Loss of red cell A, B, and H antigens is frequent in myeloid malignancies

Body-wide chimerism and mosaicism are predominant causes of naturally occurring ABO discrepancies

Routine ABO blood group typing of apparently healthy individuals sporadically uncovers unexplained mixed-field reactions. Such blood group discrepancies can either result from a haematopoiesis-confined or body-wide dispersed chimerism or mosaicism. Taking the distinct clinical consequences of these four different possibilities into account, we explored the responsible cause in nine affected individuals. Genotype analyses revealed that more than three-quarters were chimaeras (two same-sex females, four same-sex males, one sex-mismatched male), while two were mosaics. Short tandem repeat analyses of buccal swab, hair root and nail DNA suggested a body-wide involvement in all instances. Moreover, genome-wide array analyses unveiled that in both mosaic cases the causative genetic defect was a unique copy-neutral loss of heterozygosity encompassing the entire long arm of chromosome 9. The practical transfusion- or transplantation-associated consequences of such incidental discoveries are well known and therefore easily manageable. Far less appreciated is the fact that such findings also call attention to potential problems that directly ensue from their specific genetic make-up. In case of chimerism, these are the appearance of seemingly implausible family relationships and pitfalls in forensic testing. In case of mosaicism, they concern with the necessity to delineate innocuous pre-existent or age-related from disease-predisposing and disease-indicating cell clones.

Clinical significance of decreased or loss of ABO blood group expression in acute myeloid leukaemia: A single-centre retrospective study

BACKGROUND AND OBJECTIVES

Decreased or loss of ABO blood group antigen expression has been observed in acute myeloid leukaemia (AML) patients. We studied the clinical significance of this group in AML patients.

MATERIALS AND METHODS

This was a retrospective, single-centre cohort study in which the data were retrieved from April 2009 to December 2019. A total of 1592 AML patients with normal ABO blood group antigen (Group I) and 65 patients of decreased or loss of ABO blood group antigen (Group II) group were enrolled. Data were collected at the time of initial admission for pathological diagnosis. To interrogate the underlying mechanism, publicly available The Cancer Genome Atlas AML data were downloaded.

RESULTS

Group II consisted of 3.9% (65/1657) of AML patients. The 90-day survival (D90) probability was higher for Group II with a mean survival of 86.4 days compared to 80.6 days for Group I (p = 0.047). Group II had higher haematocrit (28.6 vs. 27.4%) and lower d-dimer, fibrinogen degradation production and C-reactive protein. Publicly available data revealed that among 11 CpG methylation sites within the ABO gene, 4 sites with elevated methylation level were associated with improved D90 survival probability and demonstrated an inverse correlation with ABO gene expression. Lower expression of the ABO gene showed improved survival trends for D90 (p = 0.058) and 180-day survival (p = 0.072).

CONCLUSION

AML with decreased expression or loss of ABO blood group showed better early survival during D90. Transfusion support for this subgroup of AML patients should be meticulously performed considering serum typing.

CEBPA double mutations associated with ABO antigen weakness in hematologic diseases

ABSTRACT

ABO antigen weakness is rarely observed in ABO typing for transfusion. Hematologic diseases and associated gene mutations have been suggested as potential causes of this phenomenon, yet the precise etiology has not been elucidated. Through ABO typing and genetic analysis data conducted over 7 years, we have reconfirmed the association between ABO antigen weakness and hematologic diseases, especially acute myeloid leukemia (odds ratio [OR], 2.55; 95% confidence interval [CI], 1.12-5.83) and myelodysplastic syndrome (OR, 6.94; 95% CI, 2.86-16.83), and discovered previously unidentified candidate genes, CEBPA (OR, 43.70; 95% CI, 18.12-105.40), NRAS (OR, 3.37; 95% CI, 1.46-7.79), U2AF1 (OR, 8.12; 95% CI, 2.86-23.03), and PTPN11 (OR, 4.52; 95% CI, 1.51-13.50), seemingly associated with this phenomenon. Among these, CEBPA double mutations displayed a significant association, with ABO antigen weakness being observed in 20 of the 25 individuals (80.0%) possessing these mutations. From this study, new factors associated with ABO antigen weakness have been identified.

Association of Leukemia With ABO Blood Group Distribution and Discrepancy: A Review Article

The ABO system is an essential blood group in clinical transfusion medicine implicated in several human diseases. The ABO system has been investigated for over a century, with various studies exploring potential links to disease susceptibility. The study examines the possible relationship between leukemia and the distribution and the ABO blood group system discrepancy. A comprehensive review was conducted on the recommended databases to review the ABO blood groups, their association with leukemia, and the expected changes in blood groups among leukemia patients. The study highlights different kinds of leukemia, such as acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and chronic lymphocytic leukemia (CLL), their characteristics, and their relationship with ABO blood groups. The document concludes that studying ABO blood group distributions among leukemia patients showed that the most common blood group in acute leukemia is the A group, while in chronic leukemia, the O group is predominant; more studies are required. This study also confirmed an association between leukemia and ABO blood group discrepancy.

