In vitro affinity reduction of biologic response modifiers from production buffy coat platelets exposed to recombinant protein receptors.
BACKGROUND
Recent studies link biologic response modifiers found in donor platelet (PLT) concentrates to transfusion reactions. We tested a novel method to deplete BRMs from PLT concentrates using apheresis.


METHODS
Whole blood from 25 donors was treated to yield PLTs for in vitro measurements on Days 2, 5, and 7. On Day 7, PLTs were filtrated through columns with either antibody-coated agarose or rh-megalin bound to antibody-coated agarose. In addition, we also tested the naked matrix (agarose) and another apheresis surface containing rh-cubilin bound to agarose. Megalin and cubilin are parts of the protein complex mediating BRM endocytosis in the human kidney.


RESULTS
Compared to before filtration (951 × 10(9)  ± 41 × 10(9) cells/L), PLT numbers decreased slightly after filtration over both naked (859 × 10(9)  ± 38 × 10(9) ) and antibody-coated (848 × 10(9)  ± 41 × 10(9) ) matrices (both p < 0.001 vs. before). Concentrations of interleukin (IL)-1β, IL-12 (p40), IL-12 (p70), and IL-7 all decreased by approximately 40% even in the absence of a recombinant surface. After filtration over rh-cubilin, but not rh-megalin, concentrations of IFN-γ, IL-1β, tumor necrosis factor-α, IL-12, and IL-7 all further decreased by 30% to 50%.


CONCLUSIONS
In a pilot study of in vitro apheresis to deplete BRMs, we found that cell numbers and function remained largely unaffected by filtration. Significant reductions in BRMs occurred already with agarose. However, apheresis with the multiligand receptor rh-cubilin was able to further decrease concentrations.
Department of Clinical Immunology and Transfusion Medicine.
Per
P
Sandgren
JJK Medical Development AB/South End Advisory AB, Stockholm, Sweden.
Jenny
J
Rönnmark
Department of Medical Biochemistry and Biophysics, Karolinska University Hospital and Karolinska Institutet.|JJK Medical Development AB/South End Advisory AB, Stockholm, Sweden.
Jonas
J
Axelsson
D055910:Antibodies, Immobilized; D058621:Blood Buffy Coat / Q000166:cytology*; D001792:Blood Platelets / Q000187:drug effects*; D002846:Chromatography, Affinity / Q000379:methods*; D002847:Chromatography, Agarose / Q000379:methods*; D005374:Filtration; D006801:Humans; D007155:Immunologic Factors / Q000097:blood*; D007163:Immunosorbent Techniques; D066298:In Vitro Techniques; D007378:Interleukins / Q000097:blood; D026561:Low Density Lipoprotein Receptor-Related Protein-2 / Q000378:metabolism*; D010865:Pilot Projects; D010983:Plateletpheresis / Q000379:methods*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011994:Recombinant Proteins
D055910:Antibodies, Immobilized; D007155:Immunologic Factors; D007378:Interleukins; D026561:Low Density Lipoprotein Receptor-Related Protein-2; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; C029486:intrinsic factor-cobalamin receptor