| 1. |
- Clausen, Frederik Banch, et al.
(författare)
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External quality assessment of noninvasive fetal RHD genotyping
- 2020
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Ingår i: Vox Sanguinis. - : Wiley. - 0042-9007 .- 1423-0410. ; 115:5, s. 466-471
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Tidskriftsartikel (refereegranskat)abstract
- Background and objectives: Fetal RHD genotyping of cell-free maternal plasma DNA from RhD negative pregnant women can be used to guide targeted antenatal and postnatal anti-D prophylaxis for the prevention of RhD immunization. To assure the quality of clinical testing, we conducted an external quality assessment workshop with the participation of 31 laboratories. Materials and methods: Aliquots of pooled maternal plasma from gestational week 25 were sent to each laboratory. One sample was fetal RHD positive, and a second sample was fetal RHD negative. A reporting scheme was supplied for data collection, including questions regarding the methodological setup, results and clinical recommendations. The samples were tested blindly. Results: Different methodological approaches were used; 29 laboratories used qPCR and two laboratories used ddPCR, employing a total of eight different combinations of RHD exon targets. Fetal RHD genotyping was performed with no false-negative and no false-positive results. One inconclusive result was reported for the RHD positive sample. All clinical conclusions were satisfactory. Conclusion: This external quality assessment workshop demonstrates that despite the different approaches taken to perform the clinical assays, fetal RHD genotyping is a reliable laboratory assay to guide targeted use of Rh prophylaxis in a clinical setting.
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| 2. |
- Clausen, Frederik Banch, et al.
(författare)
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Recommendation for validation and quality assurance of non-invasive prenatal testing for foetal blood groups and implications for IVD risk classification according to EU regulations
- 2022
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Ingår i: Vox Sanguinis. - : Wiley. - 0042-9007 .- 1423-0410. ; 117:2, s. 157-165
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Forskningsöversikt (refereegranskat)abstract
- Background and Objectives: Non-invasive assays for predicting foetal blood group status in pregnancy serve as valuable clinical tools in the management of pregnancies at risk of detrimental consequences due to blood group antigen incompatibility. To secure clinical applicability, assays for non-invasive prenatal testing of foetal blood groups need to follow strict rules for validation and quality assurance. Here, we present a multi-national position paper with specific recommendations for validation and quality assurance for such assays and discuss their risk classification according to EU regulations. Materials and Methods: We reviewed the literature covering validation for in-vitro diagnostic (IVD) assays in general and for non-invasive foetal RHD genotyping in particular. Recommendations were based on the result of discussions between co-authors. Results: In relation to Annex VIII of the In-Vitro-Diagnostic Medical Device Regulation 2017/746 of the European Parliament and the Council, assays for non-invasive prenatal testing of foetal blood groups are risk class D devices. In our opinion, screening for targeted anti-D prophylaxis for non-immunized RhD negative women should be placed under risk class C. To ensure high quality of non-invasive foetal blood group assays within and beyond the European Union, we present specific recommendations for validation and quality assurance in terms of analytical detection limit, range and linearity, precision, robustness, pre-analytics and use of controls in routine testing. With respect to immunized women, different requirements for validation and IVD risk classification are discussed. Conclusion: These recommendations should be followed to ensure appropriate assay performance and applicability for clinical use of both commercial and in-house assays.
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| 3. |
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| 4. |
- De La Vega Elena, Carlos D., et al.
