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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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2
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Yanasik M, Oguz FS, Besisik SK, Huslu M, Ozturk G, Temurhan S, Aydin F. Frequency of RHD variants in serologically weak D Turkish blood donors. Transfus Apher Sci 2020; 60:103024. [PMID: 33308979 DOI: 10.1016/j.transci.2020.103024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND RhD typing has remained of primary importance, as being the leading cause of hemolytic disease of the newborn. Among Rh system's 55 blood group antigens, RhD is the most immunogenic. We aimed with this study to determine weak D/partial D variant frequency in blood donors who were admitted to our blood center and have serologically designated blood group weak D. MATERIALS AND METHODS We screened blood donors who admitted between 2011 and 2017 to our blood center. Sixty-seven serologically weak D phenotyped donors have participated in the study. These donors' samples were studied further by Polymerase Chain Reaction Sequence- Specific Primers (PCR-SSP) for determining D variants. RESULTS Weak D phenotype was detected in 228(0.12 %) out of 177,554 donors. Sixty-seven of them agreed to take part in the study. The frequency of weak D and partial D was 68.7 % (n = 46), and 22.4 % (n = 15), in order. The most encountered weak D and partial D variant was type 15 and DFR type, respectively. CONCLUSIONS The prevalence of serologically weak D phenotypes varies by race and ethnicity. Turkey is a country covering a mixture of European and Asian DNA with different ethnic groups. Thus, our research as giving the overall distribution of RHD variants from the largest city of Turkey, which may reflect the general ethnic background of the country, would help to the establishment of a databank for blood banking. This paper is the first molecular study on RHD variants in Turkey. New molecular research would be more reliable and precise.
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Affiliation(s)
- Melek Yanasik
- Istanbul Medical Faculty Hospital Blood Center, Istanbul University, Istanbul, Turkey
| | - Fatma Savran Oguz
- Istanbul Medical Faculty, Department of Medical Biology, Istanbul University, Istanbul, Turkey.
| | | | - Mukadder Huslu
- Istanbul Medical Faculty Hospital Blood Center, Istanbul University, Istanbul, Turkey
| | - Gulyuz Ozturk
- Department of Pediatric Hematology/Oncology & Bone Marrow Transplantation Unit, School of Medicine, Altunizade Hospital, Acıbadem University, Istanbul, Turkey
| | - Sonay Temurhan
- Istanbul Medical Faculty, Department of Medical Biology, Istanbul University, Istanbul, Turkey
| | - Filiz Aydin
- Istanbul Science University, Department of Medical Biology, Istanbul, Turkey
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3
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Eryilmaz M, Müller D, Rink G, Klüter H, Bugert P. Introduction of Noninvasive Prenatal Testing for Blood Group and Platelet Antigens from Cell-Free Plasma DNA Using Digital PCR. Transfus Med Hemother 2019; 47:292-301. [PMID: 32884502 DOI: 10.1159/000504348] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 10/24/2019] [Indexed: 12/17/2022] Open
Abstract
Background Noninvasive prenatal testing (NIPT) for fetal antigens is a common standard for targeted immune prophylaxis in RhD-mediated hemolytic disease of the fetus and newborn, and is most frequently done by quantitative PCR (qPCR). A similar approach is considered for other blood group and human platelet alloantigens (HPA). Because of a higher sensitivity compared to qPCR for rare molecule detection, we established and validated digital PCR (dPCR) assays for the detection of RHD exons 3, 5 and 7, KEL1, HPA-1a, and HPA-5b from cell-free DNA (cfDNA) in plasma. The dPCR assays for the Y-chromosomal marker amelogenin and autosomal SNPs were implemented as controls for the proof of fetal DNA. Methods Validation was performed on dilution series of mixed plasma samples from volunteer donors with known genotypes. After preamplification of the target loci, two-color (FAM and VIC) TaqMan<sup>TM</sup> probe chemistry and chip-based dPCR were applied. The assays for RHD included GAPDH as an internal control. For the diallelic markers KEL1/2, HPA-1a/b, HPA-5a/b, and AMEL-X/Y and 3 autosomal SNPs, the probes enabled allelic discrimination in the two fluorescence channels. The dPCR protocol for NIPT was applied to plasma samples from pregnant women. Results The RHD exon 5 assay allowed the detection of a 0.05% RHD target in an RhD-negative background, whereas the exon 7 assay required at least a 0.25% target. The exon 3 assay showed the highest background and required at least a 2.5% RHD target for reliable detection. The dPCR assays for the diallelic markers revealed similar sensitivity and enabled the detection of at least a 0.5% target allele. The HPA-1a assay was the most sensitive and allowed target detection in plasma mixtures containing only 0.05% HPA-1a. The plasma samples from 13 pregnant women at different gestational ages showed unambiguous positive and negative results for the analyzed targets. Conclusion Analysis of cfDNA from maternal plasma using dPCR is suitable for the detection of fetal alleles. Because of the high sensitivity of the assays, the NIPT protocol for RhD, KEL1, and HPA can also be applied to earlier stages of pregnancy.
