Chimerism and central tolerance

With adequate depletion or inactivation of the pre-existing immune system and establishment of conditions permitting donor hematopoietic stem cell engraftment, a robust state of central deletional tolerance to allogeneic or xenogeneic donors can be induced. Advances have been made in the ability to achieve this permissive state without toxic, myeloablative conditioning, thus bringing this approach closer to clinical application.