The exact mechanism of this reaction is uncertain, but it is likely due to cytokines or other products which activate the same inflammatory and vasoactive mediators. Allergens in the donor blood include antibiotics or chemicals used in blood preparation, albumin and C4. Rarely, transfused IgE antibodies from the donor can initiate the reaction. It has not been documented with infusion of cryoprecipitate. This type of reaction can occur on the first tranfusion.
Treatment consists of stopping the transfusion.
For mild reactions, administration of antihistamines and corticosteroids will rapidly alleviate the clinical signs. More severe signs require intensive shock therapy, including administration of corticosteroids and, possibly, epinephrine. In human patients, this reaction has only been observed with whole blood, red cell or platelet concentrates, and fresh plasma. The reaction is suspected when there is a temperature increase of at least 1 C with no other cause for the elevation. Vomiting and tremors may also be seen.