Q: What causes Transfusion-Related Acute Lung Injury (TRALI) via pRBC transfusion?

Answer: TRALI is mostly associated with plasma components, means platelets and Fresh Frozen Plasma. TRALI with packed red blood cells (pRBCs) occur due to residual plasma in the packed cells. TRALI occurs due to the presence of leukocyte antibodies in transfused plasma. Leukoagglutination and pooling of granulocytes in the recipient's lungs causes release of the contents of leukocyte granules, and resulting injury to cellular membranes, endothelial surfaces, and potentially to lung parenchyma.