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Affiliation(s)
- Marion Eryilmaz
- Institute of Transfusion Medicine and Immunology, Heidelberg University, Medical Faculty Mannheim, German Red Cross Blood Service Baden-Württemberg - Hessen, Mannheim, Germany
| | - Dennis Müller
- Institute of Transfusion Medicine and Immunology, Heidelberg University, Medical Faculty Mannheim, German Red Cross Blood Service Baden-Württemberg - Hessen, Mannheim, Germany
| | - Gabi Rink
- Institute of Transfusion Medicine and Immunology, Heidelberg University, Medical Faculty Mannheim, German Red Cross Blood Service Baden-Württemberg - Hessen, Mannheim, Germany
| | - Harald Klüter
- Institute of Transfusion Medicine and Immunology, Heidelberg University, Medical Faculty Mannheim, German Red Cross Blood Service Baden-Württemberg - Hessen, Mannheim, Germany
| | - Peter Bugert
- Institute of Transfusion Medicine and Immunology, Heidelberg University, Medical Faculty Mannheim, German Red Cross Blood Service Baden-Württemberg - Hessen, Mannheim, Germany
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Lopez GH, McGowan EC, McGrath KA, Abaca‐Cleopas ME, Schoeman EM, Millard GM, O'Brien H, Liew Y, Flower RL, Hyland CA. A D+ blood donor with a novelRHD*D‐CE(5‐6)‐Dgene variant exhibits the low‐frequency antigen RH23 (DW) characteristic of the partial DVa phenotype. Transfusion 2016; 56:2322-30. [DOI: 10.1111/trf.13713] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 05/23/2016] [Accepted: 05/24/2016] [Indexed: 12/28/2022]
Affiliation(s)
- Genghis H. Lopez
- Clinical Services and ResearchAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
| | - Eunike C. McGowan
- Clinical Services and ResearchAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
| | - Kelli A. McGrath
- Red Cell Reference LaboratoryAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
| | - Maria E. Abaca‐Cleopas
- Red Cell Reference LaboratoryAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
| | - Elizna M. Schoeman
- Clinical Services and ResearchAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
| | - Glenda M. Millard
- Clinical Services and ResearchAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
| | - Helen O'Brien
- Clinical Services and ResearchAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
| | - Yew‐Wah Liew
- Red Cell Reference LaboratoryAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
| | - Robert L. Flower
- Clinical Services and ResearchAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
| | - Catherine A. Hyland
- Clinical Services and ResearchAustralian Red Cross Blood ServiceKelvin Grove Queensland Australia
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Moussa H, Tsochandaridis M, Chakroun T, Jridi S, Abdelneji B, Hmida S, Silvy M, Bailly P, Gabert J, Levy-Mozziconacci A, Jemni-Yacoub S. Molecular background of D-negative phenotype in the Tunisian population. Transfus Med 2012; 22:192-8. [PMID: 22420413 DOI: 10.1111/j.1365-3148.2012.01142.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Most studies of the molecular basis of Rhesus D-negative phenotype have been conducted in Caucasian and African populations. A comprehensive survey of RHD alleles was lacking in people from North Africa (Tunisians, Moroccans and Algerians) which could be very efficient for managing donors and patients carrying an RHD molecular variant. We analyse the molecular background of D-negative population in Tunisia in the present study. MATERIALS AND METHODS Blood samples were collected from native Tunisians. A total of 448 D-negative donors from different regions of Tunisia were analysed by RHD genotyping according to an adopted strategy using real-time PCR, ASP-PCR and sequencing. RESULTS Among the 448 D-negative samples, 443 were phenotyped unequivocally as true D-negative including three molecular backgrounds which were RHD gene deletion (n = 437), RHDψ pseudogene (n = 2) and RHD-CE-D hybrid gene (n = 4) with the respective frequencies of 0·9900, 0·0023 and 0·0046. The remaining five samples, in discordance with the serological results, were identified as two weak D type 11, one weak D type 29, one weak D type 4·0 and one DBT-1 partial D. CONCLUSION This study showed that the Tunisian population gets closer to Caucasians, given that the RHD gene deletion is the most prevalent cause of D-negative phenotype, but it is slightly different by the presence of the RHDψ pseudogene which was found with a very low frequency compared with that described in the African population. Nevertheless, the relative occurrence of weak D variants among studied serologically D-negative samples make necessary the adaptation of RHD genotyping strategy to the spectrum of prevalent alleles.
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Affiliation(s)
- H Moussa
- Unité de Recherche UR06SP05 Centre Régional de Transfusion Sanguine, Sousse, Tunisia
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Ye L, Wang P, Gao H, Zhang J, Wang C, Li Q, Han S, Guo Z, Yang Y, Zhu Z. Partial D phenotypes and genotypes in the Chinese population. Transfusion 2011; 52:241-6. [DOI: 10.1111/j.1537-2995.2011.03266.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
RhD blood group incompatibility between a pregnant woman and her fetus can result in maternal alloimmunization and consequent haemolytic disease of the newborn (HDN) in subsequent pregnancies. The D-negative blood group is found in 15% of whites, 3-5% of black Africans, and is rare in Asians. Recent technological advances in non-invasive prenatal determination of the fetal RHD status using cell-free fetal DNA (cffDNA) have opened new avenues for the management of D-negative pregnant women. In this review applications for the high risk women, as well as potential for routine screening will be discussed. The use of non-invasive prenatal diagnosis and the management of other blood incompatibilities will also be discussed.
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Abstract
BACKGROUND DNA-based methods are useful for enhancing immunohematology typings. Ready-to-use Conformité Européenne (CE)-marked test kits based on polymerase chain reaction with sequence-specific priming (PCR-SSP) have been developed, which enable the examination of weak, unexpected, or unclear serologic findings. DEVELOPMENT AND VALIDATION: Primers were designed according to established mutation databases. Proficiency testing for CE marking was performed in accordance with Directive 98/79EC of the European Parliament and of the Council of October 27, 1998 on in vitro diagnostic medical devices using pretyped in-house and external samples. INTENDED USE: BAGene PCR-SSP kits are in vitro diagnostic devices. Genotyping of ABO and RHD/RHCE as well as HPA and KEL, JK, and FY specificities has to be performed after the conclusion of the serologic determination. APPLICATION Ready-to-use PCR-SSP typing kits allow the determination of common, rare, or weak alleles of the ABO blood group, Rhesus, and Kell/Kidd/Duffy systems as well as alleles of the human platelet antigens. RESULTS The investigations showed clear-cut results in accordance with serology or molecular genetic pretyping. CONCLUSION PCR-SSP is a helpful supplementary technique for resolving most of the common problems caused by discrepant or doubtful serologic results, and it is an easy-to-handle robust method. Questionable cases in donor, recipient, and patient typing can be examined with acceptable cost.
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Affiliation(s)
- Martina Prager
- Department of Production Molecular Genetics, BAG--BiologischeAnalysensystemGmbH, Lich, Germany.
