Anaphylactic transfusion reaction to group B platelets related to alpha-gal syndrome: A case report

Alpha-gal syndrome (AGS), a distinct form of IgE-mediated hypersensitivity to the carbohydrate galactose-α-1,3-galactose (α-Gal), typically occurs after repeated tick bites and leads to allergic reactions after ingestion of mammalian meat. Patients with AGS may experience a broad spectrum of allergic reactions, from pruritus and urticaria to angioedema and anaphylaxis. Although classically associated with food-triggered reactions, emerging reports describe AGS-related anaphylaxis following exposure to group B blood products, including cases without accompanying gastrointestinal symptoms, highlighting an underrecognized clinical presentation.

A 29-year-old group O male with chronic myelogenous leukemia, status post stem cell transplant from group A donor, with extensive pancytopenia, received multiple blood products, including red blood cells and platelets. Although most of the transfusions were uneventful, he developed allergic reactions repeatedly, from mild to anaphylactic reactions during the transfusion of group AB or B platelets. A history of tick bites was confirmed without establishing an association between his symptoms and meat consumption. A mildly elevated galactose-α-1,3-galactose IgE was detected. No additional allergic reactions were observed after strict use of non-B blood products was implemented.

This case demonstrates a possible clinical association between AGS and anaphylactic transfusion reaction to group B blood products in non-B recipients. Early laboratory workups for AGS antibodies are recommended in non-B patients with a history of tick exposure and severe allergic reactions to meat consumption or transfusion of group B blood products. Meanwhile, transfusion of group B blood products should be avoided once AGS is suspected clinically in non-B patients.