Autoantibodies Mimicking Anti‐Jkbplus Anti‐Jk3 Associated with Autoimmune Hemolytic Anemia in a Primipara Who Delivered an Unaffected Infant

Abstract. A serum sample from a nontransfused 2 5‐year‐old Caucasian primipara contained weak anti‐Jkbplus anti‐Jk3. The direct antiglobulin test on the patient's red cells was strongly positive. Anti‐Jkbwas recovered in a heat eluate. An ether eluate contained anti‐Jk3. Her red cells typed as Jk(a‐b+)Jk:3. The anti‐Jkband anti‐Jk3 reactivity was completely absorbed both by red cell samples lacking and red cells possessing the corresponding antigens, indicating these antibody specificities to be of the mimicking variety. At 41 weeks gestation she delivered a normal, healthy infant with no detectable serum or cell bound antibody.