How does leukoreduction affect CMV risk in transfusions?

• A. Increases CMV risk by concentrating leukocytes
• B. Reduces CMV transmission by removing leukocytes that may harbor CMV
• C. Has no effect on CMV risk
• D. Only reduces bacterial contamination

Answer: (B)

Leukoreduction lowers CMV transmission by removing the white blood cells that can harbor latent CMV. CMV resides primarily in donor leukocytes, so filtering blood products to reduce leukocytes greatly decreases the reservoir of the virus in a transfusion. This substantially reduces the risk of transmitting CMV to recipients who are particularly vulnerable, such as CMV-seronegative patients or those who are immunocompromised. The effect is not absolute, but the risk is markedly diminished. Leukoreduction also has other benefits for transfusion safety, but its impact on CMV comes from eliminating the leukocytes that may carry the virus, not from reducing bacterial contamination.