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1.
Breast ; 50: 64-70, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32062536

RESUMO

BACKGROUND: STEPAUT, an Austrian non-interventional study, evaluated the safety and efficacy of everolimus plus exemestane in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) recurring/progressing on/after nonsteroidal aromatase inhibitors (NSAIs) in routine clinical practice. METHODS: Postmenopausal women with HR+, HER2- ABC progressing on/after NSAIs receiving everolimus plus exemestane in accordance with routine practice and the current version of Summary of Product Characteristics were eligible. Planned individual observation period corresponded to the duration of treatment until formal study end. RESULTS: Overall, 236 patients (median age: 65 years) were enrolled at 17 sites across Austria. The median progression-free survival (mPFS) in the overall population was 9.5 months (95% confidence interval [CI]: 8.6-10.7 months). The mPFS (95% CI) in patients who received everolimus 10 and 5 mg was 9.9 months (7.3-11.5 months) and 8 months (4.7-10.7 months), respectively. The median time to progression was numerically longer in patients who had a therapy break (11.9 months, 95% CI: 10.0-14.6 months) versus those who did not have any therapy break (10.7 months, 95% CI: 8.9-12.6 months). Patients experienced grade 1 (53.7%), grade 2 (35.9%), grade 3 (9.9%), grade 4 (0.2%) adverse events (AEs). The most common AEs of any grade were stomatitis, mucositis (53.8%), rash, exanthema (29.7%), loss of appetite, nausea (28.4%). CONCLUSIONS: Real-world safety and efficacy data from STEPAUT were consistent with results from BOLERO-2, supporting everolimus plus exemestane as a suitable treatment option for HR+, HER2- ABC recurring/progressing on/after NSAIs.


Assuntos
Androstadienos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Inibidores da Aromatase/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Everolimo/uso terapêutico , Padrões de Prática Médica , Idoso , Áustria/epidemiologia , Feminino , Humanos , Pós-Menopausa , Intervalo Livre de Progressão , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo
2.
J Allergy Clin Immunol ; 143(1): 335-345.e12, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30009843

RESUMO

BACKGROUND: Donor-specific antibodies of the IgG isotype are measured routinely for diagnostic purposes in renal transplant recipients and are associated with antibody-mediated rejection and long-term graft loss. OBJECTIVE: This study aimed to investigate whether MHC-specific antibodies of the IgE isotype are induced during allograft rejection. METHODS: Anti-MHC/HLA IgE levels were measured in sera of mice grafted with skin or heart transplants from various donor strains and in sera of kidney transplant patients with high levels of HLA IgG. Mediator release was triggered in vitro by stimulating basophils that were coated with murine or human IgE-positive serum, respectively, with specific recombinant MHC/HLA antigens. Kidney tissue samples obtained from organ donors were analyzed by using flow cytometry for cells expressing the high-affinity receptor for IgE (FcεRI). RESULTS: Donor MHC class I- and MHC class II-specific IgE was found on acute rejection of skin and heart grafts in several murine strain combinations, as well as during chronic antibody-mediated heart graft rejection. Anti-HLA IgE, including donor HLA class I and II specificities, was identified in a group of sensitized transplant recipients. Murine and human anti-MHC/HLA IgE triggered mediator release in coated basophils on stimulation with specific MHC/HLA antigens. HLA-specific IgE was not linked to atopy, and allergen-specific IgE present in allergic patients did not cross-react with HLA antigens. FcεRI+ cells were found in the human renal cortex and medulla and provide targets for HLA-specific IgE. CONCLUSION: These results demonstrate that MHC/HLA-specific IgE develops during an alloresponse and is functional in mediating effector mechanisms.


Assuntos
Rejeição de Enxerto/imunologia , Transplante de Coração , Antígenos de Histocompatibilidade Classe II/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Imunoglobulina E/imunologia , Transplante de Rim , Transplante de Pele , Aloenxertos , Animais , Feminino , Rejeição de Enxerto/patologia , Humanos , Imunoglobulina G/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C
3.
Am J Transplant ; 19(2): 591-596, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30346652

