A Dc- phenotype encoded by an RHCE-D(5-7/8)-CE hybrid allele

Molecular characterization of a rare Rh phenotype Dc-from the Indian subcontinent

Unusual Rh phenotypes such as Rh_null, D-- and Dc- etc. are rarely encountered in routine blood bank testing. The Rh_null phenotype is characterized by the absence of all Rh antigens, D-- phenotype does not express any RhCcEe antigens whereas Dc- phenotype individual lacks expression of antithetical E /e antigens. These individuals may produce multiple Rh antibodies against missing antigens. An old woman (B RhD positive) from Bangladesh with end-stage renal disease developed severe anaemia. Cross-matching with ABO and RhD compatible blood units showed +3 agglutination reaction. Detailed immunohaematological investigations showed a lack of C, E and e antigens, thus identifying the rare Rh variant as Dc-. Antibodies against C and e antigens were also detected in the patient's serum. PCR-SSP confirmed the absence of the molecular region defining the C, E and e antigens. Copy number analysis by QMPSF revealed the homozygous state of (RHCE-D(4-9)-CE) allele at the RHCE gene locus. This is the first report of the rare Dc- variant individual from the Indian subcontinent.

Hemolytic disease of the fetus and newborn caused by anti-Hr0 in a 27-year-old female with Dc- phenotype: A case report

Anti-Hr₀ (Anti-Rh17) is a rare immune Immunoglobulin G (IgG) to high-frequency Rh antigens that may cause severe and often fatal Hemolytic disease of the fetus and newborn (HDFN) in D--, Dc- and DC^w- mothers who have been exposed to red cells of the common Rh phenotype by transfusion or pregnancy. Several pregnant women have been affected by this antibody leading to perinatal death. Therefore, immediate and effective management of these cases is of great importance. We report a case of HDFN in a 27-year-old (G5, P3, L1), woman with Rh Dc- phenotype managed successfully using intravenous immunoglobulin (IVIg) and simple transfusions.

New RHCE variant alleles encoding the D- - phenotype

BACKGROUND

Variant alleles that do not produce RhCE antigens are rare. Consequently, they pose a challenge to transfusion when found in alloimmunized patients and make blood units valuable when found in donors.

STUDY DESIGN AND METHODS

Five index cases and their relatives were studied by both serologic and molecular techniques. Genomic DNA was subjected to microarray genotyping, sequencing, exon scanning, and/or copy number determination assays to identify the RHCE allele(s) responsible for their D+ C- c- E- e- (D- -) phenotype.

RESULTS

The five apparent D- - phenotypes were confirmed by molecular methods. Three of them contained unreported RHCE-null alleles, namely, RHCE*Ce-D(3-9)-Ce, RHCE*Ce87_93insT, and RHCE*cE221A.

CONCLUSION

Molecular analysis of D- - phenotypes allows the identification of new RHCE-null variants. Conversely, detection of described RHCE-null variants facilitates confirmation of D- - phenotypes in patients and donors, helping improve transfusion safety.