Hemolytic Transfusion Reactions Due to Le^a and Le^b Antibodies

A 20-year-old pregnant woman at 12 week gestation with a history of thalassemia was admitted to the hospital with Hb 60g/L. She received two transfusions of 2 units of negative crossmatched washed red blood cells (RBCs) each, but shortly after she experienced a transfusion reaction. Symptoms included chest tightness, dyspnea, chills, and soy sauce colored urine. A post-transfusion specimen was sent to the blood type reference laboratory (BTRL) for investigation, which revealed the presence of anti-Le^a and anti-Le^b antibodies causing the immediate acute hemolytic transfusion reaction; interestingly, the patient's Le^a antibody was found to be IgM, while the Le^b antibody was both IgM and IgG. This combination of antibodies is rare and highlights the potential for clinically insignificant Lewis cold antibodies to cause serious reactions. It is important to not overlook these antibodies and to select antigen-negative units rather than relying solely on blood crossmatching. The use of polybrene in crossmatching blood tests may have limitations in the presence of Lewis antibodies, so alternative methods should be considered in difficult cases to ensure safe and effective transfusions. This case emphasizes the need for thorough testing and careful selection of blood products to reduce the risk of transfusion reactions and improve overall transfusion safety.