Persistent anti-Dra in two pregnancies.
The Drori (Dr(a)) antigen is one of the ten high-prevalence antigens of the Cromer blood system, which are carried on decayaccelerating factor (DAF, CD55). The Dr(a-) phenotype was first described in a 48-year-old Jewish woman from Bukhara. Her serum contained an antibody to a high-prevalence antigen named anti-Dra. Most known individuals with the Dr(a-) phenotype are Jews from the geographic area of Bukhara, but individuals from Japan have also been described. Antibodies in the Cromer blood group system, including anti-Dra,have never been reported to cause HDN. In most of the cases with anti-Dra examined in Israel, the antibodies have been subtyped as IgG2 and IgG4. This report is of a woman with Dr(a-) phenotype and an anti-Dr(a) titer of 256 to 512 in her serum, observed during two successive pregnancies. At birth, the RBCs of the first- and second-born child were negative and positive in the DAT, respectively, and neither manifested clinical signs of HDN. The disappearance of Cromer system antibodies, including anti-Dra in midpregnancy, has been described in a previous study. In that study, it was theorized that the antibodies in the serum of the women were adsorbed onto placental DAF. The finding of a high anti-Dra titer in two successive pregnancies in this patient, with a positive DAT for the RBCs of one of the two babies at term, differs from published reports, suggesting that a different mechanism might be involved.
Rahimi-Levene
N
N
Blood Bank, Assaf-Harofeh Medical Center, Zerifin, Israel.
Kornberg
A
A
Siegel
G
G
Morozov
V
V
Shinar
E
E
Asher
O
O
Levene
C
C
Yahalom
V
V
D000328:Adult; D001789:Blood Group Antigens / Q000276:immunology; D018958:CD55 Antigens / Q000097:blood / Q000276:immunology; D005260:Female; D006801:Humans; D007518:Isoantibodies / Q000097:blood* / Q000276:immunology; D011247:Pregnancy / Q000097:blood* / Q000276:immunology
D001789:Blood Group Antigens; D018958:CD55 Antigens; D007518:Isoantibodies