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Mbeti JMM, Bénech C, Sack FN, Wete E, Pangetha HN, Ateba SN, Tchatchueng J, Nloga AN, Fichou Y. First investigation of RH gene polymorphism in patients with sickle cell disease and associated blood donors in Cameroon, Central Africa. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2024; 22:377-386. [PMID: 38315540 PMCID: PMC11390615 DOI: 10.2450/bloodtransfus.660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/29/2023] [Indexed: 02/07/2024]
Abstract
BACKGROUND Although genetic polymorphism of the RH blood group system is well known in sub-Saharan Africa, national/regional specificities still remain to be described precisely. For the first time in Cameroon, Central Africa, and in order to better characterize the molecular basis driving RH phenotype variability, as well as to identify the main antigens that may be potentially responsible for alloimmunization, we sought 1) to study the RH genes in a cohort of 109 patients with sickle cell disease; 2) to study the same genes in the corresponding donors whose red blood cells (RBCs) were transfused to the patients (108 donors in 98 patients); 3) to predict RH phenotype on the basis of the molecular data and compare the results with serologic testing; and 4) to identify retrospectively patients at risk for alloimmunization. MATERIALS AND METHODS In order to generate an exhaustive dataset, the RH genes of all patient and donor samples were systematically investigated 1) by quantitative multiplex PCR of short fluorescent fragments (QMPSF) for characterization of RHD gene zygosity and potential structural variants (SVs), and 2) by Sanger sequencing for identification of single nucleotide variants (SNVs). Subsequent to molecular analysis, the genotypes and RH phenotype were deduced and predicted, respectively, from reference databases. RESULTS In a total of 217 Cameroonian individuals, as many as 24 and up to 22 variant alleles were identified in the RHD and RHCE genes, respectively, in addition to the reference alleles. Interestingly, 65 patients with SCD (66.3%) were assumed to be exposed to one or more undesirable RH antigen(s) with varying degrees of clinical relevance. DISCUSSION Beyond the comprehensive report of the nature and distribution of RH variant alleles in a subset of Cameroonian patients treated by transfusion therapy, this work highlights the need for an extensive review of current practice, including routine serologic typing procedures, preferably in the near future.
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Affiliation(s)
- Jeanne Manga Messina Mbeti
- Université Catholique d'Afrique Centrale (UCAC), Yaoundé, Cameroon
- Centre Pasteur du Cameroun (CPC), Yaoundé, Cameroon
| | - Caroline Bénech
- Univ Brest, Inserm, EFS, UBO, UMR1078, GGB, Brest, France
- Laboratory of Excellence GR-Ex, Paris, France
| | - Françoise Ngo Sack
- Université Catholique d'Afrique Centrale (UCAC), Yaoundé, Cameroon
- Banque de sang, Hôpital Central de Yaoundé, Yaoundé, Cameroon
- Service Hémato-oncologie, Hôpital Central de Yaoundé, Yaoundé, Cameroon
| | - Estelle Wete
- Centre Mère et Enfant, Fondation Chantal Biya, Yaoundé, Cameroon
| | | | | | | | - Alexandre Njan Nloga
- Université Catholique d'Afrique Centrale (UCAC), Yaoundé, Cameroon
- Faculté des Sciences, Université de Ngaoundéré, Ngaoundéré, Cameroon
| | - Yann Fichou
- Univ Brest, Inserm, EFS, UBO, UMR1078, GGB, Brest, France
- Laboratory of Excellence GR-Ex, Paris, France
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Aburto A, Zapata D, Retamales E, Fernández J, Barra G, Peña F, Cárcamo S, Saavedra N, Sandoval C, Orellana J, Caamaño J. Genotype analysis to clarify RhD variants in discrepant samples of Chilean population. Front Immunol 2023; 14:1299639. [PMID: 38116010 PMCID: PMC10728993 DOI: 10.3389/fimmu.2023.1299639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/14/2023] [Indexed: 12/21/2023] Open
Abstract
Introduction The D antigen variants are classified as weak, partial, and extremely weak (DEL) and can be differentiated using molecular tests. In Chile, the laboratories of local blood centers do not identify variants of the D antigen, referring them for study to the Reference Laboratory of the Public Health Institute of Chile. So, our aim was to talk about the results of the molecular analysis of variants of the D antigen in samples that had different results in the serological classification. Methods In the D antigen classification of the Rh system, 479 samples with serological discrepant results were sent for molecular analysis. The Rh phenotype was performed with monoclonal anti-C, anti-c, anti-E, and anti-e antisera by direct agglutination. To find the D antigen, researchers used direct agglutination with monoclonal antisera and indirect antiglobulin testing with the column (gel) agglutination method. Molecular analysis was performed with a polymerase chain reaction with sequence-specific primers (SSP-PCR) and sequencing. Results and discussion The presence of D antigen variants was confirmed in 332 samples (69.3%), with an initial discrepancy in serological classification. In this group of discrepant samples, the frequency of weak RhD variants was 66% (219/332), that of extremely weak RhD was 28% (93/332), and that of partial RhD was 6% (20/332). The weak variants type 2 (27.4%), type 3 (8.4%), type 48 (8.4%), and type 1 (8.1%) were the next most prevalent variants after RHD*DEL43 (28%). The ccEe (R2r) phenotype was the most frequently detected (38.4%) and is present in 87% of the RHD*DEL43 samples. The E antigen is associated with the presence of this variant. Our analyses give the first description of D antigen variants in Chile. The most common variants are DEL type (RHD*DEL43) and weak (weak type 2), which are linked to the ccDEe (R2r) phenotype. These findings allow us to characterize the variants of the D antigen in Chile and, according to the obtained data, to design strategies for the management of donors, patients, and pregnant women.
