Transfusion-related adult respiratory distress syndrome.

Leukocyte antibodies are the major cause of nonhemolytic transfusion reactions. One of the less frequent but severe forms of this reaction is the adult respiratory distress syndrome, or transfusion-related acute lung injury. This rare phenomenon is the result of leukocyte antibodies forming immune complexes with granulocytes, complement activation, sequestration of activated granulocytes in the pulmonary capillary bed, and their degranulation associated with release of proteolytic and cytotoxic substances. This cascade causes endothelial damage with increased capillary permeability. Plasma fluids and proteins accumulate in the interstitial and intra-alveolar spaces, leading to respiratory insufficiency. We present two patients with transfusion-related adult respiratory distress syndrome associated with leukocyte HLA antibodies, who were successfully treated in our hospital. The pathogenesis, diagnostic measures and treatment of this uncommon yet critical condition is discussed.