Anaphylactic shock to fresh-frozen plasma inactivated with methylene blue.

BACKGROUND

Methylene blue allergy is a well-known entity associated with food or lymph node location. Inactivation of viruses by methylene blue in fresh-frozen plasma (FFP-MB) has been recently introduced in France after many years of use in other parts of Europe.

CASE REPORT: We describe here two anaphylactic shock reactions occurring during FFP-MB infusion in patients after cardiac surgery. The follow-up was favorable using epinephrine infusion in one patient and extracorporeal circulatory assistance in the other.

RESULTS

The allergy was suspected based on the following arguments: chronology of the event, absence of other allergen infused to patients, and an associated symptom (generalized rash). Methylene blue allergy was documented by prick tests and/or intradermal reactions with methylene blue and patent blue. Additional allergic tests with basophil activation tests confirm the role of the dye in the anaphylactic reaction.

CONCLUSION

These two cases questioned the safety of FFP-MB.