The homograft response to whole-organ transplantation of the canine spleen

Summary o 1. A one-stage technique of canine spleen transplantation has been developed which leaves the transplanted spleen in normal anatomic position with the splenic vessels united by end to end anastomosis. 2. Using this technique, 43 homotransplantations and 12 autotransplantations of the spleen have been carried out. Many operations failed to achieve prolonged vascularization of the spleen owing to suture line thrombosis; but 22 homografts and 6 autografts showed excellent vascularization at reexploration. Subsequent histologic changes were followed by periodic biopsies of the spleen. 3. Homotransplanted spleens usually show destruction of the splenic architecture with widespread necrosis by the end of one week. There is a transient early phase of striking follicular activity in the homotransplanted spleen which may represent an immune response of the graft against its new host. This is quickly obliterated by a far greater reaction of the host against the graft. Histologically, the reaction directed against the graft is quite analogous to renal homograft rejection. 4. Autotransplanted spleens show essentially normal follicular activity and survive indefinitely