Modification of kidney immunogenicity with standard Concanavalin A and its subfractions

Alternative applications of cyclosporin A to improve kidney allograft survival

This study applies cyclosporin A as a donor pretreatment prior to organ harvesting or as a graft pretreatment during preservation of canine kidney allografts by hypothermic pulsatile perfusion or hypothermic storage. All recipients except those in Group IX received minimal immunosuppression with azathioprine after transplantation (5 to 2.5 mg. per kg. per day). No significant differences in survival (X +/- SD) were observed between the 3 control groups which were either 1) flushed with untreated Ringer's lactate solution and immediately transplanted (Group I, no. = 8, 14 +/- 3.33 days), 2) preserved by hypothermic pulsatile perfusion for 24 hours (Group II, no. = 7, 12.0 +/- 8.92 days), or 3) hypothermically stored for 24 hours (Group III, no. = 7 13.1 +/- 11.6 days). A trend towards improved survival was seen in the 2 groups of animals that received kidneys that had been graft pretreated with cyclosporin A (12.5 mg.) during 24 hours preservation by either hypothermic pulsatile perfusion (Group IV, no. = 10, 17.4 +/- 13.32 days, p less than .25) or hypothermic storage (Group V, no. = 6, 8 +/- 12.75 days, p less than .25). Survival of recipients in Groups VI (no. = 6) and VII (no. = 9) who received kidneys whose donors had been pretreated with 25 and 50 mg. per kg. respectively was dependent on the dosage of cyclosporin A used. Donor pretreatment at 50 mg. per kg. was deleterious to kidney function (Group VI, 2.16 +/- 1.47 days, p less than 0.0005). Donor pretreatment with 25 mg. per kg. did not significantly improve survival over control groups (15.66 +/- 12.9 days). Recipients in Groups VIII (no. = 10) and IX (no. = 6) were transplanted with kidneys from cyclosporin A pretreated donors (15 mg. per kg.). These kidneys also received cyclosporin A graft pretreatment (10 mg.) during 24 hours of hypothermic storage. The only difference between Groups VIII and IX was that the animals in Group IX received minimal amounts of cyclosporin A (5 mg. per kg. per day) after transplantation. Combined donor and graft pretreatment yielded improved kidney allograft survival (Group VIII, 21.7 +/- 13.36 days, p greater than .10, Group IX, 20.83 +/- 14.2 days, p greater than .10). However, there was no significant difference observed as a result of the different immunosuppressive protocols used in Groups VIII and IX. These results indicate a trend towards improved renal allograft survival under certain conditions, after donor and graft pretreatment with cyclosporin A.

New avenues in the use of cyclosporine for transplantation. Graft and donor pretreatment

Modification of graft immunogenicity using graft (GPTX) and donor pretreatment (DPTX) has been pursued in an attempt to modify allograft immunogenicity using various immunosuppressive agents. The murine skin allograft and canine renal allograft models were used to study the efficacy of Cyclosporine (Cy A) as a DPTX and GPTX prior to transplantation. Tail skin allografts from C3HHeN male mice were grafted to Balb/c female mouse recipients. Minimal immunosuppression was given to all skin graft recipients. Skin allograft were either GPTX with Cy A, DPTX with either Cy A, methylprednisolone (MP), or cyclophosphamide (CP), or Cy A GPTX and DPTX with the three drugs alone or in combination. Cy A GPTX alone of skin allografts did not significantly prolong survival. DPTX with Cy A significantly prolonged skin graft survival, however, CP or MP alone did not. The various combinations of MP, Cy A, and CP as DPTX and MP, Cy A, and CP DPTX used together with Cy A GPTX also significantly prolonged murine skin allograft survival. Kidney allografts used unrelated mongrel dogs as donors or recipients. Renal transplant experimental groups were either: Non-pretreated and immediately transplanted, nonpretreated and hypothermically stored (HS) for 24 hours in Collins (C-2) solution, GPTX with 12.5 mg Cy A during 24 hr. HS in C-2, DPTX with Cy A (25 mg/Kg), or Cy A DPTX (15 mg/kg) and GPTX during 24 hrs. HS in C-2. Cy A GPTX during HS was sometimes effective in prolonging kidney allograft survival greater than 30 days using only minimal immunosuppression with azathioprine. Cy A DPTX prolonged survival somewhat, but not significantly. Improved results were seen, however, when Cy A DPTX was used together with Cy A graft pretreatment. These results indicate the potential for the successful use of Cy A as a donor and/or graft pretreatment, however, further studies will be necessary to optimize the use of Cy A in these modalities.