Despite substantial progress in the field long-term outcome after organ transplantation remains unsatisfactory. Lifelong treatment with non-specific immunosuppressive drugs, which is required by all transplant recipients, is ineffective in inhibiting chronic graft loss and is accompanied by severe side effects (e.g. infections, malignancies). Therefore, donor-specific tolerance remains a primary goal for transplantation research.
The approach we focus on is to induce tolerance through the transplantation of donor hematopoietic stem cells and the establishment of mixed chimerism (i.e. coexistence of donor and recipient hematopoietic cells in the host).

This strategy leads to a particularly robust state of tolerance and has been demonstrated to work not only in rodents, but also in large animals (including non-human primates) and notably in a pilot series of renal transplant recipients in the clinic.

However, even though ever milder experimental regimens for the induction of mixed chimerism have been developed, none is ready for widespread clinical translation due to remaining toxicities. Our group is working on the development of refined protocols for the transplantation of allogeneic hematopoietic cells and the delineation of the immunological mechanisms occurring in these models.