Annals of surgery
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Total lymphoid irradiation (TLI) is immunosuppressive and, in rodent, can induce a state where transplantation of allogeneic bone marrow results in chimerism and permanent acceptance of organ allografts from the donor strain. We attempted to apply this treatment to a large animal model. Twelve splenectomized dogs were treated with TLI (150 rads per fraction, total dose 1950-3000 rads) before bilateral nephrectomy and renal allotransplantation. ⋯ The response of peripheral blood lymphocytes to stimulation with phytohemagglutinin and in mixed lymphocyte culture was suppressed for at least on month after TLI. The results confirm the immunosuppressive effect of TLI. The absence of kidney rejection in two recipients of donor bone marrow show the potential of this approach to induce long-term immunologic unresponsiveness as to an organ allograft, but the outcome is unpredictable and further experiments are needed to define the optimal conditions for administration of TLI and bone marrow to the recipients.