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Neonatal alloimmune thrombocytopenia associated with maternal‐fetal incompatibility for blood group B
Author(s) -
Curtis Brian R.,
Fick Andrea,
Lochowicz Andrew J.,
McFarland Janice G.,
Ball Robert H.,
Peterson Julie,
Aster Richard H.
Publication year - 2008
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.2007.01531.x
Subject(s) - antibody , immunology , isoantibodies , platelet , neonatal alloimmune thrombocytopenia , group b , antigen , titer , serology , group a , abo blood group system , fetus , biology , medicine , pregnancy , genetics
BACKGROUND: Blood group A and B antigens are expressed only weakly on platelets (PLTs) of most individuals but are very strongly expressed on PLTs from approximately 1 percent of normal subjects (Type II high expressers). The implications of this trait for transfusion medicine are undefined. STUDY DESIGN AND METHODS: A family was studied in which two Group B infants were born with neonatal thrombocytopenia, whereas a third infant whose blood group was A 2 had a normal PLT count at birth. RESULTS: Serologic studies demonstrated a maternal antibody that reacted strongly with PLTs from the father and the two group B children in flow cytometry and with GPIIb/IIIa from their PLTs in solid‐phase assays. No PLT‐specific antibodies were detected in maternal serum sample, but it contained a high‐titer immunoglobulin G antibody specific for blood group B. All PLT‐reactive antibody in the mother's serum was removed by absorption with pooled, washed group A and B red cells (RBCs). Studies with monoclonal anti‐B and measurement of serum B‐glycosyltransferase activity showed that the father and both group B children were Type II high expressers of blood group B. CONCLUSIONS: The findings indicate that high‐titer blood group antibodies acquired from the mother can cause thrombocytopenia in infants possessing the Type II high‐expresser phenotype despite competition for antibody binding by blood group antigens expressed on RBCs and other tissues.