A 20-year-old woman with selective IgA deficiency (serum IgA <7 mg/dL) requires a blood transfusion. She develops anaphylaxis during the transfusion. The mechanism of this reaction involves:
- A Anti-IgA IgG antibodies in the recipient reacting with donor IgA ✓
- B ABO incompatibility causing complement-mediated hemolysis
- C Donor T-cell attack on recipient tissues (GVHD)
- D Bacterial contamination of the blood product
Correct answer: A. Anti-IgA IgG antibodies in the recipient reacting with donor IgA
Explanation
Selective IgA deficiency patients can form anti-IgA antibodies (IgG or IgE class). When transfused with IgA-containing blood products, these antibodies trigger anaphylaxis (Type I or III hypersensitivity). Washed RBCs and IgA-deficient donors are required. Option B describes acute hemolytic transfusion reaction. Option C describes transfusion-associated GVHD. Option D describes septic transfusion reaction.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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