Biomedical Engineering Reference
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Fig. 10.1
Marrow aspirate processing after collection
the absence of depletion-selectivity. Contrary, selective TPE guarantees high blood
purification with reduced risk of plasma constituent loss and virus transmission,
since in this procedure the removed plasma by immunoadsorbed autologous plasma
is substituted [ 20 ] (Fig. 10.1 ).
However, the optimal antibody titer in the recipient's circulation immediately
prior to ABO-incompatible transplants is not yet determined. According to some
authors [ 21 ] the acceptable titer is 16, while according to the others [ 22 ] it has to be
£8. High-level antibody depletion by commercially available immunoadsorption
columns (with synthetic group-specific oligosaccharides) is possible now, but the
essential problem of these equipment is their excessive cost. TPE followed by
donor-specific red blood cell transfusion (i.e., in vivo alloantibody binding) was
firstly described in ABO-incompatible bone marrow transplant setting, although not
without severe immune-mediated side effects [ 23 ] . The fi rst techniques intended to
in vitro depress the blood group-specific antibody reactivity were carried out in the
early 80s of the twentieth century in our Institute too [ 24 ] . The principle of this
method was the inhibition of antibodies with specific RBCs or soluble ABO and
Lewis antigens from saliva (Fig. 10.2 ).
In summary, HLA antigens and antibodies play an important role in a number of
transfusion-related events, especially in immunosuppressed patients. The rate of
HLA-mediated platelet refractoriness among recipients of multiple transfusions is
relatively high (more than 30%). Platelet refractoriness can be present when applied
viable platelets are not successful in increasing recipient's platelet count. Besides
HLA-mediated factors, refractoriness may be as a result of other causes such as
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