Cancer snap-shots: Biochemistry and glycopathology of O-glycans: A review

Cancer pathogenesis is strongly linked to the qualitative and quantitative alteration of the cell surface glycans, that are glycosidically linked to proteins and lipids. Glycans that are covalently linked to the polypeptide backbone of a protein through nitrogen or oxygen, are known as N-glycans or O-glycans, respectively. Although the role of glycans in the expression, physiology, and communication of cells is well documented, the function of these glycans in tumor biology is not fully elucidated. In this context, current review summarizes biosynthesis, modifications and pathological implications of O-glycans The review also highlights illustrative examples of cancer types modulated by aberrant O-glycosylation. Related O-glycans like Thomsen-nouveau (Tn), Thomsen-Friedenreich (TF), Lewisa/x, Lewisb/y, sialyl Lewisa/x and some other O-glycans are discussed in detail. Since, the overexpression of O-glycans are attributed to the aggressiveness and metastatic behavior of cancer cells, the current review attempts to understand the relation between metastasis and O-glycans.

Clonal hematopoiesis and acquired genetic abnormalities of the red cell: An historical review

Several syndromes affecting the red cell that mimic those induced by germline mutations may result from a somatic mutation that accompanies a myeloid malignancy. These syndromes are most notable in cases of myelodysplastic syndrome, but they are not limited to any one category of myeloid neoplasm. Their occurrence in males exceed the male predominance that is evident in myeloid neoplasms. The syndromes include disorders of globin chain synthesis (α- and β-thalassemia), heme synthesis (erythropoietic porphyria and erythropoietic uroporphyria), red cell membrane structure (elliptocytosis and spherocytosis), red cell enzyme activity (pyruvate kinase deficiency, glucose-6-phosphate dehydrogenase deficiency) and lowered expression of red cell ABO blood group antigens. This historical review describes the path to uncovering these acquired syndromes and their causal somatic mutations, where known. These syndromes often go unrecognized because of the dominant concern of the primary neoplasm. They may add to the healthcare needs of the patient.

Blood typing and transfusion therapy in a patient with A2 subtype acute myeloid leukemia M2: A case report

BACKGROUND

Acute myeloid leukemia (AML) is one of the most common types of leukemia in adults. However, AML is relatively rare in the population overall, accounting for only about 1 percent of all cancers. Treatment for AML can be very effective for some patients, yet it leaves others with serious and even life-threatening side effects. Chemotherapy is still the primary treatment for most AML, but over time, leukemia cells become resistant to chemotherapy drugs. In addition, stem cell transplantation, targeted therapy, and immunotherapy are currently available. At the same time, with the progression of the disease, the patient may have corresponding complications, such as coagulation dysfunction, anemia, granulocytopenia, and repeated infection, so transfusion supportive therapy will be involved in the overall treatment regime. To date, few articles have reported on blood transfusion treatment options for patients with ABO subtypes AML-M2. Blood transfusion therapy is an important supportive treatment for AML-M2, and accurate determination of patients' blood type is one of the most important steps in the treatment process. In this study, we explored blood typing and supportive treatment strategies for a patient with A2 subtype AML-M2 to provide the basis for treatment for all patients.

CASE SUMMARY

In order to determine the blood type of the patient, serological and molecular biological methods were used for reference tests, and the genetic background was studied to determine the patient's final blood type and select the appropriate blood products for infusion treatment. According to the results obtained by serological and molecular biological methods, the blood type of the patient was A2 subtype; the genotype was A02/001; the irregular antibody screening was negative, and anti-A1 was found in the plasma. According to the overall treatment plan, active anti-infection, elevated cells, component blood transfusion support, and other rescue and supportive treatments were given, and the patient successfully passed the stage of myelosuppression after chemotherapy. Re-examination of bone marrow smears showed that AL was in complete remission of bone marrow signs, and minimal residual leukemia lesions suggested no cells with obvious abnormal immunophenotype (residual leukemia cells < 10^-4).

CONCLUSION

The infusion of patients with A2 subtype AML-M2 with A irradiated platelets and O washing red blood cells can meet the needs of clinical treatment.

Novel evidence that the ABO blood group shapes erythropoiesis and results in higher hematocrit for blood group B carriers

The ABO blood group (BG) system is of great importance for blood transfusion and organ transplantation. Since the same transcription factors (TFs) and microRNAs (miRNAs) govern the expression of ABO BG antigens and regulate erythropoiesis, we hypothesized functional connections between both processes. We found significantly higher hemoglobin and hematocrit values in BG B blood donors compared to BG A. Furthermore, we observed that erythropoiesis in BG B hematopoietic stem/progenitor cells (HSPCs) was accelerated compared to BG A HSPCs. Specifically, BG B HSPCs yielded more lineage-specific progenitors in a shorter time (B: 31.3 ± 2.2% vs. A: 22.5 ± 3.0%). Moreover, non-BG A individuals exhibited more terminally differentiated RBCs with higher enucleation rates containing more hemoglobin compared to BG A. Additionally, we detected increased levels of miRNA-215-5p and -182-5p and decreased expression of their target TFs RUNX1 and HES-1 mRNAs in erythroid BG B precursor cells compared to BG A. This highlights the important roles of these factors for the disappearance of differentiation-specific glycan antigens and the appearance of cancer-specific glycan antigens. Our work contributes to a deeper understanding of erythropoiesis gene regulatory networks and identifies its interference with BG-specific gene expression regulations particularly in diseases, where ABO BGs determine treatment susceptibility and disease progression.

