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Background and Objectives: A newborn presented with jaundice in Thailand. The cord red cells tested positive by direct antiglobulin test (DAT) for an unknown maternal red cell antibody. Initial blood group sequencing suggested that the infant carried a novel variant RHAG c.140T>C, responsible for a low‐prevalence antigen in the RHAG blood group system (ISBT 030). We report here on testing of samples from the infant's parents and older sibling to define a new antigen in the RHAG system. Materials and Methods: Massive parallel sequencing (MPS) using a custom‐designed panel was performed on all four family members. Extended serological testing was also performed to determine whether family members with the same variant as the infant showed reactivity with the antibody in the maternal plasma. Results: We identified a novel single nucleotide variant (SNV) (RHAG c.140T>C, p.[Phe47Ser]) in samples from three of the four family members tested (the infant, the older sibling and the father). The variant was not detected in the mother's sample. Maternal plasma showed positive agglutination with all family members tested; however, when tested with routine panel cells, no reactivity was observed. Conclusion: This case study showed that the presence of the novel variant (RHAG c.140T>C), encoding a p.(Phe47Ser) change in the RhAG glycoprotein, was the apparent cause of incompatibility between maternal plasma and that of red cells from the proband, father and older sibling of the proband. We propose this variant to be a new low‐prevalence antigen in the RHAG blood group system. [ABSTRACT FROM AUTHOR]

Background and Objectives: The extremely rare Rhnull phenotype is characterized by the absence of all Rh antigens on erythrocytes. It is divided into the regulator and amorph types based on the underlying genetic background. The more common regulator type depends on critical variants silencing RHAG, which encodes RhAG glycoprotein, necessary for RhD/RhCE expression. Rhnull cells have altered expression of glycophorin B and LW glycoprotein. Materials and Methods: Four unrelated Rhnull individuals were investigated. Serological testing was performed according to standard blood bank practice. RHD/RHCE and S/s allele‐specific Polymerase chain reaction (PCR) genotyping was done on genomic DNA using in‐house PCR assays. RHAG, and in some cases also RHD/RHCE, were sequenced. Initial s phenotyping results triggered additional serological investigation. Results: Anti‐Rh29 was identified in all four individuals. Extended typing with anti‐S and anti‐s showed that the three samples predicted to type as s+ failed to react with 2 of 5 anti‐s. Sequence analysis of all 10 RHAG exons and the immediate intron/exon boundaries revealed a single nucleotide variant in the 3′‐end of intron 6, c.946 −2a>g in all samples. RHD/RHCE showed no alterations. Conclusion: A novel Nordic Rhnull allele was identified. In addition, it was shown that s+ Rhnull red blood cells are not only U− but also have qualitative changes in their s antigen expression. [ABSTRACT FROM AUTHOR]

Background The band 3 macrocomplex (also known as the ankyrin-associated complex) on the red cell membrane comprises two interacting subcomplexes: a band 3/glycophorin A subcomplex, and a Rh/Rh AG subcomplex. Glycophorin B ( GPB) is a component of the Rh/Rh AG subcomplex that is also structurally associated with glycophorin A ( GPA). Expression of glycophorin B-A-B hybrid GP.Mur enhances band 3 expression and is associated with lower levels of Rh-associated glycoprotein (Rh AG) and Rh polypeptides. The goal of this study was to determine whether GP.Mur influenced erythroid Rh/Rh AG expression at the transcript level. Materials and Methods GP.Mur was serologically determined in healthy participants from Taitung County, Taiwan. RNA was extracted from the reticulocyte-enriched fraction of peripheral blood, followed by reverse transcription and quantitative PCR for Rh AG, RhD and RhCcEe. Results Quantification by real-time PCR revealed significantly fewer Rh AG and RhCcEe transcripts in the reticulocytes from subjects with homozygous GYP*Mur. Independent from GYP.Mur, both Rh AG and RhD transcript levels were threefold or higher than that of RhCcEe. Also, in GYP.Mur and the control samples alike, direct quantitative associations were observed between the transcript levels of Rh AG and RhD, but not between that of Rh AG and RhCcEe. Conclusion Erythroid RhD and RhCcEe were differentially expressed at the transcript levels, which could be related to their different degrees of interaction or sensitivity to Rh AG. Further, the reduction or absence of glycophorin B in GYP.Mur erythroid cells affected transcript expressions of Rh AG and RhCcEe. Thus, GPB and GP.Mur differentially influenced Rh/Rh AG expressions prior to protein translation. [ABSTRACT FROM AUTHOR]

Background and Objectives: The extremely rare Rh null phenotype is characterized by the absence of all Rh antigens on erythrocytes. It is divided into the regulator and amorph types based on the underlying genetic background. The more common regulator type depends on critical variants silencing RHAG, which encodes RhAG glycoprotein, necessary for RhD/RhCE expression. Rh null cells have altered expression of glycophorin B and LW glycoprotein., Materials and Methods: Four unrelated Rh null individuals were investigated. Serological testing was performed according to standard blood bank practice. RHD/RHCE and S/s allele-specific Polymerase chain reaction (PCR) genotyping was done on genomic DNA using in-house PCR assays. RHAG, and in some cases also RHD/RHCE, were sequenced. Initial s phenotyping results triggered additional serological investigation., Results: Anti-Rh29 was identified in all four individuals. Extended typing with anti-S and anti-s showed that the three samples predicted to type as s+ failed to react with 2 of 5 anti-s. Sequence analysis of all 10 RHAG exons and the immediate intron/exon boundaries revealed a single nucleotide variant in the 3'-end of intron 6, c.946 -2a>g in all samples. RHD/RHCE showed no alterations., Conclusion: A novel Nordic Rh null allele was identified. In addition, it was shown that s+ Rh null red blood cells are not only U- but also have qualitative changes in their s antigen expression., (© 2023 The Authors. Vox Sanguinis published by John Wiley & Sons Ltd on behalf of International Society of Blood Transfusion.)