FORMATION OF AGGREGATES IN STORED RED CELL CONCENTRATES WITH MAP SOLUTION

Macroaggregates are found frequently in stored red cell concentrates with MAP solution (RC-M·A·P). Incidence and causative factors of macroaggregate formation were investigated compared to concentrated red cells containg CPD (CRC). The number of microaggregates was also compared. The incidence of macroaggregate formation in RC-M·A·P increased during storage. They were found in 36 or 67% of RC-M·A·P at 3 weeks of storage and in more than 70% at 5 to 6 weeks, while in 8.6% of CRC at 3 weeks. The macroggregate formation was not sufficiently affected either by mannitol or citrate concentrations in MAP solution. Such macroaggregates were composed of leukocytes, platelets and fibrin like substances. The leukocytes in RCM·A·P drastically decreased during storage. Fibrinopeptide-A (FAP) in RCM·A·P gradually increased during storage, which significantly correlated to the decrease of leukocytes, but not in CRC. These results suggested that macroaggregate formation was not due to mannitol, but may be related to the degeneration of leukocytes and the activation of coagulation system. The number of microaggregates which pass through transfusion filter was statistically less in RC-M·A·P than in CRC. Therefore, the incidence of side effects caused by them might be decreased by using RC-M·A·P.