Suppression of Reticuloendothelial Function in the Rat with Cyclophosphamide

Effects of cyclophosphamide immunosuppressive therapy upon reticuloendothelial function in the rat have been studied. Numerous side effects including leukopenia, hematuria, diarrhea, hemorrhagic cystitis, and petechial hemorrhage in the lungs and the small bowel were observed. Studies utilizing (32)P-labeled bacteria revealed no change in the ability of the liver, spleen, lungs, or kidneys to ingest Pseudomonas aeruginosa. Utilization of labeled Staphylococcus aureus revealed an impairment of splenic uptake in animals receiving the maximal dose of 100 mg/kg. However, the liver, lungs, and kidneys were not affected. Although no generalized defect in the ingestive powers of these organs was observed, the ability of the lungs and kidneys from treated animals to kill ingested bacteria was significantly impaired. Regardless of the bacterium employed, the lungs and kidneys revealed a decrease in bactericidal ability with increasing drug dosages. Neither the liver nor the spleen from treated animals exhibited any decrease in bactericidal effect. Possible causes of this reduction in the bactericidal ability of alveolar and renal tissue following immunosuppression with cyclophosphamide are discussed.