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The Kg‐antigen, RhAG with a Lys164Gln mutation, gives rise to haemolytic disease of the newborn
Author(s) -
Tanaka Mitsunobu,
Abe Takaaki,
Minamitani Takeharu,
Akiba Hiroki,
Horikawa Toshihiro,
Tobita Ryutaro,
Isa Kazumi,
Ogasawara Kenichi,
Takahashi Hideo,
Tateyama Hidemi,
Tone Satomi,
Tsumoto Kouhei,
Yasui Teruhito,
Kimura Takafumi,
Fujimura Yoshihiro,
Hirayama Fumiya,
Tani Yoshihiko,
Takihara Yoshihiro
Publication year - 2020
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/bjh.16955
Subject(s) - antigen , monoclonal antibody , population , biology , antibody , microbiology and biotechnology , recombinant dna , flow cytometry , immunology , virology , gene , genetics , medicine , environmental health
Summary The Kg‐antigen was first discovered in an investigation of a mother whose infant had haemolytic disease of the newborn (HDN). The antibody against the Kg‐antigen is believed to be responsible for HDN. The Kg‐antigen is provisionally registered under the number 700045, according to the Red Cell Immunogenetics and Blood Group Terminology. However, the molecular nature of the Kg‐antigen has remained a mystery for over 30 years. In this study, a monoclonal antibody against the Kg‐antigen and the recombinant protein were developed that allowed for the immunoprecipitation analysis. Immunoprecipitants from the propositus' red blood cell ghosts were subjected to mass spectrometry analysis, and DNA sequence analysis of the genes was also performed. A candidate for the Kg‐antigen was molecularly isolated and confirmed to be a determinant of the Kg‐antigen by cell transfection and flow cytometry analyses. The Kg‐antigen and the genetic mutation were then screened for in a Japanese population. The molecular nature of the Kg‐antigen was shown to be RhAG with a Lys164Gln mutation. Kg phenotyping further clarified that 0.22% of the Japanese population studied was positive for the Kg‐antigen. These findings provide important information on the Kg‐antigen, which has been clinically presumed to give rise to HDN.