Acute irreversible rejection after withdrawal of azathioprine in renal allograft recipients.

Azathioprine was withdrawn from five recipients after renal transplantation because of hepatic damage. In three out of five cases, clinical courses were uneventful for more than 1 year after withdrawal (Group A). In the other two cases, rejection episodes occurred 3 and 5 months after withdrawal (Group B). Differences in histocompatibility, the interval between the operation and withdrawal, and the maintenance dosis of prednisolone were not practically striking in either group, but rejection episodes occurred early in group B. We evaluated the results and considered the mechanisms of tolerance after withdrawal of azathioprine because of hepatic damage in renal allograft recipients.