1
|
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.
Collapse
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
| |
Collapse
|
2
|
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: 1] [Impact Index Per Article: 1.0] [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.
Collapse
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.
| |
Collapse
|
3
|
Next-generation sequencing of 35 RHD variants in 16 253 serologically D- pregnant women in the Finnish population. Blood Adv 2021; 4:4994-5001. [PMID: 33057632 DOI: 10.1182/bloodadvances.2020001569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/11/2020] [Indexed: 12/17/2022] Open
Abstract
Fetal RHD screening for targeted routine antenatal anti-D prophylaxis has been implemented in many countries, including Finland, since the 2010s. Comprehensive knowledge of the RHD polymorphism in the population is essential for the performance and safety of the anti-D prophylaxis program. During the first 3 years of the national screening program in Finland, over 16 000 samples from RhD- women were screened for fetal RHD; among them, 79 samples (0.5%) containing a maternal variant allele were detected. Of the detected maternal variants, 35 cases remained inconclusive using the traditional genotyping methods and required further analysis by next-generation sequencing (NGS) of the whole RHD gene to uncover the variant allele. In addition to the 13 RHD variants that have been previously reported in different populations, 8 novel variants were also detected, indicating that there is more variation of RHD in the RhD- Finnish population than has been previously known. Three of the novel alleles were identified in multiple samples; thus, they are likely specific to the original Finnish population. National screening has thus provided new information about the diversity of RHD variants in the Finnish population. The results show that NGS is a powerful method for genotyping the highly polymorphic RHD gene compared with traditional methods that rely on the detection of specific nucleotides by polymerase chain reaction amplification.
Collapse
|
4
|
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
| |
Collapse
|
5
|
de Paula Vendrame TA, Prisco Arnoni C, Guilhem Muniz J, de Medeiros Person R, Pereira Cortez AJ, Roche Moreira Latini F, Castilho L. Characterization of RHD alleles present in serologically RHD-negative donors determined by a sensitive microplate technique. Vox Sang 2019; 114:869-875. [PMID: 31587310 DOI: 10.1111/vox.12851] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 08/15/2019] [Accepted: 09/08/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND OBJECTIVES Weak D phenotypes with very low antigen densities and DEL phenotype may not be detected in RhD typing routine and could be typed as D-negative, leading to D alloimmunization of D-negative recipients. The present study aimed to investigate the presence of RHD-positive genotypes in blood donors typed as D-negative by an automated system using the solid-phase methodology as a confirmatory test. METHODS Two screenings were performed in different selected donor populations. For the first screening, we selected 1403 blood donor samples typed as D-negative regardless of the CE status, and in the second screening, we selected 517 donor samples typed as D-negative C+ and/or E+. RhD typing was performed by microplate in an automated equipment (Neo-Immucor®), and the confirmatory test was performed by solid-phase technique using Capture R® technology. A multiplex PCR specific to RHD and RHDψ was performed in a pool of 6 DNA samples. Sequencing of RHD exons was performed in all RHD-positive samples, and a specific PCR was used to identify the D-CE(4-7)-D hybrid gene. RESULTS AND CONCLUSION No weak D type was found in either screening populations. Additionally, 353 (18·4%) D-negative samples presented previously reported non-functional RHD genes, 2 samples had a DEL allele, and 6 samples demonstrated new alleles, including one novel DEL allele. Our study identified six new RHD alleles and showed that the inclusion of a confirmatory test using serological methodology with high sensitivity can reduce the frequency of weak D samples typed as D-negative.
