An experimental assessment of the effect of blood transfusion on susceptibility to bacterial infection.

Clinical investigations in patients who have undergone transplantation and patients with cancer and infection suggest that blood transfusions have an immunosuppressive effect. To investigate the impact on responses to infection, an experimental transfusion model was developed in the rat with allogeneic or syngeneic transfusions. Animals were given either a moderate or severe bacterial challenge, both simulating a clinical surgical infection, immediately after transfusion or 1 week later; hypotension and hemodilution were especially avoided. Blood transfusion adversely affected the animals' capacity to resist immediate moderate challenge, but not a later one. The effect was maximized by allogeneic transfusion but was not demonstrable after severe bacterial challenge, whether immediate or late.