Anti-Bisohemagglutinins in the serum of a patient with a weak red cell B antigen.

The occurrence of variants of the erythrocyte B agglutinogen, although rare, is of considerable practical importance because it may lead to errors in blood grouping. Subgroups of the B antigen have not been established although variants have been described. Moullec and co-workers reported a weakly reacting B antigen in 1955. They named it B. In 1958 Levine and associates described the genetically determined phenotype B, which also reacted as a weak B antigen. One year later Cameron and associates and Giles and co-authors reported the occurrence of a weak B antigen together with anti-B antibody in additional persons. They assumed that the antigen was acquired during old age and chronic disease. In 1961 Morrow and associates described a weak erythrocyte B agglutinogen that coexisted with anti-B antibody. They associated it with the blood group A that had been described by Andersen 1 year previously.