Transcript Leucocyte depleted blood products.

Leucocyte depleted
blood products.
BCSH;Transfusion Medicine, 1998,8,59-71
Dr. Tariq Roshan
23rd March 2003
Objective
In which circumstances would you
recommend the use of leucocyte depleted
blood products?
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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.
Definition.
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Leucocyte depleted blood products must contain
<0.5x109 leucocytes per unit red cells or adult
therapeutic dose of plateletts.
Practical aspects.
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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.
Indications for the leucocytedepleted 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-poor
Leuco-free
Leuco-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
Methods
Centrifugation
Freeze / Thaw
Filtration
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Most common used technique
Aphaeresis with the use of filtration or without the use of
filtration
Filters
1st generation filters. Removes large clots and particulate debris
2nd generation filters. Designed to remove micro-aggregates of
fibrin, platelets and leucocytes from red cell concentrates
3rd 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
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With in short time after collection
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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
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Can be carried out prior to release of component by doing
leucocyte counts
Flow cytometry
Large volume microscopic chambers
Labeling and storage
Must be labeled as leucocyte depleted
Shelf life and storage does not differ, if closed procedure
used
FNHTRs
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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
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HLA alloimmunization is the usual cause but not in case of red
cell transfusion
Reaction do not always recurs
FNHTR can be prevented by buffy coat depleted blood
In cases of recurrence with buffy coat depleted blood,
leucodepleted blood is recommended.
Used in patients dependent on long term transfusion support
Associated with platelet transfusion
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Pyrogenic cytokines
Usually not prevented by bedside filtration techniques as
cytokines released during storage at room temperature
Recommendations for FNHTRs
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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 platelets leuco-depletion prior to storage
is recommended
Bedside filtration is not recommended
Platelet refractoriness
Common problem of failure to obtain satisfactory
responses to platelet transfusions
Immune mechanism
Non-immune mechanism
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Immune cause is potentially more readily preventable
HLA alloimmunization was only initiated by intact cells
expressing both HLA I & II classes
Platelets only express class I antigens
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
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
Recommendation
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HLA alloimmunization reduces with the use of leucocytedepleted products
Prevention of transmission of viral
infections by blood transfusion
CMV
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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
Failure to detect low level antibodies
Loss of antibodies in previously infected donors
Transfusion of components prepared from recently infected
donors
Recommendations
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CMV seronegative pregnant women
CMV seronegative recipients of allogeneic BMT
AIDS
Premature infants born to CMV seronegative women
HTLV I & II
Immunomodulation
Post operative infection
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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
(other studies denies these findings)
Cancer recurrence
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Results are conflicting
In AML improved relapse free survival was found in one study
of patients receiving leucocyte-depleted blood
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
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Latent infection may become reactivated after an
immunological stimulus such as transfusion
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
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Recommendatoins
Patients with severe AA and potential haemopoietic
cell transplant recipients should receive leucocytedepleted blood components
Leucocyte-depleted blood components are not
indicated for patients undergoing transplantation for
haematological malignancies
Haemoglobinopathies
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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
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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
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Recommendations
Leucocyte-depleted blood components should be
used for intra-utrine transfusion and for all
transfusion to infants below 1 year of age