The LW blood group system: not just "tagging along" with D.

This update of the Landsteiner-Wiener (LW) blood group system (Grandstaff Moulds MK. The LW blood group system: a review. Immunohematology 2011;27:136-42. Storry JR. Review: the LW blood group system. Immunohematology 1992;8:87-93) reports new information on the distribution of genetic variants in ICAM4 and reviews the complex serologic identification of the high-prevalence LWEM antigen. The role of ICAM4 in sickle cell disease and malaria susceptibility is discussed.

Yes, MAM: how the cancer-related EMP3 protein became a regulator of erythropoiesis and the key protein underlying a new blood group system.

The MAM blood group system (International Society of Blood Transfusion [ISBT] 041) consists of one high-prevalence antigen to date, first detected in a 31-year-old woman during her third pregnancy. Epithelial membrane protein 3 (EMP3) was recently identified as the gene coding the MAM antigen. Six unique genetic variants have been described in EMP3 in 11 MAM- individuals. EMP3 is an 18-kDa glycoprotein with a large extracellular domain containing at least one N-glycosylation site. The normal function of EMP3 is still unclear, but ex vivo culture of erythropoietic progenitor cells from MAM- individuals shows an increased yield of reticulocytes, suggesting that EMP3 acts as a brake during normal erythropoiesis. EMP3 is abundant on different cell types, including many epithelial tissues and blood cells. Interestingly, EMP3 expression has been suggested as a prognostic marker for a number of cancer types, both for good and poor prognoses. EMP3 may act as a tumor suppressor or an oncogene in different cancer contexts. The protein appears to interact with other cell surface receptors and affects the downstream signaling and function of these proteins. MAM- red blood cells express low levels of CD44 and, consequently, the antigens of the Indian blood group system are only weakly expressed. Clinically, the MAM blood group antigen is important with regard to blood transfusion and pregnancy. Anti-MAM can cause severe hemolytic disease of the fetus and newborn in some pregnancies but have little to no effect in other pregnancies. Cases are typically not detected until problems occur during pregnancy, making the availability of compatible blood a challenge.

The Ok blood group system: an update.

This update of the Ok (OK) blood group system (Smart EA, Storry JR. The OK blood group system: a review. Immunohematology 2010;26:124-6) focuses on new information on the role of basigin (BSG), the carrier molecule of the Ok blood group antigens. No further antigens have been identified since the original review. However, the role of BSG in malaria continues to be explored. Immunohematology 2021;37:18-19.This update of the Ok (OK) blood group system (Smart EA, Storry JR. The OK blood group system: a review. Immunohematology 2010;26:124­6) focuses on new information on the role of basigin (BSG), the carrier molecule of the Ok blood group antigens. No further antigens have been identified since the original review. However, the role of BSG in malaria continues to be explored. Immunohematology 2021;37:18­19.

The Cromer blood group system: an update.

This update of the Cromer (CROM) blood group system (Storry JR, Reid ME, Yazer MH. The Cromer blood group system: a review. Immunohematology 2010;26:109-17) includes additional variants to the Cromer system (ISBT021), both new antigens and new molecular bases underlying the null phenotype. The molecule on which the Cromer blood group antigens are carried, CD55 (DAF), is an important receptor for the malaria parasite, Plasmodium falciparum, and the role of CD55 in health and disease continues to expand.This update of the Cromer (CROM) blood group system (Storry JR, Reid ME, Yazer MH. The Cromer blood group system: a review. Immunohematology 2010;26:109­17) includes additional variants to the Cromer system (ISBT021), both new antigens and new molecular bases underlying the null phenotype. The molecule on which the Cromer blood group antigens are carried, CD55 (DAF), is an important receptor for the malaria parasite, Plasmodium falciparum, and the role of CD55 in health and disease continues to expand.

A and B antigen levels acquired by group O donor-derived erythrocytes following ABO-non-identical transfusion or minor ABO-incompatible haematopoietic stem cell transplantation.

BACKGROUND AND OBJECTIVES: ABO-incompatible haematopoietic stem cell transplantation (HSCT) presents a challenge to blood component transfusion. The aim of this study was to investigate the weak blood group A or B antigen expression by donor-derived group O red blood cells (RBC) observed following transfusion or minor ABO-incompatible HSCT. In addition, in vitro experiments were performed to elucidate possible mechanisms underlying this phenomenon. MATERIALS AND METHODS: A sensitive flow cytometry assay for the semi-quantification of RBC A/B antigen levels was used to assess patient samples and evaluate in vitro experiments. RESULTS: Analysis of blood samples from patients, originally typed as A, B and AB but recently transplanted or transfused with cells from group O donors, revealed the A antigen expression on donor-derived RBC, ranging from very low levels in non-secretor individuals to almost subgroup Ax -like profiles in group A secretors. The B antigen expression was less readily detectable. In vitro experiments, in which group O donor RBC were incubated with (i) group A/B secretor/non-secretor donor plasma or (ii) group A/B donor RBC in the absence of plasma, supported the proposed adsorption of A/B antigen-bearing glycolipids from secretor plasma but also indicated a secretor-independent mechanism for A/B antigen acquisition as well as direct cell-to-cell transfer of ABO antigens. CONCLUSION: The in vivo conversion of donor-derived blood group O RBC to ABO subgroup-like RBC after transfusion or minor ABO-incompatible HSCT raises the question of appropriate component selection. Based on these data, AB plasma should be transfused following ABO-incompatible HSCT.

