Renal transplant patients treated with total lymphoid irradiation show specific unresponsiveness to donor antigens the mixed leukocyte reaction (MLR).
A group of 25 cadaveric renal transplant recipients received total lymphoid irradiation (TLI) before transplantation, rabbit anti-thymocyte globulin on alternate days for 10 days after transplantation, and low dose prednisone (5 to 10 mg/day) as the sole maintenance immunosuppressive therapy. Allograft function and the mixed leukocyte reaction (MLR) were monitored serially. After 18 to 30 mo, nine patients were selected on the basis of a return of the MLR such that the mean stimulation index to a panel of normal stimulator cells was greater than or equal to 5, a stable serum creatinine level which was less than or equal to 2 mg/dl, and a history of no more than one rejection episode. The MLR of these patients' post-transplant peripheral blood mononuclear leukocytes (PBML) against cryopreserved donor cells was compared with that against cryopreserved normal third-party cells. In control experiments, the MLR of cryopreserved pre-TLI recipient PBML or fresh normal PBML were tested against the same panel of donor and third-party stimulator cells. Seven of the nine recipients showed a pattern of specific unresponsiveness to the donor cells more than 18 mo after transplantation. Preliminary attempts to identify antigen specific suppressor cells were unsuccessful. The pattern of unresponsiveness may indicate a state of specific immune tolerance to the allogeneic graft.
D000328:Adult; D006649:Histocompatibility Antigens / Q000276:immunology; D006801:Humans; D007165:Immunosuppression Therapy / Q000379:methods*; D016030:Kidney Transplantation; D007959:Lymphocyte Culture Test, Mixed; D008221:Lymphoid Tissue / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D013997:Time Factors
D006649:Histocompatibility Antigens