Background: Transfusion of PLT concentrates may cause TRALI, a life-threatening reaction that has been linked to the infusion of anti-WBC immunoglobulins or older, stored PLTs that contain bioactive lipids. We hypothesize that lipids generated during storage of PLTs cause TRALI in a two-event animal model.
Study design and methods: Plasma from both whole-blood PLTs (WB-PLTs) and apheresis PLTs (A-PLTs) was isolated on Day 0 (D.0) and Day 5 (D.5) of storage and heat-treated before use. Rats were pretreated with saline or 2 mg per kg endotoxin (LPS), anesthetized, and the lungs were ventilated, isolated, and perfused with saline or 5-percent PLT plasma. Pulmonary artery pressure, pulmonary edema, and leukotriene B4 levels (perfusate) were measured.
Results: Plasma from D.5, but not D.0, of the identical WB-PLT and A-PLT units caused injury in lungs from LPS-pretreated rats (LPS/D.5) evidenced by increases in pulmonary edema and leukotriene B4 (p < 0.05). Lipid extracts and purified lipids from D.5 PLT plasma also elicited injury in lungs from LPS-pretreated rats (p < 0.05). Saline/D.5 plasma or lipids or LPS/D.0 did not cause pulmonary edema. Prestorage WBC reduction was ineffective in inhibiting TRALI.
Conclusion: PLT-induced TRALI may be the result of two events: 1) the clinical condition of the patient and 2) the infusion of lipids in stored PLTs.