RESUMO

Resistance to parental bone marrow (BM) grafts in F1 hybrid recipients is due to natural killer (NK) cell-mediated rejection triggered through "missing self" recognition. "Hybrid resistance" has usually been investigated in lethally irradiated F1 recipients in conjunction with pharmacological activation of NK cells. Here, we investigated BM-directed NK-cell alloreactivity in settings of reduced conditioning. Nonlethally irradiated (1-3 Gy) or nonirradiated F1 (C57BL6 × BALB/c) recipient mice received titrated doses (5-20 x 106 ) of unseparated parental BALB/c BM without pharmacological NK cell activation. BM successfully engrafted in all mice and multilineage donor chimerism persisted long-term (24 weeks), even in the absence of irradiation. Chimerism was associated with the rearrangement of the NK-cell receptor repertoire suggestive of reduced reactivity to BALB/c. Chimerism levels were lower after transplantation with parental BALB/c than with syngeneic F1 BM, indicating partial NK-mediated rejection of parental BM. Activation of NK cells with polyinosinic-polycytidylic acid sodium salt poly(I:C), reduced parental chimerism in nonirradiated BM recipients but did not prevent hematopoietic stem cell engraftment. In contrast, equal numbers of parental lymph node cells were completely rejected. Hence, hybrid resistance leads to incomplete rejection of parental BM under reduced conditioning settings.


Assuntos
Transplante de Medula Óssea/métodos , Medula Óssea/imunologia , Rejeição de Enxerto/imunologia , Tolerância Imunológica/imunologia , Células Matadoras Naturais/imunologia , Quimeras de Transplante/imunologia , Animais , Medula Óssea/efeitos da radiação , Feminino , Células Matadoras Naturais/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL
4.
J Heart Lung Transplant ; 37(9): 1119-1130, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29699851

RESUMO

BACKGROUND: The mixed chimerism approach for intentional induction of donor-specific tolerance was shown to be successful in various models from mice to humans. For transplant patients, the approach would obviate the need for long-term immunosuppression and associated side effects; moreover, it would preclude the risk of late graft loss due to chronic rejection. Widespread clinical application is hindered by toxicities related to recipient pre-conditioning. Herein we aimed to investigate a clinically relevant protocol for tolerance induction to cardiac allografts, sparing CD40 blockade or T-cell depletion. METHODS: B6 mice were conditioned with non-myeloablative total body irradiation, fully mismatched BALB/c bone marrow cells, and short-term therapy, based on either anti- lymphocyte function-associated antigen-1 (anti-LFA-1) or anti-CD40L. Multilineage chimerism was followed by flow-cytometric analysis, tolerance was assessed with skin and heart allografts from fully or major histocompatibility complex-mismatched donors. Mechanisms of tolerance were investigated by analysis of donor-specific antibodies (DSAs), mixed lymphocyte reaction (MLR) assays, and deletion of donor-reactive T cells. RESULTS: We found that the combination of cytotoxic T-lymphocyte antigen 4 immunoglobulin (CTLA4Ig) and rapamycin with LFA-1 blockade enhanced bone marrow engraftment and led to more efficient T-cell engraftment and subsequent tolerization. Although fully mismatched skin grafts were chronically rejected, primarily vascularized heart allografts survived indefinitely and without signs of chronic rejection, independent of minor antigen mismatches. CONCLUSIONS: We have demonstarted a robust protocol for the induction of tolerance for cardiac allografts in the absence of CD40 blockade. Our findings demonstrate the potential of a clinically relevant minimal conditioning protocol designed to induce lifelong immunologic tolerance toward cardiac allografts.


Assuntos
Rejeição de Enxerto/fisiopatologia , Sobrevivência de Enxerto/fisiologia , Antígeno-1 Associado à Função Linfocitária/fisiologia , Linfócitos T/fisiologia , Quimeras de Transplante/fisiologia , Animais , Antígenos CD40/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos
5.
Surgery ; 161(3): 735-746, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27776794

RESUMO

BACKGROUND: Interleukin-15 has become a promising molecule in the context of eliciting an effective, antitumor immune response because it is able to stimulate cells of the innate and adaptive immune system. METHODS: We generated an interleukin-15-expressing oncolytic influenza A virus for the treatment of an established murine tumor model. RESULTS: Our oncolytic influenza A virus produced large amounts of interleukin-15 and induced proliferation and activation of human T cells in vitro. Intraperitoneal administration increased the amount of mouse natural killer cells and effector memory T cells, as well as T cell reactivity in vivo. Moreover, intratumoral injection induced a profound decrease in growth of established tumors in mice and increased the amount of tumor-infiltrating T cells and natural killer cells. CONCLUSION: We established a stable, IL-15-producing oncolytic influenza A virus with promising immunostimulatory and antitumor attributes.


