RHD alleles and D antigen density among serologically D-C+Brazilian blood donors

摘要

The D-negative phenotype may be caused by the lack of functional RhD protein or by the presence of aberrant forms of RhD not expressing the D antigen. Numerous single nucleotide polymorphism (SNPs) changes in the RHD gene are currently known. The weak D has been shown to be caused by SNPs in most cases, leading to amino acid changes in the transmembraneous, or intracellular, parts of the D protein, consequently showing reduced D antigen density (Wagner et al, 1999; Wagner et al, 2000). Very weakly expressed weak D, or D only detectable by adsorption-elution techniques, named DELs, were frequently unidentified by routine serologic procedures, and large groups of completely unexpressed RHD alleles only became evident by DNA-typing methods (Gassner et al, 2005). Several studies have confirmed unexpressed RHD alleles in association with D — Ce or cE phenotypes (Gassner et al, 2005; Christiansen et al, 2010).