Collapse
|
6
|
Luo X, Keller MA, James I, Grant M, Liu S, Massey KS, Czulewicz A, Nance S, Li Y. Strategies to identify candidates for D variant genotyping. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2018; 16:293-301. [PMID: 28488958 PMCID: PMC5919842 DOI: 10.2450/2017.0274-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/21/2016] [Indexed: 12/17/2022]
Abstract
BACKGROUND RhD variants have altered D epitopes and/or decreased antigen copies per red cell. Individuals carrying these variants may test antigen negative, weakly positive, or positive by serology, and may or may not be at risk of alloimmunisation after exposure. There have been recommendations to perform RHD genotyping of patients, pregnant women and females of childbearing potential with serological weak D phenotype, to guide prophylactic use of Rh immune globulin (RhIG), and better conserve D-negative blood products. The purpose of this study was to evaluate the performance of a set of empirical criteria to identify such patients. MATERIALS AND METHODS A two-method strategy of gel testing (GT) and tube testing (TT) was used for Rh typing of patients with no historical blood type in the present institution. A monoclonal-polyclonal blend anti-D was used for Rh typing by TT at immediate spin. Three empirical criteria were used to identify candidates for genotyping: C1: discrepancy between the two test methods and a GT reaction strength >2+ stronger than TT; C2: weak serological reaction, defined as reaction strength ≤2+ regardless of testing method if both GT and TT were performed or reaction strength ≤2+ if only GT was performed, or reaction strength ≤1+ if only TT was performed; C3: presence of anti-D in D-positive patients with no history of RhIG use in the preceding 3 months and in whom alloanti-D is suspected. RESULTS Overall, 50 patients, ranging from newly born to 93 years old, were identified. Genomic testing confirmed D variants in 49/50 cases with a positive predictive value of 98%. DISCUSSION This two-method strategy is a powerful screening tool for identifying candidates for RHD genotyping. This strategy meets the current requirements of two blood type determinations/two specimens in pre-transfusion testing while simultaneously identifying candidates for RHD genotyping with a minimal increase in work load and cost.
Collapse
Affiliation(s)
- Xunda Luo
- Department of Pathology and Laboratory Medicine, Temple University Hospital, Temple University, Philadelphia, PA, United States of America
| | - Margaret A. Keller
- American Red Cross, Temple University, Philadelphia, PA, United States of America
| | - Ian James
- Department of Pathology and Laboratory Medicine, Temple University Hospital, Temple University, Philadelphia, PA, United States of America
| | - Michelle Grant
- Department of Pathology and Laboratory Medicine, Temple University Hospital, Temple University, Philadelphia, PA, United States of America
| | - Shiguang Liu
- Department of Pathology and Laboratory Medicine, Temple University Hospital, Temple University, Philadelphia, PA, United States of America
| | - Kellie Simmons Massey
- Department of Pathology and Laboratory Medicine, Temple University Hospital, Temple University, Philadelphia, PA, United States of America
| | - Andrew Czulewicz
- Department of Pathology, Jeanes Hospital, Temple University, Philadelphia, PA, United States of America
| | - Sandra Nance
- American Red Cross, Temple University, Philadelphia, PA, United States of America
- University of Pennsylvania, Department of Pathology and Laboratory Medicine, Division of Transfusion Medicine, Temple University, Philadelphia, PA, United States of America
| | - Yanhua Li
- Department of Pathology and Laboratory Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States of America
| |
Collapse
|
7
|
Sandler SG, Chen L, Flegel WA. Serological weak D phenotypes: a review and guidance for interpreting the RhD blood type using the RHD genotype. Br J Haematol 2017; 179:10-19. [PMID: 28508413 PMCID: PMC5612847 DOI: 10.1111/bjh.14757] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Approximately 0·2-1% of routine RhD blood typings result in a "serological weak D phenotype." For more than 50 years, serological weak D phenotypes have been managed by policies to protect RhD-negative women of child-bearing potential from exposure to weak D antigens. Typically, blood donors with a serological weak D phenotype have been managed as RhD-positive, in contrast to transfusion recipients and pregnant women, who have been managed as RhD-negative. Most serological weak D phenotypes in Caucasians express molecularly defined weak D types 1, 2 or 3 and can be managed safely as RhD-positive, eliminating unnecessary injections of Rh immune globulin and conserving limited supplies of RhD-negative RBCs. If laboratories in the UK, Ireland and other European countries validated the use of potent anti-D reagents to result in weak D types 1, 2 and 3 typing initially as RhD-positive, such laboratory results would not require further testing. When serological weak D phenotypes are detected, laboratories should complete RhD testing by determining RHD genotypes (internally or by referral). Individuals with a serological weak D phenotype should be managed as RhD-positive or RhD-negative, according to their RHD genotype.
