Preventing or delaying alloimmunization to leukocyte antigens in selected patients who are chronic transfusion candidates. Platelet survival is frequently diminished in patients who require repeated transfusions. This is most commonly due to antibodies directed against HLA Class I antigens expressed both on white cells and platelets. There is evidence that it is the leukocytes in platelet concentrates, rather than the platelets, which induce the formation of HLA antibodies. Rates of platelet alloimmunization can be reduced if the white cell content of red cells or platelets is less than 5.0 x 106/unit. Leukodepletion of this order can be achieved with most of the third generation filters, and also with newer apheresis platelet collection procedures.
Deterrence/Prevention
* Delayed hemolytic transfusion reactions
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o Properly identify the serology of alloantibodies prior to transfusion, and properly identify antigen-negative RBCs if alloantibodies are present.
o Patients with alloantibodies require fully crossmatched (ie, anti-immunoglobulin phase) donor units.
o In ethnic minorities who have received multiple transfusions, testing patients for commonly involved antigens (eg, Rh, Kell, Kidd, Duffy) and using antigen-negative units can significantly reduce the frequency of alloimmunization. However, the cost effectiveness of this approach must be considered because most patients who have received multiple transfusions do not form clinically significant alloantibodies. A more cost-effective approach is to match the ethnic origin of donors and recipients, reserving extensive antigen typing for recipients who have been previously alloimmunized. These patients may also benefit from leukodepleted RBCs because leukoreduction appears to decrease the frequency of alloimmunization to RBC antigens, possibly due to decreased stimulation of TH2 lymphocytes associated with transfusions.
o If attempting to transfuse Rh-positive units (RBCs, platelets, or granulocytes) into an Rh-negative recipient, prevent alloimmunization to the D antigen by administering intravenous Rh-immunoglobulin (eg, WinRho SD, 10-12 mcg/mL of transfused Rh-positive RBCs). If transfusing a large number of Rh-positive units, reduce the dose of Rh-immunoglobulin after removing the antigen load by RBC exchange.
* Refractoriness to platelet transfusions
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o Primary alloimmunization to class I HLA antigens present on platelets involves active donor APCs.
o Removing leukocytes by filtration or buffy coat removal or deactivating APCs by ultraviolet-B irradiation reduces the frequency of alloimmunization.
o Leukocyte reduction is indicated in all patients who are expected to be transfused repeatedly, especially candidates for bone marrow transplantation. These patients may also benefit from initial HLA typing and transfusions from crossmatched or HLA-matched platelets.
Hi!
I have recently started reading on the net for my daughter who is a thal major and found this forum pretty useful i have to say people like andy and sajid are doing an awesome job keep it up :hugfriend.
Can someone tell me the advantages of using a filter during transfusion and also one of the doctors said that it will lower the amount of iron that goes in due to transfusion (is it true) . In Pakistan it costs around $40, could someone please guide me that spending this amount is really necessary each time.
Hello Mumtaz!
Thanks for the tip. I will talk to the Tx people, lets see if they can do this for us.. Have you tried using a filter that we have been discussing in this post. If you have do let me know how has it affected your child.
Thanks
M Tariq khan