Understanding the effects of platelet transfusions in neonates.

Platelet transfusions represent a common life-saving intervention used in intensive critical settings to treat neonates with thrombocytopenia, at risk of or actively bleeding, or undergoing clinical complications that make transfusions part of the management. Even though it is intended to help restore hemostasis in patients, platelet transfusions can, under certain circumstances, lead to negative effects, greater inflammation, and rarely increased mortality. It is the occurrence of these unforeseen and yet to be defined transfusion-associated complications that are at the center of a renewed effort to identify those factors increasing risk or that make a subset of patients more likely to develop adverse events as a result of transfusions. Platelets are active members of the native immune system and, as such, express surface receptors that mediate directly cross-talk with immune cells or do so indirectly though secretion of cytokines and chemokines that activate immune cells. Together with inherent differences between donated adult platelets and platelets in neonates, the reasons for negative responses begin to come into focus.