The Diego blood group system is composed of two principal antigens Diegoª (Diª) and Diego b (Di b). In the Caucasian population the prevalence of Diª is rare with a frequency of about 0.02% and can lead to the production of antibodies that are important in newborn babies and in transfusional medicine. The present study reports on anti-Diª antibodies in a Caucasian pregnant woman, detected by indirect anti-globulin testing shortly before delivery. The direct anti-globulin test of the newborn's blood cord was negative because its phenotype was Di (a- b+). So the newborn did not develop any hemolytic diseases. A phenotyping study of the whole family was performed which revealed that probably the mother became sensitive during her second pregnancy of twins where the two children presented with the Diª antigen phenotype inherited from the father.
Alloimunization; anti-Di (a); Diego blood groups system
