1c Immunomodulation by blood transfusion: cancer recurrence and infection

Abstract

The risks of cancer recurrence and post-operative bacterial infection which are attributed by some authors to an immunomodulatory effect of allogeneic transfusion have remained controversial for 15 years, as many observational studies and four randomized controlled trials have produced contradictory results. A review of these discrepant findings suggests that a deleterious immunomodulatory transfusion effect might exist, but it might operate only in specific surgical settings. The challenge is to identify those settings and to determine the magnitude of the adverse effect if it exists. This will require further randomized controlled trials designed to establish causal relationships and new observational studies designed to explain disagreements between published investigations. Lessons learned from the methodological limitations of the earlier reports can guide the design of future studies. It is hoped that the new studies will permit the formulation of rational guidelines for peri-operative transfusion practice which will prevent any deleterious effect(s) of transfusion-induced immunomodulation.