SPLENIC HOMOTRANSPLANTATION*

Abstract

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 homo-graft survival. Those dogs treated with azathioprine (Imuran) 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 nephrecto-mized 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. No evidence of secondary disease was observed in these dogs. In one animal, azathioprine was discontinued after 120 days. He remains alive, three and one-half months later. In addition, whole-organ spleen homo-transplantation was carried out in five patients. In four instances the purpose was to provide a continuous endogenous source of antibody against a malignant tumor. In the fifth case, it was hoped that the homo-graft would supply the immunologic deficiency in a child with congenital sex-linked hypogammaglobulinemia. The clinical experience was disappointing. In the patients with tumor, no alteration of the progression of the disease was obtained. In one patient of A+ blood type, who received a spleen from an O+ donor, severe hypersplenism developed shortly after transplantation. One patient is alive 11 months post-operatively with radiographic evidence of progression of his alveolar cell carcinoma. In the child with hypogammaglobulinemia, evidence for production of gamma globulin by the homografted spleen could not be obtained by a variety of techniques.