Leucocyte depleted blood products. BCSH;Transfusion Medicine, 1998,8,59-71 Dr. Tariq Roshan 23 rd March 2003

Objective In which circumstances would you recommend the use of leucocyte depleted blood products? To able to answer the question regarding leucocyte depleted blood products. To able to answer the question regarding leucocyte depleted blood products. For better understanding and to pave way for provision of leucocyte depleted products by Department of Hematology in HUSM. For better understanding and to pave way for provision of leucocyte depleted products by Department of Hematology in HUSM.

Definition. Leucocyte depleted blood products must contain <0.5x10 9 leucocytes per unit red cells or adult therapeutic dose of plateletts. Leucocyte depleted blood products must contain <0.5x10 9 leucocytes per unit red cells or adult therapeutic dose of plateletts. Practical aspects. To achieve residual count less than specified, process should be completed with in 48 hours form collection of the donor unit. To achieve residual count less than specified, process should be completed with in 48 hours form collection of the donor unit. Quality should be assured by monitoring the components for 100% compliance. Quality should be assured by monitoring the components for 100% compliance.

Indications for the leucocyte- depleted blood components Recommended FNHTRs (Febrile non haemolytic transfusion reactions) To prevent recurrent FNHTRs Reducing graft rejection after haemopoietic cell transplantation. Prevention of transmission of viral infections by blood transfusion. Fetal/Neonatal transfusions. Possible Platelet refractoriness Kidney transplants. Immunomodulation. Progression of HIV infection. Non indication TAGvHD

The presence of leucocytes in blood components; responsible for many of complications associated with blood transfusion Patients receiving standard blood transfusion receive large numbers of allogeneic leucocytes Confusing terms Leuco-poorLeuco-freeLeuco-reduced Leuco-depleted is the accepted term There is confusion with the use of buffy coat depleted red cell concentrate and pooled platelet concentrates (leucocyte levels are reduced but not to the level of leucocyte depleted components

MethodsCentrifugation Freeze / Thaw Filtration Most common used technique Most common used technique Aphaeresis with the use of filtration or without the use of filtration Aphaeresis with the use of filtration or without the use of filtration Filters Filters 1 st generation filters. Removes large clots and particulate debris 2 nd generation filters. Designed to remove micro-aggregates of fibrin, platelets and leucocytes from red cell concentrates 3 rd generation filters. Designed specifically to remove free leucocytes. The reduction of leucocytes are three orders of magnitude Site of filtration Bedside during the transfusion Component processing laboratory

Timing of leucocyte-depletion With in short time after collection With in short time after collection Advantage Advantage Leucocytes are removed before cytokines are removed Fragments of cell membranes and possible intracellular viruses removed Cytokines are not released which results in FNHTR s HLA alloimmunization can occur with leucocyte fragments Laboratory filtration assures quality monitoring and also the time of filtration Filtration is done within 48 hours One school of thought favors processing of units after 6 hours as it allows phagocytosis of any bacteria present Quality assurance Quality assurance Can be carried out prior to release of component by doing leucocyte counts Flow cytometry Large volume microscopic chambers Labeling and storage Labeling and storage Must be labeled as leucocyte depleted Shelf life and storage does not differ, if closed procedure used

FNHTRs Mechanism is different for both platelets and red cell transfusion Mechanism is different for both platelets and red cell transfusion 6.8% after red cell transfusion 37.5% after platelet transfusion Associated with red cell transfusion HLA alloimmunization is the usual cause but not in case of red cell transfusion HLA alloimmunization is the usual cause but not in case of red cell transfusion Reaction do not always recurs Reaction do not always recurs FNHTR can be prevented by buffy coat depleted blood FNHTR can be prevented by buffy coat depleted blood In cases of recurrence with buffy coat depleted blood, leucodepleted blood is recommended. In cases of recurrence with buffy coat depleted blood, leucodepleted blood is recommended. Used in patients dependent on long term transfusion support Used in patients dependent on long term transfusion support Associated with platelet transfusion Pyrogenic cytokines Pyrogenic cytokines Usually not prevented by bedside filtration techniques as cytokines released during storage at room temperature Usually not prevented by bedside filtration techniques as cytokines released during storage at room temperature

Recommendations for FNHTRs For prevention of FNHTRs after red cells buffy coat depleted red cell concentrates is recommended For prevention of FNHTRs after red cells buffy coat depleted red cell concentrates is recommended For patients continue to have FNHTRs despite buffy coat or bedside filtered red cell concentrates, leuco-depleted blood is recommended For patients continue to have FNHTRs despite buffy coat or bedside filtered red cell concentrates, leuco-depleted blood is recommended For platelets leuco-depletion prior to storage is recommended For platelets leuco-depletion prior to storage is recommended Bedside filtration is not recommended Bedside filtration is not recommended

