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BACKGROUND: Examples of group B red cells that react weakly or not at all with anti-B have been described. Subgroups of B such as B3, Bx, Bm, and Bel are rare and are less frequently reported. We studied the frequency of subgroups of B in our healthy blood donor population and serologically characterized and differentiated these subgroups. MATERIALS AND METHODS: The 9-year prospective study included 84,534 healthy blood donors. Initial blood grouping and antibody screening of all donor samples were performed using automated solid-phase assay. Any sample showing blood group discrepancy or weaker agglutination was subjected to further immunohematological investigations. RESULTS: Among 84,534 healthy donors, “B” blood group was found in 29,190 (34.53%). Weak B phenotypes were demonstrated in 9 (0.031%) B donors. Among the 9 weak B phenotypes, B3 was the most common followed by Bm. The frequency of B3, Bm, Bx, and Bel in our blood donor population was found to be 1 in 21,133, 1 in 28,178, 1 in 84,534, and 1 in 84,534, respectively. Red cell agglutination with anti-B and anti-AB varied from Wk+ to 2+ with or without mixed-field agglutination in the B3 and Bx phenotypes. Naturally occurring anti-B of immunoglobulin M type was detected in the Bx donor. Two (22.2%) of the 9 donors were found to be nonsecretor. Adsorption-elution demonstrated “B” antigen specificity in different strengths in Bm, Bx, and Bel phenotypes. CONCLUSION: We conclude that differentiating weak subgroups of “B” by serological assays is possible to a great extent with technical expertise. Mistyping weak subgroups of B as “O” group may lead to reporting errors and wrong blood transfusion. Therefore, blood centers in developing countries including India should establish simple techniques to detect and differentiate weak subgroups and develop procedures to ensure safe blood transfusion and transplantation.

BACKGROUND: Examples of group B red cells that react weakly or not at all with anti-B have been described. Subgroups of B such as B3, Bx, Bm, and Bel are rare and are less frequently reported. We studied the frequency of subgroups of B in our healthy blood donor population and serologically characterized and differentiated these subgroups. MATERIALS AND METHODS: The 9-year prospective study included 84,534 healthy blood donors. Initial blood grouping and antibody screening of all donor samples were performed using automated solid-phase assay. Any sample showing blood group discrepancy or weaker agglutination was subjected to further immunohematological investigations. RESULTS: Among 84,534 healthy donors, "B" blood group was found in 29,190 (34.53%). Weak B phenotypes were demonstrated in 9 (0.031%) B donors. Among the 9 weak B phenotypes, B3 was the most common followed by Bm. The frequency of B3, Bm, Bx, and Bel in our blood donor population was found to be 1 in 21,133, 1 in 28,178, 1 in 84,534, and 1 in 84,534, respectively. Red cell agglutination with anti-B and anti-AB varied from Wk+ to 2+ with or without mixed-field agglutination in the B3 and Bx phenotypes. Naturally occurring anti-B of immunoglobulin M type was detected in the Bx donor. Two (22.2%) of the 9 donors were found to be nonsecretor. Adsorption-elution demonstrated "B" antigen specificity in different strengths in Bm, Bx, and Bel phenotypes. CONCLUSION: We conclude that differentiating weak subgroups of "B" by serological assays is possible to a great extent with technical expertise. Mistyping weak subgroups of B as "O" group may lead to reporting errors and wrong blood transfusion. Therefore, blood centers in developing countries including India should establish simple techniques to detect and differentiate weak subgroups and develop procedures to ensure safe blood transfusion and transplantation. [ABSTRACT FROM AUTHOR]

This case report describes a 5-year-old female with antenatally detected multi-cystic dysplastic left kidney (MCDK) who was diagnosed with moderate patent ductus arteriosus (PDA) with left to right shunt and required shunt closure under general anesthesia. During the pre-operative workup, the patient’s blood group was found to be B Rh D+ve, but there were discrepancies in the reverse grouping suggesting the presence of an irregular antibody in the patient’s serum. Further immunohematological workup identified the presence of naturally occurring anti-M antibody. The patient did not have a history of previous surgery, ICU admission, transfusion, or any significant past or family history. This case highlights the importance of immunohematological workup and crossmatching in patients requiring blood transfusions and also the presence of naturally occurring antibodies (NOAs), which can complicate the transfusion process and increase the risk of hemolytic transfusion reactions (HTRs).

