| 1. |
- Moslemi, Camous, et al.
(författare)
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Genetic prediction of 33 blood group phenotypes using an existing genotype dataset
- 2023
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Ingår i: Transfusion. - 0041-1132. ; 63:12, s. 2297-2310
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Tidskriftsartikel (refereegranskat)abstract
- Background: Accurate blood type data are essential for blood bank management, but due to costs, few of 43 blood group systems are routinely determined in Danish blood banks. However, a more comprehensive dataset of blood types is useful in scenarios such as rare blood type allocation. We aimed to investigate the viability and accuracy of predicting blood types by leveraging an existing dataset of imputed genotypes for two cohorts of approximately 90,000 each (Danish Blood Donor Study and Copenhagen Biobank) and present a more comprehensive overview of blood types for our Danish donor cohort. Study Design and Methods: Blood types were predicted from genome array data using known variant determinants. Prediction accuracy was confirmed by comparing with preexisting serological blood types. The Vel blood group was used to test the viability of using genetic prediction to narrow down the list of candidate donors with rare blood types. Results: Predicted phenotypes showed a high balanced accuracy >99.5% in most cases: A, B, C/c, Coa/Cob, Doa/Dob, E/e, Jka/Jkb, Kna/Knb, Kpa/Kpb, M/N, S/s, Sda, Se, and Yta/Ytb, while some performed slightly worse: Fya/Fyb, K/k, Lua/Lub, and Vel ~99%–98% and CW and P1 ~96%. Genetic prediction identified 70 potential Vel negatives in our cohort, 64 of whom were confirmed correct using polymerase chain reaction (negative predictive value: 91.5%). Discussion: High genetic prediction accuracy in most blood groups demonstrated the viability of generating blood types using preexisting genotype data at no cost and successfully narrowed the pool of potential individuals with the rare Vel-negative phenotype from 180,000 to 70.
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| 2. |
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| 3. |
- Kelemu, Tsehayneh, et al.
(författare)
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Association of Maternal Regulatory Single Nucleotide Polymorphic CD99 Genotype with Preeclampsia in Pregnancies Carrying Male Fetuses in Ethiopian Women
- 2020
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 21:16
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Tidskriftsartikel (refereegranskat)abstract
- Preeclampsia (PE) is a human specific syndrome with unknown etiology causing maternal and fetal morbidities and mortalities. In PE, maternal inflammatory responses are more exaggerated if the fetus is male than female. Other pregnancy complications such as spontaneous abortions are also more common if the fetus is male. Recent transcriptome findings showed an increased expression of CD99 in erythroid cells from male cord blood in PE. The single nucleotide polymorphism (SNP) rs311103, located in a GATA-binding site in a regulatory region on the X/Y chromosomes, governs a coordinated expression of the Xg blood group members CD99 and Xga in hematopoietic cells in a sex-dependent fashion. The rs311103C disrupts the GATA-binding site, resulting in decreased CD99 expression. We aimed to investigate the association between PE and the allele frequency of rs311103 in pregnancies in a fetal sex-dependent fashion. In a case-controlled study, we included 241 pregnant women, i.e., 105 PE cases and 136 normotensive controls. A SNP allelic discrimination analysis was performed on DNA from maternal venous blood and fetal cord blood by qPCR. A statistically significant association was observed between rs311103 allele frequency and PE in mothers carrying male fetuses. Therefore, the rs311103 genotype may play a role in the pathogenesis of PE in a fetal sex-specific manner.
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| 4. |
- Kristiansson, Amanda, et al.
(författare)
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Human radical scavenger α1-microglobulin protects against hemolysis in vitro and α1-microglobulin knockout mice exhibit a macrocytic anemia phenotype
- 2021
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Ingår i: Free Radical Biology & Medicine. - : Elsevier BV. - 0891-5849. ; 162
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Tidskriftsartikel (refereegranskat)abstract
- During red blood cell (RBC) lysis hemoglobin and heme leak out of the cells and cause damage to the endothelium and nearby tissue. Protective mechanisms exist; however, these systems are not sufficient in diseases with increased extravascular hemolysis e.g. hemolytic anemia. α1-microglobulin (A1M) is a ubiquitous reductase and radical- and heme-binding protein with antioxidation properties. Although present in the circulation in micromolar concentrations, its function in blood is unclear. Here, we show that A1M provides RBC stability. A1M-/- mice display abnormal RBC morphology, reminiscent of macrocytic anemia conditions, i.e. fewer, larger and more heterogeneous cells. Recombinant human A1M (rA1M) reduced in vitro hemolysis of murine RBC against spontaneous, osmotic and heme-induced stress. Moreover, A1M is taken up by human RBCs both in vitro and in vivo. Similarly, rA1M also protected human RBCs against in vitro spontaneous, osmotic, heme- and radical-induced hemolysis as shown by significantly reduced leakage of hemoglobin and LDH. Addition of rA1M resulted in decreased hemolysis compared to addition of the heme-binding protein hemopexin and the radical-scavenging and reducing agents ascorbic acid and Trolox (vitamin E). Furthermore, rA1M significantly reduced spontaneous and heme-induced fetal RBC cell death. Addition of A1M to human whole blood resulted in a significant reduction of hemolysis, whereas removal of A1M from whole blood resulted in increased hemolysis. We conclude that A1M has a protective function in reducing hemolysis which is neither specific to the origin of hemolytic insult, nor species specific.
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| 5. |
- Kristiansson, Amanda, et al.
(författare)
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The Role of α1-Microglobulin (A1M) in Erythropoiesis and Erythrocyte Homeostasis-Therapeutic Opportunities in Hemolytic Conditions
- 2020
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 21:19, s. 1-21
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Forskningsöversikt (refereegranskat)abstract
- α1-microglobulin (A1M) is a small protein present in vertebrates including humans. It has several physiologically relevant properties, including binding of heme and radicals as well as enzymatic reduction, that are used in the protection of cells and tissue. Research has revealed that A1M can ameliorate heme and ROS-induced injuries in cell cultures, organs, explants and animal models. Recently, it was shown that A1M could reduce hemolysis in vitro, observed with several different types of insults and sources of RBCs. In addition, in a recently published study, it was observed that mice lacking A1M (A1M-KO) developed a macrocytic anemia phenotype. Altogether, this suggests that A1M may have a role in RBC development, stability and turnover. This opens up the possibility of utilizing A1M for therapeutic purposes in pathological conditions involving erythropoietic and hemolytic abnormalities. Here, we provide an overview of A1M and its potential therapeutic effect in the context of the following erythropoietic and hemolytic conditions: Diamond-Blackfan anemia (DBA), 5q-minus myelodysplastic syndrome (5q-MDS), blood transfusions (including storage), intraventricular hemorrhage (IVH), preeclampsia (PE) and atherosclerosis.