International Society of Blood Transfusion Working Party on red cell immunogenetics and blood group terminology: Cancun report (2012).

The International Society of Blood Transfusion Working Party on red cell immunogenetics and blood group terminology convened during the International congress in Cancun, July 2012. This report details the newly identified antigens in existing blood group systems and presents three new blood group systems.

KEL*02 alleles with alterations in and around exon 8 in individuals with apparent KEL:1,-2 phenotypes.

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.

Alloanti-c in a c-positive, JAL-positive patient.

BACKGROUND AND OBJECTIVES: In the Rh blood group system, partial D, C, and e antigens are well-known, but a partial c antigen resulting in the production of alloanti-c in a c+ individual is rare. One example of an alloanti-c in a c+ person was an anti-Rh26, which can appear as anti-c, and another was an alloanti-c in a c+ person with a presumed R(1)r phenotype. The finding of an apparent alloanti-c in a transfused c+ patient initiated this investigation. MATERIALS AND METHODS: Haemagglutination tests, DNA extraction, polymerase chain reaction (PCR)-based assays (PCR-restriction fragment length polymorphism, allele-specific PCR), reticulocyte mRNA extraction, reverse transcriptase (RT)-PCR and sequencing were performed by standard procedures. RESULTS: Plasma from a 64-year-old African American woman with a wound infection following a mastectomy contained anti-E, anti-S, anti-K, anti-Fy(a) and anti-Jk(b), reacting by the indirect antiglobulin test. In addition, the patient's plasma gave reactions that were consistent with an anti-c, while her pre-transfusion red blood cells typed c+ with some anti-c reagents. These results are consistent with a partial c antigen. The patient's red blood cells also typed V+(W)VS- and JAL+. Analyses of DNA and Rh-transcripts from this patient showed the presence of the following genes: RHD*D, RHD*DAU0, RHCE*Ce and RHCE*ce(S)(340). CONCLUSION: The nucleotide 340C>T change in RHCE exon 3 (predicted to encode 114Trp) of the RHCE*ce(S)(340) allele is associated with a JAL+ phenotype and the altered expression of the c, V and VS antigens. This alteration in the c antigen allowed the patient to make an alloanti-c. This case reveals that the RHCE*ce(S)(340) allele encodes a partial c antigen.

The ABO blood group system revisited: a review and update.

The antigens of the ABO system were the first to be recognized as blood groups and actually the first human genetic markers known. Their presence and the realization of naturally occurring antibodies to those antigens lacking from the cells made sense of the erratic failure of blood transfusion hitherto and opened up the possibility of a safe treatment practice in life-threatening blood loss. Although initially apparently simple, the ABO system has come to grow in complexity over the years. The mass of knowledge relating to carbohydrate chemistry, enzymology, molecular genetics, and structural and evolutionary biology is now enormous thanks to more than a century of research using ABO as a principal model. This has provided us with data to form a solid platform of evidence-based transfusion and transplantation medicine used every day in laboratories and clinics around the globe. This review aims to summarize key findings and recent progress made toward further understanding of this surprisingly polymorphic system.

A simple screening assay for the most common JK*0 alleles revealed compound heterozygosity in Jk(a-b-) probands from Guam.

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*0 alleles have been identified, and this information can be used in DNA-based typing. We selected five JK*0 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*0 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.

International society of blood transfusion working party on red cell immunogenetics and terminology: report of the Seoul and London meetings.

The Working Party has met twice since the last report: in Seoul, South Korea 2014, and in London, UK 2015, both in association with the International Society of Blood Transfusion (ISBT) Congress. As in previous meetings, matters pertaining to blood group antigen nomenclature were discussed. Eleven new blood group antigens were added to seven blood group systems. This brings the current total of blood group antigens recognized by the ISBT to 346, of which 308 are clustered within 36 blood groups systems. The remaining 38 antigens are currently unassigned to a known blood group system.

Cell typing the sensitized transfusion-dependent patient.

