The Effect of Washed versus Unwashed Packed Red Blood Cell Transfusion on Immune Responses in the Extremely Preterm Newborn: A Pilot Randomised Trial

A growing body of observational data has recognised that transfusion exposure results in adverse responses and increased rates of morbidity in the recipient. The current study suggests that the association between transfusion and poor outcome may have a predominantly immunomodulatory basis, a relationship that may be altered by the use of washed packed red blood cells for the extremely preterm infant. Transfusion with washed packed red blood cells resulted in significant post-transfusion decreases in plasma pro-inflammatory cytokines and chemokines, while transfusion with unwashed packed red blood cells resulted in the opposite, with significant increases in IL-17A and TNF. Further, by the 3rd transfusion exposure, this response to unwashed blood was also associated with increases in markers of endothelial activation, an effect not seen with washed s. These alterations in pro-inflammatory cytokines and markers of endothelial activation in response to early, repeated transfusion exposure comparing the response to unwashed and washed packed red blood cells are novel. While the mechanisms underlying transfusion associated morbidities and immunomodulation are not yet fully understood, the current results provide strong mechanistic data supporting a potentially beneficial effect of transfusion of washed packed red blood cells in this high-risk population.