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| 6. |
- Lee, Yan Quan, et al.
(författare)
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A large deletion spanning XG and GYG2 constitutes a genetic basis of the Xgnull phenotype, underlying anti-Xga production
- 2019
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Ingår i: Transfusion. - : Wiley. - 1537-2995 .- 0041-1132. ; 59:5, s. 1843-1849
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The PBDX/XG gene encoding the Xga blood group antigen was described in 1994, but the genetic determinant of XG expression on RBCs was reported only in 2018. However, the frequencies of Xg(a-) individuals could not explain the rarity of anti-Xga makers. We therefore sought to elucidate the molecular basis of the Xg(a-) phenotype in people producing anti-Xga .STUDY DESIGN AND METHODS: Two genomic DNA (gDNA) and 13 plasma-derived cell-free DNA (cfDNA) samples from anti-Xga makers were investigated (14 males and one female). PBDX/XG exon sequencing was attempted on one gDNA sample. Polymerase chain reaction assays were developed and bioinformatics used to define a suspected deletion in all samples.RESULTS: Investigation of one gDNA sample revealed a 114-kb deletion (esv2662319) on the X chromosome that spans XG exons 4 through 10 and the downstream GYG2 gene. A 3555-bp fragment bridging this deletion was amplified to confirm its presence. Another deletion-specific polymerase chain reaction of 714 bp enabled identification of esv2662319 in both gDNA samples and eight cfDNA samples while ruling it out in one cfDNA. Males were hemizygous for esv2662319 and the female likely homozygous. Four cfDNA sample results were inconclusive, probably due to poor sample quality. Sanger sequencing recognized the recombination junctions as a heterogeneous LTR6B sequence.CONCLUSION: We identified a large deletion on the X chromosome, resulting in a true, tissue-wide Xgnull phenotype. This deletion was found in 10 of 11 anti-Xga makers from which DNA could be amplified. One sample remained unexplained, indicating further heterogeneity to be explored.
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| 7. |
- Svensson, Lola, 1948, et al.
(författare)
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Forssman expression on human erythrocytes: biochemical and genetic evidence of a new histo-blood group system
- 2013
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 121:8, s. 1459-68
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Tidskriftsartikel (refereegranskat)abstract
- Abstract In analogy with histo-blood group A antigen, Forssman (Fs) antigen terminates with α3-N-acetylgalactosamine and can be utilized by pathogens as a host receptor in many mammals. However, primates including humans lack Fs synthase activity and have naturally-occurring Fs antibodies in plasma. We investigated individuals with the enigmatic ABO subgroup Apae and found them to be homozygous for common O alleles. Their erythrocytes had no A antigens but instead expressed Fs glycolipids. The unexpected Fs antigen was confirmed in structural, serological and flowcytometric studies. The Fs synthase gene, GBGT1, in Apae individuals encoded an arginine to glutamine change at residue 296. Gln296 is present in lower mammals whereas Arg296 was found in six other primates, >250 blood donors and Apae family relatives without the Apae phenotype. Transfection experiments and molecular modelling showed that 296Gln reactivates the human Fs synthase. Uropathogenic E.coli containing prsG-adhesin-encoding plasmids agglutinated Apae but not group O cells, suggesting biological implications. Predictive tests for intravascular hemolysis with crossmatch-incompatible sera indicated complement-mediated destruction of Fspositive erythrocytes. Taken together, we provide the first conclusive description of Fs expression in normal human hematopoietic tissue and the basis of a new histo-blood group system in man, FORS.
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| 8. |
- Alattar, Abdul Ghani, et al.
(författare)
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Evidence that CD36 is expressed on red blood cells and constitutes a novel blood group system of clinical importance
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Ingår i: Vox Sanguinis. - 1423-0410. ; , s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES: Polymorphic molecules expressed on the surface of certain blood cells are traditionally categorized as blood groups and human platelet or neutrophil antigens. CD36 is widely considered a platelet antigen (Nak a ) and anti-CD36 can cause foetal/neonatal alloimmune thrombocytopenia (FNAIT) in CD36-negative pregnant women. CD36 is used as a marker of differentiation in early erythroid culture. During the experimental culture of CD34+ cells from random blood donors, we observed that one individual lacked CD36. We sought to investigate this observation further and determine if CD36 fulfils the International Society of Blood Transfusion criteria for becoming a blood group. MATERIALS AND METHODS: Surface markers were monitored by flow cytometry on developing cells during the erythroid culture of CD34+ cells. Genetic and flow cytometric analyses on peripheral blood cells were performed. Proteomic datasets were analysed, and clinical case reports involving anti-CD36 and foetal anaemia were scrutinized.RESULTS: Sequencing of CD36-cDNA identified homozygosity for c.1133G>T/p.Gly378Val in the CD36-negative donor. The minor allele frequency of rs146027667:T is 0.1% globally and results in abolished CD36 expression. CD36 has been considered absent from mature red blood cells (RBCs); however, we detected CD36 expression on RBCs and reticulocytes from 20 blood donors. By mining reticulocyte and RBC datasets, we found evidence for CD36-derived peptides enriched in the membrane fractions. Finally, our literature review revealed severe cases of foetal anaemia attributed to anti-CD36.CONCLUSIONS: Based on these findings, we conclude that CD36 fulfils the criteria for becoming a new blood group system and that anti-CD36 is implicated not only in FNAIT but also foetal anaemia.
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| 9. |
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| 10. |
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| 11. |
- Brumit, M C, et al.
(författare)
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Moderate hemolytic disease of the newborn (HDN) due to anti-Rh17 produced by a black female with an e variant phenotype
- 2002
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Ingår i: Immunohematology. - 0894-203X. ; 18:2, s. 40-42
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Tidskriftsartikel (refereegranskat)abstract
- The Rh blood group antigen e is of high incidence and has many epitopes. Partial expression may occur, more commonly in black persons. Individuals with e variant phenotypes can make antibodies to epitopes they lack. While some of these antibodies may be specific for an antigen, e.g., hrB, others, like anti-Rh17 (anti-Hro), show broader specificity, compatible only with D-- and Rhnull red blood cells (RBCs). Anti-Rh17 in persons of the D-- phenotype has been reported to cause mild to fatal HDN. We report an example of anti-Rh17 produced by a black female with an e variant RBC phenotype that caused moderate HDN. A panel of seven monoclonal anti-e demonstrated her RBCs carried a variant e antigen, and her genotype was RHD, RHce by PCR-RFLP analysis. Amniotic fluid with.OD450 values from 30 to 35 weeks' gestation predicted moderate HDN probability by the Liley method. At 38+ weeks, a viable 3165 g female infant was delivered. The infant's direct antiglobulin test was 2+ with anti-IgG. Total bilirubin rose to 14.2 mg/dL within 48 hours. Indirect bilirubin peaked at 14.7 mg/dL. The bilirubin responded to triple phototherapy. The infant was discharged on day 6. Potential for infant morbidity due to anti-Rh17- mediated HDN and the importance of specifying risks to women with this antibody if they contemplate pregnancy are discussed.
