Allo‐Antigens and Allo‐Antibodies of the Ko System, Serological and Genetic Study

Four new cases of anti‐Koa allo‐antibodies and a third case of anti‐Kob antibody are described. These IgM thromboagglutinating antibodies present a maximum reactivity at 37 °C and at pH 7. The cross‐reaction of anti‐Kob antibody with antigen Koa is confirmed. Gene and phenotype frequencies of Koa and Kob alloantigens are determined through a study of 254 Caucasians. Among 63 families, 26 informative families in a double back‐cross situation made it possible to confirm that there is no close linkage between the Ko system and the HL‐A, Rhesus, MNSs, Kell, Duffy and Lewis system.