Using a nonlymphopenic model of autoimmune pneumonitis and T(Reg) with known Ag specificity, in this study we demonstrated that these T(Reg) can actively suppress activation of self-reactive T cells and protect mice from fatal autoimmune pneumonitis. The protection required T(Reg) with the same Ag specificity as the self-reactive T cells and depended on IL-10 and TGF-beta. These results suggest that suppression of autoimmunity by T(Reg) in vivo consists of multiple layers of regulation and advocate for a strategy involving Ag-specific T(Reg) for treating organ-specific autoimmunity, because they do not cause generalized immune suppression.

Topics: Animals; Autoantigens; Autoimmune Diseases; Disease Models, Animal; Epitopes, T-Lymphocyte; Interleukin-10; Lymphopenia; Mice; Mice, Inbred BALB C; Mice, Transgenic; Pneumonia; Receptors, Antigen, T-Cell; Receptors, Interleukin-2; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

A case of Evans' syndrome with IgM deficiency and lymphopenia was studied before and after splenectomy. The lymphopenia was as a result of profound reduction of CD4 and CD8 cells. Study of cytokine secretion before splenectomy revealed a spontaneous Th1- and Th2-type cytokine production, and complete suppression of transforming growth factor (TGF)-beta. After splenectomy, the patient achieved clinical remission, the natural killer (NK) cell number increased and the pattern of cytokine production showed normalization of interleukin (IL)-2, IL-4, IL-10, TGF-beta and abolition of interferon (IFN)-gamma production. We conclude that splenectomy had a beneficial effect owing to an increase in NK cells and an associated increase in TGF-beta production.

Topics: Anemia, Hemolytic, Autoimmune; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Child; Cytokines; Humans; Immunoglobulin M; Interferon-gamma; Interleukin-10; Interleukin-2; Interleukin-4; Killer Cells, Natural; Lymphocyte Count; Lymphopenia; Male; Purpura, Thrombocytopenic, Idiopathic; Splenectomy; Syndrome; Th1 Cells; Th2 Cells; Transforming Growth Factor beta

TGF-beta 1 null (TGF-beta1-/-) mice die at 3-4 wk of age and show an autoimmune inflammatory phenotype associated with enhanced expression of both class I and II MHC molecules. To determine the role of MHC class I Ags in the autoimmune manifestations and the inflammation observed in TGF-beta 1-/- mice, we generated TGF-beta 1-/- mice in the genetic background of beta 2-microglobulin deficiency (beta 2M-/-). TGF-beta 1-/-;beta 2M-/- mice had improved survival compared with TGF-beta 1-/- mice. Histopathological examination showed less severe inflammation, especially in the heart, where Mac-2 reactive macrophages were significantly decreased as compared with TGF-beta 1-/- mice. In vivo depletion of CD8+ T cells in TGF-beta 1-/- mice confirmed suppression of inflammation and reduction in the severity of the wasting syndrome. MHC class II mRNA expression in TGF-beta 1-/-;beta 2M-/- mice was also lower than that in TGF-beta 1-/- mice, suggesting reduced systemic inflammation. Autoimmune response as judged by serum Ab titers to ssDNA and 16/6 Id and by immune complex deposits in kidney was reduced in TGF-beta 1-/-;beta 2M-/- mice, when compared with that in TGF-beta 1-/- mice. Our data thus indicate that MHC class I molecules influence the development of the autoimmunity and the inflammation seen in TGF-beta 1-/- mice and CD8+ T cells may have a contribution to the inflammation in TGF-beta 1-/- mice.

Topics: Animals; Antigen-Antibody Complex; Autoantibodies; beta 2-Microglobulin; CD8-Positive T-Lymphocytes; Crosses, Genetic; Embryonic and Fetal Development; Flow Cytometry; Genes, Lethal; Genotype; Histocompatibility Antigens Class II; Inflammation; Kidney; Leukopoiesis; Lymphocyte Depletion; Lymphopenia; Mice; Mice, Knockout; Mice, Transgenic; Phenotype; RNA, Messenger; Survival Analysis; Transforming Growth Factor beta