Assuntos
Vírus da Influenza A , Interleucina-15/fisiologia , Melanoma Experimental/patologia , Terapia Viral Oncolítica , Vírus Oncolíticos , Neoplasias Cutâneas/patologia , Animais , Técnicas de Cultura de Células , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Células Matadoras Naturais/efeitos dos fármacos , Melanoma Experimental/terapia , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias Cutâneas/terapia , Linfócitos T/efeitos dos fármacos
6.
JCI Insight ; 1(7): e85911, 2016 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-27699263

RESUMO

Central clonal deletion has been considered the critical factor responsible for the robust state of tolerance achieved by chimerism-based experimental protocols, but split-tolerance models and the clinical experience are calling this assumption into question. Although clone-size reduction through deletion has been shown to be universally required for achieving allotolerance, it remains undetermined whether it is sufficient by itself. Therapeutic Treg treatment induces chimerism and tolerance in a stringent murine BM transplantation model devoid of myelosuppressive recipient treatment. In contrast to irradiation chimeras, chronic rejection (CR) of skin and heart allografts in Treg chimeras was permanently prevented, even in the absence of complete clonal deletion of donor MHC-reactive T cells. We show that minor histocompatibility antigen mismatches account for CR in irradiation chimeras without global T cell depletion. Furthermore, we show that Treg therapy-induced tolerance prevents CR in a linked suppression-like fashion, which is maintained by active regulatory mechanisms involving recruitment of thymus-derived Tregs to the graft. These data suggest that highly efficient intrathymic and peripheral deletion of donor-reactive T cells for specificities expressed on hematopoietic cells preclude the expansion of donor-specific Tregs and, hence, do not allow for spreading of tolerance to minor specificities that are not expressed by donor BM.


Assuntos
Transplante de Medula Óssea , Deleção Clonal , Tolerância Imunológica , Antígenos de Histocompatibilidade Menor/imunologia , Linfócitos T Reguladores/citologia , Animais , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL
7.
EBioMedicine ; 7: 230-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27322476

RESUMO

BACKGROUND: Therapeutic strategies for the prophylaxis of IgE-mediated allergy remain an unmet medical need. Cell therapy is an emerging approach with high potential for preventing and treating immunological diseases. We aimed to develop a cell-based therapy inducing permanent allergen-specific immunological tolerance for preventing IgE-mediated allergy. METHODS: Wild-type mice were treated with allergen-expressing bone marrow cells under a short course of tolerogenic immunosuppression (mTOR inhibition and costimulation blockade). Bone marrow was retrieved from a novel transgenic mouse ubiquitously expressing the major grass pollen allergen Phl p 5 as a membrane-anchored protein (BALB/c-Tg[Phlp5-GFP], here mPhl p 5). After transplantation recipients were IgE-sensitized at multiple time points with Phl p 5 and control allergen. RESULTS: Mice treated with mPhl p 5 bone marrow did not develop Phl p 5-specific IgE (or other isotypes) despite repeated administration of the allergen, while mounting and maintaining a strong humoral response towards the control allergen. Notably, Phl p 5-specific T cell responses and allergic airway inflammation were also completely prevented. Interestingly allergen-specific B cell tolerance was maintained independent of Treg functions indicating deletional tolerance as underlying mechanism. CONCLUSION: This proof-of-concept study demonstrates that allergen-specific immunological tolerance preventing occurrence of allergy can be established through a cell-based therapy employing allergen-expressing leukocytes.


