Blood group A and B antigens are strongly expressed on platelets of some individuals.
It is widely thought that expression of ABH antigens on platelets is insufficient to materially affect the survival of ABH-incompatible platelets in transfusion recipients, but anecdotal reports of poor survival of A and B mismatched platelets suggest that this is not always the case. The A and B antigen expression on platelets of 100 group A(1) and group B blood donors was measured, and 7% and 4%, respectively, had platelets whose A and B antigen levels consistently exceeded the mean plus 2 SD. On the basis of flow cytometric and statistical analysis, donors whose platelets contained higher than normal levels of A antigen were subdivided into 2 groups, designated Type I and Type II ("high expressers"). Serum A(1)- and B-glycosyltransferase levels of A and B high expressers were significantly higher than those of group A(1) and B individuals with normal expression. H antigen levels were low on the red cells of high expressers, indicating that the anomaly affects other cell lineages. Immunochemical studies demonstrated high levels of A antigen on various glycoproteins (GPs) from high-expresser platelets, especially GPIIb and PECAM (CD31). The A(1) Type II high-expresser phenotype was inherited as an autosomal dominant trait in one family. The sequences of exons 5, 6, and 7 of the A(1)-transferase gene of one Type II A(1) high expresser and exon 7 from 3 other genes were identical to the reported normal sequences. Further studies are needed to define the molecular basis for the high-expresser trait and to characterize its clinical implications. (Blood. 2000;96:1574-1581)
Curtis
B R
BR
Blood Research Institute, The Blood Center of Southeastern Wisconsin, Milwaukee, WI 53233, USA. brcurtis@bcsew.edu
Edwards
J T
JT
Hessner
M J
MJ
Klein
J P
JP
Aster
R H
RH
D000017:ABO Blood-Group System / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D001792:Blood Platelets / Q000276:immunology*; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D008297:Male; D010375:Pedigree
D000017:ABO Blood-Group System