Cyclosporin conversion versus conventional immunosuppression: long-term follow-up and histological evaluation.

129 patients who received a cadaver renal transplant entered a randomised prospective trial of cyclosporin for 3 months with conversion to azathioprine and prednisolone compared with conventional therapy of azathioprine and prednisolone. In the 64 patients who received cyclosporin, actuarial patient survival was 92%, and actuarial graft survival was 72% and 67% at 1 and 4 years after transplantation. Graft survival was significantly better (p less than 0.03) than in the 65 patients who received conventional therapy, in whom actuarial patient survival was 94%, and actuarial graft survival was 59% and 47% at 1 and 4 years. Renal function and other side-effects improved quickly after conversion with the better renal function maintained throughout follow-up. Renal biopsies at 90 days and 1 year in all patients did not show consistent improvement after conversion from cyclosporin in the histological features that might be attributable to cyclosporin toxicity. After conversion, 32% of the patients had acute rejection, generally within 30 days. 1 graft was lost to early acute rejection after conversion and another was lost 3 months later from acute-on-chronic rejection. A total of 8 grafts were lost to chronic rejection in the cyclosporin-treated group and 6 in the conventional group. The improvement in renal function obtained with this protocol of short-term cyclosporin with conversion to azathioprine and prednisolone has to be balanced against the risk of acute rejection and even loss of the graft after conversion.