Today we’ll be discussing TRALI, or transfusion-related acute lung injury. A major cause of TRALI is donor antibodies to white blood cells such as HLA and HNA, which activate leukocytes and neutrophils, and trigger the innate immune response. This process leads to acute lung injury. Other non-immune mediators, however, such as cell debris and biologically active lipids and peptides, can also cause TRALI.
Dr. Mark Popovsky, who helped characterize TRALI 30 years ago, adds:
“There have been significant gains in our understanding of the syndrome, specifically patient and transfusion risk factors and the prevention strategies that have been implemented over the last decade, particularly involving the use of male-only frozen plasma has clearly saved many lives.”
Current measures to prevent TRALI have been successful by reducing plasma transfusions from female donors who may have HLA antibodies. Many present cases of TRALI, however, are now due to non-plasma transfusions and non-immune-mediated forms of the disease.
Understanding TRALI through innovative models may help further our understanding and guide the development of new preventive strategies.
Dr. Theodore Warkentin describes one such model:
“Using parallels with an immune-mediated adverse drug reaction—heparin-induced thrombocytopenia (HIT)—as a model disease, we suggest that the immune and non-immune-mediated forms of TRALI be clearly distinguished, such that laboratory detectability of leukocyte-reactive alloantibodies reactive against cognate recipient leukocyte alloantigens is made a cornerstone of diagnosis of immune-mediated TRALI.”
In a separate TRANSFUSION article, Middleburg and van der Bom proposed models based on TRALI’s multicausal nature. They argue that individual risk factors for TRALI should not be combined. By considering risk factors separately, we may be able to tease apart the etiology of TRALI.
Dr. Popovsky also envisions new preventive strategies to prevent TRALI:
“I think we’ll see red cell preventive strategies being implemented over the next decade. Anything that’ll be able to reduce plasma content, so whether or not we’ll need to use different type of storage solutions or we’ll be washing red cells more often or be freezing, using frozen red cells more frequently, that remains to be seen.”
TRALI is still the number one cause of death from transfusions, but novel preventive strategies and innovative studies of the disease’s etiology may help prevent more cases.
We’ll be back with another edition of Transfusion News on May 30th. Thanks for joining us.
References
1. Middleburg RA, van der Bom JG. Transfusion-related acute lung injury not a two-hit, but a multicausal model. Transfusion 2015;55(5):953-60.
2. Popovsky MA. TRALI: Transfusion-related acute lung injury: three decades of progress but miles to go before we sleep. Transfusion 2015;55(5):930-934.
3. Warkentin TE, Greinacher A, Bux J. The transfusion-related acute lung injury controversy: lessons from heparin-induced thrombocytopenia. Transfusion 2015;55(5):1128-1134.
