Molecular basis of DEL phenotype in the Chinese population

Abstract

BackgroundRh blood group system is the most complex and immunogenetic blood group system. Prevalent RHD alleles vary in different populations. We conducted the present study to examine the genotype of DEL individuals and to elucidate whether novel alleles exist in the Chinese population.MethodsDEL phenotype was identified by a serologic adsorption-elution method. The nucleotide sequences of ten RHD exons and exon-intron boundary regions were evaluated by RHD gene-specific PCR-SSP and sequencing.ResultsOf 42306 samples from individual donors and patients, 165 samples were typed as D-negative. Among these D-negative samples, 41 DEL individuals were observed. Thirty-seven DELs were confirmed to have the RHD1227A allele. Two DELs seemed to have RHD-CE-D hybrid alleles, including one RHD-CE (4–7)-D and one RHD-CE (2–5)-D. Two novel RHD alleles were found among the rest of the DEL samples, including one RHD93T > A and one RHD838G > A.ConclusionIn this study, about 24.85% (41/165) of the apparent D-negative Chinese individuals were DEL. RHD1227G > A is the most frequent allele in Chinese DEL phenotypes, accounting for 90.24% (37/41). The RHD-CE-D hybrid allele might be the second most frequent DEL allele in the Chinese population. Our study would contribute to the understanding of the molecular mechanism underlying D antigen expression of DEL individuals and provide useful information for designing suitable genotyping strategies in RhD-negative individuals in Asia.

It's time to phase inRHDgenotyping for patients with a serologic weakDphenotype

“…41,148 The Asian-type DEL displays the complete repertoire of RhD antigen epitopes. 38,72,92 DEL phenotypes, which are found more commonly among persons of Asian ancestry, do not present as a serologic weak D phenotype. Therefore, the Work Group did not formulate a recommendation for managing DEL phenotypes, although DEL phenotypes have been implicated as the cause of RhD alloimmunization when RhD-negative/DEL-positive RBCs were unknowingly transfused to RhD-negative recipients.…”

“…DEL phenotypes present by conventional blood typing as RhD‐negative and are not detected serologically unless adsorption and elution studies are performed . The Asian‐type DEL displays the complete repertoire of RhD antigen epitopes . DEL phenotypes, which are found more commonly among persons of Asian ancestry, do not present as a serologic weak D phenotype.…”

Serological weak D phenotypes: a review and guidance for interpreting the RhD blood type using the RHD genotype

“…There are significant differences in the prevalence of DEL phenotypes and the RHD (1227G>A) allele (Wagner et al , 2001) among RhD-negative individuals in different racial and ethnic populations. Less than 1% of Chinese Han are RhD-negative (Gu et al , 2014; Yang et al , 2007) and of these, as many as 30% express the DEL phenotype (Shao et al , 2002, Wagner et al , 2005). In Japanese, 0.5% are RhD-negative (Okubo et al , 1991) and 28% of these express a DEL phenotype (Fukumori et al , 1997).…”

“…1 is lacking from the mature protein in the red cell membrane, and the arch depicts the Rh protein vestibule (modified from Flegel, 2006). (Yang et al, 2007;Gu et al, 2014) and of these, as many as 30% express the DEL phenotype (Shao et al, 2002;Wagner et al, 2005). In Japanese, 0Á5% are RhD-negative (Okubo et al, 1991) and 28% of these express a DEL phenotype (Fukumori et al, 1997).…”

Molecular basis of D-negative phenotype (literature review and case reports)

“…Эритроциты с антигеном DEL обычно идентифици-руют как RhD-отрицательные при использовании се-рологических методов. Этот антиген иногда нельзя выявить даже методами адсорбции и элюции [43], хо-тя азиатский его тип имеет все эпитопы RhD-белка [44]. Aнтиген RhDEL имеет клиническое значение, так как вызывает аллоиммунизацию у RhD-отрицательных реципиентов [45,46], и доноры с таким антигеном должны быть отнесены к резус-положи-тельным [28].…”