RHD positive among C/E+ and D-negative blood donors in Tunisia

The aim of this study was to investigate RHD alleles among Tunisian blood donors with D-negative phenotype and positive for C and/or E antigen.

A total of 100 D-negative and C/E+ samples were analyzed by RHD genotyping using an initial test for RHD exon 10. In case of a positive reaction, further molecular investigations including real time quantitative PCR, allele specific PCR and nucleotide sequencing were done to elucidate the RHD involved mechanisms.

Seventy-five percent of the studied samples lacked the RHD gene. Twenty-three percent carried the hybrid RHD-CE-D alleles (16 RHD-CE(3-7)-D, 5 RHD-CE(4-7)-D, 1 RHD-CE(4-8)-D, 1 RHD-CE(3-8)-D) and 2% were weak D (1 weak D type 1 and 1 weak D type 5).

Our study proved the high frequency of RHD gene among serologically D-negative samples, positive for C and/or E antigen. Thus achieving systematically RHCE phenotyping in all transfusion centers on the Tunisian territory and considering blood donated from D-negative C/E+ persons as D-positive will be recommended to reduce anti-D allo-immunization.