Do multiple blood transfusions predispose for a higher rate of non-blood-related infection complications?

Allogeneic transfusions of red blood cell (RBC) concentrates have been related to an increase in postoperative infections. Leukocytes present in RBC units might have deleterious effects on the receptor immune system, provoking a state of immunosuppression that favors the development of postoperative infections (TRIM effect). The bioactive substances released by leukocytes in a time-dependent form, accumulating in blood components during storage, might be responsible for the TRIM effect. Multiple observational studies with logistic regression have demonstrated a direct relationship between transfusion and infection. However, several factors related to surgical difficulty and patient illness severity might act as strong confounding variables on the relationship studied. Randomized controlled trials designed to establish a causal relationship between transfusion and infection have yielded contradictory results. While we await new studies, allogeneic transfusions should be considered as a possible risk factor for postoperative infection.