Assuntos
Alérgenos/imunologia , Transplante de Medula Óssea/métodos , Hipersensibilidade/prevenção & controle , Imunoglobulina E/metabolismo , Alérgenos/genética , Animais , Modelos Animais de Doenças , Humanos , Hipersensibilidade/imunologia , Tolerância Imunológica , Camundongos , Camundongos Transgênicos , Pólen/imunologia , Profilaxia Pré-Exposição/métodos
8.
PLoS One ; 11(1): e0146245, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26731275

RESUMO

Cell therapy with recipient Tregs achieves engraftment of allogeneic bone marrow (BM) without the need for cytoreductive conditioning (i.e., without irradiation or cytotoxic drugs). Thereby mixed chimerism and transplantation tolerance are established in recipients conditioned solely with costimulation blockade and rapamycin. However, clinical translation would be substantially facilitated if Treg-stimulating pharmaceutical agents could be used instead of individualized cell therapy. Recently, it was shown that interleukin-2 (IL-2) complexed with a monoclonal antibody (mAb) (clone JES6-1A12) against IL-2 (IL-2 complexes) potently expands and activates Tregs in vivo. Therefore, we investigated whether IL-2 complexes can replace Treg therapy in a costimulation blockade-based and irradiation-free BM transplantation (BMT) model. Unexpectedly, the administration of IL-2 complexes at the time of BMT (instead of Tregs) failed to induce BM engraftment in non-irradiated recipients (0/6 with IL-2 complexes vs. 3/4 with Tregs, p<0.05). Adding IL-2 complexes to an otherwise effective regimen involving recipient irradiation (1Gy) but no Treg transfer indeed actively triggered donor BM rejection at higher doses (0/8 with IL-2 complexes vs. 9/11 without, p<0.01) and had no detectable effect at two lower doses (3/5 vs. 9/11, p>0.05). CD8 T cells and NK cells of IL-2 complex-treated naïve mice showed an enhanced proliferative response towards donor antigens in vitro despite the marked expansion of Tregs. However, IL-2 complexes also expanded conventional CD4 T cells, CD8 T cells, NK cells, NKT cells and notably even B cells, albeit to a lesser extent. Notably, IL-2 complex expanded Tregs featured less potent suppressive functions than in vitro activated Tregs in terms of T cell suppression in vitro and BM engraftment in vivo. In conclusion, these data suggest that IL-2 complexes are less effective than recipient Tregs in promoting BM engraftment and in contrast actually trigger BM rejection, as their effect is not sufficiently restricted to Tregs but rather extends to several other lymphocyte populations.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Transplante de Medula Óssea/métodos , Interleucina-2/uso terapêutico , Linfócitos T Reguladores/imunologia , Transferência Adotiva , Animais , Anticorpos Monoclonais/farmacologia , Medula Óssea/efeitos dos fármacos , Medula Óssea/imunologia , Feminino , Interleucina-2/farmacologia , Camundongos , Linfócitos T Reguladores/efeitos dos fármacos , Tolerância ao Transplante/imunologia
9.
J Immunol Res ; 2015: 562935, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26273682

RESUMO

Induction of donor-specific tolerance is still considered as the "Holy Grail" in transplantation medicine. The mixed chimerism approach is virtually the only tolerance approach that was successfully translated into the clinical setting. We have previously reported successful induction of chimerism and tolerance using cell therapy with recipient T regulatory cells (Tregs) to avoid cytotoxic recipient treatment. Treg therapy is limited by the availability of cells as large-scale expansion is time-consuming and associated with the risk of contamination with effector cells. Using a costimulation-blockade based bone marrow (BM) transplantation (BMT) model with Treg therapy instead of cytoreductive recipient treatment we aimed to determine the most potent Treg population for clinical translation. Here we show that CD4(+)CD25(+) in vitro activated nTregs are superior to TGFß induced iTregs in promoting the induction of chimerism and tolerance. Therapy with nTregs (but not iTregs) led to multilineage chimerism and donor-specific tolerance in mice receiving as few as 0.5 × 10(6) cells. Moreover, we show that only recipient Tregs, but not donor or third-party Tregs, had a beneficial effect on BM engraftment at the tested doses. Thus, recipient-type nTregs significantly improve chimerism and tolerance and might be the most potent Treg population for translation into the clinical setting.


