References of "BARON, Frédéric"
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See detailAnti-thymocyte globulin as graft-versus-host disease prevention in the setting of allogeneic peripheral blood stem cell transplantation: a review from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.
Baron, Frédéric ULiege; Mohty, Mohamad; Blaise, Didier et al

in Haematologica (2017)

Allogeneic hematopoietic stem cell transplantation is increasingly used as treatment for patients with life threatening blood diseases. Their curative potential is largely based on immune-mediated graft ... [more ▼]

Allogeneic hematopoietic stem cell transplantation is increasingly used as treatment for patients with life threatening blood diseases. Their curative potential is largely based on immune-mediated graft-versus-leukemia effects caused by donor T cells contained in the graft. Unfortunately, donor T cells are also the cause of graft-versus-host disease. The vast majority of HLA-matched allogeneic hematopoietic stem cell transplantations are nowadays carried out with peripheral blood stem cells (PBSC) as stem cell source. In comparison with bone marrows, PBSC contain more hematopoietic stem/progenitor cells but also one log more T cells. Consequently, the use of PBSC instead of bone marrow has been associated with faster hematological recovery and a lower risk of relapse in patients with advanced disease, but also with a higher incidence of chronic graft-versus-host disease. These observations have been the basis for several studies aimed at assessing the impact of immunoregulation with anti-thymocyte globulin (ATG) on transplantation outcomes in patients given HLA-matched PBSC from related or unrelated donors. After a brief introduction on ATG, this article reviews recent studies assessing the impact ATG on transplantation outcomes in patients given PBSC from HLA-matched related or unrelated donors as well as in recipients of grafts from HLA-haploidentical donors. [less ▲]

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See detailA surprising and dramatic neuroendocrine-immune phenotype of mice deficient in Growth Hormone-Releasing Hormone (GHRH)
Farhat, Khalil; Bodart, Gwennaelle; Martens, Henri ULiege et al

in Neuroimmunomodulation (2017)

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See detailNovel strategies for improving hematopoietic reconstruction after allogeneic hematopoietic stem cell transplantation or intensive chemotherapy.
Baron, Frédéric ULiege; Nagler, Arnon

in Expert Opinion on Biological Therapy (2017)

INTRODUCTION: High-dose conditioning regimens for allogeneic hematopoietic cell transplantation (allo-HCT) as well as intensive poly-chemotherapy for acute myeloid leukemia (AML) induce prolonged periods ... [more ▼]

INTRODUCTION: High-dose conditioning regimens for allogeneic hematopoietic cell transplantation (allo-HCT) as well as intensive poly-chemotherapy for acute myeloid leukemia (AML) induce prolonged periods of neutropenia. The duration of the neutropenia is particularly long following umbilical cord blood transplantation (UCBT). Areas covered: After briefly reviewing the impact of hematopoietic growth factors administration to hasten hematologic reconstitution after allo-HCT or intensive AML chemotherapy, this article summarizes recent approaches that have been investigated to prompt hematologic reconstruction after UCBT or intensive AML chemotherapy. Expert opinion: In the allo-HCT setting, administration of G-CSF or GM-CSF shortened the duration of the neutropenia but failed to decrease infection-related mortality or to improve survival. Novel approaches to hasten hematological reconstruction after UCBT such as double UCBT with expansion of one of the 2 UCB units with Notch ligand, mesenchymal stromal cells, nicotinamide, or StemRegenin 1, co-transplanting a single UCB unit with HLA-haploidentical CD34+ cells, or increasing UCB HSC homing to marrow niches via direct intra bone UCB administration, pulse treatment with dmPGE2 or enforced fucosylation are promising and deserve further investigations in prospective phase III studies. In the AML setting, G-CSF or GM-CSF administration after intensive chemotherapy decreased the duration of the neutropenia without improving survival. [less ▲]

