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Plasma treated with methylene blue and light: clinical efficacy and safety profile
Miguel Lozano1, Joan Cid, Thomas H Müller
1Department of Hemotherapy and Hemostasis, University Clinic Hospital, Barcelona, Spain.
Abstract:
Methylene blue (MB) was the first method developed for pathogen inactivation of a labile blood component that was introduced in 1991. MB and light (MBL) inactivates most lipid-enveloped viruses and those non-enveloped are, in general, resistant. MBL treatment affects several coagulation factors, most noticeably fibrinogen and factor VIII with a loss of approximately 30%. Using endogenous thrombin potential, a global hemostasis evaluation, MBL treatment of plasma resulted in a 7% to 10% of reduction in thrombin potential. Although, originally, the scientific evidence of its efficacy and safety were scarce, the 4.4 million of units transfused have provided a wide body of evidence of its efficacy and safety in most of clinical situations. Nevertheless, some doubts have arisen about the efficacy of MBL plasma when used as a replacement solution for plasma exchange in the treatment of patients suffering from TTP. Probably only randomized controlled trials would provide definite evidence to clarify this point. Reports of severe allergic reactions in a few patients receiving MBL plasma have provoked the recent decision to remove the product from the market in France. Interestingly hemovigilance data in countries such as the same France, Spain, and United Kingdom have not corroborated an increase in severe allergic reaction. Close monitoring of the patients receiving plasma and suffering from allergic reactions and reporting to hemovigilance schemes hopefully will provide the needed data to definitely establish the exact risk of this complication for MBL vs other types of plasma.
Insights
Methylene blue (MB) light treatment inactivates many viruses in blood components but affects coagulation factors. Despite concerns, extensive use shows safety, though efficacy in TTP treatment requires further study.
Area of Science:
- Blood component safety
- Pathogen inactivation technologies
- Transfusion medicine
Background:
- Methylene blue (MB) light treatment, introduced in 1991, is a primary method for pathogen inactivation in labile blood components.
- MBL effectively inactivates lipid-enveloped viruses, while non-enveloped viruses generally show resistance.
Purpose of the Study:
- To evaluate the efficacy and safety of Methylene Blue (MB) light treatment in blood components.
- To assess the impact of MBL treatment on coagulation factors and hemostasis.
- To investigate concerns regarding MBL plasma efficacy in TTP treatment and allergic reactions.
Main Methods:
- Assessment of MBL's effect on viral inactivation, including lipid-enveloped and non-enveloped viruses.
- Analysis of MBL's impact on coagulation factors (fibrinogen, factor VIII) and endogenous thrombin potential.
- Review of clinical data and hemovigilance reports concerning MBL plasma transfusions and adverse events.
Main Results:
- MBL treatment leads to a significant reduction (approx. 30%) in fibrinogen and factor VIII.
- A 7-10% reduction in thrombin potential was observed in plasma treated with MBL.
- Extensive transfusion data (4.4 million units) supports the general efficacy and safety of MBL, but specific doubts remain for TTP treatment.
Conclusions:
- MBL is a proven pathogen inactivation method with a substantial safety record, though it impacts certain coagulation factors.
- Further randomized controlled trials are needed to confirm MBL plasma efficacy in TTP treatment.
- Hemovigilance data does not support an increased risk of severe allergic reactions with MBL plasma compared to other plasma types, despite market withdrawal in France.
