RHCE*ceMO is frequently in cis to RHD*DAU0 and encodes a hr(S) -, hr(B) -, RH:-61 phenotype in black persons: clinical significance.

Background: RHCE*ceMO has nucleotide changes 48G>C and 667G>T, which encode, respectively, 16Cys and 223Phe associated with altered expression of e antigen. RHD*DAU0 has Nucleotide 1136C>T, which encodes 379Met associated with normal levels of D. We compiled serologic and DNA testing data on samples with RHCE*ceMO to determine the red blood cell (RBC) antigen expression, antibody specificity, RHD association, and the prevalence in African-American persons.

Study Design And Methods: Serologic testing was performed by standard methods. Genomic DNA was used for polymerase chain reaction-restriction fragment length polymorphism and RH-exon sequencing, and for some, Rh-cDNA was sequenced. Seventy-seven (50 donor and 27 patient) samples with RHCE*ceMO were studied, and 350 African-American persons were screened for allele prevalence.

Results: RBCs from RHCE*ceMO homozygotes (or heterozygotes with RHCE*cE in trans) were weak or nonreactive with some anti-e and were nonreactive with polyclonal anti-hr(S) and anti-hr(B) . Twenty-three transfused patients homozygous for RHCE*ceMO/ceMO or with RHCE*ceMO in trans to RHCE*cE or *ce had alloanti-e, anti-f, anti-hr(S) /hr(B) , or an antibody to a high-prevalence Rh antigen. Three patients with alloanti-c had RHCE*ceMO in trans to RHCE*Ce. RHD*DAU0 was present in 30% of African-American persons tested and in 69 of 77 (90%) of samples with RHCE*ceMO.

Conclusions: RHCE*ceMO encodes partial e, as previously reported, and also encodes partial c, a hr(S) - and hr(B) - phenotype, and the absence of a high-prevalence antigen (RH61). The antibody in transfused patients depended on the RHCE allele in trans. RHCE*ceMO was present in one in 50 African-American persons with an allele frequency of 0.01, is often linked to RHD*DAU0, and is potentially of clinical significance for transfusion.