Transfusion-related acute lung injury: transfusion, platelets and biological response modifiers.

Transfusion-related acute lung injury (TRALI) may be induced by plasma, platelet concentrates and red blood cell concentrates. The mechanism leading to TRALI is thought to involve two steps. The priming step consists of previous inflammatory pathological conditions or external factors attracting leukocytes to lung vessels and creating conditions favorable for the second step, in which anti-HLA or anti-HNA antibodies or biologically active lipids, usually in transfused blood products, stress leukocytes and inflame lung epithelia. Platelets may be involved in the pathogenesis of TRALI because of their secretory potential and capacity to interact with other immune cells. There is no drug based-prophylaxis, but transfusion strategies are used to mitigate the risk of TRALI.