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9
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Flegel WA, Wagner FF, Chen Q, Schlanser G, Frame T, Westhoff CM, Moulds MK. The RHCE allele ceCF: the molecular basis of Crawford (RH43). Transfusion 2006; 46:1334-42. [PMID: 16934069 DOI: 10.1111/j.1537-2995.2006.00901.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The Crawford antigen (RH43) was described in 1980. It occurred in African American people, as a low-prevalence Rhesus antigen, who were also VS+. STUDY DESIGN AND METHODS Twelve blood samples were analyzed because of inquiries into discrepant reactions in routine anti-D typing. The RHCE alleles were determined by nucleotide sequencing from genomic DNA. The D epitope profile was determined with 60 monoclonal anti-D. The population frequency was estimated in four major US regional blood centers. RESULTS The novel RHce(W16C, Q233E, L245V) allele, dubbed ceCF, was found to be occurring in the cde haplotype as cause of the reactivity with the immunoglobulin M anti-D GAMA401. The ceCF phenotype expressed few D epitopes resembling but not matching the reaction patterns observed with other RhCE variants, like R0 (Har), ceRT, and ceSL. The frequency of the ceCF phenotype was 0.056 percent among African American persons and 0.007 percent in the general US population. CONCLUSION The novel RHce(W16C, Q233E, L245V) allele, which is a variant of the known ce(s) allele, RHce(W16C, L245V), occurs in a haplotype with the RHD deletion and represents the molecular basis of the Crawford antigen.
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Affiliation(s)
- Willy A Flegel
- Department of Transfusion Medicine, University Hospital, Ulm, Germany.
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10
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Zhou L, Thorson JA, Nugent C, Davenport RD, Butch SH, Judd WJ. Noninvasive prenatal RHD genotyping by real-time polymerase chain reaction using plasma from D-negative pregnant women. Am J Obstet Gynecol 2005; 193:1966-71. [PMID: 16325598 DOI: 10.1016/j.ajog.2005.04.052] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 04/15/2005] [Accepted: 04/25/2005] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Prenatal noninvasive determination of fetal Rh status is an important aid to the management of hemolytic disease of the fetus and newborn. We performed real-time polymerase chain reaction on fetal DNA derived from maternal plasma to determine fetal Rh status. STUDY DESIGN Cell-free plasma DNA from 98 D-negative pregnant women was tested for the presence of exons 4, 5, and 10 of RHD. The presence of fetal DNA was confirmed by detection of SRY or biallelic insertion/deletion polymorphisms in the maternal plasma and buffy coat. RESULTS Seventy-two D-positive infants and 26 D-negative infants were determined by serologic studies. All 3 RHD exon sequences were detected in 68 of 72 mothers of D-positive infants. The presence of fetal DNA in mothers of D-negative infants was confirmed in all 10 boys and in 14 of 16 girls. CONCLUSION Fetal RHD genotyping in this study correctly predicted fetal Rh status in 92 of 98 (94%) cases.
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Affiliation(s)
- Lan Zhou
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA.
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11
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Reid ME, Storry JR, Sausais L, Tossas E, Rios M, Hue-Roye K, Gloster ES, Miller ST, Wolf C, Lomas-Francis C. DAK, a new low-incidence antigen in the Rh blood group system. Transfusion 2003; 43:1394-7. [PMID: 14507270 DOI: 10.1046/j.1537-2995.2003.00517.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Some low-incidence antigens in the Rh blood group system (e.g., VS, Rh32, FPTT) are expressed by more than one Rh complex. We describe a new low-incidence antigen that is present on RBCs with the partial D phenotypes, DIIIa or DOL, on RN RBCs and on one example of STEM+S RBCs. STUDY DESIGN AND METHODS Standard hemagglutination testing was performed with two sera that agglutinated DIIIa RBCs on our in-house antibody identification panel. DNA-based assays were performed on selected samples. RESULTS RBCs with the DIIIa (n = 31), DOL (n = 5), or RN (n = 10) phenotype were agglutinated by both sera, as were RBCs from one STEM+S person. Reactivity with RBCs of either DIIIa or DOL phenotypes was stronger than with RN RBCs and could not be separated by adsorption and elution. CONCLUSION An antibody, anti-DAK, which recognizes a novel low-incidence antigen that is more strongly expressed on DIIIa and DOL RBCs than on RN RBCs is described. The antibody agglutinated RBCs from 4 percent of D+ African American blood donors in New York. The antigen, DAK, has been assigned the ISBT number RH54 (004.054).
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Affiliation(s)
- Marion E Reid
- Immunohematology and Immunochemistry Laboratories, New York Blood Center, New York, New York 10021, USA.
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Cotorruelo CM, Biondi CS, Borrás SEG, Di Mónaco RA, Racca A. A Dc- phenotype encoded by an RHCE-D(5-7/8)-CE hybrid allele. Vox Sang 2003; 85:102-8. [PMID: 12925162 DOI: 10.1046/j.1423-0410.2003.00332.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND AND OBJECTIVES The Rh system is genetically controlled by the homologous RHD and RHCE genes that encode the RhD and RhCcEe polypeptides, respectively. Deletions, point mutations and rearrangements between both genes are responsible for the great polymorphism of this system. The aim of this work was to analyse the genetic basis of a Dc- phenotype. MATERIALS AND METHODS DNA samples from the Dc- propositus and family members were obtained from peripheral blood. RHCE intron 4-exon 5 and RH exons 4, 5, 6 and 7 were analysed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Exon 9 was studied by PCR-sequence-specific primers (SSP). The RH locus was further analysed by using a PCR designed for a hybrid allele. RESULTS No RHCE-specific fragments were found when analysing exons 5, 6 and 7 of the RH locus from the propositus' DNA, while exons 4 and 9 of both RH genes were present. CONCLUSIONS The results obtained indicated that the Dc- phenotype is encoded by a novel RHCE-D(5-7/8)-CE hybrid allele.
