[Transfusion-related acute lung injury]

Transfusion-related acute lung injury (TRALI) is a major complication of blood transfusions. The pathogenesis of TRALI is thought to occur in 2 phases: the 'double-hit theory'. The first phase is an underlying condition present in the patient, such as a surgical procedure or sepsis, which leads to priming, i.e. the activation of endothelium and subsequent sequestration of neutrophils in the lungs. The second phase is the transfusion of a blood product resulting in the activation of the neutrophils. Antibodies against human leukocyte antigens (HLA) or against human neutrophil antigens (HNA) present in the donor blood are involved in this step. The long-term storage of cell-containing blood products may also be a causative factor. The incidence of TRALI in patients with an underlying condition is high; up to 15% of transfused patients are at risk. Anti-HLA and anti-HNA antibodies are highly prevalent in multiparous female donors. The exclusion of female donors for plasma and thrombocyte products has led to a 33-66% reduction in the incidence of TRALI.