Platelet refractoriness Common problem of failure to obtain satisfactory responses to platelet transfusions Immune mechanism Non-immune mechanism Immune cause is potentially more readily preventable Immune cause is potentially more readily preventable HLA alloimmunization was only initiated by intact cells expressing both HLA I & II classes HLA alloimmunization was only initiated by intact cells expressing both HLA I & II classes Platelets only express class I antigens Platelets only express class I antigens This provides a rationale for the use of leucocyte-depleted blood This provides a rationale for the use of leucocyte-depleted blood HLA alloimmunization in non leucocyte depleted blood products and pregnancy is 31% as compared to the patients receiving leucocyte depleted blood and no previous pregnancy HLA alloimmunization in non leucocyte depleted blood products and pregnancy is 31% as compared to the patients receiving leucocyte depleted blood and no previous pregnancy Pregnancy also presensitized the patients, reducing the dose of trasfused leucocytes for further immunization Pregnancy also presensitized the patients, reducing the dose of trasfused leucocytes for further immunization Irradiation of platelet concentrates with ultraviolet-B light, showed reduced alloimmunization Irradiation of platelet concentrates with ultraviolet-B light, showed reduced alloimmunizationRecommendation HLA alloimmunization reduces with the use of leucocyte- depleted products HLA alloimmunization reduces with the use of leucocyte- depleted products

Prevention of transmission of viral infections by blood transfusion CMV The use of CMV seronegative blood components has been shown to reduce the incidence of CMV infection in at risk groups to a level of about 1-3% The use of CMV seronegative blood components has been shown to reduce the incidence of CMV infection in at risk groups to a level of about 1-3% Transfusion transmitted infection is not completely prevented may be due to Transfusion transmitted infection is not completely prevented may be due to Failure to detect low level antibodies Loss of antibodies in previously infected donors Transfusion of components prepared from recently infected donors Recommendations Recommendations CMV seronegative pregnant women CMV seronegative pregnant women CMV seronegative recipients of allogeneic BMT CMV seronegative recipients of allogeneic BMT AIDS AIDS Premature infants born to CMV seronegative women Premature infants born to CMV seronegative women HTLV I & II

Immunomodulation Post operative infection Increase incidence on infection in the group receiving blood transfusion after colorectal cancer as compared to the group receiving no transfusion Increase incidence on infection in the group receiving blood transfusion after colorectal cancer as compared to the group receiving no transfusion Incidence was same in patients receiving leucocyte-depleted blood as in non transfused group Incidence was same in patients receiving leucocyte-depleted blood as in non transfused group (other studies denies these findings) Cancer recurrence Results are conflicting Results are conflicting In AML improved relapse free survival was found in one study of patients receiving leucocyte-depleted blood In AML improved relapse free survival was found in one study of patients receiving leucocyte-depleted blood Recommendations Recommendations There is insufficient evidence to recommend the routine use of leucocyte-depleted blood components for surgical patients for the prevention of either post-operative infection or tumour recurrence

Reactivation of latent infections CMV / HIV Latent infection may become reactivated after an immunological stimulus such as transfusion Latent infection may become reactivated after an immunological stimulus such as transfusion Recommendation Recommendation Leucocyte-depleted blood components may be used as an alternative to CMV-seronegative blood components to all pregnant women irrespective to their CMV status In patients with HIV infection, there is insufficient evidence of the reactivation of HIV

Avoidance of sensitization to transplantation antigens in potential transplant recipients Sensitization by blood transfusion showed to have adverse effects Severe AA Increase risk of graft rejection if preceded by blood transfusion Recommendatoins Recommendatoins Patients with severe AA and potential haemopoietic cell transplant recipients should receive leucocyte- depleted blood components Leucocyte-depleted blood components are not indicated for patients undergoing transplantation for haematological malignancies

Haemoglobinopathies Recommendations Recommendations Buffy-coat depleted or bedside filtered red cell concentrates are recommended for the prevention of FNHTRs Leucocyte-depleted blood components can be used in potential candidates for haemopoietic stem cell transplantation to reduce the risk of graft rejection Solid tumors Recommendations Recommendations Pre-transplant blood transfusion may confer some benefit to renal transplant recipients, although some patients will become alloimmunized leading to difficulties in the selection of donor kidneys HLA alloimmunizations should be prevented unless they are part of pre-transplant immunosuppression protocol Leucocyte-depleted blood is not recommended for liver and heart transplant

Fetal / Neonatal transfusion Fetal / neonatal transfusion often consist of relatively fresh blood containing viable leucocytes Increase risk of transmission of CMV Presence of viable lymphocytes may cause TA-GvHD Recommendations Recommendations Leucocyte-depleted blood components should be used for intra-utrine transfusion and for all transfusion to infants below 1 year of age