Turning universal O into rare Bombay type blood

Red blood cell antigens play critical roles in blood transfusion since donor incompatibilities can be lethal. Recipients with the rare total deficiency in H antigen, the Oh Bombay phenotype, can only be transfused with group Oh blood to avoid serious transfusion reactions. We discover FucOB from the mucin-degrading bacteria Akkermansia muciniphila as an α-1,2-fucosidase able to hydrolyze Type I, Type II, Type III and Type V H antigens to obtain the afucosylated Bombay phenotype in vitro. X-ray crystal structures of FucOB show a three-domain architecture, including a GH95 glycoside hydrolase. The structural data together with site-directed mutagenesis, enzymatic activity and computational methods provide molecular insights into substrate specificity and catalysis. Furthermore, using agglutination tests and flow cytometry-based techniques, we demonstrate the ability of FucOB to convert universal O type into rare Bombay type blood, providing exciting possibilities to facilitate transfusion in recipients/patients with Bombay phenotype.

ABO Blood Group and the Risk and Prognosis of Lymphoma

ABO blood group antigens exhibit alternative phenotypes and genetically derived structures that are located on the red cell surface. The role of ABO blood group in cancer biology has been intensely reported by several studies, and it is now widely recognized that ABO antigens are associated with the risk and prognosis of several types of tumors, namely gastric cancer and pancreatic cancer. However, there have been contentious limited issues with the association between the ABO blood group and lymphoma. In this narrative review, based on literature data, we discuss the role of ABO blood group in the risk and prognosis of lymphoma and summarize the current knowledge of the underlying pathogenic mechanisms of the association. The possible association of ABO blood group with racial disparities and pathological classification in lymphoma patients is also discussed.

Changes in the incidence of transfusion reactions in hematological patients over the past 30 years

BACKGROUND

Patients with hematological diseases are polytransfused and often immunocompromised, therefore susceptible to transfusion reactions (TR). This study aims to document the incidence of TRs in adult hematological patients and assess the effect of changes in the production of blood components and transfusion practice on their occurrence.

STUDY DESIGN AND METHODS

Retrospective observational analysis of TRs reported from 1993 to 2019 was performed. For the analysis of the effect of changes on the incidence of TRs, the evaluated time was divided into two periods: the 1st period before the introduction of changes in production, when leukoreduced blood components were used only selectively, and the 2nd period, when semi-automated method of production and universal leukoreduction was introduced.

RESULTS

The decrease in the incidence of TRs was observed for both red blood cell (RBC) and platelet concentrate (PC) transfusions in the 2nd period. Since platelet additive solution has been used, a further decrease in the incidence was reported. The decrease in incidence was also observed for delayed hemolytic/serological transfusion reactions and for transfusion-transmitted bacterial infections. Four cases of incorrect blood transfusions were uniquely related to the hematological patients, caused by antigen loss and transfusion ordering after ABO-incompatible hematopoietic stem cell transplantation.

DISCUSSION

Our results provided evidence that the introduction of tools offered by modern transfusion medicine: universal leukodepletion, plasma replacement with additive solutions, sensitive laboratory techniques, prophylactic antigen matching policy, informatization, and automatization, decreased the incidence of TRs and improved transfusion safety.

Reduction of blood group A antigen on erythrocytes in a patient with myelodysplastic syndrome harboring somatic mutations in RUNX1 and GATA2

BACKGROUND

Reduction of blood group ABO antigens on red blood cells (RBCs) is well known in patients with leukemias, and this reduction of ABO expression is strongly associated with DNA methylation of the ABO promoter. Previously, we reported a two-nucleotide deletion in RUNX1 encoding an abnormally elongated protein lacking the trans-activation domain in a patient with myelodysplastic syndrome (MDS) showing A-antigen loss on RBCs. This prompted us to investigate the underlying mechanism responsible for A-antigen reduction on RBCs in another patient with MDS.

STUDY DESIGN AND METHODS

Screening of somatic mutations was carried out using a targeted sequencing panel with genomic DNA from peripheral blood mononuclear cells from the patient and eleven MDS controls without A- or B-antigen loss. DNA methylation of the ABO promoter was examined by bisulfite genomic sequencing. Transient transfection assays were performed for functional evaluation of mutations.

RESULTS

Screening of somatic mutations showed missense mutations in RUNX1 and GATA2 in the patient, while no mutation was found in exons of those genes in the controls. There was no significant difference in ABO promoter methylation between the patient and the controls. Transient transfection experiments into COS-7 and K562 cells suggested that the amino acid substitutions encoded by those mutations reduced or lost the trans-activation potential of the ABO expression.

CONCLUSION

Considering the discrepancy between the variant frequencies of these mutations and the ratios of the RBCs with A-antigens loss, the antigen reduction might be associated with these somatic mutations and hypermethylation of the ABO promoter.