(författare)
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A rare blood group: p phenotype
- 2009
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Ingår i: Medicina. - 1648-9144. ; 69:6, s. 651-654
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Tidskriftsartikel (refereegranskat)abstract
- A rare blood group: p phenotype. A rare blood group is usually defined as the absence of a high prevalence antigen or the absence of several antigens within a single blood group system. These individuals may develop clinically significant red cell antibodies to the high incidence red cell antigens they lack. A 33-year-old alloimmunized woman was referred to our center at the 12th week of her third pregnancy for evaluation and follow up. The laboratory work-up grouped her as belonging to "p" phenotype, associated with difficulties to find compatible blood for transfusion and a high incidence of recurrent miscarriage. At 36 weeks, a baby girl was born by induced labor due to fetal suffering. With a negative direct antiglobulin test but a positive elution test, she was in the neonatology ward for one week receiving luminotherapy. Homozygosity for a missense mutation at position 752 (c.752C > T) in the A4GALT gene was found to be responsible for the p phenotype. This mutation changes a proline to a leucine at codon 251 of the 4-alpha-galactosyltransferase. Recently, due to an imminent chirurgical intervention and the impossibility to have compatible blood available for transfusion. an autologous donation plan was designed to satisfy probable demand. This case showed the need for blood bank facilities capable to respond satisfactorily to these situations in Argentina. This would facilitate the storage of cryopreserved blood from individuals with rare blood groups for homologous use or to develop rare blood donors programs.
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| 5. |
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| 6. |
- Gassner, Christoph, et al.
(författare)
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International Society of Blood Transfusion Working Party on Red Cell Immunogenetics and Blood Group Terminology Report of Basel and three virtual business meetings : Update on blood group systems
- 2022
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Ingår i: Vox Sanguinis. - : Wiley. - 1423-0410 .- 0042-9007. ; 117:11, s. 1332-1344
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES: Under the ISBT, the Working Party (WP) for Red Cell Immunogenetics and Blood Group Terminology is charged with ratifying blood group systems, antigens and alleles. This report presents the outcomes from four WP business meetings, one located in Basel in 2019 and three held as virtual meetings during the COVID-19 pandemic in 2020 and 2021.MATERIALS AND METHODS: As in previous meetings, matters pertaining to blood group antigen nomenclature were discussed. New blood group systems and antigens were approved and named according to the serologic, genetic, biochemical and cell biological evidence presented.RESULTS: Seven new blood group systems, KANNO (defined numerically as ISBT 037), SID (038), CTL2 (039), PEL (040), MAM (041), EMM (042) and ABCC1 (043) were ratified. Two (039 and 043) were de novo discoveries, and the remainder comprised reported antigens where the causal genes were previously unknown. A further 15 blood group antigens were added to the existing blood group systems: MNS (002), RH (004), LU (005), DI (010), SC (013), GE (020), KN (022), JMH (026) and RHAG (030).CONCLUSION: The ISBT now recognizes 378 antigens, of which 345 are clustered within 43 blood group systems while 33 still have an unknown genetic basis. The ongoing discovery of new blood group systems and antigens underscores the diverse and complex biology of the red cell membrane. The WP continues to update the blood group antigen tables and the allele nomenclature tables. These can be found on the ISBT website (http://www.isbtweb.org/working-parties/red-cell-immunogenetics-and-blood-group-terminology/).
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| 7. |
- Hellberg, Åsa, et al.
(författare)
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A novel nonsense variant in RHAG underlies a Nordic Rhnull phenotype
- 2023
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Ingår i: Vox Sanguinis. - : John Wiley & Sons. - 0042-9007 .- 1423-0410. ; 118:8, s. 690-694
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Tidskriftsartikel (refereegranskat)abstract
- Background and ObjectivesThe 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 MethodsFour 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.ResultsAnti-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.ConclusionA 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.
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| 8. |
- Hellberg, Åsa, et al.
(författare)
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A novel RHCE*02 allele, containing the single-nucleotide change c.460A>G, encodes weakened expression of C and e antigens
- 2016
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Ingår i: Transfusion. - : Wiley. - 0041-1132 .- 1537-2995. ; 56:9, s. 2391-2392
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Tidskriftsartikel (refereegranskat)abstract
- We report a novel RHCE*02 allele in a Swedish blood donor that is characterized by the change c.460A>G (Arg154Gly). The blood donor's red blood cells showed variable reactivity with different monoclonal anti-C and anti-e and antigen strength was markedly weakened. We believe that these changes represent both a quantitative and qualitative alteration of the antigens encoded by this allele.
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