Post-transplant lymphoproliferative disease in kidney transplant patients in the new immunosuppressive era

Although the kidney transplant program at this center has been active for the past 18 yr, five out of the seven cases of post-transplant lymphoma in kidney transplant patients were observed over the past 2 yr. During this period, we have shifted from cyclosporine to tacrolimus (FK506 or prograf) for maintenance immunosuppression and for rescue therapy. We have also introduced mycophenolate (RS-61443) and have continued an antibody induction regimen in the immediate postoperative period. FK506 is 50-100 times more potent than cyclosporine. We have reported a decreased incidence of rejection, improved graft survival, and a general optimalization of patient survival with these newer regimens. Nonetheless, five cases of post-transplant lymphoma out of 233 kidney transplants (2.1%) performed during this time period (December 1993 to December 1995) occurred between 3 months to 1 yr after the transplant. Four of the five patients are still alive between 12 and 24 months after the diagnosis of lymphoma was made. All were without evidence of ongoing disease. Three of the five have grafts with excellent function for longer than 18 months after transplantation, while one is marginal and one patient expired on dialysis. The third and fourth patients had severe rejection before the diagnosis of PTLD was made. While the occurrence of five cases of post-transplant lymphoma over a 2 yr period is alarming, this is still within the 2-4% incidence of post-transplant lymphoma that has been reported in the literature in kidney transplant patients. Our results probably reflect the increasing potency of our immunosuppressive protocols but do not show any increase in the aggressiveness of this entity of post-transplant lymphoma during the continued follow up.