[The effect of blood transfusion on immunological response in mice]

Recent clinical and experimental studies have suggested that blood transfusion decreased immunological responsiveness. In order to investigate this mechanism, we performed following studies. In vivo experiments, we investigated the effect of blood transfusion on tumor growth and survival rate in mice, and added the comparative studies about the timing of blood transfusion and blood cell component transfusion. In vitro experiments, we studied on the responses of CTL and NK activity by the experimental model of postoperative blood transfusion. These experiments led to the following results: 1) Accelerated tumor growth and reduced survival rate were observed in allogeneic transfused mice. 2) These effects were seen independently of the timing of blood transfusion. 3) A transfusion of lymphocytes was capable of inducing this effect of blood transfusion. 4) Blood transfusion induced both suppression of anti-tumor CTL, TNP-CTL and NK activity. 5) The suppression of CTL was mediated by suppressor cells. From these results, it was suggested that allogenic blood transfusion induced immunosuppression in mice independently of its timing.