Kinetics of unresponsiveness induced by a short course of cyclosporin A

The kinetics of unresponsiveness induced by a short course of cyclosporin A was studied using accessory heart allografts in rats. Skin grafts from the heart donor or a third-party donor were performed at several different times after heart transplantation. The fate of the skin and heart grafts demonstrated that the properties of the unresponsive state induced by short-term cyclosporin A therapy changed with time so that three different stages could be recognized: (1) stable nonspecific immunosuppression, (2) weak weak moderately specific immunosuppression, and (3) strong stable donor-specific immunosuppression.