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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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Srivastava K, Bueno MU, Flegel WA. Transfusion support for a woman with RHD*09.01.02 and the novel RHD*01W.161 allele in trans. Immunohematology 2022; 38:17-24. [PMID: 35852060 PMCID: PMC9364384 DOI: 10.21307/immunohematology-2022-036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
According to recent work group recommendations, individuals with the serologic weak D phenotypes should be RHD genotyped and individuals with molecular weak D types 1, 2, 3, 4.0, or 4.1 should be treated as D+. We report an African American woman with a long-standing history of metrorrhagia, who presented for infertility evaluation. Blood grouping showed AB with a possible subgroup of A, based on mixed-field agglutination, and a serologic weak D phenotype. Results from routine red cell genotyping for the RHD gene was incongruent with the serologic RhCE phenotype. For the surgical procedure, the patient was hence scheduled to receive group AB, D- RBC transfusions. Subsequent molecular analysis identified the ABO*A2.01 and ABO*B.01 alleles for the ABO genotype and the novel RHD allele [NG_007494.1(RHD):c.611T>A] along with an RHD*09.01.02 allele for the RHD genotype. Using a panel of monoclonal anti-D reagents, we showed the novel RHD(I204K) allele to represent a serologic weak D phenotype, despite occurring as a compound heterozygote, designated RHD*weak D type 161 (RHD*01W.161). Individuals with a weak D type 4.2 allele are prone to anti-D immunization, while the immunization potential of novel RHD alleles is difficult to predict. For now, patients should be treated as D- in transfusion and pregnancy management, when they harbor a novel RHD allele along with any weak D allele other than weak D types 1, 2, 3, 4.0, or 4.1. This study exemplifies strategies for how and when a laboratory should proceed from routine genotyping to nucleotide sequencing before any decisions on transfusion practice is made.
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Affiliation(s)
- K Srivastava
- Staff Scientist, Department of Transfusion Medicine, National Institutes of Health (NIH) Clinical Center, Bethesda, MD United States
| | - M U Bueno
- IRL Specialist, Department of Transfusion Medicine, NIH Clinical Center, Bethesda, MD United States
| | - W A Flegel
- Chief, Laboratory Services Section, Department of Transfusion Medicine, NIH Clinical Center, 10 Center Drive, Bethesda, MD 20892 United States
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Khetan D, Shukla JS, Chaudhary RK. Molecular basis of RhD-negative phenotype in North Indian blood donor population. Indian J Med Res 2022; 155:286-292. [PMID: 35946206 PMCID: PMC9629522 DOI: 10.4103/ijmr.ijmr_1235_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background & objectives RHD gene typing is highly complex due to homology with RHCE genes. Molecular polymorphism of the RHCE and RHD genes have been characterized among various populations, but no studies have been undertaken among Indians. This study was undertaken to assess the genetic basis of RHD-negative phenotype in Indian blood donor population. Methods Sample from a total of 200 phenotypically RhD-negative blood donors were analyzed for presence of RHD gene using polymerase chain reaction (PCR). RHD genotyping was done using three primer sets designed for exons 4 and 10 and one set for identification of pseudo (RHDΨ) gene between introns (int) 3 and 4. Amplified PCR products were analyzed by gel-electrophoresis (XY Loper, Uvitech, Cambridge) and confirmed by nucleotide sequencing (ABI 3730 xl 96 capillary system). Results No PCR product was found in 195/200 (97.5%) of study samples indicating homozygous gene deletion. Of the 5/200 (2.5%) showing RHD gene polymorphisms, 4/200 (2%) were positive for presence of exon 10 only (RHD-CE-D hybrid). RHDΨ gene was not detected in any of the samples tested. One sample showed presence of all three tested regions and was negative for RHDΨ gene. Interpretation & conclusions RHD gene deletion was found to be the most common cause of an RHD-negative phenotype while RHDΨ gene was, reported to be present in up to 39 per cent of various ethnic populations, but was not detected. RHD-CE-D hybrid gene (found in 2.5% individuals) is important for predicting the requirement of Rh prophylaxis during the antenatal period.