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See detailOutcomes of UCB transplantation are comparable in FLT3+ AML: Results of CIBMTR, eurocord and EBMT collaborative analysis.
Ustun, C.; Giannotti, F.; Zhang, M.-J. et al

in Leukemia : Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K (2017)

Allogeneic hematopoietic cell transplantation (HCT) from siblings or unrelated donors (URD) during complete remission (CR) may improve leukemia-free survival (LFS) in FLT3+ acute myeloid leukemia (AML ... [more ▼]

Allogeneic hematopoietic cell transplantation (HCT) from siblings or unrelated donors (URD) during complete remission (CR) may improve leukemia-free survival (LFS) in FLT3+ acute myeloid leukemia (AML) that has poor prognosis due to high relapse rates. Umbilical cord blood (UCB) HCT outcomes are largely unknown in this population. We found that compared with sibling HCT, relapse risks were similar after UCB (n=126), (HR 0.86, P=0.54) and URD (n=91) (HR 0.81, P=0.43). UCB HCT was associated with statistically higher non-relapse mortality compared with sibling HCT (HR 2.32, P=0.02), but not vs URD (HR 1.72, P=0.07). All three cohorts had statistically not significant 3-year LFS: 39% (95% CI 30-47) after UCB, 43% (95% CI 30-54) after sibling, and 50% (95% CI 40-60) after URD. Chronic GVHD rates were significantly lower after UCB compared with either sibling (HR 0.59, P=0.03) or URD (HR 0.49, P=0.001). Adverse factors for LFS included high leukocyte count at diagnosis and HCT during CR2. UCB is a suitable option for adults with FLT3+AML in the absence of an HLA-matched sibling and its immediate availability may be particularly important for FLT3+ AML where early relapse is common thus allowing HCT in CR1 when outcomes are best.Leukemia accepted article preview online, 25 January 2017. doi:10.1038/leu.2017.42. [less ▲]

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See detailLimited Impact of Imatinib in a Murine Model of Sclerodermatous Chronic Graft-versus-Host Disease
Belle, Ludovic ULiege; Fransolet, Gilles ULiege; Somja, Joan ULiege et al

in PLoS ONE (2016), 11

Background Sclerodermatous chronic Graft-versus-Host Disease (scl-cGVHD) is one of the most severe form of cGVHD. The Platelet-derived Grotwth Factor (PDGF) and the Transforming Growth Factor-β (TGF-β ... [more ▼]

Background Sclerodermatous chronic Graft-versus-Host Disease (scl-cGVHD) is one of the most severe form of cGVHD. The Platelet-derived Grotwth Factor (PDGF) and the Transforming Growth Factor-β (TGF-β) play a significant role in the fibrosing process occurring in scl-cGVHD. This prompted us to assess the impact of the PDGF-r and c-Abl tyrosine kinase inhibitor imatinib on scl-cGVHD. Methods To assess the impact of imatinib on T cell subset proliferation in vivo, Balb/cJ recipient mice were lethally (7 Gy) irradiated and then injected with 10x106 bone marrow cells from B10.D2 mice on day 0. Fourteen days later, 70x106 carboxyfluorescein succinimidyl ester (CFSE)-labeled splenocytes from B10.D2 mice were infused and imatinib or sterile water was administered for 5 days. To induce severe scl-cGVHD, Balb/cJ mice were injected i.v. with 10.106 bone marrow cells and 70.106 splenocytes from B10.D2 donor mice after 7 Gy irradiation. Mice were then given sterile water or imatinib from day +7 after transplantation to the end of the experiment (day +52). Results Imatinib decreased the proliferation of total T cells (P = 0.02), CD8+ T cells (P = 0.01), and of regulatory T cells (Tregs) (P = 0.02) in the spleen. In the severe scl-cGVHD model, imatinib-treated mice had significantly lower levels of PDGF-r phosphorylation than control mice on day 29 after transplantation (P = 0.008). However, scl-cGVHD scores were similar between vehicle- and imatinib-treated mice during the whole experiment, while there was a suggestion for less weight loss in imatinib-treated mice that reached statistical significance at day +52 following transplantation (P = 0.02). [less ▲]

