The first example of anti-Dia was discovered in Venezuela in 1956, as a cause of hemolytic disease of the newborn. The family was Caucasian but there appeared to be Native American admixture. This led to the recognition that Dia was a useful marker for persons of Mongolian descent while being of very low frequency in other populations. The frequency in Native Americans ranges from 2-36% while 3-10% of Orientals are positive. Anti-Dib was not recognized until 1967 when two examples were reported in two Mexican women that were being transfused.
The Diego system remained a two antigen system until the 1990s when Dia, Dib and the Wright antigens (Wra and Wrb) were determined to be amino acid substitutions on band 3, the anion exchange protein (AE1). The system quickly expanded when other antigens of low frequency were also identified on band 3 including: ELO, Redelberger, Traversu, Warrior, Wulfsberg, VanVugt, Waldner, Bishop, Hughes and Moen. No red cell lacking band 3 has been reported for this system which may indicate that its loss is lethal. There has been only one report of the Di(a-b-) phenotype. Antibodies to Wra are frequently found in patients having autoimmune hemolytic anemia or individuals having a positive direct antiglobulin test.
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