Effect of packed red cell and whole blood transfusion on liver-associated immune function

In order to clarify the effect of allogeneic blood transfusion on liver metastases from primary cancer, liver-associated immune function after blood transfusion was evaluated in a murine model. Hepatic sinusoidal lymphocytes (HSL) were strongly cytotoxic to conventional natural killer cell-sensitive target (YAC-1), as well as to natural killer cell-resistant solid adenocarcinoma cells (colon 26), compared with splenic lymphocytes. Allogeneic whole blood transfusion strikingly suppressed the cytotoxic activities of HSL. Red blood cell transfusions also suppressed cytotoxicity to the same degree. In an animal model, allogeneic transfusion increased the rate of liver metastases. Flow cytometric analysis showed that transfusion caused a temporary decrease in the class II antigen positive cell fraction, mainly Kupffer's cells. This phenomenon occurred in parallel with changes in hepatic antitumor activity, indicating the possible importance of the involvement of Kupffer's cell in the development of the killer activity of HSL. These results suggest that blood transfusion may be a significant risk factor for hepatic metastasis by transiently suppressing the immunocompetence of the liver.