Effects of methylene blue-treated plasma on red cells and stored platelet concentrates

BACKGROUND: Photochemical methods can effectively inactivate extracellular Viruses and bacteria found in blood components. Treatment of plasma with me thylene blue (MB), a phenothiazine dye, and visible light inactivates envel oped Viruses including HIV-1. The effects of MB-treated plasma on cellular components stored in vitro have not been well characterized. STUDY DESIGN AND METHODS: MB-treated plasma (83 mu g MB/250 mL plasma) was added to single-donor platelets, stored AS-1 red cells (RBCs), irradiated R BCs, and frozen-deglycerolized RBCs. In vitro platelet assays performed aft er 1 and 5 days of storage in MB-treated plasma included pH, pO(2), pCO(2), HCO3, platelet number, lactate dehydrogenase, glucose, osmotic recovery, a nd CD62 expression. RBC components were examined at specific intervals for leakage of potassium, plasma hemoglobin level, and percentage of hemolysis. Direct antiglobulin tests, osmotic fragilities, and RBC antigen stability tests were also performed on RBCs stored in MB-treated plasma. Components s tored with autologous plasma or nontreated allogeneic plasma served as cont rols. RESULTS: Similar storage-induced changes in pH, glucose, and platelet numbe rs, as well as increases in lactate dehydrogenase, CD62 expression, and lac tate were seen in single-donor platelets stored with MB-treated and control plasma. Platelet morphology scores and osmotic recoveries were not altered . Plasma hemoglobin and potassium and percentage of hemolysis increased equ ally in the Various RBC components stored with MB-treated or nontreated pla sma. Osmotic fragility and RBC antigen stability were not appreciably alter ed by MB-treated plasma. CONCLUSION: Plasma treated by MB photoinactivation can be used for in vitro resuspension and storage of platelets or RBCs, because of the lack of infl uence of MB-treated plasma on a variety of in vitro platelet and RBC assays .