TRALI: Leukopenia

TRALI: a inflammatory (non-hydrostatic) pulmonary edema Characterized by:

• acute respiratory distress
• hypoxemia
• hypotension
• fever
• widespread pulmonary infiltrates
• The majority of cases occur within minutes

Most are within 1-2 hours, but must be <6 hours after blood product transfusions to qualify as TRALI

• Happens in 1/5000 blood product transfusions
• Leading cause of transfusion-related mortality
• Occurs at all age groups and equally in both sexes
• Increased susceptibility in the critically ill
• All blood components have been associated with TRALI
• Greatest incidence with plasma-rich components such as: plasma, platelets, and whole blood
• Generally thought to occur via a two-hit hypothesis:
• Neutrophil sequestration and priming: endothelial damage, etc. leads to increased adhesion molecules in the vasculature of the lungs, and they are primed by cytokine release
• Neutrophil activation: Sequestered neutrophils are activated by donor anti-leukocyte antibodies or bioactive lipids
• TRALI rarely occurs in neutropenic patients

Leukopenia in TRALI

• Following pulmonary sequestration of neutrophils, there is a transient neutropenia
• Nakagawa M, Toy P: Acute and transient decrease in neutrophil count in transfusion related acute lung injury: Cases in one hospital. Transfusion 2004; 44:1689–1694
• A white blood cell count should be obtained immediately on recognition of the signs and symptoms, because the leukopenia is transient (Ref. 1)
• The amount of leukopenia reported in some case reports is from 8% to 30% of the pre-TRALI WBC (Ref. 2)
• The time of duration, as stated in some case reports, is a gradual increase back to baseline over 6-10 hours. (Ref. 2)
• No other acute transfusion reaction is accompanied by leukopenia