Factor VIII von Willebrand factor complex in methylene blue-treated fresh plasma

BACKGROUND: The effect of virus inactivation of fresh plasma with methylene blue has been studied on the factor VIII/von Willebrand factor molecular complex (FVIII/vWF), factor XIII, and fibrinogen. STUDY DESIGN AND METHODS: FVIII function or activity, vWF activity, VWF antigen, vWF:Ag, vWF multimeric structure, fibrinogen, and factor XIII were analyzed in paired samples of control fresh plasma (untreated) and the same fresh plasma treated with methylene blue. Treated plasma was filtered (0.8-1.2 mu m), mixed with a methylene blue solution (300 mu g/L), and illuminated at 50,000 lux for 30 minutes on both sides. RESULTS: Average loss of biologic activity of coagulation factors studied was 25 percent (FVIII function, 29%; fibrinogen, 39%; factor XIII, 16%; and vWF activity, 18%). Reduction in vWF activity was significantly lower than that in FVIII function (p<0.05), and the vWF multimeric structure did not show alterations. CONCLUSION: Methylene blue-treated plasma and the cryoprecipitates obtained from it may be effective for replacement therapy in cases of von Willebrand disease and deficiencies of factor XIII and fibrinogen, but the clinical studies are needed to verify that possibility.