Analysis of ABO grouping discrepancies among patients from a tertiary hospital in Korea

BACKGROUND

Accurate ABO typing is essential for preventing ABO incompatibility reactions. However, the causes of ABO grouping discrepancy has not been sufficiently studied, and it may vary among different ethnic populations. Thus, the aim of this retrospective study was to investigate the causes of ABO discrepancy in the East Asian population.

MATERIALS AND METHODS

A retrospective observational study on ABO typing discrepancy among patients in a tertiary hospital was carried out using the electronic medical record database of Samsung Medical Center (Seoul, Korea) between July 2016 and May 2019.

RESULTS

ABO grouping was performed on 551,959 blood samples during the study period; 1468 events of serologic ABO discrepancy were determined from 1334 (0.24 %) samples. A total of 134 samples (0.02 %) presented multiple causes of ABO discrepancy. Weak/missing serum reactivity (594, 40.5 %) was the most frequent reason for ABO discrepancy, followed by extra serum reactivity (370, 25.2 %), weak/missing red cell reactivity (267, 18.2 %), mixed-field red cell reactivity (176, 12.0 %), and extra red cell reactivity (61, 4.2 %). In the category of weak/missing red cell reactivity, ABO subgroup was the most common reason, and using ABO genotyping, 26.2 % of the cases genotyped were found to be related to the cis-AB allele.

CONCLUSIONS

Our results suggest that the incidence and cause of ABO typing discrepancies vary among institutes and ethnic groups. Our data helps to better understand and facilitate the resolution of ABO typing discrepancies in patients.

Characterization and statistical modeling of glycosylation changes in sickle cell disease

Sickle cell disease is an inherited genetic disorder that causes anemia, pain crises, organ infarction, and infections in 13 million people worldwide. Previous studies have revealed changes in sialic acid levels associated with red blood cell sickling and showed that stressed red blood cells bare surface-exposed clustered terminal mannose structures mediating hemolysis, but detailed glycan structures and anti-glycan antibodies in sickle cell disease remain understudied. Here, we compiled results obtained through lectin arrays, glycan arrays, and mass spectrometry to interrogate red blood cell glycoproteins and glycan-binding proteins found in the plasma of healthy individuals and patients with sickle cell disease and sickle cell trait. Lectin arrays and mass spectrometry revealed an increase in α2,6 sialylation and a decrease in α2,3 sialylation and blood group antigens displayed on red blood cells. Increased binding of proteins to immunogenic asialo and sialyl core 1, Lewis A, and Lewis Y structures was observed in plasma from patients with sickle cell disease, suggesting a heightened anti-glycan immune response. Data modeling affirmed glycan expression and plasma protein binding changes in sickle cell disease but additionally revealed further changes in ABO blood group expression. Our data provide detailed insights into glycan changes associated with sickle cell disease and refer glycans as potential therapeutic targets.

Loss and Reappearance of A Antigen After Chemotherapy Leading to Blood Group Discrepancy in Acute Myeloid Leukemia: A Case Report

A male patient aged 11 years diagnosed with acute myeloid leukemia presented with complaints of fever, lethargy, and bleeding manifestations. On ordering red blood cells and platelet transfusion, his blood group was tested. Blood group discrepancy was observed in that forward grouping showed the O Rh D positive blood group and reverse grouping revealed the A Rh D positive. The patient's previous blood group record was O Rh D positive, and he had a transfusion history of O Rh D positive red blood cells and platelets in other hospital. Initial immunohematological workup results, including adsorption and heat elution, were consistent with the O Rh D-positive blood group, but further workups on follow-up after the commencement of chemotherapy showed that his original blood group was A Rh D positive, in which the A antigen expression was previously masked by the underlying disease condition of the patient. Hence, the correlation of laboratory results with clinical details and case history is an essential step in resolving such blood group discrepancies.

The Potential Significance of ABO Genotyping for Donor Selection in Kidney Transplantation

Background

The ABO blood group system is clinically important in kidney transplantation, but ABO genotyping fails to attract sufficient attention in some countries and regions. We identified one case of early graft dysfunction due to an ABO genotype mismatch. Here, we performed ABO genotyping in blood samples, analyzed grouping discrepancies, and investigated the weak A subgroup frequency in kidney transplantation candidates.

Methods

Blood samples from 302 uremic patients with grouping discrepancies and 356 uremic patients with type A blood were analyzed using standard serologic serotyping techniques. The ABO genotypes and alleles were analyzed by polymerase chain reaction sequence-specific primer (PCR-SSP) and sequence-based typing (PCR-SBT).

Results

All 302 uremic patients with grouping discrepancies carried weak ABO subgroup alleles and 77.48% carried irregular ABO antibodies. The discrepancy rate between serotyping and genotyping was 42.38%, and the mismatching rate of donor selection according to serotype reached 88.74%. And 2.53% of 356 uremic patients with type A blood were determined to be in the weak A subgroup, which was a higher percentage than that observed in the healthy Chinese population (0.53%) by serological screening, but much lower than that observed in Caucasians (20%).