Assuntos
Linfócitos T Reguladores/imunologia , Doadores de Tecidos , Transplantados , Tolerância ao Transplante/imunologia , Animais , Transplante de Medula Óssea , Feminino , Sobrevivência de Enxerto/imunologia , Isoanticorpos/imunologia , Camundongos , Transplante de Pele , Quimeras de Transplante
10.
Eur J Immunol ; 45(9): 2470-9, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26200095

RESUMO

Establishing donor-specific immunological tolerance could improve long-term outcome by obviating the need for immunosuppressive drug therapy, which is currently required to control alloreactivity after organ transplantation. Mixed chimerism is defined as the engraftment of donor hematopoietic stem cells in the recipient, leading to viable coexistence of both donor and recipient leukocytes. In numerous experimental models, cotransplantation of donor bone marrow (BM) into preconditioned (e.g., through irradiation or cytotoxic drugs) recipients leads to transplantation tolerance through (mixed) chimerism. Mixed chimerism offers immunological advantages for clinical translation; pilot trials have established proof of concept by deliberately inducing tolerance in humans. Widespread clinical application is prevented, however, by the harsh preconditioning currently necessary for permitting BM engraftment. Recently, the immunological mechanisms inducing and maintaining tolerance in experimental mixed chimerism have been defined, revealing a more prominent role for regulation than historically assumed. The evidence from murine models suggests that both deletional and regulatory mechanisms are critical in promoting complete tolerance, encompassing also the minor histocompatibility antigens. Here, we review the current understanding of tolerance through mixed chimerism and provide an outlook on how to realize widespread clinical translation based on mechanistic insights gained from chimerism protocols, including cell therapy with polyclonal regulatory T cells.


Assuntos
Transplante de Medula Óssea , Quimerismo , Linfócitos T Reguladores/imunologia , Quimeras de Transplante/imunologia , Tolerância ao Transplante , Animais , Anticorpos Monoclonais/uso terapêutico , Ensaios Clínicos como Assunto , Raios gama/uso terapêutico , Regulação da Expressão Gênica , Humanos , Imunossupressores/uso terapêutico , Camundongos , Antígenos de Histocompatibilidade Menor/genética , Antígenos de Histocompatibilidade Menor/imunologia , Linfócitos T Reguladores/citologia , Quimeras de Transplante/genética , Condicionamento Pré-Transplante/métodos
11.
Circulation ; 132(2): 122-31, 2015 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-25957225

RESUMO

BACKGROUND: Organ transplantation has seen an increased use of organs from older donors over the past decades in an attempt to meet the globally growing shortage of donor organs. However, inferior transplantation outcomes when older donor organs are used represent a growing challenge. METHODS AND RESULTS: Here, we characterize the impact of donor age on solid-organ transplantation using a murine cardiac transplantation model. We found a compromised graft survival when older hearts were used. Shorter graft survival of older hearts was independent of organ age per se, because chimeric young or old organs repopulated with young passenger leukocytes showed comparable survival times. Transplantation of older organs triggered more potent alloimmune responses via intragraft CD11c+ dendritic cells augmenting CD4+ and CD8+ T-cell proliferation and proinflammatory cytokine production, particularly that of interleukin-17A. Of note, depletion of donor CD11c+ dendritic cells before engraftment, neutralization of interleukin-17A, or transplantation of older hearts into IL-17A(-/-) mice delayed rejection and reduced alloimmune responses to levels observed when young hearts were transplanted. CONCLUSIONS: These results demonstrate a critical role of old donor CD11c+ dendritic cells in mounting age-dependent alloimmune responses with an augmented interleukin-17A response in recipient animals. Targeting interleukin-17A may serve as a novel therapeutic approach when older organs are transplanted.


Assuntos
Envelhecimento/imunologia , Antígeno CD11c/imunologia , Células Dendríticas/imunologia , Rejeição de Enxerto/imunologia , Transplante de Coração/efeitos adversos , Interleucina-17/imunologia , Envelhecimento/patologia , Animais , Células Dendríticas/patologia , Rejeição de Enxerto/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , Transplante Homólogo/efeitos adversos
12.
J Heart Lung Transplant ; 33(4): 429-37, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24468120

