The induction of immunologic unresponsiveness to improve renal allograft survival was attempted in 151 patients by the pretransplant administration of donor-specific whole blood or buffy coat in conjunction with continuous Aza immunosuppression. All donor-recipient combinations were at least one-haplotype disparate and 21 were two-haplotype disparate. Presensitization was present in ten patients and attempts at desensitization were uniformly unsuccessful. Of the 151 nonpresensitized patients, transient sensitization occurred in 3% and permanent sensitization in 7%. Of 140 nonsensitized patients, 135 underwent renal transplantation from the specific blood donor and 56% have never experienced a rejection episode. The allograft survival rate at two years (93%) and seven years (87%) is significantly better (p less than .01) than our historical experience with one-haplotype living-related transplants at two years (68%) and seven years (59%). The low rate of sensitization (7%) has permitted almost all patients to undergo eventual renal transplantation from the specific blood donor. This and the low rate of early rejection (2%) argues for a modification of the immunologic response, perhaps by clonal deletion, rather than a selecting out process as the mechanism for improved allograft survival.
Azathioprine B-Lymphocytes