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| 12. |
- Christophersen, Mikael K., et al.
(författare)
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SMIM1 variants rs1175550 and rs143702418 independently modulate Vel blood group antigen expression
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- The Vel blood group antigen is expressed on the red blood cells of most individuals. Recently, we described that homozygosity for inactivating mutations in SMIM1 defines the rare Vel-negative phenotype. Still, Vel-positive individuals show great variability in Vel antigen expression, creating a risk for Vel blood typing errors and transfusion reactions. We fine-mapped the regulatory region located in SMIM1 intron 2 in Swedish blood donors, and observed a strong correlation between expression and rs1175550 as well as with a previously unreported tri-nucleotide insertion (rs143702418; C > CGCA). While the two variants are tightly linked in Caucasians, we separated their effects in African Americans, and found that rs1175550G and to a lesser extent rs143702418C independently increase SMIM1 and Vel antigen expression. Gel shift and luciferase assays indicate that both variants are transcriptionally active, and we identified binding of the transcription factor TAL1 as a potential mediator of the increased expression associated with rs1175550G. Our results provide insight into the regulatory logic of Vel antigen expression, and extend the set of markers for genetic Vel blood group typing.
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| 13. |
- Gassner, Christoph, et al.
(författare)
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International Society of Blood Transfusion Working Party on Red Cell Immunogenetics and Blood Group Terminology Report of Basel and three virtual business meetings : Update on blood group systems
- 2022
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Ingår i: Vox Sanguinis. - : Wiley. - 1423-0410 .- 0042-9007. ; 117:11, s. 1332-1344
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES: Under the ISBT, the Working Party (WP) for Red Cell Immunogenetics and Blood Group Terminology is charged with ratifying blood group systems, antigens and alleles. This report presents the outcomes from four WP business meetings, one located in Basel in 2019 and three held as virtual meetings during the COVID-19 pandemic in 2020 and 2021.MATERIALS AND METHODS: As in previous meetings, matters pertaining to blood group antigen nomenclature were discussed. New blood group systems and antigens were approved and named according to the serologic, genetic, biochemical and cell biological evidence presented.RESULTS: Seven new blood group systems, KANNO (defined numerically as ISBT 037), SID (038), CTL2 (039), PEL (040), MAM (041), EMM (042) and ABCC1 (043) were ratified. Two (039 and 043) were de novo discoveries, and the remainder comprised reported antigens where the causal genes were previously unknown. A further 15 blood group antigens were added to the existing blood group systems: MNS (002), RH (004), LU (005), DI (010), SC (013), GE (020), KN (022), JMH (026) and RHAG (030).CONCLUSION: The ISBT now recognizes 378 antigens, of which 345 are clustered within 43 blood group systems while 33 still have an unknown genetic basis. The ongoing discovery of new blood group systems and antigens underscores the diverse and complex biology of the red cell membrane. The WP continues to update the blood group antigen tables and the allele nomenclature tables. These can be found on the ISBT website (http://www.isbtweb.org/working-parties/red-cell-immunogenetics-and-blood-group-terminology/).
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| 14. |
- Gassner, Christoph, et al.
(författare)
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Two Prevalent ∼100-kb GYPB Deletions Causative of the GPB-Deficient Blood Group MNS Phenotype S-s-U-in Black Africans
- 2020
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Ingår i: Transfusion Medicine and Hemotherapy. - : S. Karger AG. - 1660-3796 .- 1660-3818. ; 47:4, s. 326-336
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Tidskriftsartikel (refereegranskat)abstract
- The U antigen (MNS5) is one of 49 antigens belonging to the MNS blood group system (ISBT002) carried on glycophorins A (GPA) and B (GPB). U is present on the red blood cells in almost all Europeans and Asians but absent in approximately 1.0% of Black Africans. U negativity coincides with negativity for S (MNS3) and s (MNS4) on GPB, thus be called S-s-U-, and is thought to arise from homozygous deletion of GYPB. Little is known about the molecular background of these deletions. Bioinformatic analysis of the 1000 Genomes Project data revealed several candidate regions with apparent deletions in GYPB. Highly specific Gap-PCRs, only resulting in positive amplification from DNAs with deletions present, allowed for the exact genetic localization of 3 different breakpoints; 110.24- A nd 103.26-kb deletions were proven to be the most frequent in Black Americans and Africans. Among 157 CEPH DNAs, deletions in 6 out of 8 African ethnicities were present. Allele frequencies of the deletions within African ethnicities varied greatly and reached a cumulative 23.3% among the Mbuti Pygmy people from the Congo. Similar observations were made for U+var alleles, known to cause strongly reduced GPB expression. The 110- A nd 103-kb deletional GYPB haplotypes were found to represent the most prevalent hereditary factors causative of the MNS blood group phenotype S-s-U-. Respective GYPB deletions are now accessible by molecular detection of homo- A nd hemizygous transmission.
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| 15. |
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| 16. |
- Goel, Suchi, et al.
(författare)
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RIFINs are adhesins implicated in severe Plasmodium falciparum malaria
- 2015
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 21:4, s. 314-317
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Tidskriftsartikel (refereegranskat)abstract
- Rosetting is a virulent Plasmodium falciparum phenomenon associated with severe malaria. Here we demonstrate that P. falciparum-encoded repetitive interspersed families of polypeptides (RIFINs) are expressed on the surface of infected red blood cells (iRBCs), bind to RBCs-preferentially of blood group A-to form large rosettes and mediate microvascular binding of iRBCs. We suggest that RIFINs have a fundamental role in the development of severe malaria and thereby contribute to the varying global distribution of ABO blood groups in the human population.
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| 17. |
- Hagman, Jennifer Ricci, et al.
