Granulocyte transfusion therapy of experimental Pseudomonas septicemia: Study of cell dose and collection technique

Abstract

To determine the contributions of cell dose and collection technique to the success of granulocyte transfusion therapy, we developed a canine model of granulocytopenia with gram-negative septicemia. Beagles were made granulocytopenic with a single intravenous (i.v.) injection of cyclophosphamide (40 mg/kg); 5 days later, when all animals were granulocytopenic, graded doses of Pseudomonas aeruginosa were injected i.v., followed in 4 hr by antibiotics with or without granulocyte transfusions. Survival of animals not treated with granulocytes was related to the dose of Pseudomonas injected, with 1 x 108 bacteria/kg being lethal in greater than 95% of animals. Survival of animals treated with daily granulocyte transfusions after 1 x 108 bacteria/kg was critically dependent on the dose of cells transfused and the collection technique employed. When continuous-flow centrifugation was the method employed none of five animals receiving 1 x 108 granulocytes (PMN)/kg daily survived the infectious episode, while four of five receiving 1.5 x 108 and five of five receiving 2.0 x 108 PMN/kg survived. When cells collected by filtration leukapheresis were used, 2.5 to 3.0 times more PMN were necessary to provide the same protection: none of five survived at 2.0 x 108 PMN/kg, one of five survived at 3.0 x 108, three of five survived at 4.0 x 108, and five of five survived at 5.0 x 108 PMN/kg. Pretreatment of the recipient of filtration leukapheresis PMN with 25 mg hydrocortisone did not alter the ability of these cells to provide protection. These findings show that the success of PMN transfusion therapy for sepsis is critically dependent on the dose of PMN transfused and the collection technique employed.