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See detailXenogeneic graft-versus-host disease: Impact of Th17 cells.
Delens, Loïc ULiege; SERVAIS, Sophie ULiege; Vrancken, Louise et al

Poster (2016, December 08)

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See detailLimited impact of imatinib in a murine model of sclerodermatous chronic graft-versus-host disease (scl-cGVHD)
Fransolet, Gilles ULiege; Belle, Ludovic; SOMJA, Joan ULiege et al

Conference (2016, December 08)

- Introduction: Graft-versus-host disease (GVHD) remains one of the major complications following haematopoietic stem cell transplantation (HSCT). Approximately 15% of the patients with chronic GVHD ... [more ▼]

- Introduction: Graft-versus-host disease (GVHD) remains one of the major complications following haematopoietic stem cell transplantation (HSCT). Approximately 15% of the patients with chronic GVHD develop the sclerodermatous form of the disease characterized by multiple organ fibrosis and loss of skin elasticity. Several studies have shown the potential benefits of imatinib, a tyrosine kinase inhibitor (TKI), as a treatment of fibrosis in cGVHD due to its ability to inhibit simultaneously PDGF-R and c-Abl pathways which are both involved in fibrosis mechanisms. - Aims: Some early-phase clinical studies have assessed the impact of TKIs in patients with steroid-refractory cGVHD. Unfortunately, these studies yielded to conflicting results underlying the importance of re-assessing the impact of imatinib in scl-cGVHD pre-clinical models. This work investigates the possible benefits of imatinib on fibrosis in a murine model of sclerodermatous chronic GVHD (scl-cGVHD). - Methods and results: Lethally irradiated Balb/cJ mice (7 Gy TBI) were injected i.v. with 1.106 or 10.106 bone marrow cells and 2.106 or 70.106 splenocytes from B10.D2 donnor mice (Moderate and Classical scl-cGVHD models respectively). Mice were then treated with sterile water or imatinib (150 mg/kg/day) by oral gavage from day +7 to day +52 following transplantation. cGVHD severity was assessed three times/week with a scoring system encompassing 5 criteria (mice posture, weight loss, activity, hair loss, skin integrity ; 0-1-2 point(s)/criteria). Skin biopsies were performed on day +29 following transplantation to assess phosphorylation of c-Abl (TGF-β pathway) and PDGF receptor. Our results show that imatinib failed to prevent/improve GVHD with a similar evolution of the GVHD severity with no differences between groups (neither in moderate cGVHD model, nor in the classical cGVHD model). Mice weight loss during the experiments was also comparable between groups in both models of cGVHD. In the classical model, histological analyses indicate a significant reduction of the phosphorylation level of the PDGR receptor (p = 0.0079). In vivo cell proliferation assay with CFSE were also performed and showed a reduced proliferation of T cells and subsets (CD4, CD8 and Tregs) in spleen, lymph nodes, bone marrow and blood after imatinib treatment. Finally, FACS analyses performed on days +21 and +35 after transplantation did not show any differences in the absolute T-cell counts. - Conclusions: Although we have observed a decreased phosphorylation level of PDGR receptor and less proliferation of T cells and subsets in vivo, imatinib failed to alleviate scl-cGVHD both in moderate and classical murine models of scl-cGVHD. [less ▲]

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See detailImpact des cellules Th17 sur la GVH xénogénique
Delens, Loïc ULiege; SERVAIS, Sophie ULiege; Ehx, Grégory ULiege et al

Conference (2016, November 18)

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See detailAzacytidine prevents experimental xenogeneic graft-versus-host disease without abrogating graft-versus-leukemia effects
Ehx, Grégory ULiege; Fransolet, Gilles ULiege; de Leval, Laurence ULiege et al

Conference (2016, November 18)