Weaker subgroups have the potential to cause problems in the immunohaematological testing in the blood banks. We report here a case of rare weaker subgroup A, detected during the usual ABO grouping. A 49-year-old lady exhibited a discrepancy in the forward and reverse groupings. In forward-grouping, there was a mixedfield reaction with anti-A and anti-A,B while there was no reaction with anti-B. The reverse grouping showed no reaction with the A1 and A2 cells, but the reaction with B-cell was 4+. Further tests were performed and revealed a weaker subgroup of A. It is crucial to properly investigate and resolve any discrepancy in ABO grouping before commencing transfusion to avoid any wrong blood transfusion. This case report may assist others in resolving the ABO blood group discrepancies. [ABSTRACT FROM AUTHOR]

In this study, we aimed to determine and analyze the genetic differences of the FUT1 and FUT2 genes within an individual exhibiting the Para-Bombay phenotype. Standard serological tests were conducted to analyze the ABO phenotype. The amplification of FUT1 and FUT2 genes was conducted by polymerase chain reaction and amplicons were sequenced. The determination of the ABO genotype was conducted by sequencing exons 1 to 7 of the ABO gene. The Lewis phenotype was defined as Le(a−b+); Despite this, red blood cells (RBCs) did not show signs of A, B and H antigens using the serological method utilized in this study. However, Analyses of sequencing and cloning demonstrated the existence of a FUT1 mutation at position c.658C>T and an inactive allele FUT1*01N.06 (c.551_552delAG). Genetic testing for ABO blood types was subsequently determined to be ABO*B.01/ABO*B.01 (c.297A>G; c.526C>G; c.657C>T; c.703G>A; c.796C>A; c.803G>C; c.930G>A). Heterozygosity for indel and missense mutation within the coding region of FUT1 are likely to be responsible for development of the Para-Bombay phenotype.

Introduction: The para-Bombay phenotype, or H-deficient secretor, results from different mutations of the FUT1, with or without the FUT2 mutation. Consequently, there is an absent or weak expression of the H antigen on red blood cells (RBCs). Routine ABO blood grouping for two siblings with blood group O showed discrepant results with their parental blood group AB. Fragments encompassing the entire coding region of the FUT1 and FUT2 genes were investigated. Methods: Blood and saliva specimens were collected to verify the correct ABO grouping by cell grouping, serum grouping and the hemagglutination inhibition (HI) test, respectively. The FUT1 and FUT2 genomes were identified using the whole-exome sequencing (WES) in two children's DNA blood specimens and may have caused, or been relative to, their blood group. Genetic variations of the FUT1 and FUT2 genes have been investigated in the other family members using the Sanger sequencing. Results: The serologic reaction results of the proband revealed that A, B and H antigens were absent on RBCs, and that the serum contained anti-H. However, ABH and AH antigens were present in the saliva PB1 and PB2, respectively. The probands PB1 and PB2 were assigned as AB and A blood groups, respectively. Blood genotyping confirmed that heterozygous mutations of the FUT1 gene, c.551_552delAG, were identified. Three family members, PB3, PB, and PB8, also showed normal ABO blood groups, but their genotypes were also the FUT1 mutation c.551_552delAG. Conclusions: The FUT1 mutation c.551_552delAG may result in the reduced or absent H antigen production on RBCs, which characterizes the para-Bombay phenotypes. Blood genotyping is essential if these individuals need a blood transfusion or are planning to donate blood.

Since the advent of the pandemic, ABO blood group has a role in the immunopathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Disagreement between forward and reverse typing leads to ABO discrepancy which arise either due to intrinsic problems or from the technical errors in performing the test. Here, we document the two cases of transient absence anti-A and anti-B antibodies among two COVID patients proved by serological techniques, with the photographic representation of their immunohematological workups. SARS-CoV-2 viral envelop proteins mimicking as A and B antigen expressed on red blood cells (ABOs) and anti-A and anti-B antibodies acting as viral neutralizing antibodies, possible explanation for appearance of such phenomenon among patients. The ABO blood grouping of such discrepancy patients should be cautiously reported and advised to repeat once after full recovery. Transfusion center should be prepared appropriately in case of blood component support needed among such patients.

Red blood cell (RBC) alloimmunization can occur because of exposure to various sensitizing factors and poses a constant threat in transfusion. Assisted reproductive technology (ART) involves manipulation of sperm, ova, or embryos in vitro with the goal of producing a pregnancy. We present an interesting case of ART-induced maternal alloimmunization (AIMA) due to anti-c in a woman carrying a twin pregnancy. A 35-year-old primigravida, whose blood sample typed as group B, D+ and showed anti-c in her plasma, delivered twins by cesarean section. The spouse's blood group was also B, D+. The blood groups of twins I and II were confirmed to be B, D+ and AB, D+, respectively. The RBCs of twin I were c+, but those of twin II and the spouse were c-. On enquiry, history of ART with donor sperm insemination was noted. Because there were no previous sensitizations, antigenic inheritance from the sperm donor to twin I could be the possible sensitizing factor for maternal alloimmunization. To the best of our knowledge, this case is the first report of ART-induced maternal RBC alloimmunization in the literature. History of ART exposures should be documented, and appropriate RBC phenotyping of the parent as well as potential ART donors will help in timely detection or prevention of hemolytic disease of the fetus and newborn or other AIMA-related complications., (© 2024 Deepti Sachan et al., published by Sciendo.)

