Further progress in the induction of allogeneic unresponsiveness in the adult host

At present, the state of allogeneic unresponsiveness produced in adult dogs by total body irradiation (TBI) and autologous bone marrow transplantation (ABMT), followed by host exposure to a renal allograft appears to be specific for the kidney donor; it exhibits a degree of organ specificity and appears to be mediated by the retransplanted marrow stem cells. The successful induction of unresponsiveness requires at least one cycle of cell generation in the microenvironment of the irradiated host. One new approach to boosting unresponsiveness involves the exposure of the circulating blood cells of the recipient to extracorporeal irradiation. Neck vessels of dogs were exposed, through an arterio-venous shunt, to radioactive cesium for a cumulative dose of 22-40 thousand rads over 4-5 weeks. Following TBI, ABMT and renal allograft, bilateral nephrectomy was performed. Eight of ten animals thus treated have remained unresponsive to their renal allografts for more than 250 days. Other approaches are also described