Methylene Blue Photochemical Virus-Inactivated Plasma: Safety, Efficacy, and Clinical Applications

Abstract Background: Methylene blue is widely used in plasma products as a photosensitizer for pathogen inactivation, owing to its capacity to damage viral nucleic acids via photoactivation. Methylene blue photochemical (MB-P) virus-inactivated plasma is currently utilised in clinical practice for managing multiple conditions. However, concerns persist regarding the potential toxicity of methylene blue and the possible adverse reactions it may trigger following infusion. The technology of methylene blue photochemical inactivation inevitably impacts plasma volume, storage quality, and plasma composition. Its application in the treatment of thrombotic thrombocytopenic purpura remains a subject of ongoing debate. Is the infusion of methylene blue-inactivated plasma safe? This review aims to address this issue. Summary: This review outlines the mechanism of action of methylene blue photochemical inactivation of viruses in plasma, summarizes existing evidence regarding its feasibility and safety in clinical disease treatment, and preliminarily explores the benefits of combining methylene blue with novel technologies. The primary evidence demonstrates that MB-P virus-inactivated plasma effectively prevents the transmission of severe transfusion-transmitted viral diseases and enhances the safety of blood transfusion therapy for patients, showing promising prospects in clinical treatment. The scope of inactivated viruses and the range of applicable diseases are limited, and the volume of plasma lost during processing is significant; however, this issue may be resolved in the future by integrating new technologies. Key Messages: The findings indicate that the methylene blue photochemical treatment system substantially reduces residual methylene blue concentrations, effectively inactivates the vast majority of pathogens—not limited to viruses—and may extend plasma shelf life. Although this method unavoidably impacts plasma volume and coagulation properties, it does not compromise therapeutic efficacy. Clinical treatment data statistics reveal that compared to other pathogen inactivation protocols, the adverse event rate following infusion of MB-P virus-inactivated plasma was merely 0.5 per 10,000 units, demonstrating substantial clinical advantages. Furthermore, recent studies indicate that integrating methylene blue with novel techniques could expand the spectrum of inactivatable pathogens.