The demethylating agent 5-azacytidine (AZA) has proven its efficacy as treatment for myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate FOXP3 intron 1 (FOXP3i1) leading ... [more ▼]

The demethylating agent 5-azacytidine (AZA) has proven its efficacy as treatment for myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate FOXP3 intron 1 (FOXP3i1) leading to the generation of regulatory T cells (Treg). Here, we investigated the impact of AZA on xenogeneic graft-versus-host disease (xGVHD) and graft-versus-leukemia effects in a humanized murine model of transplantation (human PBMCs-infused NSG mice), and described the impact of the drug on human T cells in vivo. We observed that AZA improved both survival and xGVHD scores. Further, AZA significantly decreased human T-cell proliferation as well as IFN-γ and TNF-α serum levels, and reduced the expression of GRANZYME B and PERFORIN 1 by cytotoxic T cells. In addition, AZA significantly increased Treg frequency through hypomethylation of FOXP3i1 as well as increased Treg proliferation. The later was subsequent to higher STAT5 signaling in Treg from AZA-treated mice, which resulted from higher IL-2 secretion by conventional T cells from AZA-treated mice itself secondary to demethylation of the IL-2 gene promoter by AZA. Importantly, Tregs harvested from AZA-treated mice were suppressive and stable over time since they persisted at high frequency in secondary transplant experiments. Finally, graft-versus-leukemia effects (assessed by growth inhibition of THP-1 cells, transfected to express the luciferase gene) were not abrogated by AZA. In summary, our data demonstrate that AZA prevents xGVHD without abrogating graft-versus-leukemia effects. These findings could serve of basis for further studies of GVHD prevention by AZA in acute myeloid leukemia patients offered an allogeneic transplantation. [less ▲]

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See detailLimited impact of imatinib in a murine model of sclerodermic chronic graft-versus-host disease
Belle, Ludovic; Fransolet, Gilles ULiege; SOMJA, Joan ULiege et al

Poster (2016, November 17)

Background: Graft-versus-host disease (GVHD) remains one of the major complications following haematopoietic stem cell transplantation (HSCT). Approximately 15% of the patients with chronic GVHD develop ... [more ▼]

Background: Graft-versus-host disease (GVHD) remains one of the major complications following haematopoietic stem cell transplantation (HSCT). Approximately 15% of the patients with chronic GVHD develop the sclerodermatous form of the disease characterized by multiple organ fibrosis and loss of skin elasticity. Several studies have shown the potential benefits of imatinib, a tyrosine kinase inhibitor, as a treatment of fibrosis in cGVHD due to its ability to inhibit simultaneously PDGF-R and c-Abl pathways which are both involved in fibrosis mechanisms. This work investigates the possible benefits of imatinib on fibrosis in a murine model of sclerodermatous chronic GVHD (sclcGVHD). Methods: Lethally irradiated Balb/cJ mice (7 Gy TBI) were injected i.v. with 10.106 bone marrow cells and 70.106 splenocytes from B10.D2 donnor mice. Mice were then treated with sterile water or imatinib (150 mg/kg/day) by oral gavage from day +7 to day +52 following transplantation. GVHD severity was assessed three times/week with a scoring system encompassing 5 criteria (mice posture, weight loss, activity, hair loss, skin integrity ; 0-1-2 point(s)/criteria). Results: Our results show that imatinib failed to prevent/improve GVHD with a similar evolution of the GVHD severity with no differences between groups. Histological analyses indicate a significant reduction of the phosphorylation level of the PDGR receptor (p = 0,033) and a trend to a decreased level of phosphorylated c-Abl (p = 0,1854). In vivo cell proliferation assay with CFSE were also performed and showed a reduced proliferation of T cells and subsets (CD4, CD8 and Tregs) in spleen, lymph nodes, bone marrow and blood after imatinib treatment. Finally, FACS analyses performed on days +21 and +35 after transplantation did not show any differences in the absolute T-cell counts. Conclusion: Although we have observed a decreased phosphorylation level of PDGR receptor and less proliferation of T cells and subsets in vivo, imatinib failed to alleviate scl-cGVHD in a murine model of severe scl-cGVHD. [less ▲]