(författare)
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Other protein blood groups
- 2022
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Ingår i: Rossi's Principles of Transfusion Medicine. - : Wiley. - 9781119719793 - 9781119719755 ; , s. 109-117
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Bokkapitel (refereegranskat)abstract
- Antigens of the remaining 35 blood group systems are carried by glycoproteins. This chapter addresses only those antigens that elicit formation of clinically significant antibodies while briefly commenting on the other blood group systems. The most commonly encountered antibodies are directed against the M, N, S, and s antigens. The Lutheran blood group system contains multiple antigens; however, clinically significant antibodies are rarely encountered. The Kell glycoprotein is a member of the neprilysin (M13) family of zinc metalloproteases. The Duffy glycoprotein has seven transmembrane a-helical domains and is homologous with proteins of the G-coupled protein receptor family. Kidd is an integral protein with 10 transmembrane domains and both N-and C-termini located intracellularly. Antigens of the Diego blood group system are carried by band 3, the most abundant integral protein of the red cell membrane together with glycophorin A.
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| 18. |
- Hagman, Jennifer Ricci, et al.
(författare)
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Use of a recombinant deacetylase to convert A1 red blood cells to the acquired B phenotype for quality control purposes
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Ingår i: Blood Transfusion. - 1723-2007.
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Tidskriftsartikel (refereegranskat)abstract
- Background - Correct blood group typing is the cornerstone of transfusion medicine. In patients whose gastrointestinal wall is compromised, bacterial enzymes can cause deacetylation of blood group A, converting N-acetylgalactosamine to galactosamine, which resembles the B-defining galactose. This acquired B (acqB) phenomenon, first described 1959, can lead to blood grouping errors. Herein, we explore the possibility of producing acqB red blood cells (RBCs) by enzymatic conversion, for quality control purposes.Materials and methods - A1 RBCs along with group B and O control RBCs were subjected to enzymatic digestion by bacterially derived deacetylase, FpGalNAcDeAc. RBCs were tested with monoclonal anti-A, anti-B, acquired-B-reactive anti-B (ES4 clone), and a panel of donor plasmas. Standard serological techniques were used. RBCs were subsequently frozen by a glycerolisation method, stored at −80 oC, and thawed for testing to evaluate stability.Results - Specific deacetylation of A antigen was achieved at both enzyme concentrations. Enzymatically modified A1 RBCs reacted 1-3+ with clone ES4 but not with other anti-B reagents. Group B and O RBC controls reacted as expected. Crossmatch testing revealed 1-3+ reactions in 17/26 group A plasma with modified RBCs but not with untreated controls. Furthermore, 2/3 group AB plasmas reacted strongly with the modified RBCs. The acqB phenotype was maintained upon freezing/thawing.Discussion - Using a recombinant deacetylase, we demonstrated the feasibility of creating acqB RBCs from donor A1 RBCs, thus providing a reagent for quality assurance of monoclonal anti-B. These RBCs can be frozen once treated, providing a reliable source of this unusual but clinically important phenotype.
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| 19. |
- Halverson, Gregory R, et al.
(författare)
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Murine monoclonal anti-s and other anti-glycophorin B antibodies resulting from immunizations with a GPB.s peptide.
- 2009
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Ingår i: Transfusion. - : Wiley. - 1537-2995 .- 0041-1132. ; 49, s. 485-494
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The blood group antigens S and s are defined by amino acids Met or Thr at position 29, respectively, on glycophorin B (GPB). Commercial anti-s reagents are expensive to produce because of the scarcity of human anti-s serum. Our aim was to develop hybridoma cell lines that secrete reagent-grade anti-s monoclonal antibodies (MoAbs) to supplement the supply of human anti-s reagents. STUDY DESIGN AND METHODS: Mice were immunized with the GPB(s) peptide sequence TKSTISSQTNGETGQLVHRF. Hybridomas were produced by fusing mouse splenocytes with mouse myeloma cells (X63.Ag8.653). Screening for antibody production was done on microtiter plates by hemagglutination. Characterization of the MoAbs was done by hemagglutination, immunoblotting, and epitope mapping. RESULTS: Eight immunoglobulin G MoAbs were identified. Five antibodies are specific by hemagglutination for s and two MoAbs, when diluted, are anti-S-like, but additional analyses shows a broad range of reactivity for GPB. Typing red blood cells (RBCs) for s from 35 donors was concordant with molecular analyses as were tests on RBCs with a positive direct antiglobulin test (DAT) from 15 patients. The anti-s MoAbs are most reactive with peptides containing the (31)QLVHRF(36) motif, with (29)Thr. By Pepscan analyses, the anti-S-like MoAbs reacted within the same regions as did anti-s, but independently of (29)Met. One antibody was defined serologically as anti-U; however, its epitope was identified as (21)ISSQT(25), a sequence common for both GPA and GPB. CONCLUSION: In addition to their value as typing reagents, these MoAbs can be used to phenotype RBCs with a positive DAT without pre-test chemical modification.
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| 20. |
- Hellberg, Åsa, et al.
(författare)
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A novel nonsense variant in RHAG underlies a Nordic Rhnull phenotype
- 2023
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Ingår i: Vox Sanguinis. - : John Wiley & Sons. - 0042-9007 .- 1423-0410. ; 118:8, s. 690-694
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Tidskriftsartikel (refereegranskat)abstract
- Background and ObjectivesThe extremely rare Rhnull phenotype is characterized by the absence of all Rh antigens on erythrocytes. It is divided into the regulator and amorph types based on the underlying genetic background. The more common regulator type depends on critical variants silencing RHAG, which encodes RhAG glycoprotein, necessary for RhD/RhCE expression. Rhnull cells have altered expression of glycophorin B and LW glycoprotein.Materials and MethodsFour unrelated Rhnull individuals were investigated. Serological testing was performed according to standard blood bank practice. RHD/RHCE and S/s allele-specific Polymerase chain reaction (PCR) genotyping was done on genomic DNA using in-house PCR assays. RHAG, and in some cases also RHD/RHCE, were sequenced. Initial s phenotyping results triggered additional serological investigation.ResultsAnti-Rh29 was identified in all four individuals. Extended typing with anti-S and anti-s showed that the three samples predicted to type as s+ failed to react with 2 of 5 anti-s. Sequence analysis of all 10 RHAG exons and the immediate intron/exon boundaries revealed a single nucleotide variant in the 3′-end of intron 6, c.946 −2a>g in all samples. RHD/RHCE showed no alterations.ConclusionA novel Nordic Rhnull allele was identified. In addition, it was shown that s+ Rhnull red blood cells are not only U− but also have qualitative changes in their s antigen expression.
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| 21. |
- Hellberg, Åsa, et al.
