Modified antigen-capture ELISAによる血小板同種抗原Br^a/Br^bの検出

抄録

A platelet alloantigen system, Br^a/Br^b, is defined recently and is implicated in several cases of neonatal alloimmune thrombocytopenic purpura (NATP) in Europe. Since each platelet has only 1, 000-2, 000 molecules of Br^aBr^b antigens, it is very hard to phenotype platelets by methods in which whole platelets are used as antigens. In this study, we employed modified antigen-capture ELISA (MACE) to phenotype platelets for Br^a/Br^b. Platelets were easily phenotyped qualitatively and semiquantitatively by MACE in which a murine monoclonal anti-glycoprotein (GP) IIa (4B4; CD29) was used to capture GP Ia-IIa complex. Phenotypic frequencies of Br^a and Br^b among 67 Japanese were 11.7% and over 98.3%, respectively. Their frequencies among Japanese were significantly differed from those among Caucasians and chilean Indians. Br^a/Br^b antigen system would be responsible for some cases of NATP and platelet transfusion refractoriness in Japan. MACE would be extremely useful to identify Br^a/Br^b incompatibility in those cases.