Splenic Homotransplantation*

A series of canine splenic homografts was performed. Animals pretreated with total-body irradiation showed markedly shortened red cell half-life and sharp drops in hematocrit with no potentiation of homograft survival. Those dogs treated with azathioprine had no change in red cell half-life, hematocrit changes were much less than in the irradiated animals, and homograft survival was increased as judged by pathologic studies. In another series of animals, simultaneous renal and splenic homografts were performed to bilaterally nephrectomized dogs. Function of both transplanted organs was inferred from the behavior of the renal homograft. Control animals receiving no therapy showed a somewhat delayed rejection. Those dogs treated with total-body irradiation frequently developed severe hemolytic anemia and graft survival was less than in untreated animals. Both the spleen and the kidney appeared to be particularly susceptible to the rejection reaction in this series, and of the two organs, the spleen appeared to be more damaged than the kidney. When azathioprine was used as the immunosuppressive agent, survival of both renal and splenic homografts was obtained to as long as seven and one-half months. Anemia was not noted in these animals after the first month and gross and microscopic examination at seven months revealed both organs to be viable. (Author)