From the Guidelines
Leukoreduction of blood products is strongly recommended for all patients requiring blood transfusions due to its significant benefits in reducing febrile non-hemolytic transfusion reactions, transmitting cell-associated viruses, and preventing HLA alloimmunization. The primary advantage of leukoreduction is a significant reduction in febrile non-hemolytic transfusion reactions, which are commonly caused by recipient antibodies reacting against donor white blood cells or cytokines released by these cells during storage 1. Leukoreduced blood also decreases the risk of transmitting cell-associated viruses such as cytomegalovirus (CMV), making it particularly valuable for immunocompromised patients, pregnant women, and neonates. Additionally, leukoreduction helps prevent HLA alloimmunization, which can lead to platelet refractoriness in patients requiring multiple transfusions.
The process of leukoreduction typically removes approximately 99.9% of white blood cells from blood components, bringing the residual count below 5 × 10^6 cells per unit. While leukoreduction adds some cost to blood products, many institutions have adopted universal leukoreduction protocols due to these significant clinical benefits across various patient populations. The American Society of Clinical Oncology recommends the use of leukoreduced blood products for patients with acute myeloid leukemia (AML) receiving induction chemotherapy, as it decreases the incidence of alloantibody-mediated refractoriness to platelet transfusion 1.
Other advantages of prestorage leukoreduction include a substantial reduction in transfusion reactions and in transmission of cytomegalovirus (CMV) infection 1. The evidence quality for these recommendations is high, and the strength of recommendation is strong. Overall, the benefits of leukoreduction in reducing morbidity, mortality, and improving quality of life for patients requiring blood transfusions make it a crucial component of transfusion therapy.
Key benefits of leukoreduction include:
- Reduction in febrile non-hemolytic transfusion reactions
- Decreased risk of transmitting cell-associated viruses such as CMV
- Prevention of HLA alloimmunization and platelet refractoriness
- Reduced rates of post-operative infections and decreased immunomodulatory effects
- Improved outcomes for immunocompromised patients, pregnant women, and neonates.
From the Research
Benefits of Leukoreduced Blood Products
The use of leukoreduced blood products has been studied extensively in various patient populations, including those requiring blood transfusions due to trauma, anemia, and human immunodeficiency virus (HIV) infection. The benefits of leukoreduced blood products include:
- Reduced risk of febrile nonhemolytic transfusion reactions 2
- Minimized risk of HLA alloimmunization and platelet refractoriness in multitransfused patients 2
- Prevention of transmission of leukotropic viruses such as EBV and CMV 2
- Potential reduction in infectious complications in trauma patients 3
Reduction in Infectious Complications
Studies have shown that the use of leukoreduced red blood cell products is associated with fewer infectious complications in trauma patients 3. A retrospective before-and-after cohort study found that patients receiving leukoreduced RBC products had a 45% reduction in nosocomial pneumonia and a significant reduction in the development of any type of infection 3. Additionally, a subset analysis of patients receiving massive transfusion (>6 units in 24 hours) found that the use of leukoreduced RBC products was associated with a reduced risk of infection and pneumonia 3.
Lack of Clear Evidence for Routine Use
However, a systematic review and meta-analysis found no clear evidence to support or reject the routine use of leukoreduction in all patients requiring packed red blood cell transfusion for preventing transfusion-related acute lung injury, death, infection, non-infectious complications, and other adverse events 4. The quality of evidence was found to be very low to low, and more evidence is needed before a definitive conclusion can be drawn.
Specific Patient Populations
In patients with HIV infection, a randomized controlled trial found no evidence of HIV, CMV, or cytokine activation following blood transfusion, and leukoreduction provided no clinical benefit 5. In contrast, a study found that leukoreduction of blood transfusions does not diminish transfusion-associated microchimerism in trauma patients 6.