Infectious and immunologic consequences of blood transfusion

Blood transfusions remain common practice in the critical care and surgical settings. Transfusions carry significant risks, including risks for transmission of infectious agents and immune suppression. Transmission of bacterial infections, although rare, is the most common adverse event with transfusion. The risk for transmission of viral infections has decreased over time, clearly because tests are becoming more sensitive in detecting certain viral infections such as hepatitis B, hepatitis C, and HIV. Several immunomodulatory effects are thought to be related to transfusions, and these can result in cancer recurrence, mortality, and postoperative infections. Numerous studies have been performed to examine the role of leukoreduction in decreasing these transfusion-related complications but results remain contradictory. We review the infectious risks associated with blood transfusion and the most recent data on its immunologic effects, specifically on cancer recurrence, mortality, and postoperative infections in surgical patients. We also review the use of leukoreduction in blood transfusion and its role in preventing transfusion-transmitted infections and immunomodulatory complications.