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Flegel WA, Srivastava K. 40 years of researching the Del phenotype results in a change of transfusion practice. Transfusion 2024. [PMID: 38899801 DOI: 10.1111/trf.17913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/20/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024]
Abstract
Anti-D cannot agglutinate red cells of any Del phenotype in routine serology. Many individuals with East Asian ancestry who type D-negative in serology harbor a Del phenotype. Almost all such individuals carry one distinct DEL variant, dubbed Asian-type DEL, known as RHD*01EL.01, RHD*DEL1, RHD:c.1227G>A, formerly known as RHD(K409K). Clinical evidence strongly suggests that Asian-type DEL individuals can safely be transfused with RhD-positive blood and do not need anti-D prophylaxis in pregnancy.
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Affiliation(s)
- Willy Albert Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Kshitij Srivastava
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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2
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Srivastava K, Bueno MU, Flegel WA. Breakpoint regions of an RHD-CE(4-9)-D allele and a rare JK allele in a Pacific Islander individual. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2024; 22:189-197. [PMID: 37677094 PMCID: PMC11073622 DOI: 10.2450/bloodtransfus.534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/07/2023] [Indexed: 09/09/2023]
Abstract
BACKGROUND Among 710 RHD alleles, 3 alleles have been shown to express CcEe antigens and, among 67 hybrid alleles of the RHD gene, 2 alleles have evolved to include RHCE exons 4-9. No breakpoint region had been described for such RHD-CE(4-9)-D hybrid alleles. In the Kidd blood group system, the JK*02N.01 null allele is found with high prevalence in the Polynesian population. We investigated a self-identified Pacific Islander with discrepant serologic and molecular results for his C and Jkb antigens. Another 8 samples with genotype-phenotype discrepancies in the Kidd blood group system were assessed. MATERIALS AND METHODS A combination of published molecular methods and commercial kits were applied to analyze the RHD, RHCE, and SLC14A1 gene sequences, as were hemagglutination tests to determine the serologic phenotypes. RESULTS Nucleotide sequencing of the RHD gene in the index case, including relevant intron stretches, and cDNA identified an RHD-CE(4-9)-D hybrid allele. Nucleotide sequencing of his RHCE gene confirmed the presence of 2 RHCE*ce alleles despite expressing the C antigen. Sequencing of his SLC14A1 gene documented the JK*02N.01 null allele. In the other 8 samples, 5 previously known SLC14A1 nucleotide substitutions were identified. The JK*02N.17 allele was determined to be Jkb-positive. DISCUSSION We determined the 2 breakpoint regions of his RHD-CE(4-9)-D hybrid allele, which was likely distinct from the 2 previously published hybrid alleles due to the differences in the linked RHCE allele. His RHD variant was shown to express the C antigen. An SLC14A1 substitution was underlying his unexpected Jkb-negative phenotype. In a quality improvement project, we resolved 8 samples with similarly discrepant results between Jk serology and red cell genotyping.
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Affiliation(s)
- Kshitij Srivastava
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, United States of America
| | - Marina U Bueno
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, United States of America
| | - Willy A Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, United States of America
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Hutchison CJ, Srivastava K, Polin H, Bueno MU, Flegel WA. Rh flow cytometry: An updated methodology for D antigen density applied to weak D types 164 and 165. Transfusion 2023; 63:2141-2151. [PMID: 37792462 PMCID: PMC10680490 DOI: 10.1111/trf.17543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 10/05/2023]
Abstract
BACKGROUND An original methodology for determining the D antigen density on red cells was published in 2000 and has been applied in many publications since. This flow cytometry-based assay remained largely unrevised utilizing monoclonal anti-Ds that are not readily available anymore. We updated the methodology to quantify erythrocyte D antigen sites using microspheres and monoclonal anti-Ds that are commercially available today. METHODS The absolute D antigen density of a frozen standard CcDEe cell, drawn in 2003, a fresh blood donation from the same individual, drawn in 2022, and an internal control CcDEe cell, was quantified by flow cytometry using fluorescence-labeled microspheres. The internal control CcDEe cell was used in conjunction with 9 commercial anti-Ds to determine D antigen densities of 7 normal D, 4 partial D, and 11 weak D type samples, including 2 novel alleles. RESULTS The reproducibility of the updated assay was evaluated with red cells of published D antigen densities. The current results matched the known ones closely. The new weak D types 164 and 165 carried 4500 and 1505 D antigens/red cell, respectively. The absolute D antigen density decreased from 27,231 to 26,037 in an individual over 19 years. DISCUSSION The updated assay gave highly reproducible results for the D antigen densities of Rh phenotypes. Readily available anti-Ds allowed for the determination of the D antigen densities of 7 weak D types. The assay is suitable to evaluate the effects of distinct amino acid substitutions on the RhD phenotype.
