TRALI risk reduction: donor and component management strategies

Transfusion-related lung injury (TRALI) occurs in approximately 1 in 5,000 transfusions and may cause considerably more morbidity and mortality that is not recognized in clinical practice. Based on the current understanding of the etiology of TRALI, blood centers have implemented or are evaluating various donor and component management strategies in an effort to mitigate the risk of TRALI. Many cases of TRALI are likely caused by antibodies to leukocyte antigens (HLA or HNA) in blood components. Approximately 10 to 20% of female blood donors with a history of pregnancy and 1 to 5% of male blood donors harbor these antibodies. Alternatively, TRALI may be mediated by other bioactive lipids or substances that accumulate during storage and cause a reaction when transfused to susceptible patients. The complex interplay among various donor-, component-, and patient-related factors underlying TRALI guarantees that effective prevention will not be a single or simple intervention but rather will require a multifaceted approach. Perhaps, the most important risk reduction strategy is the effort to ensure appropriate use of blood products and eliminate unnecessary transfusions. Blood collection agencies, however, have more proximate control over donor selection and component management than transfusion practice. AABB has provided some guidance on deferring donors implicated in TRALI and minimizing the preparation of high plasma volume components from donors who have anti-leukocyte antibodies or are at increased risk of leukocyte alloimmunization. Blood centers have taken various approaches to mitigate the risk of TRALI, and the possible benefit and the inherent limitations of the current strategies will be reviewed.