PRELIMINARY-RESULTS OF INTRATHYMIC INJECTION OF DONOR CELLS TO PREVENT ACUTE REJECTION IN HUMAN HEART-TRANSPLANTATION

In rodents, the intrathymic injection of donor cells or major histocom patibility complex peptides induces indefinite survival of a subsequen t allograft with little or no immunosuppression. Here, experiments hav e been performed in two patients with cardiac transplantation to estab lish (1) the safety and tolerability of the intrathymic injection of d onor leukocytes at the time of transplant surgery and (2) whether conv entional immunosuppression interfered with the process of the thymic r ecognition of alloantigens. It was shown that the intrathymic inoculat ion of donor cells is safe and can be done without undesired effects. However, the procedure, as performed, did not protect from acute graft rejection. There are data enough to attribute the failure of the thym us technique in these two patients to the concomitant use of immunosup pressants. The results of this study are relevant for future trials ai med at finding the appropriate experimental conditions for the use of the thymic approach in human organ transplantation.