Anaphylactic reaction after methylene blue-treated plasma transfusion.

Methylene blue-treated fresh-frozen plasma (MB-FFP) is mainly used in Europe. The advantage of the methylene blue system is that units can be treated individually. The combined action of methylene blue and illumination is a photodynamic process preventing viral RNA and DNA replication. We report the first immediate allergic hypersensitivity reaction to methylene blue-treated plasma transfusion. The clinical course and subsequent assessment of the allergic reaction, including skin tests and basophil activation test, confirmed methylene blue-induced IgE-mediated anaphylaxis. All immediate reactions after MB-FFP transfusion should be investigated to document the underlying mechanism.