Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related mortality. The current pathophysiological model implicates:

• A ABO incompatibility causing complement-mediated hemolysis and pulmonary edema
• B Hypervolemia from rapid transfusion causing cardiogenic pulmonary edema
• C Donor-derived anti-leukocyte antibodies (HLA or HNA antibodies) activating neutrophils in the pulmonary vasculature ✓
• D Citrate toxicity from massive transfusion causing hypocalcemia and pulmonary vasoconstriction

Explanation

TRALI is caused by donor-derived antibodies (primarily anti-HLA class I/II or anti-human neutrophil antigen antibodies) in the transfused plasma that recognize recipient leukocyte antigens, triggering neutrophil sequestration and activation in the pulmonary vasculature, resulting in non-cardiogenic pulmonary edema within 6 hours of transfusion. It is distinct from TACO (transfusion-associated circulatory overload), which is cardiogenic. UK and major blood services now use predominantly male or parous-tested female donors for plasma and platelets to minimize anti-HLA antibodies.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.