RHCE*ceCF encodes partial c and partial e but not CELO, an antigen antithetical to Crawford.

BACKGROUND

RH43 (Crawford) is encoded by RHCEce with nucleotide changes 48G>C, 697C>G, and 733C>G (RHCEceCF). We investigated the Rh antigen expression and antibody specificities in four patients with this allele.

STUDY DESIGN AND METHODS

Hemagglutination tests, DNA extraction, polymerase chain reaction (PCR)-restriction fragment length polymorphism, allele-specific PCR, reticulocyte RNA isolation, reverse transcription-PCR cDNA analyses, cloning, and sequencing were performed by standard procedures.

RESULTS

Red blood cells (RBCs) from two patients typed D+C-E-c+e+/-, hrS-/+W, hrB- and their serum was reactive (3+) with all RBC samples of common Rh phenotype tested, but nonreactive with Rhnull or D-- RBCs (apparent alloanti-Rh17). At the RHCE locus, Patient 1 was homozygous for RHCEceCF, and Patient 2 inherited RHCEceCF in trans to a silenced RHCEcE. Cross-testing of serum and RBCs from these two samples showed mutual compatibility, indicating that both antibodies define the same novel high-prevalence antigen on Rhce. Two additional patients, one whose serum contained alloanti-c but the RBCs typed C+c+ and one whose serum contained anti-e but the RBCs typed E+e+, also had RHCEceCF. RHCECe was present in trans in the former and RHCEcE in the latter patient.

CONCLUSION

We report that amino acid changes on RhceCF (Trp16Cys, Gln233Glu, and Leu245Val) alter the protein to the extent that c and e antigens are partial, and a high-prevalence antigen, we have named CELO (provisional ISBT Number 004058; RH58) is not expressed. CELO is antithetical to RH43 (Crawford).