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Affiliation(s)
- Chloe Jayne Hutchison
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Kshitij Srivastava
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Helene Polin
- Department of Immunogenetics, Red Cross Transfusion Service for Upper Austria, Linz, Austria
| | - Marina Ursula Bueno
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Willy Albert Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
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Yin Q. DEL variants: review of molecular mechanisms, clinical consequences and molecular testing strategy. Funct Integr Genomics 2023; 23:318. [PMID: 37840046 DOI: 10.1007/s10142-023-01249-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 10/17/2023]
Abstract
Patients with DEL phenotype, a D variant with a low number of D antigens per red blood cell, are routinely typed as RhD-negative in serology testing and are detectable only by adsorption and elution techniques or molecular methods. DEL is of clinical importance worldwide, as indicated by its genotype-phenotype discrepancies among different populations and its potential to cause anti-D alloimmunization when DEL phenotype individuals are inadvertently managed as RhD-negative. This narrative review summarized the DEL alleles causing DEL phenotype and the underlying mechanisms. The clinical consequences and current molecular testing approach were discussed to manage the transfusion needs of patients and donors with DEL phenotype.
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Affiliation(s)
- Qinan Yin
- Henan Engineering Research Center of Digital Pathology and Artificial Intelligence Diagnosis, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, China.
- Precision Medicine Laboratory, School of Medical Technology and Engineering, Henan University of Science and Technology, Luoyang, China.
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Yin Q, Ouchari M. Transfusion management of Africans with RHD variants in China. Transfus Clin Biol 2023; 30:287-293. [PMID: 36702201 DOI: 10.1016/j.tracli.2023.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023]
Abstract
The presence of D variant among minorities could produce a higher rate of alloimmunization observed in patients from this group. This is partly due to the ethnic and racial specificity of RHD variants and the limited availability of Rh-matched blood donors. Approximately half a million African migrants in China carrying distinct Rh blood type composition have presented to the health care system with an imperative safety requirement of blood transfusion among 1.3 billion Chinese individuals. We depict the clinically significant RHD alleles among African migrants living in China and identify the genetic similarities and disparities to Chinese. We discussed practical strategies to manage the unique transfusion needs of African migrants in China.
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Affiliation(s)
- Qinan Yin
- School of Medical Technology and Engineering, Henan University of Science and Technology, Luoyang, Henan, China
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Yin Q, Flegel WA. DEL in China: the D antigen among serologic RhD-negative individuals. J Transl Med 2021; 19:439. [PMID: 34670559 PMCID: PMC8527646 DOI: 10.1186/s12967-021-03116-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 09/21/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Providing RhD-negative red cell transfusions is a challenge in East Asia, represented by China, Korea, and Japan, where the frequency of RhD-negative is the lowest in the world. FINDINGS Among 56 ethnic groups in China, the RhD-negative frequency in Han, the prevalent ethnicity, is 0.5% or less, similar to most other ethnic groups. The Uyghur ethnic group has the highest reported RhD-negative frequency of up to 4.7%, as compared to 13.9% in the US. However, an estimated 7.15 million RhD-negative people live in China. The RhD-negative phenotype typically results from a loss of the entire RHD gene, causing the lack of the RhD protein and D antigen. The DEL phenotype carries a low amount of the D antigen and types as RhD-negative in routine serology. The DEL prevalence in RhD-negative individuals averages 23.3% in the Han, 17% in the Hui and 2.4% in the Uyghur ethnicities. The Asian type DEL, also known as RHD*DEL1 and RHD:c.1227G > A allele, is by far the most prevalent among the 13 DEL alleles observed in China. CONCLUSION The purpose of this review is to summarize the data on DEL and to provide a basis for practical strategy decisions in managing patients and donors with DEL alleles in East Asia using molecular assays.
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Affiliation(s)
- Qinan Yin
- Laboratory Services Section, Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
- Henan University of Science and Technology, Luoyang, Henan, China
| | - Willy Albert Flegel
- Laboratory Services Section, Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA.
- Huazhong University of Science and Technology, Wuhan, Hubei, China.
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Thongbut J, Laengsri V, Raud L, Promwong C, I-Na-Ayudhya C, Férec C, Nuchnoi P, Fichou Y. Nation-wide investigation of RHD variants in Thai blood donors: Impact for molecular diagnostics. Transfusion 2020; 61:931-938. [PMID: 33377204 DOI: 10.1111/trf.16242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/23/2020] [Accepted: 12/06/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND Knowledge of the molecular determinants driving antigen expression is critical to design, optimize, and implement a genotyping approach on a population-specific basis. Although RHD gene variability has been extensively reported in Caucasians, Africans, and East-Asians, it remains to be explored in Southeast Asia. Thus the molecular basis of non-D+ blood donors was investigated in Thailand. STUDY DESIGN AND METHODS First, 1176 blood samples exhibiting an inconclusive or negative result by automated serological testing were collected in the 12 Regional Blood Centres of the Thai Red Cross located throughout Thailand. Second, the RHD gene was analyzed in all samples by 1) quantitative multiplex PCR of short fluorescent fragments, and 2) direct sequencing, when necessary, for identifying structural variants and single nucleotide variants, respectively. RESULTS Additional serological typing yielded 51 and 1125 samples with weak/partial D and D-negative (D-) phenotype, respectively. In the first subset, partial RHD*06.03 was the most common variant allele (allele frequency: 18.6%). In the second subset, the whole deletion of the gene is largely the most frequent (allele frequency: 84.9%), followed by the Asian DEL allele found in 15.6% of the samples. Eight novel alleles with various mutational mechanisms were identified. CONCLUSION We report, for the first time at the national level, the molecular basis of weak/partial D and serologically D- phenotypes in Thai blood donors. The design and implementation of a dedicated diagnostic strategy in blood donors and patients are the very next steps for optimizing the management and supply of RBC units in Thailand.
