Splenic autotransplantation: Optimal functional factors

That splenic autotransplantation has merit is proven, but optimal methods and sites for such "transplants" remain speculative and provide the subject of this report. Strain A mice were divided into 10 groups: controls, sham, splenectomy, in situ splenic devascularization, splenic fragmentation with transplanaation to subcutaneous flank or free peritoneal cavity, and whole organ transplantation to subcutaneous, free peritoneal cavity, omental wrap or small bowel mesentery sites. After 6 mo, six mice in each group underwent reticuloendothelial (RE) assessment by tin and ⁹⁹Tc labeled isologous red cell scans. Scores were favorable for autotransplants of whole spleen into peritoneal cavity sites, though not significantly when compared with fragments or subcutaneous sites. However, all transplants demonstrated significantly better RE function than devascularized in situ spleens. Tc-99 flow scans demonstrated subcutaneous transplants and in situ devascularized spleens to drain via the systemic circulation while all transplants within the peritoneal cavity drained via the portal route. After 10 mo, 161 mice received intraperitoneal injections of four colony units of pneumococcus. At 24 hr, all splenectomized mice had died, but the mortality in recipients of whole spleen transplants to peritoneal cavity, small bowel mesentery, and omental wrap or fragment transplants to the peritoneal cavity was 76%, 75%, 76%, and 77%, the first three being significantly favored (p<0.05). Mortality in the other three groups varied from 87% to 100%, and mice were not protected by the persistent spleen. These data suggest that the in situ devascularized spleen offers little RE or antibacterial protection while function is apparent after whole spleen transplants, especially in sites draining via the portal circulation.