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See detailAzacytidine prevents experimental xenogeneic graft-versus-host disease without abrogating graft-versus-leukemia effects
Ehx, Grégory ULiege; Fransolet, Gilles ULiege; de Leval, Laurence ULiege et al

Poster (2016, October 14)

The demethylating agent 5-azacytidine (AZA) has proven its efficacy as treatment for myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate FOXP3 intron 1 (FOXP3i1) leading ... [more ▼]

The demethylating agent 5-azacytidine (AZA) has proven its efficacy as treatment for myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate FOXP3 intron 1 (FOXP3i1) leading to the generation of regulatory T cells (Treg). Here, we investigated the impact of AZA on xenogeneic graft-versus-host disease (xGVHD) and graft-versus-leukemia effects in a humanized murine model of transplantation (human PBMCs-infused NSG mice), and described the impact of the drug on human T cells in vivo. We observed that AZA improved both survival and xGVHD scores. Further, AZA significantly decreased human T-cell proliferation as well as IFN-γ and TNF-α serum levels, and reduced the expression of GRANZYME B and PERFORIN 1 by cytotoxic T cells. In addition, AZA significantly increased Treg frequency through hypomethylation of FOXP3i1 as well as increased Treg proliferation. The later was subsequent to higher STAT5 signaling in Treg from AZA-treated mice, which resulted from higher IL-2 secretion by conventional T cells from AZA-treated mice itself secondary to demethylation of the IL-2 gene promoter by AZA. Importantly, Tregs harvested from AZA-treated mice were suppressive and stable over time since they persisted at high frequency in secondary transplant experiments. Finally, graft-versus-leukemia effects (assessed by growth inhibition of THP-1 cells, transfected to express the luciferase gene) were not abrogated by AZA. In summary, our data demonstrate that AZA prevents xGVHD without abrogating graft-versus-leukemia effects. These findings could serve of basis for further studies of GVHD prevention by AZA in acute myeloid leukemia patients offered an allogeneic transplantation. [less ▲]

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See detailUse of Tyrosine Kinase Inhibitors to Prevent Relapse After Allogeneic Hematopoietic Stem Cell Transplantation for Patients With Philadelphia Chromosome–Positive Acute Lymphoblastic Leukemia: A Position Statement of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation
Giebel, S.; Czyz, A.; Ottmann, O. et al

in Cancer (2016), 122(19), 2941-2951

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a standard of care for patients with Philadelphia chromosome (Ph)–positive acute lymphoblastic leukemia (ALL). The introduction of tyrosine ... [more ▼]

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a standard of care for patients with Philadelphia chromosome (Ph)–positive acute lymphoblastic leukemia (ALL). The introduction of tyrosine kinase inhibitors (TKIs) to first-line therapy has improved overall outcomes; however, a significant proportion of patients still relapse after alloHSCT. Posttransplant TKI maintenance was demonstrated to reduce the risk of relapse in a large retrospective study and, therefore, should be considered a valuable option. This consensus paper, written on behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation, presents an overview of clinical studies on the use of TKIs after alloHSCT and proposes practical recommendations regarding the choice of TKI, treatment timing, and dosage. It is hoped that these recommendations will become the state of art in this field and, more importantly, lead to a reduction of Ph-positive ALL relapse after alloHSCT. [less ▲]

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See detailAzacytidine mitigates experimental sclerodermic chronic graft-versus-host disease
Fransolet, Gilles ULiege; Ehx, Grégory ULiege; SOMJA, Joan ULiege et al

in Journal of Hematology & Oncology (2016), 9

Background <br />Previous studies have demonstrated that regulatory T cells (Tregs) play a protective role in the pathogenesis of chronic graft-versus-host disease (cGVHD). Tregs constitutively express ... [more ▼]

