The induction of donor-specific transplant tolerance is one of the main goals of modern immunology. Establishment of a mixed chimerism state in the transplant recipient has proven to be a suitable strategy for the induction of long-term allograft tolerance; however, current experimental recipient preconditioning protocols have many side effects, and are not feasible for use in future therapies. In order to improve the current mixed chimerism induction protocols, we developed a non-myeloablative bone-marrow transplant (NM-BMT) protocol using retinoic acid (RA)-induced alloantigen-specific Tregs, clinically available immunosuppressive drugs, and lower doses of irradiation. We demonstrate that RA-induced alloantigen-specific Tregs in addition to a NM-BMT protocol generates stable mixed chimerism and induces tolerance to allogeneic secondary skin allografts in mice. Therefore, the establishment of mixed chimerism through the use of donor-specific Tregs rather than non-specific immunosuppression could have a potential use in organ transplantation.
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http://dx.doi.org/10.3389/fimmu.2015.00596 | DOI Listing |
Transplantation
January 2025
Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
Background: Long-term renal allograft acceptance has been achieved in macaques using a transient mixed hematopoetic chimerism protocol, but similar regimens have proven unsuccessful in heart allograft recipients unless a kidney transplant was performed simultaneously. Here, we test whether a modified protocol based on targeting CD154, CD2, and CD28 is sufficient to prolong heart allograft acceptance or promote the expansion of regulatory T cells.
Methods: Eight macaques underwent heterotopic allo-heart transplantation from major histocompatibility complex-mismatched donors.
Cells
December 2024
Departments of Blood and Marrow Transplant, Royal Manchester Children's Hospital, Manchester M13 9WL, UK.
Myeloid chimerism better reflects donor stem cell engraftment than whole-blood chimerism in assessing graft function following allogeneic hematopoietic stem cell transplant (HCT). We describe our experience with 130 patients aged younger than 18 years, treated with allogeneic HCT using bone marrow or PBSC from HLA-matched donors for non-malignant diseases, whose pre-transplant conditioning therapy included alemtuzumab and who were monitored with lineage-specific chimerism after transplant. At 6 years post-transplant, overall survival (OS) was 91.
View Article and Find Full Text PDFStem Cell Res Ther
December 2024
Department of Pediatrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No.107, West Yan Jiang Road, Guangzhou, 510120, Guangdong, China.
Background: Allo-HSCT is a curative therapy for patients with transfusion-dependent thalassemia (TDT). The high incidence of transplant-related complications is becoming an obstacle to safe and effective unrelated donor (URD) transplantation.
Methods: In this retrospective study, we reported the survival outcomes and complications of transplantation in thalassemia patients using a novel regimen consisting of pre-transplantation immunosuppression (PTIS) and modified myeloablative conditioning based on intravenous busulfan, cyclophosphamide, fludarabine, and rabbit anti-human thymocyte immunoglobulin.
Med
December 2024
Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Berlin, Germany. Electronic address:
Background: Distinguishing donor- vs. recipient-derived myelodysplastic neoplasm (MDS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is challenging and has direct therapeutical implications.
Methods: Here, we took a translational approach that we used in addition to conventional diagnostic techniques to resolve the origin of MDS in a 38-year-old patient with acquired aplastic anemia and evolving MDS after first allo-HSCT.
Front Immunol
November 2024
Laboratory of Genomic Medicine, Center of Experimental Research, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil.
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