Red cell transfusions are associated with inflammation and thrombosis, both arterial and venous, the mechanisms of which are not understood. Although a necessary life saving procedure in modern medicine, transfusions have rarely been subjected to modern assessments of efficacy and safety, including randomized trials. Storage of red blood cells induces changes, including the release of free hemoglobin and the accumulation of biologically active soluble mediators and microparticles. These mediators likely play a direct role in the inflammatory and pro-thrombotic properties of red cell transfusions. Methods such as leukoreduction, washing of red cells and rejuvenation may improve the quality of red cell transfusions.

Platelet transfusion has long been practiced with rudimentary knowledge about optimal storage conditions and their implications for efficacy and, particularly, safety. Recent concerns about complications such as inflammation, thrombosis and altered recipient immunity have been raised about platelet transfusion. This review will discuss recent important findings that have raised these issues about platelet transfusion associated morbidity, mortality and the possible role of platelet storage in these associations.