Further analysis of D_el (D‐elute) using polymerase chain reaction (PCR) with RHD gene‐specific primers

Abstract

Del (D-elute) in the Rh blood group system is a variant with very weak D antigen and no agglutination is found by the indirect antiglobulin test. This variant is characterized by the presence of anti-D eluate obtained after an adsorption-elution test using anti-D antibodies. We studied here the molecular genetic status of Del by using polymerase chain reaction with sequence-specific primers (PCR-SSP). We screened 306 serologically apparent D-negative Japanese donors comprising 102 Del types for exons 7, 4 and 10 of the RHD gene. No PCR product was found in all 204 non-Del samples from the D-seronegative donors. However, PCR products were found in all 102 Del samples and all 70 D-seropositive samples tested by the three PCR methods for exons 7, 4 and 10 analysis. Del was found with CCee, CcEe and Ccee, but not with CCEe, CcEE, ccEE, ccEe or ccee phenotype. The incidences of Del in the samples with the serological phenotypes CCee, CcEe and Ccee were 80.0% (4/5), 68.2% (45/66) and 61.6% (53/86), respectively. The results provide evidence that Del samples have exons 4, 7 and 10 of an RHD gene present in some form. This is consistent with the evidence that D antigen is present on the cells although only detected by antibody adsorption and elution. The PCR-SSP method in the present study is useful to confirm Del among serologically apparent D-negative samples.

RhC Phenotyping, Adsorption/Elution Test, and SSP-PCR: The Combined Test for D-Elute Phenotype Screening in Thai RhD-Negative Blood Donors

“…Most DEL donors are typed as RhD-negative because the routine serological typing does not distinguish RhD-negative from the DEL phenotype. Previous reports have indicated that the presence of the RHD gene in DEL samples seems to relate strictly to the RhC phenotype with high incidence of RhC(+) in the apparent RhD-negative persons [12, 16, 17]. All DEL persons with intact RHD gene showed the CC or Cc phenotype but not the cc phenotype.…”

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

“…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). In Koreans, 0.15% are RhD-negative and of these, 17% express a DEL phenotype (Kim et al , 2005, Lüttringhaus et al , 2006).…”

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

“…Вариантом антигена D, не распознаваемым моно-клональными анти-D-реактивами, но идентифициру-емым методами адсорбции-элюции [37], является фенотип DEL (D el ), часто встречающийся у предста-вителей монголоидной расы [38][39][40]. Молекулярная основа данного варианта гена RHD -делеция 1013 пар оснований между интронами 8 и 9, выпадение почти всего экзона 9 и присутствие аллеля 1227А [41,42].…”