The RoHar antigenic complex is associated with a limited number of D epitopes and alloanti-D production: a study of three unrelated persons and their families.
BACKGROUND
the RoHar antigenic complex has been characterized serologically by difficulties in D typing, weak e expression, lack of G antigen, presence of Rh33, a low-frequency Rh antigen, and, more recently, a second low-frequency antigen, FPTT. Allocation to one of the partial D catagories was not considered because of the unuaual reactions of RoHar cells and because anti-D production was not observed in RoHar persons.


METHODS
Three unrelated RoHar donors and their families were studied in detail with special emphasis on D epitope mapping, e and G typing, and screening for antibodies.


RESULTS
Only D epitopes 5 and 6/7 were demonstrable, and D epitopes 1, 2, 3, 4, 8, and 9 seem to be absent in the RoHar complex. In one individual, the presence of alloanti-D with limited specificity, not reacting with RoHar red cells of other individuals, was found 6 months after a second D+ pregnancy.


CONCLUSIONS
The finding of alloanti-D in an RoHar r person supports the concept that the D characteristic of this phenotype is a partial D antigen, which is consistent with the presence of the limited number of D epitopes found in epitope mapping. As has been suggested for other partial D antigens, RoHar individuals should be regarded as D- for the receipt of blood, and pregnant RoHar women who have had D+ pregnancies should receive anti-D prophylaxis.
Beckers
E A
EA
Red Cross Blood Bank and the Department of Hematology, University Hospital, Rotterdam, the Netherlands.
Porcelijn
L
L
Ligthart
P
P
Vermey
H
H
Von dem Borne
A E
AE
Overbeeke
M A
MA
van Rhenen
D J
DJ
D000939:Epitopes; D006801:Humans; D007518:Isoantibodies / Q000096:biosynthesis*; D012204:Rh-Hr Blood-Group System / Q000235:genetics / Q000276:immunology*
D000939:Epitopes; D007518:Isoantibodies; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen