Discovery of 4a and 4b.
D001803:Blood Transfusion / Q000266:history; D005260:Female; D005602:France; D006680:HLA Antigens; D015235:HLA-B Antigens; D006650:Histocompatibility Testing / Q000266:history; D049673:History, 20th Century; D006801:Humans; D011247:Pregnancy
D006680:HLA Antigens; D015235:HLA-B Antigens