When the Immune System Misfires
A 9-year-old boy develops fever and chills near the end of a packed RBC transfusion. He is hemodynamically stable and has no dyspnea, rash, hypotension, flank pain, or dark urine. His symptoms improve after the transfusion is stopped. Workup for hemolysis is negative.
Which of the following best explains this reaction?
A. Preformed recipient antibodies causing intravascular hemolysis of donor RBCs
B. Donor plasma proteins binding recipient IgE on mast cells
C. Cytokines released from donor leukocytes in stored blood products
D. Antibody-mediated destruction of donor and recipient platelets
E. Bacterial contamination of the transfused product
Answer: C. Cytokines released from donor leukocytes in stored blood products
A 32-year-old woman with a history of recurrent sinopulmonary infections develops hypotension, wheezing, urticaria, and respiratory distress within minutes of starting a plasma-containing transfusion. She improves after IM epinephrine.
Which of the following is the most likely underlying mechanism?
A. Delayed anamnestic response to donor RBC antigens
B. Type I hypersensitivity to donor plasma proteins in a recipient with IgA deficiency
C. Complement-mediated destruction of donor RBCs due to ABO incompatibility
D. Primed neutrophils in pulmonary endothelium activated by donor antibodies
E. Volume expansion causing cardiogenic pulmonary edema
Answer: B. Type I hypersensitivity to donor plasma proteins in a recipient with IgA deficiency