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Affiliation(s)
- Dheeraj Khetan
- Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
| | - Jai Shukla Shukla
- Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
| | - Rajendra K Chaudhary
- Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
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Flegel WA. Proceed with care: the "uncommon" serologic weak D phenotypes. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2021; 19:272-276. [PMID: 34704554 PMCID: PMC8297679 DOI: 10.2450/2021.0147-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Willy Albert Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, United States of America
- Huazhong University of Science and Technology, Wuhan, Hubei, China
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Flegel WA, Denomme GA, Queenan JT, Johnson ST, Keller MA, Westhoff CM, Katz LM, Delaney M, Vassallo RR, Simon CD, Sandler SG. It's time to phase out "serologic weak D phenotype" and resolve D types with RHD genotyping including weak D type 4. Transfusion 2020; 60:855-859. [PMID: 32163599 DOI: 10.1111/trf.15741] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 01/21/2020] [Accepted: 02/15/2020] [Indexed: 12/21/2022]
Affiliation(s)
- Willy A Flegel
- Department of Pathology and Laboratory Medicine, MedStar Georgetown University Hospital, Washington, DC, USA.,Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | | | - John T Queenan
- Department of Obstetrics and Gynecology, MedStar Georgetown University Hospital, Washington, DC, USA
| | | | - Margaret A Keller
- National Molecular Laboratory, American Red Cross Biomedical Services, Philadelphia, Pennsylvania, USA
| | - Connie M Westhoff
- Laboratory of Immunohematology and Genomics, New York Blood Center Enterprises, New York, New York, USA
| | - Louis M Katz
- Mississippi Valley Regional Blood Center, Davenport, Iowa, USA
| | | | | | - Clayton D Simon
- Defense Health Agency, Armed Services Blood Program Office, Falls Church, Virginia, USA
| | - S Gerald Sandler
- Department of Pathology and Laboratory Medicine, MedStar Georgetown University Hospital, Washington, DC, USA
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Thongbut J, Raud L, Férec C, Promwong C, Nuchnoi P, Fichou Y. Comprehensive Molecular Analysis of Serologically D-Negative and Weak/Partial D Phenotype in Thai Blood Donors. Transfus Med Hemother 2019; 47:54-60. [PMID: 32110194 DOI: 10.1159/000499087] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 02/21/2019] [Indexed: 12/13/2022] Open
Abstract
Background Molecular genetics of the Rh system has been extensively studied in Caucasians, Black Africans, East Asians, and Indians more recently. In this work, we sought to investigate the molecular basis of variant D expression in the Thai population, which remains unknown. Materials and Methods Blood samples from 450 Thai donors showing the variant D phenotype were collected. The RHD gene was analyzed by quantitative multiplex polymerase chain reaction of short fluorescent fragments and/or Sanger sequencing. Results The most frequent alleles in 200 D-negative and 121 DEL samples were the whole RHD gene deletion and the Asian DEL alleles, respectively. In 129 weak/partial D samples, 36 variant alleles were identified, including eight novel alleles. RHD*06.03, which is common in variant D samples from South China, is the most prevalent variant allele, followed by the recently reported Indian RHD*01W.150 allele. Discussion For the first time, a comprehensive overview of the nature and distribution of variant RHD alleles in Thailand is reported. It is a milestone to pave the way towards improvement of the current screening strategy to identify DEL donors accurately. The next step will be the design and implementation of a simple molecular test for screening the most frequent alleles, specifically in this population.
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Affiliation(s)
- Jairak Thongbut
- Department of Clinical Microscopy, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand.,National Blood Centre, Thai Red Cross Society, Bangkok, Thailand
| | - Loann Raud
- Univ Brest, INSERM, EFS, UMR 1078, GGB, Brest, France.,Laboratoire de Génétique Moléculaire et d'Histocompatibilité, CHU Morvan, Brest, France
| | - Claude Férec
- Univ Brest, INSERM, EFS, UMR 1078, GGB, Brest, France.,Laboratoire de Génétique Moléculaire et d'Histocompatibilité, CHU Morvan, Brest, France.,Laboratory of Excellence GR-Ex, Brest, France
| | | | - Pornlada Nuchnoi
- Department of Clinical Microscopy, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand.,Center for Research and Innovation, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Yann Fichou
- Univ Brest, INSERM, EFS, UMR 1078, GGB, Brest, France.,Laboratoire de Génétique Moléculaire et d'Histocompatibilité, CHU Morvan, Brest, France
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Heuft HG, Mansouri Taleghani B. Hemovigilance. Transfus Med Hemother 2018; 45:148-150. [PMID: 29928167 PMCID: PMC6006618 DOI: 10.1159/000490075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 11/19/2022] Open
Affiliation(s)
- Hans-Gert Heuft
- Institute for Transfusion Medicine, Hannover Medical School, Hanover, Germany
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