Transfusion-Related Immunomodulation in Relation to Perioperative Infection/Cancer: Biology, Evidence, and Controversy in Transfusion

Transfusion-related immunomodulation is a side effect of allogeneic transfusion. During the development of orthotopic renal transplantation, red cell transfusions were administered as an effective immunosuppressant. In the 1980s–90s, the focus and lay hysteria was on viral transmission (hepatitis and AIDS) as risks for blood transfusion. These viral risks are now reduced to very low levels and evidence has emerged that transfusion-related immunomodulation contributes to a number of adverse outcomes associated with allogeneic transfusion. Controversy remains due to the largely retrospective data published. This review will outline historical perspectives as well as look into mechanisms and outcomes. It is important to understand the controversy so that research going forward may be well focused and evidence based.