The expression of IgG allotypes on platelets and immunization to IgG
allotypes in multitransfused thrombocytopenic patients
TS Kickler, PM Ness, HG Braine, L Richardson and M Farkosh
Johns Hopkins University School of Medicine, Pathology Department.
We investigated whether the platelet-membrane surface carries IgG allotypic
antigens and whether these determinants may be important in platelet
transfusion therapy. Using a hemagglutination inhibition assay, we showed
that the G1m IgG allotypes (a, x, f) and K1m and K3m light-chain allotypes
are expressed on the surface of platelets, whereas G3m allotype antigenic
determinants were not detectable. In 146 multitransfused thrombocytopenic
patients, 35 (24%) patients were found to have antiallotypic antibodies. To
study the effect of antiallotypic antibodies on platelet transfusion
outcome, patients received platelet transfusions from donors, either
positive or negative for the IgG allotype to which patients were immunized.
Of the 19 antigen-positive and 19 antigen-negative platelet transfusions
given, respectively, the mean platelet count increments at 1 hour were
8,402 +/- 6,402 +/- 6,721 (1 SD) and 9,799 +/- 5,559 (1 SD) P less than .2.
Transfusion reactions were not more common when antigen-positive platelet
transfusions were given. Despite the presence of IgG allotypic determinants
on platelets, allotypic antibodies do not decrease platelet transfusion
recovery. Furthermore, passive administration of plasma containing IgG
allotypes to patients with antiallotypic antibodies does not lead to
innocent bystander-mediated platelet destruction.
Volume 76,
Issue 4,
pp. 849-852,
08/15/1990
Copyright © 1990 by The American Society of Hematology
