[Leukocyte depletion of blood products and post-transfusion infections]

The transmission of unwanted infection agents to patients, through white blood cells, in blood products is now well established. Therefore the leukodepletion procedure undertaken in blood banks is justified. Leukodepletion prior to transfusion prevents the transmission of leukocyte-associated viruses such as CMV, EBV and HTLV 1 and 2 of viruses present both in plasma and inside leukocytes such as HTLV 1 and 2 viruses and B 19 parvovirus. The mechanism of the immunosuppressive effect of transfusion is still uncertain. The risks of transmitting bacterial diseases through blood transfusions is also a well-known source of concern, particularly the transmission of Yersinia Enterocolitica. However such an event seems to be prevented through leukocyte depletion by filtration when these procedures are performed after a hold of whole blood at 22 degrees C for 6 to no longer than 24 hours. Leukocyte-free blood components prepared by filtration may have a sufficiently reduced rate of infection to provide adequate prophylaxis. In any case the final number of leukocytes should be < or = 10(6) per unit of blood product. Leukocyte filtration must be performed before the onset of a disintegration process of granulocytes.