(författare)
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A novel RHCE*02 allele, containing the single-nucleotide change c.460A>G, encodes weakened expression of C and e antigens
- 2016
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Ingår i: Transfusion. - : Wiley. - 0041-1132 .- 1537-2995. ; 56:9, s. 2391-2392
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Tidskriftsartikel (refereegranskat)abstract
- We report a novel RHCE*02 allele in a Swedish blood donor that is characterized by the change c.460A>G (Arg154Gly). The blood donor's red blood cells showed variable reactivity with different monoclonal anti-C and anti-e and antigen strength was markedly weakened. We believe that these changes represent both a quantitative and qualitative alteration of the antigens encoded by this allele.
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| 22. |
- Hult, Annika K, et al.
(författare)
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A new missense variant in exon 7 of the ABO gene, c.662G>A, in a family with B w phenotype.
- 2022
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Ingår i: Transfusion. - : Wiley. - 1537-2995 .- 0041-1132. ; 62:10, s. 55-58
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Tidskriftsartikel (refereegranskat)abstract
- 1 BACKGROUNDWeak expression of ABO antigens is encountered in the clinical laboratory occasionally, and subgroups of A are more commonly observed in Europeans than subgroups of B. To date, weakly expressing B variant phenotypes have been associated with 38 different alleles according to ISBT (https://www.isbtweb.org/resource/001aboalleles.html). This number is an underrepresentation since there have been several reports of aberrant B expression due to variant alleles since the last update of the ISBT allele table. The current study was initiated by an unusual blood group typing result in a 55-year-old male patient of Czech origin and previously reported as an abstract.12 BRIEF METHODSBlood grouping was performed according to standard blood banking practice, initially using an automatic analyzer (Galileo, Immucor) followed by confirmation with manual gel (BioRad; DG-Gel) and tube agglutination techniques. Initial genotyping analysis was done using a PCR-SSP kit (Innotrain), microarray (BloodChip Reference, Progenika) and subsequently verified by expanded PCR-ASP and PCR-RFLP as described previously.2, 3 ABO exons 1–7 and splice sites were amplified and analyzed, together with the product(s) of PCR-ASP for exons 6–7, by Sanger sequencing.4 A single nucleotide variation (SNV) was detected, and the localization of the affected amino acid is visualized in a 3D-model of ABO glycosyltransferase by Cn3D (v.4.3.1, www.ncbi.nih.gov) and a detailed view obtained by AlphaFold.5, 6 Flow cytometry testing with monoclonal ABO reagents was performed as described previously.73 RESULTSThe proband's red blood cells (RBCs) initially typed as group O but the plasma typing gave negative or weak reactions with test RBCs of group B, depending on the method used, Table 1. An ABO*B.01/O.01.01 genotype was revealed, normally consistent with group B. Screening for selected A and B subgroup allele markers was negative.2 After informed consent, samples from family members were drawn and further investigation was performed.In samples from the proband, his sister and niece, sequence analysis revealed heterozygosity for a SNV in ABO exon 7, c.662G>A (no rs number available) in an otherwise normal ABO*B.01 allele. Significantly weakened B antigen expression was observed in all three individuals. An overview of serological testing and genetic results is shown in Table 1.SNV c.662G>A encodes an amino acid change, p.Gly221Asp. The glycine residue is completely evolutionarily conserved among the members of the GT6 family of glycosyltransferases8 and centrally located in the enzyme, seven amino acids away from the DVD motif (pp. 211–213) that coordinates the Mn2+ ion and the UDP part of the UDP-galactose donor substrate (Figure 1A). However, it is not directly interfering with the catalytic site. Instead, the change of the small neutral glycine to the bulkier and charged aspartic acid is predicted to abolish selected hydrogen bonds and is therefore hypothesized to destabilize the protein conformation (Figure 1B).5, 6
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| 23. |
- Jongruamklang, Philaiphon, et al.
(författare)
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Characterization of GYP*Mur and novel GYP*Bun-like hybrids in Thai blood donors reveals a qualitatively altered s antigen
- 2020
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Ingår i: Vox Sanguinis. - : Wiley. - 0042-9007 .- 1423-0410. ; 115:5, s. 472-477
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Tidskriftsartikel (refereegranskat)abstract
- Background and objectives: The Mi(a+) GP(B-A-B) hybrid phenotypes occur with a prevalence of 2%–23% across Southeast Asia. While the s antigen is alleged to be altered, no evidence for specific variants is known. Screening using a monoclonal IgM anti-s mistyped six S‒s+ RBC units as S‒s‒. Further, alloanti-s was identified in an S+s+ patient. Our objective was to investigate the s antigen further. Materials and methods: DNA from 63 Thai blood donor samples PCR-positive for a GYP(B-A-B) hybrid was sequenced with primers spanning GYPB exons 3–4. Flow cytometry was used for semiquantitative analysis of s expression and correlated with the glycophorin genotype. Results: DNA sequencing showed that GYP*Mur was carried by 56/63 samples (88·9%) of which 5/56 lacked normal GYPB: three of these were GYP*Mur homozygotes, one was a compound heterozygote carrying GYP*Mur and a GYP*Bun-like allele (designated GYP*Thai), and the fifth sample carried GYP*Mur and another GYP*Bun-like allele. Seven samples (7/63) were GYP*Thai heterozygotes. IgM monoclonal anti-s (P3BER) did not react with the s antigen carried by GP.Mur or GP.Bun, whereas two IgG anti-s showed enhanced reactivity. Conclusions: We confirmed that GYP*Mur is the most frequent variant in Thai blood donors and also identified GYP*Thai with a frequency of 1·1%. We showed that s antigen on Mi(a+) GP(B-A-B) hybrids is qualitatively altered and should be considered when selecting reagents for phenotyping where such hybrids are prevalent, endemically and in blood centres worldwide.
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| 24. |
- Jongruamklang, Philaiphon, et al.
