Pathogen reduction of fresh plasma using riboflavin and ultraviolet light: effects on plasma coagulation proteins

Treatment with riboflavin and ultraviolet (UV) light reduces the pathogens present in blood components. This study assessed changes to the coagulation proteins that had occurred during this treatment of fresh plasma units before freezing.

Twenty fresh plasma units (230 +/- 30 mL) were treated by the Mirasol process (CaridianBCT Biotechnologies) and frozen within 8 hours of donation. Plasma units were combined with 35 mL of a 500 micromol/L riboflavin solution in an illumination bag to achieve a final concentration of approximately 60 micromol/L riboflavin. The bag was placed in the Mirasol illuminator and exposed to UV light (6.24 J/mL). Samples were frozen before and after treatment.

Recoveries observed were 67.7 +/- 3.9% Factor (F)XI, 68.5 +/- 3.3% FVIII:C, 78.8 +/- 4.5% fibrinogen, 78.9 +/- 4.1% FV, 79.0 +/- 4.2% FVII, 79.0 +/- 8.6% F IX, 79.7 +/- 2.6% FX, and 85.0 +/- 3.7% FII. Von Willebrand factor (VWF) antigen, VWF:ristocetin cofactor, and ADAMTS13 recoveries were 87.0 +/- 7.1, 85.5 +/- 6.6, and 73.3 +/- 15.2%, respectively, while that of protein C was 83.6 +/- 2.6%. A loss of high-molecular-weight VWF multimers was observed in most units. Recoveries for protein S, antithrombin, and plasmin inhibitor were greater than 90%. The mean FVIII:C concentration, after treatment, was 0.76 +/- 0.17 IU/mL.

As with other pathogen reduction technologies, the Mirasol process resulted in some loss of coagulation factor activity. For most Mirasol-treated units and for most of the tested factors this is unlikely to have clinical impact, but trials are required to demonstrate this.