The use of local allograft irradiation following renal transplantation.

Over a 10 year period, 67 recipients of 71 renal allografts received graft irradiation following the diagnosis of rejection. The majority of kidneys were treated with a total dose of 600 rad, 150 rad per fraction, in 4 daily fractions. Fifty-three kidneys were irradiated following the failure of standard systemic immunosuppression and maximally tolerated antirejection measures (pulse high dose steroids, Actinomycin, ATG) to reverse an episode of acute rejection. Seven of these patients (13%) had greater than a 50% improvement in serum creatinine (Cr) 1 week following completion of the irradiation. Twenty-two (42%) of these allografts were noted to have stable (i.e. no deterioration) or improved function 1 month following the treatment with irradiation. Eleven (21%) of these allografts maintained function 1 year following transplantation. There were 10 patients whose allografts were irradiated because of renal dysfunction in a clinical setting which did not permit the administration of further immunosuppression, i.e., infection or hematologic dyscrasias. Three of these patients (30%) had greater than a 50% improvement in serum Cr 1 week following completion of the irradiation. Nine (90%) of these allografts had stable or improved function 1 month following the treatment with irradiation. Biopsies were obtained of 41 allografts. Of the 24 renal allografts with predominantly cellular rejection, 10 (42%) had the process reversed or stabilized at 1 month following irradiation. Five (21%) of these allografts were functioning at 1 year following irradiation. Rejection was reversed or stabilized in 6 of 17 (35%) allografts at 1 month when the histologic features of renal biopsy suggested predominantly vascular rejection. One (6%) of these allografts was functioning at 1 year following transplantation. Local graft irradiation has helped maintain a limited number of allografts in patients whose rejection has failed to respond to systemic immunosuppression. Irradiation may also benefit patients with ongoing rejection in whom further systemic immunosuppression is contra-indicated.