(författare)
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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of 36 blood group alleles among 396 Thai samples reveals region-specific variants
- 2018
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Ingår i: Transfusion. - : Wiley. - 0041-1132 .- 1537-2995. ; 58:7, s. 1752-1762
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Blood group phenotype variation has been attributed to potential resistance to pathogen invasion. Variation was mapped in blood donors from Lampang (northern region) and Saraburi (central region), Thailand, where malaria is endemic. The previously unknown blood group allele profiles were characterized and the data were correlated with phenotypes. The high incidence of the Vel-negative phenotype previously reported in Thais was investigated. STUDY DESIGN AND METHODS: DNA from 396 blood donors was analyzed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. Outliers were investigated by serology and DNA sequencing. Allele discrimination assays for SMIM1 rs1175550A/G and ACKR1 rs118062001C/T were performed and correlated with antigen expression. RESULTS: All samples were phenotyped for Rh, MNS, and K. Genotyping/phenotyping for RhD, K, and S/s showed 100% concordance. Investigation of three RHCE outliers revealed an e-variant antigen encoded by RHCE*02.22. Screening for rs147357308 (RHCE c.667T) revealed a frequency of 3.3%. MN typing discrepancies in 41 samples revealed glycophorin variants, of which 40 of 41 were due to Mia. Nine samples (2.3%) were heterozygous for FY*01W.01 (c.265C>T), and six samples (1.5%) were heterozygous for JK*02N.01. All samples were wildtype SMIM1 homozygotes with 97% homozygosity for rs1175550A. CONCLUSIONS: Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry is an efficient method for rapid routine genotyping and investigation of outliers identified novel variation among our samples. The expected high prevalence of the Mi(a+) phenotype was observed from both regions. Of potential clinical relevance in a region where transfusion-dependent thalassemia is common, we identified two RHCE*02 alleles known to encode an e-variant antigen.
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| 25. |
- Jongruamklang, Philaiphon, et al.
(författare)
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Platelets inhibit erythrocyte invasion by Plasmodium falciparum at physiological platelet:erythrocyte ratios
- 2022
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Ingår i: Transfusion Medicine. - : Wiley. - 0958-7578 .- 1365-3148. ; 32:2, s. 168-174
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To evaluate the effect of platelet:erythrocyte (P:E) ratios on Plasmodium falciparum erythrocyte invasion.BACKGROUND: Recent reports have shown that platelets are directly involved in the immune response towards P. falciparum during erythrocyte invasion. However, the literature both supports and conflicts with a role for platelets in limiting invasion. Also, the effect of platelet numbers on invasion (parasitemia) has not been thoroughly investigated.METHODS/MATERIALS: The P. falciparum strains FCR3S1.2 and W2mef were cultured with group O erythrocytes. The cultures were synchronised and supplemented with pooled platelets at P:E ratios ranging from 1:100 to 1:2. Parasitemia was measured at 40 h by flow cytometry and by microscopy of blood smears.RESULTS: A linear relationship was observed between reduced invasion and increased platelet numbers at P:E ratios ranging from 1:100 to 1:20. However, this effect was reversed at lower ratios (1:10-1:2). Microscopic evaluation revealed aggregation and attachment of platelets to erythrocytes, but not specifically to parasitised erythrocytes.CONCLUSION: We have shown that under physiological P:E ratios (approx. 1:10-1:40), platelets inhibited P. falciparum invasion in a dose-dependent manner. At ratios of 1:10 and below, platelets did not further increase the inhibitory effect and, although the trend was reversed, inhibition was still maintained.
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| 26. |
- Kelley, Liam P., et al.
(författare)
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Dimerization of small integral membrane protein 1 promotes cell surface presentation of the Vel blood group epitope
- 2020
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Ingår i: FEBS Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 594:8, s. 1261-1270
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Tidskriftsartikel (refereegranskat)abstract
- The Vel blood group antigen is carried on the short extracellular segment of the 78-amino-acid-long, type II transmembrane protein SMIM1 of unknown function. Here, using biochemical analysis and flow cytometry of cells expressing wild-type and mutant alleles of SMIM1, we demonstrate that dimerization of SMIM1 promotes cell surface display of the Vel epitope. We show that SMIM1 dimerization is mediated both by an extracellular Cys77-dependent, homomeric disulfide linkage and via a GxxxG helix–helix interaction motif in the transmembrane domain. These results provide important context for the observed variability in reactivity patterns of clinically important anti-Vel identified in patient sera.
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| 27. |
- Lee, Yan Q., et al.
(författare)
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The Xg blood group system : no longer forgotten
- 2020
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Ingår i: Immunohematology. - 0894-203X. ; 36:1, s. 4-6
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This update of the Xg blood group system (Johnson NC. XG: The forgotten blood group system. Immunohematology 2011;27:68-71) notes the identification of a cis-regulatory element of both XG and CD99 expression, remarkably by two independent groups during 2018, and confirmed by another in 2019. A single nucleotide change at the XG locus (rs311103) abolishes GATA1 binding and suppresses both XG and CD99. The last blood group system to resist elucidation of its genetic basis was thereby resolved. Soon afterwards, it was discovered that the rare anti-Xga response, mainly seen in men, is produced by individuals primarily carrying a large deletion in the X chromosome that truncates XG and leads to the Xgnull phenotype.
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| 28. |
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| 29. |
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| 30. |
- Möller, Mattias, et al.
(författare)
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Disruption of a GATA1-binding motif upstream of XG/PBDX abolishes Xga expression and resolves the Xg blood group system
- 2018
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 132:3, s. 334-338
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Tidskriftsartikel (refereegranskat)abstract
- The Xga blood group is differentially expressed on erythrocytes from men and women. The underlying gene, PBDX, was identified in 1994, but the molecular background for Xga expression remains undefined. This gene, now designated XG, partly resides in pseudoautosomal region 1 and encodes a protein of unknown function from the X chromosome. By comparing calculated Xga allele frequencies in different populations with 2612 genetic variants in the XG region, rs311103 showed the strongest correlation to the expected distribution. The same single-nucleotide polymorphism (SNP) had the most significant impact on XG transcript levels in whole blood (P 5 2.0 3 10222). The minor allele, rs311103C, disrupts a GATA-binding motif 3.7 kb upstream of the transcription start point. This silences erythroid XG messenger RNA expression and causes the Xg(a2) phenotype, a finding corroborated by SNP genotyping in 158 blood donors. Binding of GATA1 to biotinylated oligonucleotide probes with rs311103G but not rs311103C was observed by electrophoretic mobility shift assay and proven by mass spectrometry. Finally, a luciferase reporter assay indicated this GATA motif to be active for rs311103G but not rs311103C in HEL cells. By using an integrated bioinformatic and molecular biological approach, we elucidated the underlying genetic basis for the last unresolved blood group system and made Xga genotyping possible.
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| 31. |
- Saleh, Bandar Hasan, et al.