Background <br />Previous studies have demonstrated that regulatory T cells (Tregs) play a protective role in the pathogenesis of chronic graft-versus-host disease (cGVHD). Tregs constitutively express the gene of the transcription factor Foxp3 whose CNS2 region is heavily methylated in conventional CD4+ T cells (CD4+Tconvs) but demethylated in Tregs. <br />Methods <br />Here, we assessed the impact of azacytidine (AZA) on cGVHD in a well-established murine model of sclerodermic cGVHD (B10.D2 (H-2d) → BALB/cJ (H-2d)). <br />Results <br />The administration of AZA every 48 h from day +10 to day +30 at the dose of 0.5 mg/kg or 2 mg/kg mitigated chronic GVHD. Further, AZA-treated mice exhibited higher blood and thymic Treg frequencies on day +35, as well as higher demethylation levels of the Foxp3 enhancer and the IL-2 promoter in splenocytes at day +52. Interestingly, Tregs from AZA-treated mice expressed more frequently the activation marker CD103 on day +52. AZA-treated mice had also lower counts of CD4+Tconvs and CD8+ T cells from day +21 to day +35 after transplantation, as well as a lower proportion of CD4+Tconvs expressing the Ki67 antigen on day +21 demonstrating an anti-proliferating effect of the drug on T cells. <br />Conclusions <br />Our results indicate that AZA prevented sclerodermic cGVHD in a well-established murine model of cGVHD. These data might serve as the basis for a pilot study of AZA administration for cGVHD prevention in patients at high risk for cGVHD. [less ▲]

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See detailNovel approaches for preventing acute graftversus- host disease after allogeneic hematopoietic stem cell transplantation
SERVAIS, Sophie ULiege; BEGUIN, Yves ULiege; Delens, Loïc ULiege et al

in Expert Opinion on Investigational Drugs (2016), 9

Introduction Allogeneic hematopoietic stem cell transplantation (alloHSCT) offers potential curative treatment for a wide range of malignant and nonmalignant hematological disorders. However, its success ... [more ▼]

Introduction Allogeneic hematopoietic stem cell transplantation (alloHSCT) offers potential curative treatment for a wide range of malignant and nonmalignant hematological disorders. However, its success may be limited by post-transplant acute graft-versus-host disease (aGVHD), a systemic syndrome in which donor’s immune cells attack healthy tissues in the immunocompromised host. aGVHD is one of the main causes of morbidity and mortality after alloHSCT. Despite standard GVHD prophylaxis regimens, aGVHD still develops in approximately 40–60% of alloHSCT recipients. Areas covered In this review, after a brief summary of current knowledge on the pathogenesis of aGVHD, the authors review the current combination of a calcineurin inhibitor with an antimetabolite with or without added anti-thymocyte globulin (ATG) and emerging strategies for GVHD prevention. Expert opinion A new understanding of the involvement of cytokines, intracellular signaling pathways, epigenetics and immunoregulatory cells in GVHD pathogenesis will lead to new standards for aGVHD prophylaxis allowing better prevention of severe aGVHD without affecting graft-versus-tumor effects. [less ▲]

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See detailAzacytidine Enhances Regulatory T-Cells In Vivo and Prevents Experimental Xenogeneic Graft-Versus-Host Disease
Ehx, Grégory ULiege; Fransolet, Gilles ULiege; de Leval, Laurence ULiege et al

in Biology of Blood and Marrow Transplantation (2016, March), 22(3), 393

Background. The demethylating agent 5-azacytidine (AZA) has proven its efficacy as treatment for myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate FOXP3 intron 1 ... [more ▼]

