Fresh Frozen Plasma Has the Highest Incidence of Transfusion-Related Acute Lung Injury (TRALI)
Fresh frozen plasma (FFP) has been identified as the blood component with the highest risk for causing TRALI due to its high plasma volume and potential for containing leukocyte antibodies. 1
Why FFP Has the Highest TRALI Risk
- FFP and platelet concentrates are the most frequently implicated blood products in TRALI, with FFP having the highest risk 2, 1
- The TRALI risk per component is 6.9 times higher for FFP than for red blood cells 3
- FFP contains high concentrations of plasma, which may contain donor antibodies (particularly from female donors) that can react with recipient leukocytes 1, 4
- These antibodies, particularly anti-HLA and anti-neutrophil antibodies, are the primary cause of immunogenic TRALI 4
Pathophysiology of TRALI
- TRALI is primarily caused by donor antibodies that recognize leukocyte antigens in the transfused recipient (immunogenic TRALI) 4
- These antibodies trigger neutrophil activation in the pulmonary vasculature, leading to endothelial damage and capillary leak 4
- Non-immunogenic TRALI can also occur due to biologically active lipids that accumulate during storage of blood products 4
- The "two-hit" model explains why critically ill patients are more susceptible to TRALI - they often have pre-existing inflammatory conditions that prime neutrophils (first hit), making them more reactive to antibodies or biological response modifiers in transfused products (second hit) 5
Evidence for FFP as Highest Risk Product
- Studies have shown that the risk of TRALI due to FFP was 15.5 per million units issued compared to lower rates for other blood components 3
- In donors of implicated FFP/platelets, white blood cell antibodies were found 3.6 times more often than by chance (p ≤ 0.0001) 3
- Female donors were particularly implicated in TRALI cases, as they are more likely to have developed leukocyte antibodies during pregnancy 3, 6
Risk Reduction Strategies
- Implementation of male-only plasma for component therapy has significantly reduced TRALI incidence 1, 6
- After introducing male-only plasma policies, the risk of highly likely/probable TRALI due to FFP fell from 15.5 per million units to 3.2 per million units (p = 0.0079) 3
- The Netherlands reported a 33% reduction in TRALI cases after implementing male-only plasma policies 6
- Blood banks now routinely screen donors for leukocyte antibodies to further reduce risk 1, 7
Clinical Implications
- TRALI presents with acute respiratory distress within 6 hours of transfusion, with hypoxemia and bilateral pulmonary infiltrates 7
- It must be differentiated from Transfusion-Associated Circulatory Overload (TACO), which presents with similar respiratory symptoms but includes cardiovascular changes and evidence of fluid overload 7
- Management includes immediate cessation of transfusion, oxygen support, and sometimes mechanical ventilation 7, 8
- Unlike TACO, diuretics are ineffective and potentially harmful in TRALI 7, 4
In summary, FFP carries the highest risk of TRALI among blood products due to its high plasma content and potential for containing leukocyte antibodies. The implementation of male-only plasma policies has significantly reduced this risk, confirming the causal relationship between FFP and TRALI.