(författare)
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Autoantibodies against red blood cell antigens are common in a Malaria endemic area
- 2023
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Ingår i: Microbes and Infection. - : Elsevier BV. - 1769-714X .- 1286-4579. ; 25:3
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Tidskriftsartikel (refereegranskat)abstract
- Plasmodium falciparum malaria can cause severe anemia. Even after treatment, hematocrit can decrease. The role of autoantibodies against erythrocytes is not clearly elucidated and how common they are, or what they are directed against, is still largely unknown. We have investigated antibodies against erythrocytes in healthy adult men living in a highly malaria endemic area in Uganda. We found antibodies in more than half of the individuals, which is significantly more than in a non-endemic area (Sweden). Some of the Ugandan samples had a broad reactivity where it was not possible to determine the exact target of the autoantibodies, but we also found specific antibodies directed against erythrocyte surface antigens known to be of importance for merozoite invasion such as glycophorin A (anti-En a, anti-M) and glycophorin B (anti-U, anti-S). In addition, several autoantibodies had partial specificities against glycophorin C and the blood group systems Rh, Diego (located on Band 3), Duffy (located on ACKR1), and Cromer (located on CD55), all of which have been described to be important for malaria and therefore of interest for understanding how autoantibodies could potentially stop parasites from entering the erythrocyte. In conclusion, specific autoantibodies against erythrocytes are common in a malaria endemic area.
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| 32. |
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| 33. |
- Sjöberg Wester, Elisabet, et al.
(författare)
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KEL*02 alleles with alterations in and around exon 8 in individuals with apparent KEL:1,-2 phenotypes.
- 2010
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Ingår i: Vox Sanguinis. - : Wiley. - 1423-0410 .- 0042-9007. ; May 4, s. 150-157
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objectives Antibodies to antigens in the Kell blood group system, especially anti-KEL1, are involved in both haemolytic disease of the newborn and foetus and haemolytic transfusion reactions. Correct typing results are important and discrepancies between serologic and genetic typing must be resolved. Here, we describe the investigation of three healthy individuals who were initially phenotyped as KEL:1,-2. Materials and Methods Antigen typing was performed by standard serological techniques and by flow cytometric analysis. The KEL*01/02 polymorphism was tested by an allele-discrimination TaqMan assay as well as by PCR with allele-specific primers and PCR-RFLP. DNA sequencing of the KEL coding region was also performed. Results Two KEL*02N alleles with mutated splice sites around exon 8 were identified: intron 7 -1g>c (novel) and intron 8 +1g>t (previously reported in one case of K(0)). In the third sample, a missense mutation in exon 8, 787G>A (novel) predicting Gly263Arg, was detected on a KEL*02 allele and associated with dramatically weakened KEL2 antigen expression. Conclusion Resolution of discrepant phenotype/genotype results identified silencing mutations in or around exon 8. A combination of molecular and serologic methods has the potential to improve the quality of test results and was required to ensure both the accurate KEL2 antigen status and KEL*01 zygosity of these individuals.
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| 34. |
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| 35. |
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| 36. |
- Storry, Jill R., et al.
(författare)
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International Society of Blood Transfusion Working Party on Red Cell Immunogenetics and Blood Group Terminology : Report of the Dubai, Copenhagen and Toronto meetings
- 2019
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Ingår i: Vox Sanguinis. - : Wiley. - 0042-9007. ; 114:1, s. 95-102
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Tidskriftsartikel (refereegranskat)abstract
- Background and objectives: The International Society of Blood Transfusion (ISBT) Working Party for Red Cell Immunogenetics and Blood Group Terminology meets in association with the ISBT congress and has met three times since the last report: at the international meetings held in Dubai, United Arab Emirates, September 2016 and Toronto, Canada, June 2018; and at a regional congress in Copenhagen, Denmark, June 2017 for an interim session. Methods: As in previous meetings, matters pertaining to blood group antigen nomenclature and classification were discussed. New blood group antigens were approved and named according to the serologic and molecular evidence presented. Results and conclusions: Fifteen new blood group antigens were added to eight blood group systems. One antigen was made obsolete based on additional data. Consequently, the current total of blood group antigens recognized by the ISBT is 360, of which 322 are clustered within 36 blood groups systems. The remaining 38 antigens are currently unassigned to a known system. Clinically significant blood group antigens continue to be discovered, through serology/sequencing and/or recombinant or genomic technologies.
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| 37. |
- Storry, Jill R, et al.
(författare)
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The Vel blood group system : a review
- 2017
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Ingår i: Immunohematology. - 0894-203X. ; 33:2, s. 56-59
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Forskningsöversikt (refereegranskat)abstract
- CONCLUSIONS: The blood group antigen Vel has been one of immunohematology's greatest enigmas: the variation in antigen strength from one individual to another, the property of anti-Vel to readily hemolyze Vel+ red blood cells (RBCs), and the difficulty to screen for sufficient numbers of Vel- blood donors had made Vel a tough nut to crack. In 2013, a small, previously unknown protein called small integral membrane protein 1 (SMIM1) was identified on the RBC by three independent research groups using different approaches, and all three groups demonstrated that Vel- RBCs lacked SMIM1. This discovery correlated with homozygosity for deletion c.64_60del in SMIM1 and meant that for the first time there was a universal method to screen for Vel- blood donors. This finding was not the whole answer, however, and an explanation behind the variability in antigen strength was later shown to be due to polymorphism in SMIM1 intron 2, a region that is responsible for gene transcription. Clinically, anti-Vel is important and has caused severe transfusion reactions, although hemolytic disease of the fetus and newborn caused by anti-Vel is uncommon. However, while screening for Vel- blood donors has become easier, the function of SMIM1 is still unknown, and despite its well-conserved sequence across the animal kingdom, the enigma continues.
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| 38. |
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| 39. |
- Thornton, Nicole, et al.
(författare)
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Disruption of the tumour-associated EMP3 enhances erythroid proliferation and causes the MAM-negative phenotype
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The clinically important MAM blood group antigen is present on haematopoietic cells of all humans except rare MAM-negative individuals. Its molecular basis is unknown. By whole-exome sequencing we identify EMP3, encoding epithelial membrane protein 3 (EMP3), as a candidate gene, then demonstrate inactivating mutations in ten known MAM-negative individuals. We show that EMP3, a purported tumour suppressor in various solid tumours, is expressed in erythroid cells. Disruption of EMP3 by CRISPR/Cas9 gene editing in an immortalised human erythroid cell line (BEL-A2) abolishes MAM expression. We find EMP3 to associate with, and stabilise, CD44 in the plasma membrane. Furthermore, cultured erythroid progenitor cells from MAM-negative individuals show markedly increased proliferation and higher reticulocyte yields, suggesting an important regulatory role for EMP3 in erythropoiesis and control of cell production. Our data establish MAM as a new blood group system and demonstrate an interaction of EMP3 with the cell surface signalling molecule CD44.
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| 40. |
- Tijani, Muyideen K, et al.