RESUMO

BACKGROUND: The mixed chimerism approach induces donor-specific tolerance in both pre-clinical models and clinical pilot trials. However, chronic rejection of heart allografts and acute rejection of skin allografts were observed in some chimeric animals despite persistent hematopoietic chimerism and tolerance toward donor antigens in vitro. We tested whether additional cell therapy with regulatory T cells (Tregs) is able to induce full immunologic tolerance and prevent chronic rejection. METHODS: We recently developed a murine "Treg bone marrow (BM) transplantation (BMT) protocol" that is devoid of cytoreductive recipient pre-treatment. The protocol consists of a moderate dose of fully mismatched allogeneic donor BM under costimulation blockade, together with polyclonal recipient Tregs and rapamycin. Control groups received BMT under non-myeloablative irradiation and costimulation blockade without Treg therapy. Multilineage chimerism was followed by flow cytometry, and tolerance was assessed by donor-specific skin and heart allografts. RESULTS: Durable multilineage chimerism and long-term donor skin and heart allograft survival were successfully achieved with both protocols. Notably, histologic examination of heart allografts at the end of follow-up revealed that chronic rejection is prevented only in chimeras induced with the Treg protocol. CONCLUSIONS: In a mouse model of mixed chimerism, additional Treg treatment at the time of BMT prevents chronic rejection of heart allografts. As the Treg-chimerism protocol also obviates the need for cytoreductive recipient treatment it improves both efficacy and safety over previous non-myeloablative mixed chimerism regimens. These results may significantly impact the development of protocols for tolerance induction in cardiac transplantation.


Assuntos
Transplante de Medula Óssea , Transplante de Coração , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/transplante , Quimeras de Transplante/imunologia , Tolerância ao Transplante/imunologia , Aloenxertos , Animais , Doença Crônica , Feminino , Camundongos , Camundongos Endogâmicos , Sirolimo/farmacologia , Transplante de Pele , Imunologia de Transplantes/imunologia
13.
Eur J Immunol ; 43(9): 2451-60, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23765421

RESUMO

The transplantation of allergens (e.g. Phl p 5 or Bet v 1) expressed on BM cells as membrane-anchored full-length proteins leads to permanent tolerance at the T-cell, B-cell, and effector-cell levels. Since the exposure of complete allergens bears the risk of inducing anaphylaxis, we investigated here whether expression of Phl p 5 in the cytoplasm (rather than on the cell surface) is sufficient for tolerance induction. Transplantation of BALB/c BM retrovirally transduced to express Phl p 5 in the cytoplasm led to stable and durable molecular chimerism in syngeneic recipients (∼20% chimerism at 6 months). Chimeras showed allergen-specific T-cell hyporesponsiveness. Further, Phl p 5-specific TH 1-dependent humoral responses were tolerized in several chimeras. Surprisingly, Phl p 5-specific IgE and IgG1 levels were significantly reduced but still detectable in sera of chimeric mice, indicating incomplete B-cell tolerance. No Phl p 5-specific sIgM developed in cytoplasmic chimeras, which is in marked contrast to mice transplanted with BM expressing membrane-anchored Phl p 5. Thus, the expression site of the allergen substantially influences the degree and quality of tolerance achieved with molecular chimerism in IgE-mediated allergy.


Assuntos
Alérgenos/imunologia , Antígenos de Plantas/imunologia , Linfócitos B/imunologia , Células da Medula Óssea/imunologia , Tolerância Imunológica , Proteínas de Plantas/imunologia , Células 3T3 , Alérgenos/biossíntese , Animais , Células da Medula Óssea/virologia , Transplante de Medula Óssea/imunologia , Linhagem Celular , Proliferação de Células , Quimera/imunologia , Feminino , Hipersensibilidade/imunologia , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Linfócitos T/imunologia , Estomatite Vesicular/imunologia , Vírus da Estomatite Vesicular Indiana/imunologia
14.
Transplantation ; 95(12): 1431-8, 2013 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-23694950

RESUMO

BACKGROUND: Allogeneic bone marrow transplantation is under investigation for a range of nonmalignant indications, including tolerance induction through mixed chimerism. This strategy has so far been tested experimentally only in young recipients. Due to immunosenescence, older patients have an increase in memory T cells (TMEM) as well as other alterations to their immune system, which may influence the potential to induce tolerance. We therefore investigated the impact of immunosenescence on chimerism-based tolerance induction. METHODS: Groups of young (2 months) and old (12 months) C57BL/6 recipients received BALB/c bone marrow under nonmyeloablative (3 Gy) and minimal (1 Gy) total body irradiation and treatment with costimulation blockade, T-cell depletion, or rapamycin. Multilineage chimerism, clonal deletion, and lymphocyte subsets were analyzed by flow cytometry. Tolerance was assessed by skin and heart grafts and enzyme-linked immunospot, intracellular cytokine, and mixed lymphocyte reaction assays. RESULTS: Unexpectedly, chimerism and tolerance were established in old recipients with comparable-and in some cases increased-efficacy as in young recipients employing costimulation blockade-based or T-cell depletion-based conditioning with 1 or 3 Gy total body irradiation. TMEM reactivity in (naïve) old mice was augmented in response to polyclonal but not to allogeneic stimulation, providing a mechanistic underpinning for the susceptibility to chimerism induction despite increased TMEM frequencies. Tolerance in old recipients was associated with peripheral and central clonal deletion and a higher frequency of regulatory T cells. CONCLUSION: Advanced age does not impair bone marrow engraftment, thereby widening the clinical potential of experimental protocols inducing transplantation tolerance through mixed chimerism.