Conclusion

We revealed the high risk of blood type misjudgment and genetically ABO-mismatched transplantation if serological test was performed only in blood-group typing. Improved precision of ABO genotyping is crucial for successful kidney transplantation and reasonable organ allocation.

Regulation of ABO blood group antigen expression by miR-331-3p and miR-1908-5p during hematopoietic stem cell differentiation

The ABO blood group system is the most important factor in clinical transfusion medicine and is implicated in a number of human diseases. ABO antigens are not confined to red blood cells (RBCs) and are widely expressed in a variety of human cells and tissues. To date, many alleles with variant ABO expression have been identified and in many cases traced to one of the >250 reported genetic variations in the respective glycosyltransferase. The role of microRNAs (miRNAs) in the regulation of blood group antigens during erythropoiesis has not been addressed, however. Here, we show that miR-331-3p and miR-1908-5p directly target the mRNA of glycosyltransferases A and B. Expression levels of miR-331-3p and miR-1908-5p inversely correlated with levels of blood group A antigen. In addition, we found that overexpression of these miRNAs in hematopoietic stem cells led to a significantly reduced number of blood group A antigens per RBC. Simultaneous targeting of the transcription factor (TF) SP1 by miR-331-3p further enhanced these effects. The targeting rendered SP1 incapable of binding to the ABO gene promoter, causing further downregulation of blood group A antigen expression by up to 70%. Taken together, expression changes in these miRNAs may account for rare cases of weak A/B phenotypes that genetic variations in the glycosyltransferase coding region cannot explain. These results also suggest an explanation for the disappearance of ABH antigens during carcinogenesis and point to new therapeutic targets in ABO mismatched organ transplantation.

IMMUNOGENETIC AND PHARMACOCHEMICAL CHARACTERIZATION OF THE ABO SYSTEM GLYCOPROTEIN PROPERTIES AS CRITERIA OF INDIVIDUAL SENSITIVITY TO ANTITUMOR AGENT BORTEZOMIB IN THE PLASMA CELL MYELOMA PATIENTS

OBJECTIVE

Experimental study of the effect profile of bortezomib in the plasma cell myeloma (PCM) patients depend- ing on a specific phenotype carrier state and a pharmacochemical characteristics of ABO system glycoproteins.

MATERIALS AND METHODS

The research was conducted on the 104 PCM patients, including the Chornobyl NPP acci- dent survivors (n = 49) and 65 study subjects in the comparison group. Immunogenetic criteria for positive response to the applied treatment protocols were issued according to the duration of remission, absence of infectious com- plications, and evidence of chronic renal failure as a disease complication.

RESULTS

Possibility of glycoproteins A and B participation in the formation of human biological individuality at a level of protein-protein interaction with antineoplastic drug bortezomib, which is widely used in cancer management prac- tice, in particular in the PCM treatment is considered. The glycoprotein B was shown being a selective target for borte- zomib, slowing down the recognition and interaction of antigen B with monoclonal anti-B antibody, while the agglu- tination period lengthens at that by 66 %. Assumption that the formation of bortezomib complex with glycoprotein B provides a background for interaction with the key reaction of proteasome 26S inhibition, which to some extent con- tributes to the drug effect retardation was confirmed through the quantum-chemical calculations. Equilibrium is shift- ed toward the main reaction leading to a higher drug efficacy in patients with blood groups O (I) and A (II).

CONCLUSIONS

Since the complexation occurs predominantly in alkaline medium the administration of drugs with alkaline reaction should be restricted for at least round the clock after administration of bortezomib according to its half-life in plasma in patients with B (III) blood group and chronic renal failure.

RUNX1 mutation in a patient with myelodysplastic syndrome and decreased erythrocyte expression of blood group A antigen

BACKGROUND

Loss of blood group ABO antigens on red blood cells (RBCs) is well known in patients with leukemias, and such decreased ABO expression has been reported to be strongly associated with hypermethylation of the ABO promoter. We investigated the underlying mechanism responsible for A-antigen reduction on RBCs in a patient with myelodysplastic syndrome.

STUDY DESIGN AND METHODS

Genetic analysis of ABO was performed by PCR and sequencing using peripheral blood. RT-PCR were carried out using cDNA prepared from total bone marrow (BM) cells. Bisulfite genomic sequencing was performed using genomic DNA from BM cells. Screening of somatic mutations was carried out using a targeted sequencing panel with genomic DNA from BM cells, followed by transient transfection assays.

RESULTS

Genetic analysis of ABO did not reveal any mutation in coding regions, splice sites, or regulatory regions. RT-PCR demonstrated reduction of A-transcripts when the patient's RBCs were not agglutinated by anti-A antibody and did not indicate any significant increase of alternative splicing products in the patient relative to the control. DNA methylation of the ABO promoter was not obvious in erythroid cells. Targeted sequencing identified somatic mutations in ASXL1, EZH2, RUNX1, and WT1. Experiments involving transient transfection into K562 cells showed that the expression of ABO was decreased by expression of the mutated RUNX1.

CONCLUSION

Because the RUNX1 mutation encoded an abnormally elongated protein without a transactivation domain which could act as dominant negative inhibitor, this frame-shift mutation in RUNX1 may be a genetic candidate contributing to A-antigen loss on RBCs.

