A panel of 897 randomly chosen Danish donors of blood groups 0 and A was tested for the LKE antigen using a human anti-LKE. In this sample, 78.7% were LKE positive, 20.6% were weakly positive, whereas 0.7% were LKE negative. These phenotype frequencies are similar to those obtained by the first discovered human alloserum and by the monoclonal anti-SSEA-4 in previous studies. The previously reported lower LKE antigen strength in group A versus group 0 donors, and the association of LKE to the P system was confirmed.