Collapse
Affiliation(s)
- S. Gerald Sandler
- Department of Pathology and Laboratory Medicine, MedStar Georgetown University Hospital, Washington, DC
| | - Leonard Chen
- Department of Pathology and Laboratory Medicine, MedStar Georgetown University Hospital, Washington, DC
| | - Willy A. Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, United States
| |
Collapse
|
8
|
Fichou Y, Le Maréchal C, Scotet V, Jamet D, Férec C. Insights into RHCE Molecular Analysis in Samples with Partial D Variants: the Experience of Western France. Transfus Med Hemother 2015; 42:372-7. [PMID: 26733768 DOI: 10.1159/000382086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 12/05/2014] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Although systematic blood group genotyping of patients/donors is virtually possible, serological studies remain the gold standard to identify samples of clinical interest that may be further genotyped. In this context, we sought to identify variant D alleles that are likely to be clinically relevant in terms of other Rh antigens in a subset of population genotyped in Western France. METHODS Samples presenting with the RHD*weak D type 4.2.2 allele (n = 47) were selected for the study. RHCE exons 1-7 were directly sequenced, and expression of Rh antigens was predicted on the basis of the molecular data. RESULTS Of the 47 samples tested, 19 (40.4%) were predicted to be of potential clinical interest. Moreover, we could show that selecting the samples to be genotyped by the nature of their variant D allele (i.e., RHD*weak D type 4.2.2 allele) rather than by their Duffy-null status appears to increase significantly the likelihood of identifying clinically relevant individuals for Rh status. CONCLUSION On the basis of our findings we suggest that all individuals genotyped as weak D type 4.2.2 should be systematically screened for RHCE variants by molecular analysis on a routine basis.
Collapse
Affiliation(s)
- Yann Fichou
- French Blood Institute (EFS-Bretagne), Brest, France; National Institute of Health and Medical Research (Inserm, UMR1078), Brest, France
| | - Cédric Le Maréchal
- French Blood Institute (EFS-Bretagne), Brest, France; National Institute of Health and Medical Research (Inserm, UMR1078), Brest, France; Faculty of Medicine and Health Sciences, University of Western Brittany, Brest, France; Molecular Genetics and Histocompatibility Laboratory, Regional University Hospital (CHRU), Morvan Hospital, Brest, France
| | - Virginie Scotet
- French Blood Institute (EFS-Bretagne), Brest, France; National Institute of Health and Medical Research (Inserm, UMR1078), Brest, France
| | - Déborah Jamet
- French Blood Institute (EFS-Bretagne), Brest, France
| | - Claude Férec
- French Blood Institute (EFS-Bretagne), Brest, France; National Institute of Health and Medical Research (Inserm, UMR1078), Brest, France; Faculty of Medicine and Health Sciences, University of Western Brittany, Brest, France; Molecular Genetics and Histocompatibility Laboratory, Regional University Hospital (CHRU), Morvan Hospital, Brest, France
| |
Collapse
|
9
|
Sandler SG, Flegel WA, Westhoff CM, Denomme GA, Delaney M, Keller MA, Johnson ST, Katz L, Queenan JT, Vassallo RR, Simon CD. It's time to phase in RHD genotyping for patients with a serologic weak D phenotype. College of American Pathologists Transfusion Medicine Resource Committee Work Group. Transfusion 2015; 55:680-9. [PMID: 25438646 PMCID: PMC4357540 DOI: 10.1111/trf.12941] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 10/07/2014] [Accepted: 10/07/2014] [Indexed: 11/29/2022]
Affiliation(s)
- S Gerald Sandler
- Department of Pathology and Laboratory Medicine, MedStar Georgetown University Hospital, Washington, DC
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Distribution of Rhesus blood group antigens and weak D alleles in the population of Albania. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2014; 12:565-9. [PMID: 24960662 DOI: 10.2450/2014.0240-13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 12/30/2013] [Indexed: 11/21/2022]
Abstract
BACKGROUND Determination of Rhesus (Rh) status is of critical importance in the field of both transfusion and obstetric medicine. As the distribution of Rh phenotypes was unknown in the Albanian population, we investigated the donor population in Albania to estimate the prevalence of each phenotype, as well as to identify and characterise the variants at the molecular level. MATERIALS AND METHODS A total of 38,836 blood donors were phenotyped for Rh D, C, c, E and e antigens by routine serological methods, and samples with reduced D antigen expression underwent molecular characterisation by a Tm-shift genotyping method and direct sequencing. RESULTS Among all donors 89.00% and 10.86% were D-positive and D-negative, respectively, while 0.14% (n=55) of the donors were found to be weak D-positive. Overall 45/55 samples (81.8%) were resolved by Tm-shift screening, showing that approximately 67% of the variant D alleles were weak D type 1, while weak D type 3 (9.1%) and weak D type 2 (3.6%) were less common. A novel c.932A>G (p.Y311C) variant was also found in the heterozygous state by direct sequencing. DISCUSSION This extensive study reveals the distribution of Rh phenotypes in the Albanian population, the low prevalence of individuals with a weak D phenotype, and the specific pattern of distribution of the three most common variant alleles in this Caucasian population.
Collapse
|