A patient develops acute transfusion-related acute lung injury (TRALI) 2 hours after receiving 2 units of FFP. Which pathophysiological mechanism best explains this reaction?

• A ABO incompatibility causing complement-mediated haemolysis and pulmonary oedema
• B Volume overload from rapid FFP infusion causing cardiogenic pulmonary oedema
• C Donor anti-HLA or anti-HNA antibodies binding to recipient neutrophils, activating them in pulmonary capillaries ✓
• D Cytokine storm from allogeneic leucocytes in the transfused product

Explanation

TRALI is most commonly caused by donor antibodies (anti-HLA class I/II, anti-HNA) — predominantly from multiparous female donors — that react with recipient leucocyte antigens, activating neutrophils in pulmonary capillaries and causing non-cardiogenic pulmonary oedema. It presents within 6 hours of transfusion with acute hypoxia (PaO2/FiO2 <300), bilateral pulmonary infiltrates, and fever without evidence of fluid overload. Volume overload causes TACO (transfusion-associated circulatory overload), not TRALI. Female donor exclusion or male-only FFP programmes have significantly reduced TRALI incidence.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.