Bone marrow transplantation improves outcome in a mouse model of congenital muscular dystrophy

AbstractWe examined whether pathogenesis in dystrophin-deficient (mdx) mice and laminin-α2-deficient (dy) mice is ameliorated by bone marrow transplantation (BMT). Green fluorescent protein (GFP) mice were used as donors. In mdx mice, BMT failed to produce any significant differences in muscle pathology, although some GFP-positive fibers with restored dystrophin expression were observed. In contrast, in the dy mice, BMT led to a significant increase in lifespan and an increase in growth rate, muscle strength, and respiratory function. We conclude that BMT improved outcome in dy mice but not mdx mice

HLA-Haploidentical Peripheral Blood Stem Cell Transplantation with Post-Transplant Cyclophosphamide after Busulfan-Containing Reduced-Intensity Conditioning

AbstractAllogeneic hematopoietic stem cell transplantation (allo-SCT) using post-transplant cyclophosphamide (PTCy) is increasingly performed. We conducted a multicenter phase II study to evaluate the safety and efficacy of PTCy-based HLA-haploidentical peripheral blood stem cell transplantation (PTCy-haploPBSCT) after busulfan-containing reduced-intensity conditioning. Thirty-one patients were enrolled; 61% patients were not in remission and 42% patients had a history of prior allo-SCT. Neutrophil engraftment was achieved in 87% patients with a median of 19 days. The cumulative incidence of grades II to IV and III to IV acute graft-versus-host disease (GVHD) and chronic GVHD at 1 year were 23%, 3%, and 15%, respectively. No patients developed severe chronic GVHD. Day 100 nonrelapse mortality (NRM) rate was 19.4%. Overall survival, relapse, and disease-free survival rates were 45%, 45%, and 34%, respectively, at 1 year. Subgroup analysis showed that patients who had a history of prior allo-SCT had lower engraftment, higher NRM, and lower overall survival than those not receiving a prior allo-SCT. Our results suggest that PTCy-haploPBSCT after busulfan-containing reduced-intensity conditioning achieved low incidences of acute and chronic GVHD and NRM and stable donor engraftment and low NRM, particularly in patients without a history of prior allo-SCT

study design of a phase 3 randomized open label multicenter study to evaluate ruxolitinib over bat in patients with corticosteroid refractory chronic graft vs host disease after allogeneic hematopoietic stem cell transplantation reach 3

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Mammalian Target of Rapamycin Inhibitors Permit Regulatory T Cell Reconstitution and Inhibit Experimental Chronic Graft-versus-Host Disease

Chronic graft-versus-host disease (GVHD) remains a major late complication of allogeneic bone marrow transplantation (BMT). In a previous study, impaired thymic negative selection of the recipients permitted the emergence of pathogenic T cells that cause chronic GVHD using MHC class II-deficient (H2-Ab1 KO) B6 into OH model and CD4(+) T cells isolated from chronic GVHD mice caused chronic GVHD when administered into the secondary recipients. In this study, we evaluated the kinetics of regulatory T cell (Treg) reconstitution in wild type B6 into C3H model. After myeloablative conditioning, host Tregs disappeared rapidly, followed by expansion of Tregs derived from the donor splenic T cell inoculum. However, the donor splenic T cell derived Treg pool contracted gradually and was almost completely replaced by newly generated donor bone marrow (BM)-derived Tregs in the late post-transplantation period. Next, we compared the effects of cyclosporine (CSA) and mammalian target of rapamycin (mTOR) inhibitors on Treg reconstitution. Administration of CSA significantly impaired Treg reconstitution in the spleen and thymus. In contrast, BM-derived Treg reconstitution was not impaired in mTOR inhibitor-treated mice. Histopathological examination indicated that mice treated with GSA, but not mTOR inhibitors, showed pathogenic features of chronic GVHD on day 120. Mice treated with CSA until day 60, but not mTOR inhibitors, developed severe chronic GVHD followed by adoptive transfer of the pathogenic CD4(+) T cells isolated from H2-Ab1 KO into C3H model. These findings indicated that long-term use of CSA impairs reconstitution of BM-derived Tregs and increases the liability to chronic GVHD. The choice of immunosuppression, such as calcineurin inhibitor-free GVHD prophylaxis with mTOR inhibitor, may have important implications for the control of chronic GVHD after BMT

Mocravimod, a Selective Sphingosine-1-Phosphate Receptor Modulator, in Allogeneic Hematopoietic Stem Cell Transplantation for Malignancy

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the sole curative option for patients with acute myelogenous leukemia. Outcomes are limited by leukemia relapse, graft-versus-host disease (GVHD), and abnormal immune reconstitution. Mocravimod (KRP203) is an oral sphingosine-1-phosphate receptor (S1PR) modulator that blocks the signal required by T cells to egress from lymph nodes and other lymphoid organs. Mocravimod retains T cell effector function, a main differentiator to immunosuppressants. In preclinical models, mocravimod improves survival by maintaining graft-versus-leukemia (GVL) activity while reducing GVHD. In patients undergoing allo-HSCT for hematological malignancies, mocravimod is postulated to prevent GVHD by redistributing allogeneic donor T cells to lymphoid tissues while allowing a sufficient GVL effect in the lymphoid, where malignant cells usually reside. The primary objective of this study was to assess the safety and tolerability of mocravimod in patients undergoing allo-HSCT for hematologic malignancies. Secondary objectives were to determine the pharmacokinetic profiles of mocravimod and its active metabolite mocravimod-phosphate in this patient group, as well as to assess GVHD-free, relapse free survival at 6 months after the last treatment. In this 2-part, single- and 2-arm randomized, open-label trial, we evaluated the safety, tolerability, and pharmacokinetics of mocravimod in allo-HSCT recipients (ClinicalTrials.gov identifier NCT01830010). Patients received either 1 mg or 3 mg mocravimod per day on top of standard of care GVHD prophylaxis with either cyclosporine A/methotrexate or tacrolimus/methotrexate. We found that mocravimod can be safely added to standard treatment regimens in patients with hematologic malignancies requiring allo-HSCT. Mocravimod resulted in a significant reduction of circulating lymphocyte numbers and had no negative impact on engraftment and transplantation outcomes. Our results indicate that mocravimod is safe and support a larger study to investigate its efficacy in a homogeneous acute myelogenous leukemia patient population undergoing allo-HSCT

The Wnt agonist R-spondin1 regulates systemic graft-versus-host disease by protecting intestinal stem cells

R-spondin1 stimulates the proliferation of intestinal stem cells through the Wnt signaling pathway and protects against graft-versus-host disease