Background. The demethylating agent 5-azacytidine (AZA) has proven its efficacy as treatment for myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate FOXP3 intron 1 (FOXP3i1) leading to the generation of regulatory T cells (Tregs). Objective. We investigated the impact of AZA on xenogeneic graft-versus-host disease (xGVHD) in a humanized murine model of transplantation, and described the impact of the drug on human T cells in vivo. Methods. In order to induce xGVHD, human peripheral blood mononuclear cells (huPBMC) were administered intravenously in NOD-scid IL-2Rγnull (NSG) mice. Results. AZA successfully improved both survival (p<0.0001) and xGVHD scores (p<0.0001). Further, AZA significantly decreased human T-cell proliferation as well as INF-γ and TNF-α serum levels, and reduced the expression of GRANZYME B and PERFORIN 1 by cytotoxic T cells. In addition, AZA administration significantly increased the function, proliferation and frequency of Tregs through demethylation of FOXP3i1 and higher secretion of IL-2 by conventional T cells due to IL2 gene promoter site 1 demethylation. Interestingly, among AZA-treated mice surviving the acute phase of xGVHD, there was an inverse correlation between the presence of Tregs and signs of chronic GVHD. Finally, Tregs harvested from the spleen of AZA-treated mice were suppressive and stable over time since they persisted at high frequency in secondary transplant experiments. Conclusion. These findings emphasize a potential role for AZA as prevention or treatment of GVHD and other autoimmune diseases. [less ▲]

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See detailImmunomodulatory effects of rapamycin in Graft versus Host Disease
Ehx, Grégory ULiege; Hannon, Muriel ULiege; Humblet-Baron, Stéphanie et al

Poster (2016, January 29)

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See detailAzacytidine and Decitabine prevent experimental sclerodermic chronic graft-versus-host disease
Fransolet, Gilles ULiege; Ehx, Grégory ULiege; SOMJA, Joan ULiege et al

Poster (2016, January 29)

Introduction: Graft-versus-host disease (GVHD) remains a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Following allo-transplantation, 60% of the patients experience ... [more ▼]

Introduction: Graft-versus-host disease (GVHD) remains a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Following allo-transplantation, 60% of the patients experience chronic GVHD while approximately 15% of them develop a sclerodermic form of chronic GVHD characterized by multiple organ fibrosis and loss of skin elasticity. Regulatory T cells (Tregs) play a pivotal protective role in the pathogenesis of chronic GVHD by inhibiting alloreactive conventional T cells (Tconvs). Several studies have shown that hypomethylating agents such as Azacytidine (AZA) or Decitabine (DAC) can demethylate the master transcription factor of Treg (FoxP3), thus promoting Treg differentiation from Tconvs. This work investigates the impact of AZA and DAC in a murine model of sclerodermic chronic GVHD. Methods: Lethally irradiated (7 Gy) BALB/cJ recipient mice were injected with 107 bone marrow cells + 7.107splenocytes from B10.D2 donor mice to induce scl-cGVHD. Recipients were injected with 0.5 or 2 mg/kg of AZA or 0.75 mg/kg of DAC every 48h from day 10 to 30 following transplantation. GVHD was scored using a five criteria scale (weight loss, activity, fibrosis, hair loss and mice posture; 0-1-2 points/criteria). Mice were sacrificed at a score of 8/10. Results: Mice treated with AZA 0.5 mg/kg (n=14) or 2 mg/kg (n=17) or DAC 0.75 mg/kg (n=5) had lower clinical scores of GVHD compared to control (n=15). FACS analyses showed a higher proportion of Treg in the blood of AZA 0.5 or 2 mg/kg or DAC 0.75 mg/kg mice than in control at day 35. Results also showed a decreased number of Tconv and CD8 in AZA and DAC treated mice while proliferation of these cells expressing Ki67 was lower during AZA/DAC treatment but higher after discontinuation. Histological analyses showed less skin fibrosis in mice treated with 2 mg/kg of AZA. Finally, analyses of the blood components demonstrated that AZA mice were leuco- and lymphopenic as compared to control at day 21 and 35. Conclusion : AZA and DAC prevented sclerodermic GVHD in this murine model. [less ▲]

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