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Affiliation(s)
- C M Cotorruelo
- Laboratorio de Inmunohematología Histocompatibilidad e Inmunogenética, Departamento de Bioquímica Clínica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
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Omi T, Takahashi J, Seno T, Tanaka M, Hirayama F, Matsuo M, Ueda N, Obara K, Okuda H, Iwamoto S, Tani Y, Kajii E. Isolation, characterization, and family study of DTI, a novel partial D phenotype affecting the fourth external loop of D polypeptides. Transfusion 2002; 42:481-9. [PMID: 12076297 DOI: 10.1046/j.1525-1438.2002.00082.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The Rh system is the most polymorphic of the blood group systems and is of major importance in transfusion medicine. The partial D phenotypes lack one or more of the D epitopes. These variants appear to have arisen through hybrid RhD-CE-D or by spontaneous point mutations in RhD. The serologic findings and the molecular characterization of a novel partial D phenotype, termed DTI, are presented here. STUDY DESIGN AND METHODS RBCs from the DTI proband and RBCs from individuals with other partial D phenotypes were tested with MoAbs against 16 D epi- topes, according to the recommendations of the 4th ISBT Workshop on MoAbs (Rh Section 1A). A full-length cDNA encoding DTI and introns 4 and 5 of RhD were isolated and analyzed by DNA sequencing. A family study of the DTI allele was carried out using PCR-RFLP and long-range PCR methods. RESULTS Analysis of RBCs from the proband revealed that the DTI phenotype lacks epitopes D1, D2.1 (partial), D2.2, D5, D6 (partial), and D8. The DTI polypeptide exhibits seven amino acid substitutions in the D polypeptide: F223V, A226P, E233Q, V238M, V245L, G263R, and K267M. The genomic organization of DTI showed that the replacement of RhD with RhCE was located in intron 4, and the replacement of RhCE with RhD was located in intron 5. Family studies revealed that the DTI allele was inherited maternally, whereas the RhD- allele was inherited paternally in the proband. CONCLUSION The serologic data provide the first molecular characterization of DTI, a previously unknown partial D phenotype. This phenotype affected the D polypeptide within the fourth external loop, resulting in a new RhD-CE (entire exon 5)-D hybrid gene. It is worth noting that P226, encoded by exon 5, is derived from E of RhCE in the DTI polypeptide. Family studies demonstrated that DTI was associated with a cDTIE haplotype.
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Affiliation(s)
- Toshinori Omi
- Department of Legal Medicine and Human Genetics, Jichi Medical School, Tochigi, Japan.
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14
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Ekman GC, Billingsly R, Hessner MJ. Rh genotyping: avoiding false-negative and false-positive results among individuals of African ancestry. Am J Hematol 2002; 69:34-40. [PMID: 11835329 DOI: 10.1002/ajh.10013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
High homology, variant alleles, and silent alleles have made the development of completely reliable genotyping assays for the RHD and RHC alleles difficult. An RHD pseudogene (RHDPsi) possessing a 37-bp insertion within exon 4 is common among serologically RhD-negative individuals of African descent and generates false-positive results in previously reported RhD genotyping assays. Genotyping RhC is problematic due to exon 2 homology between RHD and RHC; however, an RHC-specific 109-bp insertion within intron 2 has been reported useful for genotyping. Primers flanking the exon 4 insertion point were used for detection of RHD and RHDPsi among a total of 231 serotyped individuals: 134 African American, 85 Caucasian, and 12 RhD serotype-negative/genotype-positive, D-sensitized women. Primers flanking the RHC-specific intron 2 insertion were used to genotype 282 serotyped individuals (128 African American, 154 Caucasian) and were compared to RHC genotyping using the exon 1 RhC-specific nt48 cytosine polymorphism. Complete correlation was observed between genotyping with the RHDPsi primer pair and serotyping among 219 individuals and 10/12 previous RHD false-positive genotyping results were resolved. RHDPsi was detected in 19% (n = 4/21) of RhD seronegative African Americans and 4.4% (n = 5/113) of RhD seropositive African Americans. When using the 109-bp intron 2 insertion for genotyping of RHC, a 23.9% (n = 11/46) false-negative rate was observed among African American RhCc serotyped heterozygotes. Utilization of the exon 1 nt48 cytosine for indirect genotyping of RHC yielded a 7.2% (n = 4/55) and 56.3% (n = 45/80) false-positive rate among Rhcc Caucasians and African Americans, respectively. We conclude that these additional reactions, though not sufficient alone, can be useful supplements to existing Rh genotyping assays.
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Affiliation(s)
- G C Ekman
- Diagnostic Laboratories, The Blood Center of Southeastern Wisconsin, Milwaukee, Wisconsin, USA
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15
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Affiliation(s)
- S Lurie
- Department of Obstetrics and Gynaecology, Wolfson Medical Center, Israel
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16
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Wagner FF, Ernst M, Sonneborn HH, Flegel WA. A D(V)-like phenotype is obliterated by A226P in the partial D DBS. Transfusion 2001; 41:1052-8. [PMID: 11493738 DOI: 10.1046/j.1537-2995.2001.41081052.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND In D category V types, the RHD exon 5 or parts thereof are replaced by the corresponding RHCE DNA segments. In D category V types I and II, the amino acid at position 226 is alanine, which is typical of the prevalent RHD allele and is observed in all RHCE alleles encoding the antigen e. A proline at position 226 in RHCE encodes the antigen E. STUDY DESIGN AND METHODS A blood sample of ccDEe phenotype was referred as suspected D category VI. The RHD nucleotide sequence and the D epitope pattern were determined. RESULTS A new partial D, DBS, encoded by an RHD-RHcE(5)-RHD hybrid allele, was found. Although it differed from D(Va) type II by an A226P substitution only, it lacked epitopes epD4, epD12, epD17, epD18, and epD22 that were present in D(Va). The 5' breakpoint region was located between the deletion in RHD intron 4 and the first polymorphic nucleotide of DBS exon 5. CONCLUSION The phenotypes of RHD alleles with gene conversions limited to exon 5 depended critically on the amino acid at position 226. If alanine was present at this position, gene conversions involving E233Q led to a D(Va)-like phenotype. If proline was present, many additional epitopes were lost, and the phenotype became reminiscent of DFR. The 5' breakpoint region is shared by 10 alleles and may represent the most active "hot spot" for gene conversions known in RH.
