[Leukocyte depletion and infection by cytomegalovirus]

Cytomegalovirus (CMV) can be transmitted by fresh blood components containing leukocytes. Consequences of CMV infection are serious in immunocompromised patients and in neonates. Thus, prevention of transfusion-transmitted CMV is of paramount importance. The use of blood products from CMV seronegative donors has been shown effective in preventing transmission. However, it does not completely eliminate the risk of transmission. Moreover, as CMV seroprevalence reaches 50 to 100% depending on the geographical and socioeconomic conditions, the availability of CMV seronegative products is limited. Leukodepletion of cellular blood products can be achieved by various filtration techniques. A method capable of achieving a residual leukocyte count < 5 x 10(6) per unit allows for the reduction of CMV transmission to a level at least equivalent to the transfusion of seronegative blood components. Moreover, leukodepletion may reduce endogenous virus reactivation. Administration of filtered blood products from CMV seronegative donors is usually recommended for those patients at major risk of severe CMV transfusion-associated disease. The ability of the most efficient methods for blood filtration in preventing CMV transmission has to be assessed. Such methods would make it possible to avoid serological screening of blood donors.