Neutrophils contain cholesterol crystals in transfusion-related acute lung injury (TRALI)

Intracellular components of transfusion-related acute lung injury (TRALI) were investigated by transmission electron microscopy. The lungs from 2 fatal TRALI cases and 2 controls, previously studied by scanning electron microscopy, were studied by transmission electron microscopy. Morphologic data by light and phase microscopy, along with scanning and transmission electron microscopic observations, were collated. The 2 fatal TRALI cases exhibited dense laminated material within capillaries and postcapillary venules, similar to material identified within their neutrophils when viewed by transmission electron microscopy. This material polarized light and is presumed to be cholesterol crystals. The damage to the pulmonary vascular endothelium in TRALI is related to formation of cholesterol crystals originating within neutrophils.