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Affiliation(s)
- F F Wagner
- Department of Transfusion Medicine, the Ulm University Clinic, Germay
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17
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Abstract
The Rh (Rhesus) blood group system is the most complex of the known human blood group polymorphisms. The expression of its antigens is controlled by a two-component genetic system consisting of RH and RHAG loci, which encode Rh30 polypeptides and Rh50 glycoprotein, respectively. Over the past decade, there has been a rapid advance in knowledge of the biochemistry, molecular biology, and genetics of the Rh genes and proteins. The primary structures of D and CcEe antigens have become well understood and the molecular genetic basis of a vast array of phenotype polymorphisms has been delineated. The identification of various molecular defects associated with Rh deficiency syndrome clarifies the nature of the amorph, suppressor, and modifier genes. The observed mutation spectrum defines a basic set of components essential for Rh complex assembly in the erythrocyte membrane. The resulting molecular information, combined with new experimental tools, is helping to dissect the fine structure of Rh antigens in terms of epitope mapping. The discovery of novel Rh homologs in primitive organisms and in nonerythroid tissues opens new avenues of research beyond the scope of erythrocytes and Rh antigens. This review provides an update on the Rh family in antigen expression, phenotype diversity, and disease association.
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Affiliation(s)
- C H Huang
- Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York 10021, USA
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Hyodo H, Ishikawa Y, Kashiwase K, Ogawa A, Watanabe Y, Tsuneyama H, Toyoda C, Uchikawa M, Akaza T, Fujii T, Kozuma S, Taketani Y, Juji T. Polymorphisms of RhDVa and a New RhDVa-Like Variant Found in Japanese Individuals. Vox Sang 2000. [DOI: 10.1046/j.1423-0410.2000.7820122.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
The Rh blood group system is one of the most polymorphic and immunogenic systems known in humans. In the past decade, intense investigation has yielded considerable knowledge of the molecular background of this system. The genes encoding 2 distinct Rh proteins that carry C or c together with either E or e antigens, and the D antigen, have been cloned, and the molecular bases of many of the antigens and of the phenotypes have been determined. A related protein, the Rh glycoprotein is essential for assembly of the Rh protein complex in the erythrocyte membrane and for expression of Rh antigens. The purpose of this review is to provide an overview of several aspects of the Rh blood group system, including the confusing terminology, progress in molecular understanding, and how this developing knowledge can be used in the clinical setting. Extensive documentation is provided to enable the interested reader to obtain further information.
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Faas BHW, Maaskant-van Wijk PA, von dem Borne AEGK, van der Schoot CE, Christiaens GCML. The applicability of different PCR-based methods for fetalRHD andK1 genotyping: a prospective study. Prenat Diagn 2000. [DOI: 10.1002/1097-0223(200006)20:6<453::aid-pd858>3.0.co;2-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Molecular Configuration of Rh D Epitopes as Defined by Site-Directed Mutagenesis and Expression of Mutant Rh Constructs in K562 Erythroleukemia Cells. Blood 1999. [DOI: 10.1182/blood.v94.12.3986.424k18_3986_3996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Rh D antigen is the most clinically important protein blood group antigen of the erythrocyte. It is expressed as a collection of at least 37 different epitopes. The external domains of the Rh D protein involved in epitope presentation have been predicted based on the analysis of variant Rh D protein structures inferred from their cDNA sequences and their D epitope expression. This analysis can never be absolute because (1) most partial D phenotypes involve multiple amino acid changes in the Rh D protein and (2) deficiency for 1 or more epitopes may be due to gross structural alteration in the variant Rh D protein structure. We report here the amino acid requirements for the majority of D epitopes. They have been defined by generating a series of novel Rh mutant constructs by mutagenesis using an Rh cE cDNA as template and mutagenic oligonucleotide primers. When transfected into K562 cells, the D epitope expression of the derived mutant clones was then assessed by flow cytometry. The introduction of 9 externally predicted Rh D-specific amino acids on the Rh cE protein was sufficient to express 80% of all tested D epitopes, whereas other clones expressed none. We concluded from our data that the D epitope expression is consistent with at least 6 different epitope clusters localized on external regions of the Rh D protein, most involving overlapping regions within external loops 3, 4, and 6.
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22
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Molecular Configuration of Rh D Epitopes as Defined by Site-Directed Mutagenesis and Expression of Mutant Rh Constructs in K562 Erythroleukemia Cells. Blood 1999. [DOI: 10.1182/blood.v94.12.3986] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe Rh D antigen is the most clinically important protein blood group antigen of the erythrocyte. It is expressed as a collection of at least 37 different epitopes. The external domains of the Rh D protein involved in epitope presentation have been predicted based on the analysis of variant Rh D protein structures inferred from their cDNA sequences and their D epitope expression. This analysis can never be absolute because (1) most partial D phenotypes involve multiple amino acid changes in the Rh D protein and (2) deficiency for 1 or more epitopes may be due to gross structural alteration in the variant Rh D protein structure. We report here the amino acid requirements for the majority of D epitopes. They have been defined by generating a series of novel Rh mutant constructs by mutagenesis using an Rh cE cDNA as template and mutagenic oligonucleotide primers. When transfected into K562 cells, the D epitope expression of the derived mutant clones was then assessed by flow cytometry. The introduction of 9 externally predicted Rh D-specific amino acids on the Rh cE protein was sufficient to express 80% of all tested D epitopes, whereas other clones expressed none. We concluded from our data that the D epitope expression is consistent with at least 6 different epitope clusters localized on external regions of the Rh D protein, most involving overlapping regions within external loops 3, 4, and 6.
