PNEUMOCOCCAL CLEARANCE FUNCTION OF THE INTACT AUTOTRANSPLANTED SPLEEN

Objective: To determine if the venous drainage of the spleen into the portal circulation is essential for its ability to protect against enc apsulated bacterial challenge. Design and Interventions: Three groups of dogs were randomly assigned to undergo either sham laparotomy, sple nectomy, or splenectomy with autotransplantation of the intact spleen into the pelvis and formation of vascular anastomoses to the iliac ves sels. Two weeks postoperatively, the dogs received a sublethal intrave nous injection of Streptococcus pneumoniae type 25. Outcome Measures: Bacterial clearances and inflammatory damage to the liver. Bacterial c learance of the autotransplanted spleen should be no different from th at of a sham-operation spleen and significantly different from that of a splenectomized animal. In addition, immunologic function of the aut otransplanted spleen should not differ from that of a sham-operation s pleen in the degree of inflammatory damage to the liver. Results: No d ifferences in bacterial clearance function were found between the anim als that had undergone sham laparotomy or splenic autotransplantation. However, bacterial clearance in the splenectomized animals was signif icantly impaired. Histologic examination of the liver 2 weeks after th e bacterial challenge revealed high-grade inflammatory damage to the l ivers of splenectomized dogs, intermediate liver damage in dogs that u nderwent autotransplantation, and essentially no damage in dogs that u nderwent sham laparotomy. Autotransplanted spleens were essentially no nreactive, lacking actively proliferating germinal centers, whereas sp lenic tissue from sham-operation animals showed reactivity.Conclusion: Although bacterial clearance function is unchanged in autotransplante d spleens, this method still does not fully protect the liver from inf lammatory damage.