Variable infection risk following allogeneic blood transfusions.

These studies address infection risk of allogeneic transfusion in an untraumatized, nonseptic rodent model. A' Segaloff Cancer Institute rats served as blood donors and Lewis rats as recipients. Lewis rats' delayed-type hypersensitivity (DTH) response and their ability to clear subdermal Staphylococcus aureus abscesses and Candida albicans pyelonephritis were measured as tests of the effect of transfusions. The effect of pharmacological immunosuppression with either cortisone acetate or cyclosporine provided a "yardstick" to measure the magnitude of transfusion effects. Repeated transfusions at 1-week intervals diminished DTH response to recall antigens (keyhole limpet hemocyanin), but otherwise they showed no evidence of immunosuppression in these experiments. In contrast, we found that transfusions by themselves produced mild immunostimulation. Subcutaneous Staphylococcus abscesses were smaller in animals receiving transfusions. The magnitude of immunostimulation from one transfusion was sufficient to reverse the immunosuppressive effect of cyclosporine by about 50% in a Candida pyelonephritis infection. These studies suggest that blood transfusions have complex interactions with different components of the immune response. T-cell function is impaired by repeated transfusions (diminished DTH response), but other inflammatory responses are accentuated. This suggests that blood transfusions may harm immune response in traumatized animals by causing excessive complement activation or cytokine release.