Protein stability of previously frozen plasma, riboflavin and UV light-treated, refrozen and stored for up to 2 years at −30 °C

BackgroundThe Mirasol pathogen reduction technology system for plasma is based on a riboflavin and UV light treatment process resulting in pathogen inactivation due to irreversible, photochemically induced damage of nucleic acids. The objective of this study was to evaluate the in vitro protein quality of previously frozen FFP, thawed, Mirasol-treated and refrozen for a final storage period of up to 2 years at −30 °C.Materials and methodsAll plasma products were held at 4 ± 2 °C, and frozen within 8 h after the start of collection. FFP was stored frozen at −30 °C for eight time intervals before riboflavin and UV light treatment and refrozen to −30 °C and stored for varying time intervals for a total storage period of up to 2 years at −30 °C. Results were compared to paired, untreated units thawed and stored for the same time intervals.ResultsThe overall mean values for all time points in riboflavin and UV light treated plasma samples indicates that all proteins were well preserved following a period of frozen storage for 2 years at −30 °C. Factors V, VII and XI, retained 70%, 65% and 53% activity, respectively. All other protein factors, anticoagulant and inhibitor proteins demonstrated retention between 74% and 100%.ConclusionRiboflavin and UV light-treated FFP maintained both coagulant and anticoagulant in vitro protein quality after double freeze/thaw storage at −30 °C for up to 2 years, a finding that may offer processing flexibility to blood centers.