Novel RHD alleles with weak hemagglutination and genetic Exon 9 diversity: weak D Types 45.1, 75, and 76.

Gassner C, Utz I, Schennach H, Ramoni A, Steiner H, Scholz S, Kreklau U, Körmöczi GF.

Abstract

Background

Molecular variant RHD allele analysis is best complemented by detailed characterization of the associated D phenotype.

Results

We discovered three novel weak D types termed weak D Types 45.1, 75, and 76 with RHD nucleotide substitutions coding for amino acid exchanges in predicted intracellular RhD polypeptide stretches; antigen densities of approximately 1.990, 900, and 240 D sites per red blood cell were found, respectively. Adsorption-elution technique-supported D epitope mapping of these three weak D types demonstrated the expression of all tested D epitopes. Initial molecular typing of the three investigated samples by RHD gene exon scanning polymerase chain reaction using sequence-specific priming yielded a negative reaction for A1193 located in RHD Exon 9 and could be explained by specific mutations for weak D Types 45.1 (C818T, G1195A), 75 (G1194C), and 76 (A1215C).

Conclusion

All novel weak D types expressed all tested D epitopes. It is of interest that for weak D Types 45.1, 75, and 76, similar alleles with a maximal divergence of one amino acid only, that is, weak D Types 45, 41, and 68, respectively, have been reported so far.

© 2013 American Association of Blood Banks.

PMID: 23550956 DOI: 10.1111/trf.12180