Universal leucocyte‐depletion of blood components: cell concentrates and plasma

The removal of leucocytes from red cell and platelet concentrates, and plasma units, has several advantages. Evidence is available that leucocyte-depletion to below 5 × 10 6 per blood component transfused results in prevention of (primary) alloimmunization against human leucocyte antigen (HLA) class I antigens, febrile transfusion reactions and transmission of infectious agents such as cytomegalovirus (CMV) and Epstein–Barr virus (EBV). There still is doubt regarding whether transfusion-induced immune modulation can be prevented by leucocyte-depletion, and there is even more doubt whether, if variant Creutzfeldt-Jacob disease (vCJD) is found to be transmissible by blood transfusion, removing leucocytes could prevent its transmission. However, there is consensus that the quality of the cellular blood components improves when leucocytes are removed prior to storage. Based on the above benefits, there are generally accepted specific indications for leucocyte-depletion. However, there is no consensus of opinion on the question of whether leucocyte-depletion should be universal, i.e. whether all red cell and platelet concentrates, as well as plasma units, should be routinely leucocyte-reduced. It seemed appropriate to obtain information on this important issue as well as on other aspects of leucocyte-reduction in an International Forum. The questions listed below were sent to experts in the field. Answers were obtained from 18. Question 1 : Are all red cell concentrates, platelet concentrates and plasma units leucocyte-depleted in your centre/ country and, if not, do you intend to institute universal leucocyte-depletion in the near future? Question 2 : What is the motivation to implement or not to implement universal leucocyte-depletion for blood products in your country? Question 3 : Do you, or will you, remove leucocytes preor poststorage and what is the reason for your choice? Question 4 : Which method of leucocyte-depletion do you use, i.e. whole blood filtration, red cell in-line filtration, red cell on-line filtration, filtration of platelets single, filtration of platelet pools, filtration of plasma single, filtration of plasma pools? If you use different procedures, can you state in what percentages the above methods are used and the reasoning for it? Question 5 : What is your maximal storage time prior to leucocyte-depletion of red cell and platelet concentrates, and plasma units? What is the temperature of filtration? Question 6 : What is the upper limit of residual leucocytes in leucocyte-depleted components and with what level of confidence should this be proven in quality control (QC) data? Which counting method(s) is/are applied? Do you have different upper limits for cellular products and plasma? If so, why? And what is the difference? What do you do when filtration has failed? Question 7 : Does your plasma fractionation institute accept filtered plasma and, if yes, what are the requirements?