Alloanti-c/ce in a c+ceAR/Ce patient suggests that the rare RHCE ceAR allele (ceAR) encodes a partial c antigen.
BACKGROUND
ceAR (RHCE ceAR) is a rare RH allele encountered in people of African/Caribbean ancestry, known to encode a partial e antigen. The homozygous ceAR/ceAR genotype encodes the rare blood group Hr-. This study describes alloanti-c/ce in a ceAR/Ce patient, suggesting that ceAR also encodes a partial c antigen.


METHODS
A 21-year-old patient suffering from intermediate beta-thalassemia, with transfusion history, was hospitalized for severe anemia. Blood samples were referred to the National Reference Laboratory for suspicion of a mixture of alloantibodies or an alloantibody to a high-prevalence antigen.


METHODS
Standard hemagglutination methods were performed to investigate the patient's RBCs and serum. A molecular analysis of RHD and RHCE was carried out by allele-specific polymerase chain reaction and DNA sequencing.


RESULTS
Blood type performed by the referring laboratory was B, D+C+E-c+e+, K-. Several antibodies were identified: anti-c/ce, anti-Fy(b), anti-Jk(a), and anti-S. Full serologic investigations showed that anti-c/ce could be very likely considered as an alloantibody. The patient's genotype was ceAR/Ce. Anti-c/ce reacted with ceAR/ceEK, ceEK/ceEK, and ceAR/ceBI but not with ceAR/ceAR, ceMO/ceMO, and ce(s)(340)/ce(s)(340) RBCs.


CONCLUSIONS
This is the first case of alloanti-c/ce related to ceAR, suggesting that this rare RHCE allele encodes a partial c antigen. The presence of the C antigen in the patient allowed for the partial expression of the c antigen encoded by ceAR. The c antigen encoded by ceAR appeared to be different than that encoded by ceEK and ceBI and may share common lacking epitopes with the c antigens encoded by ceMO and ce(s)(340).
Peyrard
Thierry
T
National Reference Laboratory for Blood Groups, National Institute of Blood Transfusion, 20, rue Bouvier, BP 79,75522 Paris Cedex 11, France. tpeyrard@ints.fr
Pham
Bach-Nga
BN
Poupel
Sylvie
S
Martin-Blanc
Stéphanie
S
Auxerre
Carine
C
Kappler-Gratias
Sandrine
S
Bonin
Philippe
P
Rouger
Philippe
P
Le Pennec
Pierre-Yves
PY
D000483:Alleles; D006386:Hemagglutination Tests; D006801:Humans; D007518:Isoantibodies / Q000276:immunology*; D008297:Male; D016133:Polymerase Chain Reaction; D012204:Rh-Hr Blood-Group System / Q000235:genetics* / Q000276:immunology*; D055815:Young Adult
D007518:Isoantibodies; C066468:RHCE protein, human; D012204:Rh-Hr Blood-Group System