An outbreak of anaphylactic transfusion reactions to group B plasma and platelets and its possible relationship to Alpha‐Gal syndrome

BACKGROUND: Alpha-gal syndrome (AGS) is a potentially life-threatening acquired meat allergy associated with tick bites. The allergen Galactose-α-1,3-Galactose is antigenically similar to the B blood group antigen. B blood group status offers some protection against development of the allergy. Although not preferred practice, transfusion of plasma and platelets from group B donors is believed to be safe for group O recipients. STUDY DESIGN AND METHODS: Anaphylactic transfusion reactions were reported for three patients in two Washington DC hospitals from Nov 2022 to February 2023. A chart review was performed for all three patients. Patients or family members were interviewed, and IgE levels to alpha-gal were measured in two of the three patients. RESULTS: One reaction was acutely fatal. All reactions were to blood group B Plasma or Platelets in blood group O recipients. One patient had two prior anaphylactic reactions to group O RBCs and group B Plasma in a previous admission. All patients came from southern Maryland where AGS is an emerging problem. Two patients had histories of tick bites, previously unexplained gastrointestinal complaints, and abnormal elevated levels of IgE to alpha gal. Two patients had cat allergies. DISCUSSION: AGS is an emerging problem which may have implications for blood transfusion practice. Avoidance of blood group B antigen containing components may be prudent in non-blood group B patients with established AGS. Investigation for AGS should be considered in the evaluation of anaphylactic transfusion reactions.