Assuntos
Envelhecimento/imunologia , Transplante de Medula Óssea/imunologia , Tolerância ao Transplante/imunologia , Animais , Células da Medula Óssea/citologia , Transplante de Medula Óssea/métodos , Citocinas/metabolismo , Feminino , Citometria de Fluxo , Memória Imunológica , Depleção Linfocítica , Linfócitos/citologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Fenótipo , Linfócitos T/imunologia , Fatores de Tempo , Quimeras de Transplante/imunologia , Tolerância ao Transplante/efeitos dos fármacos
15.
Immunobiology ; 218(9): 1139-46, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23623394

RESUMO

Molecular chimerism is a promising strategy to induce tolerance to disease-causing antigens expressed on genetically modified haematopoietic stem cells. The approach was employed successfully in models of autoimmunity and organ transplantation. Recently, we demonstrated that molecular chimerism induces robust and lasting tolerance towards the major grass pollen allergen Phl p 5. Since allergens are a group of antigens differing widely in their function, origin and structure we further examined the effectiveness of molecular chimerism using the Phl p 5-unrelated major birch pollen allergen Bet v 1, co-expressed with the reporter GFP. Besides, inhibition of CD26 was used to promote engraftment of modified stem cells. Retrovirus VSV-Betv1-GFP was generated to transduce 5-FU-mobilized BALB/c hematopoietic cells to express membrane-bound Bet v 1 (VSV-GFP virus was used as control). Myeloablated BALB/c mice received Betv1-GFP or GFP expressing bone marrow cells, pre-treated with a CD26 inhibitor. Chimerism was followed by flow cytometry. Tolerance was assessed by measuring allergen-specific isotype levels in sera, RBL assays and T-cell proliferation assays. Mice transplanted with transduced BMC developed multi-lineage molecular chimerism which remained stable long-term (>8 months). After repeated immunizations with Bet v 1 and Phl p 5 serum levels of Bet v 1-specific antibodies (IgE, IgG1, IgG2a, IgG3 and IgA) remained undetectable in Betv1-GFP chimeras while high levels of Phl p 5-specific antibodies developed. Likewise, basophil degranulation was induced in response to Phl p 5 but not to Bet v 1 and specific non-responsiveness to Bet v 1 was observed in proliferation assays. These data demonstrate successful tolerization towards Bet v 1 by molecular chimerism. Stable long-term chimerism was achieved under inhibition of CD26. These results provide evidence for the broad applicability of molecular chimerism as tolerance strategy in allergy.


Assuntos
Antígenos de Plantas/imunologia , Basófilos/imunologia , Células da Medula Óssea/metabolismo , Transplante de Medula Óssea , Quimeras de Transplante/imunologia , Tolerância ao Transplante/imunologia , Animais , Antígenos de Plantas/genética , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/imunologia , Degranulação Celular , Células Cultivadas , Dipeptidil Peptidase 4/metabolismo , Fluoruracila/administração & dosagem , Vetores Genéticos , Proteínas de Fluorescência Verde/genética , Humanos , Imunidade Humoral , Camundongos , Camundongos Endogâmicos BALB C , Engenharia de Proteínas , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Retroviridae , Transdução Genética
16.
Transpl Int ; 26(2): 206-18, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23240587

