Transfusion-related acute lung injury (TRALI)

Abstract

After a transfusion, a clinical phenomenon known as transfusion-related acute lung injury (TRALI) manifests as acute hypoxia and noncardiogenic pulmonary edema. The onset of TRALI is usually 6 hours post-transfusion. Fresh Frozen Plasma (FFP) transfusion is the most frequent cause of TRALI. About 60% of critically sick patients died due to TRALI, and the expected mortality rate is between 5% and 8%.

TRALI's mechanism is not completely understood. In the antibody-mediated method, antigen-antibody binding to the recipient neutrophils results via the passive transfer of leuko-agglutinating antibodies through plasma in blood components. A second process results from the transfusion of biologically active substances like lipids, cytokines, or antibodies that leuko-agglutinate. This process will activate the neutrophils in the endothelium and cause the withdrawal of reactive oxygen species (ROS) and proteases. It can cause pulmonary capillary leakage, pulmonary edema, and TRALI.

TRALI is characterized by symptoms such as dyspnea, cyanosis, hypotension, tachycardia, fever, cough, and pulmonary edema. The complete blood count (CBC) usually shows leukocytosis, although it is often preceded by leukopenia. The serological examinations to support TRALI are Human Leukocyte Antigen class II (HLA-II) and neutrophils-specific antibodies.

Several differential diagnoses for TRALI include Transfusion-Associated Circulatory Overload (TACO), Acute Respiratory Distress Syndrome (ARDS), transfusion reactions due to anaphylactic shock, fluid overload, and bacterial contamination. Patients with TRALI's prognosis depends on the resolution of the hypoxemic state.