Sra, a private platelet antigen on glycoprotein IIIa associated with
neonatal alloimmune thrombocytopenia
H Kroll, V Kiefel, S Santoso and C Mueller-Eckhardt
Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig
University, Giessen, West Germany.
A new platelet alloantigen, Sra, is described that was defined by an
alloantibody detected in the serum of a healthy mother who delivered a
child with typical clinical signs of neonatal alloimmune thrombocytopenia
(NAIT). The antibody reacted strongly with the child's and father's
platelets, but not with platelets of the mother or with those of a highly
selected panel representing all known platelet alloantigens. Platelets from
300 unselected normal blood donors also tested negative, suggesting a
phenotype frequency in the German population of less than 0.01. The antigen
was present in 9 of 20 members within three generations of the paternal
family, indicating autosomal codominant inheritance. By immunochemical
analysis using a glycoprotein (GP)-specific immunoassay and a variety of GP
IIb/IIIa- specific monoclonal antibodies for antigen immobilization (MAIPA
assay), radioimmunoassay, and Western blotting, we could show that the
antigen resides on a 68-Kd proteolytic fragment of GP IIIa. Immunogenetic
data and gene dosage studies revealed that the Sra antigen is not related
to any of the other known platelet alloantigens. In accordance with
established criteria, the Sra antigen represents the first example of a
"private" platelet alloantigen that bears significance in rare instances of
NAIT.
Volume 76,
Issue 11,
pp. 2296-2302,
12/01/1990
Copyright © 1990 by The American Society of Hematology
