Transplantation tolerance, defined as allograft acceptance by an immunocompetent recipient in the absence of long-term immunosuppression, has remained an elusive goal in clinical transplantation. Robust experimental tolerance induction strategies have in common methods to induce mixed hemopoietic chimerism. To date, however, chimerism induction across allogeneic barriers has required recipient ...

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....

This Special Focus on Transplantation Immunology issue of Chimerism features papers focusing on the role of chimerism in transplantation immunology. The field of immunologic tolerance, which owes its origins to an experiment of nature resulting in hematopoetic mixed chimerism, is the subject of our featured Forum article—a debate between Jeff Mold and Colin Anderson on the implications for tole...

The aim of this study was to evaluate mixed red cells population and red blood cell chimerism after hematopoietic stem cell transplantation. Red blood cell chimerism after hematopoietic stem cell transplantation was analyzed using a series of fluorescein isothiocyanate-conjugated monoclonal antibodies (BioAtlantic, France) directed against ABH, Rh (D, C, E, c, e), Kell, Duffy, Kidd, and Ss anti...

OBJECTIVE Stable mixed chimerism (MC) may result in cure for thalassemia major patients following hematopoietic stem cell transplantation (HSCT), but rejection can occur. Twenty-eight HSCTs for thalassemia major were reviewed retrospectively to evaluate the clinical course of MC with possible risk factors and predictors of outcome, with a median follow-up of 1669 days (811-3576 days). METHODS...

Hematopoietic chimerism is known to promote donor-specific organ allograft tolerance; however, clinical translation has been impeded by the requirement for toxic immunosuppression and large doses of donor bone marrow (BM) cells. Here, we investigated in mice whether durable chimerism might be enhanced by pre-treatment of the recipient with liposomal clodronate, a macrophage depleting agent, wit...

Donor lymphocyte infusions after reduced intensity conditioning allogeneic transplantation: what we need to know Recently in Blood there were 2 papers that increased our knowledge about donor lymphocyte infusions (DLIs) given after reduced intensity conditioning transplantation. 1,2 We published a United Kingdom national study in 81 similar patients 19 months ago. 3 This study had a number of l...

Bone marrow transplantation from diabetes-resistant strains with complete replacement of the recipient immune system by the allogeneic donor has led to tolerance to donor islets and cure of diabetes in a mouse model of type 1 diabetes. However, the ability to tolerize host T-cells of diabetic NOD mice is unknown. We demonstrate that nonmyeloablative conditioning achieves mixed hematopoietic chi...

We have previously postulated that donor cell chimerism in organ transplantation is needed to attain a tolerant state. Here we show that donor cell chimerism can be augmented in organ recipients if they are infused perioperatively with 3 x 10(8) per kg of unmodified donor bone marrow cells and are kept on a conventional immunosuppressive regimen of tacrolimus (FK506) and prednisolone. 36 patien...

References 1. Thiede C, Florek M, Bornhauser M, Ritter M, Mohr B, Brendel C, et al. Rapid quantification of mixed chimerism using multiplex amplification of short tandem repeat markers and fluorescence detection. Bone Marrow Transplant 1999;23:1055–60. 2. Lawler M, Humphries P, McCann SR. Evaluation of mixed chimerism by in vitro amplification of dinucleotide repeat sequences using the polymera...