Partial sequence analyses of exon 7 of the ABO locus of cynomolgus (Macaca fascicularis) and rhesus (M. mulatta) macaques: Indeterminate phenotypes show the presence of the O blood group

Compatibility tests to identify A, B, and O alleles are critical for establishing suitable donor-recipient matches among experimental animals. Using a qPCR-based SNP probe assay, we have identified A, B, AB, and indeterminate blood group phenotypes in cynomolgus and rhesus macaques. We have hypothesized, albeit without molecular confirmation, that the indeterminate phenotype represents homozygosity for the null O allele at the macaque ABO locus. The indeterminate phenotype represents the unsuccessful detection of either A or B alleles using primers targeting the A-specific and B-specific single nucleotide polymorphisms (SNPs) in a variable region of exon 7 of the ABO locus. These SNPs are associated with two functional sites, detected using two allele-specific probes in the qPCR assay where the codons leucine and methionine (at codon 266) and glycine and alanine (at codon 268) are required for the synthesis of the A and B transferases, respectively. While reference sequences for the A and B alleles exhibited no novel mutations in the functional exon, plasmid Sanger sequence analyses showed unique mutations within the diagnostic target sites in 10 macaques exhibiting the indeterminate phenotype. Eight of these indeterminate individuals exhibited SNPs at codon 268 that should prevent the syntheses of an A or B transferase. While the two other indeterminate samples had functional codons that were consistent with A or B alleles, mutations in either their probe- or primer-binding sites that altered their peptide sequences probably impeded their detection by our assay.

A novel mutation +5904 C>T of RUNX1 site in the erythroid cell-specific regulatory element decreases the ABO antigen expression in Chinese population

BACKGROUND

An erythroid cell-specific regulatory element (+5·8-kb) in the first intron of ABO is responsible for the antigen differential expression and the regulatory activity of the element was affected by the nucleotide mutation in the +5·8-kb region. Currently, many individuals with ABO subgroups were found in the Chinese population, but there was little information about the function of +5·8-kb region in these individuals. Here, we studied the mechanism of the mutation in the +5·8-kb region responsible for reducing of antigen expression in 30 ABO subtype Chinese individuals without mutation in the coding region or splicing site.

MATERIALS AND METHODS

The nucleotide sequence of the partial intron 1 covering the +5·8-kb site was amplified and directly sequenced. The haplotype with the novel mutation was obtained by the TOPO TA cloning. Both of the ABO promoter and the +5·8 kb regulatory element were subcloned into the basic luciferase reporter plasmid using the double endonuclease digestion. The promoter activity was examined by the dual-luciferase report vector with K562 cells.

RESULTS

A novel nucleotide substitution +5904 C>T located at RUNX1-binding site in the +5·8 kb site was identified from three individuals with B subtypes. +5890 T>G were found in three Bel and one Ael phenotypes. Cotransfection and luciferase assays demonstrated that the +5904 C>T could obviously reduce activity of the +5·8 kb site.

CONCLUSION

The study suggested that the transcriptional activity of the +5·8 kb site could be downregulated by the single point mutation of RUNX1 motif, leading to reduction in A or B antigen expression.

Rapid rare ABO blood typing using a single PCR based on a multiplex SNaPshot reaction

BACKGROUND

ABO subgroups would be considered when discrepancies in ABO grouping occur. Serological methods including adsorption-elution test, salivary ABH inhibition test, and anti-A1 (lectin) saline method could be used. However, these serological methods are laboring and obscure. Therefore, reliable and affordable method to assess the ABO subgroups is of particular interest.

METHODS

To solve this problem, the multiplex SNaPshot-based assays were designed to determine rare A and B subgroups. Primers used as probes for determination of rare ABO blood groups known in Taiwanese population were designed. Many ABO subtype samples were used to validate the accuracy and reproducibility of our SNaPshot panel.

RESULTS

A panel of primer probes were successfully designed in determining 8 SNP sites (261, 539, 838, 820, 745, 664, IVS6 +5, and 829 in exon 6 and 7) for A phenotype and 6 SNP sites (261, 796, IVS3 +5, 247, 523, and 502 in exon 2, 6 and 7 and intron 3) for B phenotype. SNaPshot analysis for defining blood group A alleles (A₁, A₂, A₃, A_m and A_el) and blood group B alleles (B₁, B₃, B_w and B_el) was therefore available.

CONCLUSION

SNaPshot analysis could be used in reference laboratories for typing known rare subgroups of A and B without DNA cloning and traditional sequencing. Moreover, this method would help to construct databases of genotyped blood donors, and it potentially plays a role in determining fetal-maternal ABO incompatibility.

