Prolongation of Skin Graft Survival by Methotrexate and Cross Circulation

The effect of cross-circulation and methotrexate administration on skin graft survival in the mongrel dog was studied. Three groups of 10 dogs each were compared. In the first group, dogs cross-circulated continuously for 48 hours showed an average graft survival of 8 days (range 6–12 days). Animals in the second group received 3 doses of methotrexate (0.5 mgm. per kg.) 48 hours apart and had an average graft survival of 12 days (range 6–17). Animals in the third group were cross-circulated and also given methotrexate. Graft survival averaged 23 days (range 10–59). It was concluded that exposure to cellular antigen by cross circulation supplemented by immunosuppression with methotrexate was effective in prolonging skin graft survival.