The RHCE allele ceCF: the molecular basis of Crawford (RH43).
BACKGROUND: The Crawford antigen (RH43) was described in 1980. It occurred in African American people, as a low-prevalence Rhesus antigen, who were also VS+. STUDY DESIGN AND METHODS: Twelve blood samples were analyzed because of inquiries into discrepant reactions in routine anti-D typing. The RHCE alleles were determined by nucleotide sequencing from genomic DNA. The D epitope profile was determined with 60 monoclonal anti-D. The population frequency was estimated in four major US regional blood centers. RESULTS: The novel RHce(W16C, Q233E, L245V) allele, dubbed ceCF, was found to be occurring in the cde haplotype as cause of the reactivity with the immunoglobulin M anti-D GAMA401. The ceCF phenotype expressed few D epitopes resembling but not matching the reaction patterns observed with other RhCE variants, like R0 (Har), ceRT, and ceSL. The frequency of the ceCF phenotype was 0.056 percent among African American persons and 0.007 percent in the general US population. CONCLUSION: The novel RHce(W16C, Q233E, L245V) allele, which is a variant of the known ce(s) allele, RHce(W16C, L245V), occurs in a haplotype with the RHD deletion and represents the molecular basis of the Crawford antigen.