Cancer intelligence acquired (CIA): tumor glycosylation and sialylation codes dismantling antitumor defense

Aberrant glycosylation is a key feature of malignant transformation and reflects epigenetic and genetic anomalies among the multitude of molecules involved in glycan biosynthesis. Although glycan biosynthesis is not template bound, altered tumor glycosylation is not random, but associated with common glycosylation patterns. Evidence suggests that acquisition of distinct glycosylation patterns evolves from a 'microevolutionary' process conferring advantages in terms of tumor growth, tumor dissemination, and immune escape. Such glycosylation modifications also involve xeno- and hypersialylation. Xeno-autoantigens such as Neu5Gc-gangliosides provide potential targets for immunotherapy. Hypersialylation may display 'enhanced self' to escape immunosurveillance and involves several not mutually exclusive inhibitory pathways that all rely on protein-glycan interactions. A better understanding of tumor 'glycan codes' as deciphered by lectins, such as siglecs, selectins, C-type lectins and galectins, may lead to novel treatment strategies, not only in cancer, but also in autoimmune disease or transplantation.

Simple sugars to complex disease--mucin-type O-glycans in cancer

Mucin-type O-glycans are a class of glycans initiated with N-acetylgalactosamine (GalNAc) α-linked primarily to Ser/Thr residues within glycoproteins and often extended or branched by sugars or saccharides. Most secretory and membrane-bound proteins receive this modification, which is important in regulating many biological processes. Alterations in mucin-type O-glycans have been described across tumor types and include expression of relatively small-sized, truncated O-glycans and altered terminal structures, both of which are associated with patient prognosis. New discoveries in the identity and expression of tumor-associated O-glycans are providing new avenues for tumor detection and treatment. This chapter describes mucin-type O-glycan biosynthesis, altered mucin-type O-glycans in primary tumors, including mechanisms for structural changes and contributions to the tumor phenotype, and clinical approaches to detect and target altered O-glycans for cancer treatment and management.

Red cell antigen loss in a patient with chronic myeloid leukemia: a case of ABO discrepancy

Change in ABO antigen expression on the surface of neoplastic cells have been seen for a variety of tumor types. This phenomenon has been linked with myeloid neoplasms as well but is reported infrequently. Here, we report a rare cause of ABO discrepancy in an elderly female having chronic myeloid leukemia.

Deletion of the RUNX1 binding site in the erythroid cell-specific regulatory element of the ABO gene in two individuals with the Am phenotype

BACKGROUND AND OBJECTIVES

An erythroid cell-specific regulatory element, referred to as the +5·8-kb site, had been identified in the first intron of the human ABO blood group gene. Subsequent studies revealed that either a 5·8-kb deletion including the +5·8-kb site or disruption of a GATA factor binding motif at the site was present in all Bm and ABm individuals examined. We investigated the molecular mechanism of the Am phenotype, which is analogous to the Bm phenotype.

MATERIALS AND METHODS

Genomic DNAs were prepared from peripheral blood of two Am individuals, and the nucleotide sequences were investigated using PCR and direct sequencing. Electrophoretic mobility shift assay (EMSA) and promoter assay with K562 cells were carried out.

RESULTS

A novel 23-bp nucleotide deletion was found at the +5·8-kb site in both individuals. EMSAs demonstrated binding of the transcription factor RUNX1 to the nucleotides within the deletion. Promoter assays showed that the deletion reduced the transcriptional activity of the +5·8-kb site.

CONCLUSION

Deletion of the 23-bp nucleotides including the RUNX1 binding site decreases transcription of the A allele, resulting in the reduction in A antigen expression in the Am phenotype.

ABO blood antigens define human cerebral endothelial diversity

Cerebral endothelial cells participate in the blood-brain barrier and regulate activity-dependent changes in brain blood flow. It has been assumed that all cerebral endothelial cells are similar, but genetic studies in mice suggest that there are heterogeneous populations of endothelial cells in rodent brain. In this study, we tested for molecular heterogeneity of endothelial cells in the human brain. Human brains (five A and five O blood type patients) from autopsies were analyzed by immunohistochemistry and immunofluorescence using antibodies against von Willebrand factor (vWF) and A and H blood group antigens. vWF and ABO antigens were confined to the endothelium. Although all endothelial cells expressed vWF, capillary endothelial cells from A blood type brains showed a heterogeneous expression of A and H antigens, with individual cells expressing either one or both antigens. There were no differences between the gray and the white matter in the percentage of A-reactive or H-reactive capillaries. We conclude that ABO antigen expression in the human brain is modulated at the level of the individual endothelial cell. Future studies are warranted to determine whether differences in capillary permeability and cerebral autoregulation vary over short distances within the brain.

Mutation of the GATA site in the erythroid cell-specific regulatory element of the ABO gene in a Bm subgroup individual

BACKGROUND

The ABO blood group is important in blood transfusion. Recently, an erythroid cell-specific regulatory element has been identified in the first intron of ABO using luciferase reporter assays with K562 cells. The erythroid cell-specific regulatory activity of the element was dependent upon GATA-1 binding. In addition, partial deletion of Intron 1 including the element was observed in genomic DNAs obtained from 111 Bm and ABm individuals, except for one, whereas the deletion was never found among 1005 individuals with the common phenotypes.

