Failure of chimerism formation and tolerance induction from Fas ligand mutant bone marrow donors after nonmyeloablative conditioning

• Published in: Transplant immunology Vol. 27; no. 4; pp. 184 - 188
• Main Authors: Nusair, Samir, Gincberg, Galit, Almogi-Hazan, Osnat, Breuer, Raphael, Or, Reuven, Wallach-Dayan, Shulamit B
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2012
• Subjects: Allergy and Immunology; Allografts; Animal models; Animals; Bone marrow; Bone Marrow Cells - immunology; Bronchiolitis obliterans; Busulfan; Chimerism; Cyclophosphamide; Donors; Fas ligand; Fas Ligand Protein - genetics; Fas Ligand Protein - immunology; FasL protein; Hematopoietic Stem Cell Transplantation; Hemopoiesis; Immune tolerance; Immunological tolerance; Intravenous administration; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Mutant Strains; Mice, Transgenic; Mutation; Stem cells; Tissue Donors; Trachea - pathology; Trachea - transplantation; Transgenic mice; Transplantation Chimera - immunology; Transplantation Conditioning - methods; Transplantation Tolerance - immunology; Transplantation, Homologous; bone marrow cells; BMT; bronchiolitis obliterans; GVHD; Fas Ligand; BO; bone marrow transplantation; Cyclophosphamide; FasL; Immune tolerance; BMC; Busulfan; Chimerism; graft versus host disease; Fas ligand; Bronchiolitis obliterans
• ISSN: 0966-3274; 1878-5492
• DOI: 10.1016/j.trim.2012.07.001

Abstract Formation of donor-recipient mixed chimerism after nonmyeloablative conditioning allows co-existence of donor and recipient hematopoietic stem cells, with solid organ allograft tolerance and less likeliness of graft versus host development. Using a post-transplant bronchiolitis obliterans murine model, we aimed to test the hypothesis that allograft preservation after mixed chimerism formation is dependent on the presence of a functional Fas ligand (FasL) on donor hematopoietic cells. To form mixed chimerism, two aliquots of 30 × 106 whole bone marrow cells (BMC) from either wild-type C57BL/6 in one group, or transgenic gld mice with mutant FasL (d = 0 and 2 +) in the other were used, with both groups receiving intravenous busulfan (10 mg/kg) on d − 1 and intraperitoneal cyclophosphamide (200 mg/kg) on d + 1. Tracheal allografts obtained from C57BL/6 mice were implanted into recipient BALB/c mice subcutaneously on d = 0. Tracheal allografts were harvested at d + 28 post-transplant and were evaluated by histopathology. Mixed chimerism formation was detected in wild type C57BL/6 whole BMC recipients, which was accompanied by tracheal allograft acceptance with near normal structure at d + 28 post implantation. However, in recipients of FasL mutant whole BMC, neither mixed chimerism formation nor tracheal allograft acceptance was obtained. We thus conclude that bone marrow cells lacking functional FasL molecules could not be engrafted in allogeneic recipients to form stable mixed chimerism after nonmyeloablative conditioning, thus not allowing tracheal allograft acceptance.