RESUMO

While costimulation blockade-based mixed chimerism protocols work well for inducing tolerance in rodents, translation to preclinical large animal/nonhuman primate models has been less successful. One recognized cause for these difficulties is the high frequency of alloreactive memory T cells (Tmem) found in the (pre)clinical setting as opposed to laboratory mice. In the present study, we therefore developed a murine bone marrow transplantation (BMT) model employing recipients harboring polyclonal donor-reactive Tmem without concomitant humoral sensitization. This model was then used to identify strategies to overcome this additional immune barrier. We found that B6 recipients that were enriched with 3 × 10(7) T cells isolated from B6 mice that had been previously grafted with Balb/c skin, rejected Balb/c BM despite costimulation blockade with anti-CD40L and CTLA4Ig (while recipients not enriched developed chimerism). Adjunctive short-term treatment of sensitized BMT recipients with rapamycin or anti-LFA-1 mAb was demonstrated to be effective in controlling Tmem in this model, leading to long-term mixed chimerism and donor-specific tolerance. Thus, rapamycin and anti-LFA-1 mAb are effective in overcoming the potent barrier that donor-reactive Tmem pose to the induction of mixed chimerism and tolerance despite costimulation blockade.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Células da Medula Óssea/citologia , Rejeição de Enxerto , Antígeno-1 Associado à Função Linfocitária/imunologia , Sirolimo/uso terapêutico , Animais , Anticorpos/metabolismo , Transplante de Medula Óssea , Ligante de CD40/metabolismo , Antígeno CTLA-4/metabolismo , Quimerismo , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Interferon gama/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Transplante de Pele , Linfócitos T/citologia , Tolerância ao Transplante
17.
Transpl Int ; 26(3): 242-53, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23190423

RESUMO

Aging affects all compartments of the immune response and has a major impact on transplant outcome and organ quality. Although clinical trials in the aging transplant population remain rare, our current understanding of immunosenescence provides a basis for an age-adapted immunosuppression and organ allocation with the goal to optimize utilization and to improve outcomes in older recipients. From a more general perspective, understanding the mechanisms and consequences of immunosenescence will have a broad impact on immune therapies in and beyond transplantation.


Assuntos
Envelhecimento/imunologia , Imunidade Inata/fisiologia , Transplante de Órgãos/métodos , Imunologia de Transplantes/imunologia , Fatores Etários , Idoso , Envelhecimento/fisiologia , Rejeição de Enxerto , Sobrevivência de Enxerto , Humanos , Tolerância Imunológica , Transplante de Rim/efeitos adversos , Transplante de Rim/imunologia , Transplante de Rim/métodos , Transplante de Fígado/efeitos adversos , Transplante de Fígado/imunologia , Transplante de Fígado/métodos , Doadores Vivos , Pessoa de Meia-Idade , Transplante de Órgãos/efeitos adversos , Prognóstico , Medição de Risco , Doadores de Tecidos , Imunologia de Transplantes/fisiologia
18.
Curr Opin Organ Transplant ; 17(1): 63-70, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22186093

RESUMO

PURPOSE OF REVIEW: Organ transplantation is the state-of-the-art treatment for end-stage organ failure; however, long-term graft survival is still unsatisfactory. Despite improved immunosuppressive drug therapy, patients are faced with substantial side effects and the risk of chronic rejection with subsequent graft loss. The transplantation of donor bone marrow for the induction of mixed chimerism has been recognized to induce donor-specific tolerance a long time ago, but safety concerns regarding toxicities of current bone marrow transplantation (BMT) protocols impede widespread application. RECENT FINDINGS: Recent studies in nonhuman primates and kidney transplant patients have demonstrated successful induction of allograft tolerance even though--in contrast to murine models--only transient chimerism was achieved. Progress toward the development of nontoxic murine BMT protocols revealed that Treg therapy is a potent therapeutic adjunct eliminating the need for cytotoxic recipient conditioning. Furthermore, new insight into the mechanisms underlying tolerization of CD4 and CD8 T cells in mixed chimeras has been gained and has identified possible difficulties impeding clinical translation. SUMMARY: This review will address the recent advances in murine models as well as findings from the first clinical trials for the induction of tolerance through mixed chimerism. Both the potential for more widespread clinical application and the remaining hurdles and challenges of this tolerance approach will be discussed.


Assuntos
Transplante de Medula Óssea , Quimerismo , Doença Enxerto-Hospedeiro/prevenção & controle , Imunoterapia Adotiva , Transplante de Órgãos , Tolerância ao Transplante/imunologia , Animais , Antígenos CD/imunologia , Transplante de Medula Óssea/métodos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Modelos Animais de Doenças , Doença Enxerto-Hospedeiro/imunologia , Humanos , Imunoterapia Adotiva/métodos , Camundongos , Linfócitos T Reguladores/imunologia
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