Extended red cell typing is required for the management of transfusion-dependent patients to confirm the identity of suspected alloantibodies or determine the specificity of potential additional antibodies that may be formed in the future. Typing may be complicated by the presence of circulating allogeneic cells or a positive direct antiglobulin test. Phenotyping such individuals by hemagglutination is dependent on the separation of a reticulocyte-enriched fraction by differential centrifugation. Flow cytometric typing of reticulocytes is also possible. The effectiveness of these techniques is limited in those who are heavily transfused or have low reticulocyte counts. Heavily transfused patients with sickle cell anemia may be typed, however, following hypotonic lysis of allogeneic cells. In patients with a positive direct antiglobulin test, sensitized cells are usually typed with either direct agglutinating antisera and/or IgG antisera following elution of the autoantibody. Inactivation of some antigens during the elution process or the lack of some antisera specificities limit such typing. By designing appropriate oligonucleotide primers, polymerase chain reaction (PCR) amplification of target gene sequences for most blood group systems and the identification of a large number of their allelic specificities is now possible. Peripheral blood leukocytes can be used as the DNA source. Restriction fragment length polymorphism determination is widely adopted for the identification of allelic specificity of the amplified target sequence. Alternate strategies, including allele-specific PCR, are often employed if the genetic basis of the polymorphism is more complex than a single nucleotide substitution, or if it does not create or ablate a restriction endonuclease cleavage site. These techniques may permit genotyping of sensitized transfusion-dependent patients, and can improve transfusion safety and efficacy.

Review: the LW blood group system.

The LW blood group system had its origin in the early Rh experiments of the 1940s and played an important role in our understanding of hemolytic disease of the newborn. Considered for a number of years to be the animal equivalent of the human Rh(D) antigen, LW(a) has been shown to be unique. Biochemical studies have located the antigen on a different protein from proteins of the Rh antigens; however, the interdependence of LW and D still exists. The disappearance of LW antigens in various disease states and in pregnancy, associated with production of apparent alloantibody, remains puzzling, but this phenomenon may eventually help our understanding of the immunology of disease.

Misidentification of anti-Vel due to inappropriate use of prewarming and adsorption techniques.

Two units of red blood cells (RBCs) were ordered for a 44-year-old Caucasian woman with renal failure and cancer. Pretransfnsion testing performed at the regional reference laboratory had revealed the presence of an antibody reactive with all cells at the indirect antiglobulin test but apparently nonreactive by a prewarmed IAT. The patient's RBCs were direct antiglobulin test negative. Adsorption of the serum with rabbit erythrocyte stroma or with allogeneic RBCs at 4 degrees C reduced the reactivity at the IAT. The patient was transfused with two units of washed RBCs and died 6 to 8 hours later. Retrospective testing in our laboratory detected anti-Vel in both pretransfusion and posttransfusion samples. The pretransfnsion serum was hemolytic when tested io LISS or with papain-treated RBCs. Weak reactivity (I+) was observed at the IAT. EDTA-treated serum (to prevent C'-mediated hemolysis) was strongly reactive (3+s) with Vel+ RBCs but compatible with 10 examples of Vel- RBCs. Adsorptions with rabbit RBCs did not affect reactivity. Pretransfnsion RBCs were nonreactive with three examples of anti- Vel at the IAT. The posttranshision serum was grossly hemolyzed and anti-Vel was demonstrable, although weaker than in the pre- transfusion sample. The antibody was subclassed as IgG1 and IgG3. In this case, the use of a prewarming technique precluded detection of hemolysis caused by the antibody prior to the IAT. This case stresses the importance of antibody identification and the correct use of such techniques as prewarming and adsorptions.

Low-incidence MNS antigens associated with single amino acid changes and their susceptibility to enzyme treatment.

MNS antigens are carried on glycophorin A (GPA), glycophorin B (GPB), or their variants. Antigens at the N-terminus of GPA are sensitive to cleavage by ficin, papain, and trypsin but are resistant to alpha-chymotrypsin. Antigens at the N-terminus of GPB are sensitive to cleavage by ficin, papain, and alpha-chymotrypsin but are resistant to trypsin treatment. These characteristics have been used to aid in the identification of blood group alloantibodies. Recent molecular analyses have identified changes in amino acids that are associated with several low-incidence antigens in the MNS blood group system. This review relates the molecular studies with the susceptibility or resistance of these antigens to treatment of intact red blood cells by proteolytic enzymes.

The Cromer blood group system: a review.

The antigens of the Cromer blood group system reside on decay accelerating factor (DAF), a protein belonging to the regulators of complement activation family. The blood group system consists of eight high-incidence antigens and three low-incidence antigens. The molecular basis for the antigens is known and, with the exception of IFC, each antigen is the product of a single nucleotide polymorphism in the DAF gene and has been localized to one of the four short consensus repeat regions on the DAF protein. The red blood cells (RBCs) of people with the Cromer null phenotype, Inab, lack DAF. Antibodies to Cromer antigens are rarely encountered although there is evidence that the antibodies may cause accelerated destruction of transfused RBCs. There is no risk of hemolytic disease of the newborn associated with Cromer system antibodies because the placenta is a rich source of fetally derived DAF, which is thought to adsorb the antibodies.