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Coagulation factor content of cryoprecipitate prepared from methylene blue plus light virus-inactivated plasma
V S Hornsey1, P Krailadsiri, S MacDonald
1Scottish National Blood Transfusion Service, National Science Laboratory, Edinburgh, UK. valerie.hornsey@snbts.csa.scot.nhs.uk
Abstract:
Levels of factor VIII (FVIII) and fibrinogen were assessed in control cryoprecipitate and cryoprecipitate prepared in two centres from plasma subjected to methylene blue (MB) photochemical virus inactivation. The level of coagulation FVIII activity was reduced in plasma by approximately 30% after MB photoinactivation, with only 44% (centre A) and 31% (centre B) of units meeting the current UK specification of 0.7 iu/ml. A revised specification of 0.5 iu/ml is suggested. Losses of less than 11% were seen for von Willebrand factor (VWF)-related activities. Cryoprecipitate prepared from group O or group A MB-treated plasma contained 27-40% less FVIII than control units. This reflected the lower levels in MB-treated plasma. The concentrating power of the cryoprecipitation process was not reduced for FVIII or fibrinogen in MB-treated units. MB cryoprecipitate from centre A still met the UK guideline specification for FVIII and fibrinogen content, whereas at centre B only 62.5% of the group O cryoprecipitates contained > 70 iu FVIII/unit. This may reflect the lower product volume and lower FVIII content of group O plasma used at centre B and suggests that maintenance of total coagulation factor recovery in MB-treated cryoprecipitate will require the higher product volume.
Insights
Methylene blue (MB) virus inactivation significantly reduced factor VIII (FVIII) levels in plasma and cryoprecipitate. Adjusting FVIII specifications and optimizing product volume are crucial for MB-treated cryoprecipitate quality.
Area of Science:
- Blood product safety and manufacturing
- Viral inactivation techniques
- Coagulation factor analysis
Background:
- Cryoprecipitate is a blood product rich in coagulation factors, including factor VIII (FVIII).
- Photochemical virus inactivation using methylene blue (MB) is employed to enhance the safety of plasma products.
- The impact of MB treatment on FVIII and fibrinogen levels in cryoprecipitate requires careful evaluation.
Purpose of the Study:
- To assess the levels of factor VIII (FVIII) and fibrinogen in cryoprecipitate prepared from MB-treated plasma.
- To compare FVIII and fibrinogen content against existing and proposed UK specifications.
- To evaluate the effect of MB treatment on FVIII recovery during cryoprecipitation.
Main Methods:
- Cryoprecipitate was prepared from plasma treated with methylene blue (MB) for virus inactivation.
- Factor VIII (FVIII) activity and fibrinogen levels were measured in control and MB-treated cryoprecipitate.
- von Willebrand factor (VWF)-related activities were also assessed.
- Results were compared between two preparation centers and against UK specifications.
Main Results:
- MB photoinactivation reduced FVIII activity in plasma by approximately 30%.
- Cryoprecipitate from MB-treated plasma showed reduced FVIII levels, with variable compliance with UK specifications (0.7 iu/ml).
- Losses of von Willebrand factor (VWF)-related activities were less than 11%.
- Cryoprecipitation efficiency for FVIII and fibrinogen was not reduced by MB treatment.
Conclusions:
- MB treatment significantly impacts FVIII levels in cryoprecipitate, necessitating a review of current specifications (suggesting 0.5 iu/ml).
- Cryoprecipitate from MB-treated plasma can meet specifications, but variability exists between centers.
- Optimizing product volume is essential for maintaining coagulation factor recovery in MB-treated cryoprecipitate.