Differential survival of hamster-to-rat liver and cardiac xenografts under FK 506 immunosuppression.

THE ~aj~r bame~ in clinical transplantation has been the hmltatlon ot donor organs. I Xenotransplantation has been considered an alternative source of organs, however strong immunolOgiC barriers are thought to make this option impractical. The immunosuppressant FK 506 has been shown to be several hundred times more potent than cyclosporine (CyA)2.) and it is capable of suppressing antibody produc· tion. 4 These qualities would justify a tnal of this drug in experimental organ xenografts. Indeed. Nakajima et als failed to prolong hamster cardiac xenogralts in rat recipi-. ents treated with FK 506. However. It has been demonstrated that untreated livers survive longer than the hearts in the same xenograft combination.6 •7 Thus. in this study we investigated the effect of FK S06 in the difficult ham· ster-to-rat liver and cardiac xenotransplant model and compared the results with those of Cy A.