THE EFFECT OF ANTILYMPHOCYTE-SERUM, FRACTIONATED DONOR BONE-MARROW, AND CYCLOSPORINE ON RENAL-ALLOGRAFT SURVIVAL IN MONGREL DOGS

The effect of combined treatment with antilymphocyte serum, fractionated donor bone marrow, and a limited course of cyclosporine on renal allograft survival in mongrel dogs was examined. Recipients were treated with ALS from day -5 to day +7, relative to transplantation on day 0 with an MLR-mismatched donor. Fractionated donor bone marrow cells (BMFr3) obtained by density gradient separation were infused 3-7 days after ALS treatment. CsA treatments were begun either 3-7 days after ALS plus BMFr3 infusion or 3-7 days after treatments with ALS alone. Extended allograft survival was achieved at all CsA doses in BMFr3-infused, ALS-treated recipients. Allografts were sustained throughout the CsA treatment period without rejection in the majority of recipients (6 of 8) receiving ALS plus BMFr3 and CsA at 20 Mg/kg/day for 60 days. By contrast, few grafts were sustained through 30 days of treatment with CsA at 3.2 (1 of 12) or 10 mg/kg/day (2 of 9) in ALS plus BMFr3-treated recipients. Cyclosporine treatment was ineffective at all doses in augmenting allograft prolongation in ALS-treated recipients that did not receive BMFr3. Nearly all (6 of 7) long-term survivors (> 180 days) were BMFr3-treated. Peripheral blood lymphocytes or bone marrow cells of these long-term survivors proliferated normally in response to Con A and PWM, and were MLR responsive to third-party cells but did not have reduced MLR responsiveness to donor alloantigen in all cases. These long-term survivors promptly rejected third-party renal allografts without adverse effects on the original transplant's function. These results show that long-term renal allograft survival with specific unresponsiveness to the donor can result from the combined treatment with ALS plus donor BMFr3 and a limited course of CsA.