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Affiliation(s)
- Andrés Aburto
- Sección Hematología e Inmunohematología, Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile
| | - Diego Zapata
- Sección Hematología e Inmunohematología, Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile
| | - Eduardo Retamales
- Sección Hematología e Inmunohematología, Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile
| | - Jorge Fernández
- Subdepartamento de Genética Molecular, Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile
| | - Gisselle Barra
- Subdepartamento de Genética Molecular, Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile
| | - Francisca Peña
- Laboratorio de Inmunohematología y Medicina Transfusional, Departamento de Medicina Interna, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
- Centro de Investigación en Medicina de Laboratorio – CeMLab, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
| | - Sofía Cárcamo
- Laboratorio de Inmunohematología y Medicina Transfusional, Departamento de Medicina Interna, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
| | - Nicolás Saavedra
- Centro de Investigación en Medicina de Laboratorio – CeMLab, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
- Departamento de Ciencias Básicas, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
| | - Cristian Sandoval
- Escuela de Tecnología Médica, Facultad de Salud, Universidad Santo Tomás, Osorno, Chile
- Departamento de Ciencias Preclínicas, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
| | - Juan Orellana
- Centro de Investigación en Medicina de Laboratorio – CeMLab, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
- Departamento de Salud Pública, CIGES (Capacitación, Investigación y Gestión para la Salud), Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
| | - José Caamaño
- Laboratorio de Inmunohematología y Medicina Transfusional, Departamento de Medicina Interna, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
- Centro de Investigación en Medicina de Laboratorio – CeMLab, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile
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Srivastava K, Polin H, Sheldon SL, Wagner FF, Grabmer C, Gabriel C, Denomme GA, Flegel WA. The DAU cluster: a comparative analysis of 18 RHD alleles, some forming partial D antigens. Transfusion 2016; 56:2520-2531. [PMID: 27480171 PMCID: PMC5499517 DOI: 10.1111/trf.13739] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 01/10/2023]
Abstract
BACKGROUND The Rh system is the most complex and polymorphic blood group system in humans with more than 460 alleles known for the RHD gene. The DAU cluster of RHD alleles is characterized by the single-nucleotide change producing the p.Thr379Met amino acid substitution. It is called the DAU-0 allele and has been postulated to be the primordial allele, from which all other alleles of the DAU cluster have eventually evolved. STUDY DESIGN AND METHODS For two novel DAU alleles, the nucleotide sequences of all 10 exons as well as adjacent intronic regions, including the 5' and 3' untranslated regions (UTR), were determined for the RHD and RHCE genes. A phylogenetic tree for all DAU alleles was established using the neighbor-joining method with Pan troglodytes as root. Standard hemagglutination and flow cytometry tests were performed. RESULTS We characterized two DAU alleles, DAU-11 and DAU-5.1, closely related to DAU-3 and DAU-5, respectively. A phylogenetic analysis of the 18 known DAU alleles indicated point mutations and interallelic recombination contributing to diversification of the DAU cluster. CONCLUSIONS The DAU alleles encode a group of RhD protein variants, some forming partial D antigens known to permit anti-D in carriers; all are expected to cause anti-D alloimmunization in recipients of red blood cell transfusions. The DAU alleles evolved through genomic point mutations and recombination. These results suggest that the cluster of DAU alleles represent a clade, which is concordant with our previous postulate that they derived from the primordial DAU-0 allele.
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Affiliation(s)
- Kshitij Srivastava
- Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Helene Polin
- Red Cross Transfusion Service of Upper Austria, Linz, Austria
| | - Sherry Lynne Sheldon
- Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | | | - Christoph Grabmer
- Department of Blood Group Serology and Transfusion Medicine, SALK-Paracelsus Medical University, Salzburg, Austria
| | - Christian Gabriel
- Red Cross Transfusion Service of Upper Austria, Linz, Austria
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria
| | | | - Willy Albert Flegel
- Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland.
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