(författare)
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Babesia divergens Shows Equal Predilection for Human ABO Blood Types in an In Vitro Erythrocyte Preference Assay.
- 2023
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Ingår i: Pathogens. - 2076-0817. ; 12:6, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Babesia is spread to humans via ticks or blood transfusions. Severity of Plasmodium falciparum malaria is strongly correlated to the ABO blood group of the patient. Babesia divergens is an intraerythrocytic parasite with many similarities to malaria, but the impact of ABO on the susceptibility to and progression of the infection in humans is unknown. We have now cultured B. divergens in human group A, B and O erythrocytes in vitro and measured rates of multiplication. The predilection for the different erythrocyte types was also determined using an in vitro erythrocyte preference assay when the parasites were grown in group A, B or O erythrocytes over time and then offered to invade differently stained erythrocytes of all the blood types at the same time. The results showed no difference in multiplication rates for the different blood types, and the parasite exhibited no obvious morphological differences in the different blood types. When cultured first in one blood type and then offered to grow in the others, the preference assay showed that there was no difference between the A, B or O blood groups. In conclusion, this indicates that individuals of the different ABO blood types are likely to be equally susceptible to B. divergens infections.
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| 41. |
- Wester, Elisabet Sjöberg, et al.
(författare)
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A simple screening assay for the most common JK*0 alleles revealed compound heterozygosity in Jk(a-b-) probands from Guam
- 2009
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Ingår i: Immunohematology. - 0894-203X. ; 25:4, s. 165-169
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Tidskriftsartikel (refereegranskat)abstract
- The Jk(a-b-) phenotype results from alterations in the JK gene and is characterized by absence of the RBC urea transporter in the cell membrane. The frequency of Jk(a-b-) varies among populations, but this phenotype is most commonly found in people of Polynesian and Finnish descent. Although rare, Jk(a-b-) individuals present a clinical challenge because anti-Jk3 is produced readily in response to transfusion and pregnancy, and Jk(a-b-) blood is not routinely available. Identification of Jk(a-b-) patients and donors is most often performed serologically. However, ten JK*o alleles have been identified, and this information can be used in DNA-based typing. We selected five JK*o alleles that had been encountered by our reference laboratory in two or more samples from unrelated individuals and designed an allele-specific primer PCR assay for use as an initial screening tool. After in-house validation, we tested genomic DNA from a family: a mother and her two sons referred to us for genetic investigation of their Jk(a-b-) phenotypes. Two different nucleotide substitutions, -1g>a in intron 5 (IVS5) and 956C>T in exon 10, originally associated with Polynesian and Indian/African populations respectively, were identified in the family. The mother and one son were compound heterozygotes, and the second son was homozygous for IVS5-1g>a. We conclude that the effort to design and validate such a screening assay was cost-efficient when compared with DNA sequencing costs. Furthermore, selection of the more common JK*o mutations was a practical approach that resulted in rapid identification of the genetic bases behind the Jk(a-b-) phenotypes in this unusual family. Although an obvious target for eventual inclusion into high-throughput genotyping platforms for clinical diagnostic services, current systems are very limited. Our approach provides a simple and inexpensive method for the identification of these rare alleles.
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| 42. |
- Wester, Elisabet S, et al.
(författare)
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Erythroid urea transporter deficiency due to novel JK(null) alleles
- 2008
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Ingår i: Transfusion. - : Wiley. - 1537-2995 .- 0041-1132. ; 48:2, s. 365-372
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Kidd blood group antigens Jk(a) and Jk(b) are encoded by the red blood cell (RBC) urea transporter gene. Homozygosity for silent JK alleles results in the rare Jk(a-b-) phenotype. To date, seven JK(null) alleles have been identified, and of these, two are more frequent in the Polynesians and Finns. This study reports the identification of other JK(null) alleles in Jk(a-b-) individuals of different ethnic or geographic origins. STUDY DESIGN AND METHODS: Nine Jk(a-b-) samples and a sample from a Jk(a-b+) mother of a Jk(a+b-) baby were investigated. Polymerase chain reaction amplification and sequence analysis of the JK gene was performed. Western blotting and urea lysis were used to confirm Jk(a-b-) RBCs. RESULTS: Four novel alleles were identified: two different nonsense mutations, 202C > T (Gln68Stop) and 723delA (Ile262Stop) were identified on otherwise consensus JK*1 and JK*2 alleles, respectively. A missense mutation, 956C > T (Thr319Met), was identified in a JK*1 allele from an African-American and a JK*2 allele in two people of subcontinental Indian descent. Immunoblotting and urea lysis confirmed absence of JK glycoprotein in RBC membranes from a sample carrying the 956C > T mutation. Other previously described JK(null) mutations were found in samples of origins other than in which they were first identified. CONCLUSION: The molecular bases of the Jk(a-b-) phenotype are diverse and this is the first report of JK(null) alleles in individuals of African and subcontinental Indian descent. Although rare, these alleles should be taken into consideration when planning genotyping strategies for blood donors and patients.
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| 43. |
- Westhoff, Connie M., et al.
(författare)
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Human Blood Group Antigens and Antibodies
- 2018. - 7
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Ingår i: Hematology : Basic Principles and Practice - Basic Principles and Practice. - 9780323357623 - 9781455740413 ; , s. 1687-1701
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Bokkapitel (refereegranskat)
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| 44. |
- Wu, Ping Chun, et al.
(författare)
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Elucidation of the low-expressing erythroid CR1 phenotype by bioinformatic mining of the GATA1-driven blood-group regulome
- 2023
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Ingår i: Nature Communications. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Genetic determinants underlying most human blood groups are now clarified but variation in expression levels remains largely unexplored. By developing a bioinformatics pipeline analyzing GATA1/Chromatin immunoprecipitation followed by sequencing (ChIP-seq) datasets, we identify 193 potential regulatory sites in 33 blood-group genes. As proof-of-concept, we aimed to delineate the low-expressing complement receptor 1 (CR1) Helgeson phenotype on erythrocytes, which is correlated with several diseases and protects against severe malaria. We demonstrate that two candidate CR1 enhancer motifs in intron 4 bind GATA1 and drive transcription. Both are functionally abolished by naturally-occurring SNVs. Erythrocyte CR1-mRNA and CR1 levels correlate dose-dependently with genotype of one SNV (rs11117991) in two healthy donor cohorts. Haplotype analysis of rs11117991 with previously proposed markers for Helgeson shows high linkage disequilibrium in Europeans but explains the poor prediction reported for Africans. These data resolve the longstanding debate on the genetic basis of inherited low CR1 and form a systematic starting point to investigate the blood group regulome.
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