STUDY DESIGN AND METHODS

In this study, further investigation was performed to reveal the underlying mechanism responsible for reduction of B antigen expression in the exceptional Bm individual. Peptide nucleic acid-clamping polymerase chain reaction was carried out to amplify the B-related allele, followed by sequence determination. Electrophoretic mobility assays and promoter assays were performed to examine whether a nucleotide substitution reduced the binding of a transcription factor and induced loss of function of the element.

RESULTS

Sequence determination revealed one point mutation of the GATA motif in the element. The electrophoretic mobility shift assays showed that the mutation abolished the binding of GATA transcription factors, and the promoter assays demonstrated complete loss of enhancer activity of the element.

CONCLUSION

These observations suggest that the mutation in the GATA motif of the erythroid-specific regulatory element may diminish the binding of GATA transcription factors and down regulate transcriptional activity of the element on the B allele, leading to reduction of B antigen expression in erythroid lineage cells of the Bm individual.

Transcriptional regulation of fucosyltransferase 1 gene expression in colon cancer cells

The α 1,2-fucosyltransferase I (FUT1) enzyme is important for the biosynthesis of H antigens, Lewis B, and Lewis Y. In this study, we clarified the transcriptional regulation of FUT1 in the DLD-1 colon cancer cell line, which has high expression of Lewis B and Lewis Y antigens, expresses the FUT1 gene, and shows α 1,2-fucosyltransferase (FUT) activity. 5'-rapid amplification of cDNA ends revealed a FUT1 transcriptional start site -10 nucleotides upstream of the site registered at NM_000148 in the DataBase of Human Transcription Start Sites (DBTSS). Using the dual luciferase assay, FUT1 gene expression was shown to be regulated at the region -91 to -81 nt to the transcriptional start site, which contains the Elk-1 binding site. Site-directed mutagenesis of this region revealed the Elk-1 binding site to be essential for FUT1 transcription. Furthermore, transfection of the dominant negative Elk-1 gene, and the chromatin immunoprecipitation (CHIp) assay, supported Elk-1-dependent transcriptional regulation of FUT1 gene expression in DLD-1 cells. These results suggest that a defined region in the 5'-flanking region of FUT1 is critical for FUT1 transcription and that constitutive gene expression of FUT1 is regulated by Elk-1 in DLD-1 cells.

Flow cytometry in myelodysplastic syndrome: analysis of diagnostic utility using maturation pattern-based and quantitative approaches

Flow cytometry (FCM) is being increasingly evaluated for the diagnosis of myelodysplastic syndrome (MDS). We employed multiple FCM approaches to assess MDS. Five-color FCM, morphology blind, was done on bone marrow aspirates of 57 suspected MDS and 31 normal controls. Maturation pattern, quantitative FCM for low-grade MDS that awards FCM score, and expression of selected antigens on erythroid cells and CD34(+) blasts were evaluated. FCM results were correlated with clinical and laboratory workup. Patients (n = 57) included proven MDS (n = 14), suspected MDS (n = 13), and non-MDS (n = 30). By pattern-based approach, all proven cases were FCM positive. In suspected MDS, 11 (84.61 %) were positive including morphology-negative cases, and two (15.38 %) were intermediate. In non-MDS cases, 27 of 30 (90 %) were FCM negative, 2 of 30 (6.67 %) intermediate, and 1 of 30 (3.33 %) a hematinic-responsive case, positive. Quantitative parameters that characterized MDS included FCM score of >3, percentage CD34(+) B cells, and expression of CD11b, CD15, and CD56 on myeloblasts. CD71 MFI on CD235a(+) erythroblasts and CD38 MFI on myeloblasts were significantly lower in MDS. The former was present in FCM-intermediate suspected MDS but not FCM-intermediate non-MDS cases. Used in the overall clinical context, both maturation pattern recognition and quantitative approaches, the latter for low-grade MDS, are sensitive methods of diagnosing MDS, including cases negative by morphology and cytogenetics, especially if combined with evaluation of selected antigens, CD71 on CD235a(+) cells and CD38 on CD34(+) cells. The value of FCM in morphology-negative cases needs better definition of specificity through more extensive evaluation of secondary dyspoiesis.

Identification of blood group A/A-Leb/y and B/B-Leb/y active glycotopes co-expressed on the O-glycans isolated from two distinct human ovarian cyst fluids

Although the individual human blood group A and B determinants are well defined, their co-expression pattern on a particular glycan carrier in individuals of blood group AB status has not been delineated. To address this issue, complex O-glycans were isolated from two distinct sources of human ovarian cyst glycoproteins (HOC 89 and Cyst 19) and profiled by advanced MS analyses, in conjunction with defining their binding characteristics against a panel of lectins and monoclonal antibodies. The major O-glycans of HOC 89 were found to correspond to sialyl Tn, mono- and di-sialyl T structures, whereas those of Cyst 19 were apparently more heterogeneous and extended to larger sizes. A minimal structure that carries both A and B determinants on the same molecule was identified, in which the A epitope is attached directly to the core GalNAc, whereas the B epitope is preferentially located on the six arms of a core 2 structure. Both arms can be further extended with internal fucosylation that appears to be restricted to those non-sialylated chains already carrying the terminal ABH determinants, thus giving rise to rather prominent A/B-Le(b/y) glycotopes on larger O-glycans.