Abstract
The use of absorption and elution studies on the eluates from the sensitised red cells of group A and group B infants of group 0 mothers revealed that some of the eluates contained mixtures of antibodies with varying affinities for A and B cells. Some of these antibodies gave agglutination reactions with only A or B cells although they would combine with both cells as demonstrated by absorption and elution studies. The case examples studied demonstrate the heterogeneity of the antibodies that may be implicated with ABO H.D. Thus some eluates contained only specific antibodies while others contained mixtures of specific and crossreacting or just crossreacting antibodies. The excess of group O mothers associated with the occurrence of ABO H.D. appears to be due to the quantity of antibodies capable of crossing the placenta rather than with the serological specificity of these antibodies.