RES uptake of red blood cell stroma: time course of effects on phagocytic function and susceptibility to endotoxin...

Previous studies have demonstrated that the injection of red blood cell (RBC) stroma to simulate the reticuloendothelial system (RES) uptake of RBC debris following intravascular hemolysis causes an acute depression in RES phagocytic function and an increase in shock susceptibility. The present study evaluated the time course of these changes. Initial studies demonstrated that the uptake of iodinated RBC stroma was followed by a decrease in the amount of radioactivity present in the liver between 30 and 60 min after injection. This was associated with an increase in free label in the circulation, indicating an active deiodination of the stroma. Phagocytic function was depressed at 30 min after injection of RBC stroma, but had returned to control by 60 min. Susceptibility to endotoxin shock was increased when endotoxin was injected 30 min, 1 hr, 3 hr, or 6 hr but not 24 hr after the RBC stroma. The increased mortality with endotoxin shock was shown not to be due to depletion of complement by the RBC stroma. This study demonstrated that over the period of recovery of RES phagocytic function following the ingestion of RBC stroma there is metabolism (deiodination) of the particulate material. Additionally, susceptibility to endotoxin shock is increased for a longer period of time than the depression of phagocytic function.