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Huang CH, Chen Y, Reid ME, Okubo Y. Evidence for a separate genetic origin of the partial D phenotype DBT in a Japanese family. Transfusion 1999; 39:1259-65. [PMID: 10604255 DOI: 10.1046/j.1537-2995.1999.39111259.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND In a Moroccan family, the partial D phenotype DBT is defined by an RHD-CE-D gene in which exons 5 to 7 of RHD were replaced by those of RHCE. In this study, the molecular basis and inheritance of DBT in a Japanese family are described. STUDY DESIGN AND METHODS A Japanese proposita exhibiting the DBT phenotype was analyzed by serologic methods and molecular techniques. The RH transcripts of the proposita were sequenced and compared with those of normal donors. The inheritance and structure of the RH genes in the family were determined by Southern blot analysis and exon-specific polymerase chain reaction. RESULTS The proposita typed weak D and C+c+E+e+Rh:32. Family data indicated a cotransmission of Rh32 with DBT and a linkage of C and e with DBT. Southern blot testing of the proposita's genomic DNA indicated a partial and a total absence of RHD on the respective homologous chromosomes. Sequencing of her cDNA showed expression of Ce, cE, and RHD-CE-D transcripts but not D. The RHD-CE-D hybrid was characterized by a conversion of five RHD exons into RHCE exons (exons 5-9). The 5' and 3' breakpoints in the fusion gene were localized to the intron 4/exon 5 region and intron 9. CONCLUSION The new RHD-CE-D gene defines a separate genetic origin of DBT in the Japanese family. The proximal sequence encoded by RHD exon 4 and RHCE exon 5, together with the distal RHCE sequence, may involve the cotransmission of Rh32 and DBT which behave as codominant and recessive characters, respectively.
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Affiliation(s)
- C H Huang
- Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York 10021, USA.
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24
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Affiliation(s)
- N D Avent
- Bristol Institute for Transfusion Sciences, Southmead, United Kingdom
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25
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Denomme GA, Akoury H, Sermer M, Kelton JG. RhD status of a fetus at risk for haemolytic disease with a discrepant maternal DNA-based RhD genotype. Prenat Diagn 1999; 19:424-7. [PMID: 10360510 DOI: 10.1002/(sici)1097-0223(199905)19:5<424::aid-pd562>3.0.co;2-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The cloning of the RHD gene has made it possible to determine the RhD status of fetuses at risk for haemolytic disease due to RhD iso-immunization using amniotic fluid or chorionic villi-derived DNA and the polymerase chain reaction. However, some Rh haplotypes are associated with false-positive or negative DNA-based results with the potential for an adverse outcome. We determined the RhD status of a fetus using amniotic fluid-derived DNA for an anti-D iso-immunized woman. Initially, we obtained the ethnic background and the complete RhD and RhCcEe phenotypes of both parents. The mother was RhD negative (Cde/cde) but her DNA was positive for exon 10 of the RHD gene. The fetus was positive for both exons 4 5 and exon 10. Southern analysis confirmed that the maternal DNA contained a portion of the RHD gene with a restriction pattern that was similar to RhD-positive individuals. This report illustrates that, in addition to fetal DNA genotyping, the same PCR assays, complete with RhD and RhCcEe phenotypes, and ethnic background of the parents should be obtained to alert the molecular diagnostic laboratory to the presence of rare Rh haplotypes that are associated with DNA genotyping errors.
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Affiliation(s)
- G A Denomme
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada
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26
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Omi T, Takahashi J, Tsudo N, Okuda H, Iwamoto S, Tanaka M, Seno T, Tani Y, Kajii E. The genomic organization of the partial D category DVa: the presence of a new partial D associated with the DVa phenotype. Biochem Biophys Res Commun 1999; 254:786-94. [PMID: 9920819 DOI: 10.1006/bbrc.1998.0121] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Within the Rh blood group, the partial D phenotype is a well known RhD variant, that induces Rh-incompatible blood transfusion and hemolytic diseases in the newborn. The partial D category DVa phenotype (DVa Kou.) results from a hybrid of RhD-CE-D transcript. We demonstrated a genomic organization of the hybrid RHD-CE-D gene leading to the DVa phenotype, and showed that the DVa gene were generated from gene conversion between the RHD and the RHCE genes in relatively small regions. This study also revealed that the presence of a new partial D associated with the DVa phenotype, which we termed the DVa-like phenotype. In this phenotype, five RHD-specific nucleotides were replaced with the corresponding RHCE-derived nucleotides on the exon 5 of the RHD gene. In addition, two variants of the mutated RHD genes at nucleotide 697 were revealed in the RhD variant samples. These results will provide useful information for future research into the diversification of the Rh polypeptides.
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Affiliation(s)
- T Omi
- Department of Legal Medicine and Human Genetics, Jichi Medical School, Minamikawachi-machi, Tochigi, 329-0498, Japan.
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27
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Flegel WA, Wagner FF, Müller TH, Gassner C. Rh phenotype prediction by DNA typing and its application to practice. Transfus Med 1998; 8:281-302. [PMID: 9881423 DOI: 10.1046/j.1365-3148.1998.00173.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The complexity of the RHD and RHCE genes, which is the greatest of all blood group systems, confounds analysis at the molecular level. RH DNA typing was introduced in 1993 and has been applied to prenatal testing. PCR-SSP analysis covering multiple polymorphisms was recently introduced for the screening and initial characterization of partial D. Our objective is to summarize the accrued knowledge relevant to the approaches to Rh phenotype prediction by DNA typing, their possible applications beyond research laboratories and their limitations. The procedures, results and problems encountered are highly detailed. It is recommended that DNA typing comprises an analysis of more than one polymorphism. We discuss future directions and propose a piecemeal approach to improve reliability and cost-efficiency of blood group genotyping that may eventually replace the prevalent serology-based techniques even for many routine tasks. Transfusion medicine is in the unique position of being able to utilize the most extensive phenotype databases available to check and develop genotyping strategies.