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Affiliation(s)
- Jairak Thongbut
- Center of Research and Innovation, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand.,National Blood Centre, Thai Red Cross Society, Bangkok, Thailand
| | - Vishuda Laengsri
- Center of Research and Innovation, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | | | - Charuporn Promwong
- National Blood Centre, Thai Red Cross Society, Bangkok, Thailand.,Sunpasitthiprasong Hospital, Ubon Ratchathani, Thailand
| | - Chartchalerm I-Na-Ayudhya
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Claude Férec
- Univ Brest, Inserm, EFS, Brest, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | - Pornlada Nuchnoi
- Center of Research and Innovation, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand.,Department of Clinical Microscopy, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Yann Fichou
- Univ Brest, Inserm, EFS, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
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Matteocci A, Monge-Ruiz J, Stef M, Apraiz I, Herrera-Del-Val L, Mancuso T, Fennell K, Lopez M, Larizgoitia-Martin Y, Nespoli G, Rubia-Tejero M, Collaretti A, Pierelli L, Ochoa-Garay G. Two new RHD alleles with deletions spanning multiple exons. Transfusion 2020; 61:682-686. [PMID: 33241598 DOI: 10.1111/trf.16199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/29/2020] [Accepted: 10/11/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND The most common large-deletion RHD allele (RHD*01N.01) includes the entire coding sequence, intervening regions and untranslated regions. The rest of large-deletion RHD alleles reported to-date consist of single-exon deletions, such as RHD*01N.67 which includes exon 1. MATERIALS AND METHODS Samples from two donors with RhD-negative serology yielded unclear or inconclusive results when subject to confirmatory testing on RHD genotyping arrays. To determine their RHD genotypes, genomic DNA was analyzed with a combination of allele-specific PCR, long-range PCR, Sanger sequencing, and next-generation sequencing assays. RESULTS Allele-specific PCR failed to detect products for RHD exons 1 to 3 in one sample and RHD exons 1 to 5 in the other. A quantitative next-generation sequencing assay confirmed deletion of exons 1 to 3 and 1 to 5 respectively, and detected the absence of an RHD gene in trans in both samples. Long-range PCR and Sanger sequencing enabled identification of the breakpoints for both alleles. Both deletions start within the 5' Rhesus box (upstream of the identity region for the 1-to-3 deletion, downstream of it for the 1-to-5 deletion), and end within introns. CONCLUSIONS Resolution of unclear or inconclusive results from targeted genotyping arrays often leads to the discovery of new alleles. The 5' Rhesus box may be a hot spot for genetic recombination events, such as the large deletions described in this report.
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Affiliation(s)
| | - Jorge Monge-Ruiz
- Osakidetza, Basque Center for Blood Transfusion and Human Tissues, Galdakao, Spain.,Biocruces Bizkaia Health Research Institute, Cell Therapy, Stem Cells and Tissues Group, Barakaldo, Spain
| | - Marianne Stef
- Grifols Immunohematology Center, San Marcos, Texas, USA
| | | | - Lara Herrera-Del-Val
- Osakidetza, Basque Center for Blood Transfusion and Human Tissues, Galdakao, Spain.,Biocruces Bizkaia Health Research Institute, Cell Therapy, Stem Cells and Tissues Group, Barakaldo, Spain
| | | | - Katie Fennell
- Grifols Immunohematology Center, San Marcos, Texas, USA
| | | | | | - Guido Nespoli
- Transfusion Medicine Unit, San Camillo Forlanini Hospital, Rome, Italy
| | | | - Angela Collaretti
- Transfusion Medicine Unit, San Camillo Forlanini Hospital, Rome, Italy
| | - Luca Pierelli
- Transfusion Medicine Unit, San Camillo Forlanini Hospital, Rome, Italy.,Department of Experimental Medicine, Sapienza University, Rome, Italy
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Flegel WA, Srivastava K. Frameshift variations in the RHD coding sequence: Molecular mechanisms permitting protein expression. Transfusion 2020; 60:2737-2744. [PMID: 33037655 DOI: 10.1111/trf.16123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/08/2020] [Accepted: 07/17/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Willy A Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Kshitij Srivastava
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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Flegel WA. Mosaicism by somatic non-functional mutations: one cell lineage at a time. Haematologica 2019; 104:425-427. [PMID: 30819835 DOI: 10.3324/haematol.2018.208165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Willy Albert Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD.,Department of Pathology, Georgetown University Medical Center, Washington, DC, USA
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