Opsonic Requirements for Intravascular Clearance after Splenectomy

Abstract

We investigated the opsonic requirements for intravascular clearance of pneumococci in guinea pigs and of sensitized erythrocytes in human beings after splenectomy. The impaired clearance of injected pneumococci in splenectomized guinea pigs was corrected by immunization. This improvement in clearance was due to increased hepatic sequestration of organisms. There was a significant delay in antibody-mediated clearance of autologous erythrocytes sensitized with IgG (P < 0.001), although the rate of complement-mediated clearance in splenectomized patients was normal. A fourfold increase in sensitizing antibody resulted in a significant improvement in clearance that was due to increased hepatic sequestration (P < 0.005). One patient who had an intact spleen and who had previously received Thorotrast (thorium oxide) had impaired antibody-mediated clearance despite increased sensitization. These observations suggest that, after splenectomy the remaining macrophages of the reticuloendothelial system require increased amounts of antibody to mediate efficient intravascular clearance of opsonized particles.

IgG-mediated phagocytosis in regenerated splenic tissue

“…This study has confirmed that the spleen is the most important organ for the removal from the bloodstream of particles which are poorly opsonized [2]. It also confirms that the lymphoid compartments of the spleen do not regenerate normally in autotransplants [23][24][25][26] or ties [27], and suggests further abnormalities in the vascular bed with the finding that the number of white pulp areas whieh have a central arteriole were greatly redueed.…”

“…The spleen is an integral component of the reticuloendothelial system, with major roles in the mounting of antibody responses, and the phagocytosis and clearance of matter from the blood, A number of studies have clarified the specific nature of splenic phagocytosis [1,2]. While IgM and C3b opsonized particles are removed from the circulation predominantly by the liver [3], the spleen is required for the removal of IgGcoated particles from the blood, particularly those which are poorly opsonized [4].…”

Association of circulating receptor Fc gamma RIII-positive monocytes in AIDS patients with elevated levels of transforming growth factor-beta.

“…Receptor-mediated clearance of IgG-opsonized microorganisms and antigens is important in host defense (37,38), and its fluctuation may be deleterious in certain disease states. Enhanced FcyR expression may, in fact, contribute to the pathogenesis of certain diseases (36,(37)(38)(39)(40)(41).…”

“…Enhanced FcyR expression may, in fact, contribute to the pathogenesis of certain diseases (36,(37)(38)(39)(40)(41). Immune complexes and/or mononuclear cell-derived cytokines reportedly stimulate FcyR synthesis by circulating monocytes (42).…”

Fcγriia polymorphism as a risk factor for invasive pneumococcal infections in systemic lupus erythematosus

“…This defect may allow bacterial dissemination from the lung into the bloodstream and may have even more profound effects on hepatic and splenic clearance mechanisms. In SLE, wherein functional asplenism is estimated to occur in 4.6-7.1% of all patients (15), the role of the IgGZFcyRIIA axis becomes even more critical because removal of the bacteria becomes dependent on the less efficient hepatic clearance alone (16). Of 13 cases of functional asplenism in SLE reviewed recently (17), 6 individuals developed pneumococcal sepsis, and another developed Salmonella sepsis.…”