On the trail of anti‐CDE to unexpected highlights of the RHD*weak 4.3 allele in the Upper Austrian population

Abstract

The application of a commercial available microcolumn system for ABO/RH determination lead to irregular results in CDE typing of seemingly D- blood samples. In this study, we introduce a comprehensive serological and molecular work-up of a novel haplotype carrying the RHD*weak 4.3 in combination with an aberrant RHCE*ce. The molecular background was characterized by RHD and RHCE-specific DNA sequencing, RHD cDNA sequencing and RHD zygosity testing. Haplotype-specific extraction and inheritance analysis were initiated to determine the linkage of the polymorphisms. The genetic admixture was studied by whole genome SNP array analysis. Serology was done using commercial available standard techniques and by in-house sera likewise. All samples (n = 29) were shown to harbour an altered RHD(T201R, F223V, P291R) allele known as RHD*weak 4.3 associated with a RHCE*ce(W16C, A36T, L245V) gene formation, expressing C(X) and VS. Both anti-C(X) and anti-V/VS were detected as contaminating antibodies in a commercial available microcolumn system for ABO/RH determination accounting for the positive results in CDE typing. Compared with other population data, the samples were clearly identified as Caucasian. The RHD*weak 4.3 allele with markedly reduced antigen D expression was shown to be associated with an altered RHCE gene formation leading to the expression of C(X) and VS. Its frequency was estimated 1 in 854 among apparently D- Upper Austrian blood donors.