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Affiliation(s)
- W A Flegel
- Abteilung Transfusionsmedizin, Universitätsklinikum Ulm, Germany.
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28
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Reid ME, Sausais L, Zaroulis CG, Mohandas K, Coghlan G, Lomas-Francis C. Two Examples of an Inseparable Antibody That Reacts Equally Well with DW+ and Rh32+ Red Blood Cells. Vox Sang 1998. [DOI: 10.1046/j.1423-0410.1998.7530230.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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29
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Maaskant-van Wijk PA, Faas BH, de Ruijter JA, Overbeeke MA, von dem Borne AE, van Rhenen DJ, van der Schoot CE. Genotyping of RHD by multiplex polymerase chain reaction analysis of six RHD-specific exons. Transfusion 1998; 38:1015-21. [PMID: 9838930 DOI: 10.1046/j.1537-2995.1998.38111299056309.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Qualitative RHD variants are the result of the replacement of RHD exons by their RHCE counterparts or of point mutations in RHD causing amino acid substitutions. For RHD typing, the use of at least two RHD typing polymerase chain reaction (PCR) assays directed at different regions of RHD is advised to prevent discrepancies between phenotyping and genotyping results, but even then discrepancies occur. A multiplex RHD PCR based on amplification of six RHD-specific exons in one reaction mixture is described. STUDY DESIGN AND METHODS Six RHD-specific primer sets were designed to amplify RHD exons 3, 4, 5, 6, 7, and 9. DNA from 119 donors (87 D+, 14 D- and 18 with known D variants; whites and nonwhites) with known Rh phenotypes was analyzed. RESULTS All six RHD-specific exons from 85 D+ individuals were amplified, whereas none of the RHD exons from 13 D- individuals were amplified. Multiplex PCR analysis showed that the genotypes of two donors typed as D+ were DIVa and DVa. Red cell typing confirmed these findings. From all D variants tested (DIIIc, DIVa, DIVb, DVa, DVI, DDFR, DDBT) and from RoHar, RHD-specific exons were amplified as expected from the proposed genotypes. CONCLUSION The multiplex PCR assay is reliable in determining genotypes in people who have the D+ and partial D phenotypes as well as in discovering people with new D variants. Because the multiplex PCR is directed at six regions of RHD, the chance of discrepancies is markedly reduced. The entire analysis can be performed in one reaction mixture, which results in higher speed, higher accuracy, and the need for smaller samples. This technique might be of great value in prenatal RHD genotyping.
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Abstract
Antenatal genotyping of the fetus is now in widespread use as an aid to the clinical management in cases where there is the potential of haemolytic disease of the newborn occurring. The rapid diagnosis of an antigen-negative fetus will preclude the requirement for further, potentially risky invasive procedures being performed, whilst the determination of an antigen-positive fetus allows the potential of intensifying obstetric care for this pregnancy. Molecular genotyping is a major clinical application which has led from the determination of the molecular bases of blood group antigens expressed, most of which have been defined at the level of the gene. All assays used are dependent on the Polymerase Chain Reaction amplification of fetal DNA derived from either amniotic fluid or chorionic villi. Recent work has explored the potential of utilising fetal cells found to be present in maternal peripheral blood as a source of nucleic acid for prenatal diagnosis. Using non-invasive methods will preclude exposing mother and fetus to the potential hazards of invasive methods (amniocentesis, chorionic villus sampling and cordocentesis) which include miscarriage, fetal malformations and further maternal alloimmunisation.
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Affiliation(s)
- N D Avent
- International Blood Group Reference Laboratory, Southmead, Bristol, UK.
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31
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Three Molecular Structures Cause Rhesus D Category VI Phenotypes With Distinct Immunohematologic Features. Blood 1998. [DOI: 10.1182/blood.v91.6.2157] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractRhesus D category VI (DVI) is the clinically most important partial D. DVI red blood cells were assumed to possess very low RhD antigen density and to be caused by twoRHD-CE-D hybrid alleles. Because there was no population-based work-up, we screened three populations in central Europe for DVI. Twenty-six DVI samples were detected and examined by exon-specific RHD polymerase chain reaction with sequence-specific primers (PCR-SSP). A new genotype, hereby designated D category VI type III, was characterized as a RHD-Ce(3-6)-D hybrid allele by sequencing of the cDNA, parts of intron 1, and by PCR-restriction fragment length polymorphism (PCR-RFLP) of intron 2. Rhesus introns 5 and 6 were sequenced and the 3′ breakpoints of all knownDVItypes shown to be distinct. We differentiated the 5′ breakpoints of DVItypeI andDVItype II by a newly devised RHD-PCR. Thus, the DVI phenotype originated in at least three independent molecular events. Each DVI type showed distinct immunohematologic features in flow cytometry. The number of RhD proteins accessible on the red blood cells' surface ofDVItype III was normal (about 12,000 antigens/cell; DVItypeI, 500;DVItype II, 2,400) based on the determination of an RhD epitope density profile. DVItype II and DVItype III occurred as CDe haplotypes, and DVItype I as a cDE haplotype.The distribution of the DVItypes varied significantly in three German-speaking populations. Genotyping strategies should take account of allelic variations in partial RhD. The reconsideration of previous serologic and clinical data for partial D in view of the underlying molecular structures may be worthwhile.
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32
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Abstract
Rhesus D category VI (DVI) is the clinically most important partial D. DVI red blood cells were assumed to possess very low RhD antigen density and to be caused by twoRHD-CE-D hybrid alleles. Because there was no population-based work-up, we screened three populations in central Europe for DVI. Twenty-six DVI samples were detected and examined by exon-specific RHD polymerase chain reaction with sequence-specific primers (PCR-SSP). A new genotype, hereby designated D category VI type III, was characterized as a RHD-Ce(3-6)-D hybrid allele by sequencing of the cDNA, parts of intron 1, and by PCR-restriction fragment length polymorphism (PCR-RFLP) of intron 2. Rhesus introns 5 and 6 were sequenced and the 3′ breakpoints of all knownDVItypes shown to be distinct. We differentiated the 5′ breakpoints of DVItypeI andDVItype II by a newly devised RHD-PCR. Thus, the DVI phenotype originated in at least three independent molecular events. Each DVI type showed distinct immunohematologic features in flow cytometry. The number of RhD proteins accessible on the red blood cells' surface ofDVItype III was normal (about 12,000 antigens/cell; DVItypeI, 500;DVItype II, 2,400) based on the determination of an RhD epitope density profile. DVItype II and DVItype III occurred as CDe haplotypes, and DVItype I as a cDE haplotype.The distribution of the DVItypes varied significantly in three German-speaking populations. Genotyping strategies should take account of allelic variations in partial RhD. The reconsideration of previous serologic and clinical data for partial D in view of the underlying molecular structures may be worthwhile.
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33
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Evidence of Genetic Diversity Underlying Rh D−, Weak D (Du), and Partial D Phenotypes as Determined by Multiplex Polymerase Chain Reaction Analysis of the RHD Gene. Blood 1997. [DOI: 10.1182/blood.v89.7.2568] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
The human blood group Rh antigens are expressed by proteins encoded by a pair of highly homologous genes located at chromosome 1p34-36. One of the genes (RHCE ) encodes Rh CcEe antigens, while the other (RHD) the D antigen. Point mutations in the RHCE gene generate the C/c and E/e polymorphisms, while it has been shown that an RHD gene deletion can generate the D-negative phenotype. We have analyzed intron 4 of the RHCE and RHD genes and have defined the site of an RHD-specific deletion located in this intron. Using a multiplex RHD typing assay, which combines a reverse polymerase chain reaction (PCR) primer, which straddles this RHD-specific sequence, and a pair of primers located in exon 10 of the RHD gene, we have analyzed 357 different genomic DNA samples derived from individuals expressing D+, D−, weak D, and partial D phenotypes. Of these, we have noted a significant discordance with our multiplex PCR assay in the D− phenotypes dCcee and dccEe (which have been previously described) and weak D phenotypes. Our results suggest that in five serologically D− individuals we have identified an apparently intact RHD gene. Sequence analysis of transcripts obtained from one of these individuals (of phenotype dCCee) illustrates the presence of full-length RHD transcripts, which have a point mutation at nucleotide 121 (C → T), which generates an in-frame stop codon (Gln41Stop). Thus, we describe a different molecular basis for generating the D− phenotype to the complete RHD gene deletion described previously. We also show that there are discordances with serotype and the multiplex assay in weak D and partial D phenotypes, indicating that the underlying molecular basis can be heterogeneous. Existing Rh D PCR assays assume the complete absence of the RHD gene in D− phenotypes. We describe a different molecular basis for generating the D− phenotype to the complete RHD gene deletion described previously.
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Cartron JP, Rouillac C, Le Van Kim C, Mouro I, Colin Y. Tentative model for the mapping of D epitopes on the RhD polypeptide. Transfus Clin Biol 1996; 3:497-503. [PMID: 9018815 DOI: 10.1016/s1246-7820(96)80070-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The partial D phenotypes correspond to D-positive individuals that may develop anti-D antibodies following immunization by transfusion or pregnancy, since they lack some of the D epitopes that compose the D antigen. When these red cells are tested with a panel of human monoclonal anti-D, different patterns of reactivity are observed and at least nine distinct epitopes termed epD1 to epD9 can be identified. Molecular analysis of partial D variants have shown that the loss of some D epitopes is associated either with intergenic recombination events between the D and CE genes generating hybrid gene structures D-CE-D or CE-D-CE, or with point mutations of the D gene. Based on these findings, a tentative model that correlates critical amino acid positions and D epitope expression on the D protein was proposed. Although recent studies suggest that the D antigen may be composed of as many as 30 epitopes, the relatively simple model presented here may be useful to serologists as a preliminary approach to understanding the basis of D antigenic variation in terms of structure-activity relationship.
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Affiliation(s)
- J P Cartron
- INSERM U76, Institut National de Transfusion Sanguine, Paris, France
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35
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Scott ML, Voak D, Jones JW, Avent ND, Liu W, Hughes-Jones N, Sonneborn H. A structural model for 30 Rh D epitopes based on serological and DNA sequence data from partial D phenotypes. Transfus Clin Biol 1996; 3:391-6. [PMID: 9018796 DOI: 10.1016/s1246-7820(96)80051-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Both cDNA RHD sequences and reactivity with monoclonal anti-D have been reported in a number of partial D phenotypes, where parts (some epitopes) of the normal D antigen are missing, and anti-D of restricted specificity may be made in response to challenge with normal D positive blood. This paper analyses these reports together and proposes a model for the structure which comprise the epitopes of the Rh D antigen. Some epitopes are proposed to be comprised of continuous peptide sequence within one extracellular loop, whereas others require interactions between two or the extracellular peptide loops.
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36
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Abstract
We have examined all DVI variant phenotypes submitted to the workshop by a combination of RT-PCR, multiplex RHD PCR and immunoblotting with Rh antipeptide sera. Our findings suggest that all DVI phenotypes arise through hybrid RHD-RHCE-RHD genes. Genomic DNA derived from all DVI samples were shown to be RHD intron 4 negative when analysed with an RHD intron 4/exon 10 multiplex assay. We assume therefore that all DVI phenotypes involve gene conversion events involving at least exons 4 and 5 of the RHD gene. Analysis of a novel D and E variant phenotype individual (ISBT49) by RT-PCR has allowed the identification of a hybrid Rh gene composed of exons 1-4 RHD: 5 RHCE/D and 6-10 RHD. We propose that the partial D & E phenotype observed arises through D & E expression on the hybrid RHD-RHCE-RHD protein: as no transcripts encoding Rh E could be found.
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Affiliation(s)
- N D Avent
- International Blood Group Reference Laboratory, Bristol, UK
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