Quantitative and/or qualitative differences in ABO phenotypes give rise to ABO discrepancies causing difficulties in establishing the accurate phenotype. These discrepant serological reactions result in significant delays in blood bank. The correct typing of the blood group is imperative to prevent ABO incompatibility issues. However, the discrepant results encountered in routine settings are a challenge to immunohematologists. The variants of the ABO occur very rarely particularly true for B subgroups. Here, we present a case study of a healthy blood donor, discrepant results in forward and reverse blood grouping led us to perform adsorption-elution test. The presence of anti-B in the eluate confirmed the presence of weaker variant of B antigen on the surface of red blood cells. Correct identification of blood group is mutually important for donor and recipient to prevent the occurrence of any transfusion reaction. The serologically determined weak B phenotypes, however, require further confirmation through genomic analysis.

Quantitative and/or qualitative differences in ABO phenotypes give rise to ABO discrepancies causing difficulties in establishing the accurate phenotype. These discrepant serological reactions result in significant delays in blood bank. The correct typing of the blood group is imperative to prevent ABO incompatibility issues. However, the discrepant results encountered in routine settings are a challenge to immunohematologists. The variants of the ABO occur very rarely particularly true for B subgroups. Here, we present a case study of a healthy blood donor, discrepant results in forward and reverse blood grouping led us to perform adsorption-elution test. The presence of anti-B in the eluate confirmed the presence of weaker variant of B antigen on the surface of red blood cells. Correct identification of blood group is mutually important for donor and recipient to prevent the occurrence of any transfusion reaction. The serologically determined weak B phenotypes, however, require further confirmation through genomic analysis. [ABSTRACT FROM AUTHOR]

Since the advent of the pandemic, ABO blood group has a role in the immunopathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Disagreement between forward and reverse typing leads to ABO discrepancy which arise either due to intrinsic problems or from the technical errors in performing the test. Here, we document the two cases of transient absence anti-A and anti-B antibodies among two COVID patients proved by serological techniques, with the photographic representation of their immunohematological workups. SARS-CoV-2 viral envelop proteins mimicking as A and B antigen expressed on red blood cells (ABOs) and anti-A and anti-B antibodies acting as viral neutralizing antibodies, possible explanation for appearance of such phenomenon among patients. The ABO blood grouping of such discrepancy patients should be cautiously reported and advised to repeat once after full recovery. Transfusion center should be prepared appropriately in case of blood component support needed among such patients. [ABSTRACT FROM AUTHOR]

”Auto-anti-A1” has been sparsely discussed in the literature. Only few workers in the past depicted such antibody in transfused and nontransfused patients. The current case is probably the first example of auto-anti-A1 in a healthy young blood donor who was typed as ABO Group “A1B.” The cold reacting autoantibody in the donor was serologically characterized in details and was found to be nonhemolytic. ABO discrepancy was resolved and the donor was finally typed as “A1B Negative.” Therefore, we concluded that auto-anti-A1 may be a rare cause of ABO discrepancy and its resolution is essential to confirm blood group and subsequent blood transfusion management.

Background:-ABO and Rhesus blood group system is considered as clinically significant blood group systems in transfusion practice . A feature of the ABO system is the regular occurrence of anti A and anti B in the absence of the corresponding red cell antigen. A Discrepancy exists when results of forward testing does not match with reverse testing. Blood donors and patients must be correctly ABO and Rh grouped because transfusing ABO incompatible blood transfusions which may lead even death of patient. Aims and Objectives To assess the incidence and cause of blood grouping discrepancies in Blood Bank at Tertiary care teaching hospital during Jan 2019 to December 2019. Methods : Forward and reverse grouping were performed on blood samples from inpatients,outpatients and donors during the study period. ABO discrepancies were studied with their clinical details to group their discrepancies and resolve them with suitable steps. Results: A total of 10,048 (patients and donors) who satisfied inclusion criteria were included and ABO typed among which there were 55 discrepancies were observed (15 donors and 35 patients). The problem in patients was due to expression of weak antigens. The problem in patients were due to clinical conditions, the most common being autoimmune haemolytic anaemia. Conclusions: The ABO blood group discrepancy reported in present study is 0.49%. The study helped to determine the incidence and causes of discrepancy encountered in tertiary care hospital. Discrepant results should be recorded, and resolved by suitable measures and correct ABO & Rh Blood group should be released to avoid any mismatched transfusions. [ABSTRACT FROM AUTHOR]

Introduction: The naturally occurring "Anti-M" antibody, which is usually active at temperatures below 37 °C and has no clinical significance, can lead to discrepancy in ABO blood grouping and confusion in diagnosis. Case Presentation: This paper reports the case of a 28-year-old woman whose unanticipated reaction in her reverse blood grouping was observed due to the presence of anti-M, which made interpretation of her blood group difficult. The reason for this discrepancy created an interesting case to analyze. Take-away Lesson: A laboratory should always choose the reagent that is most suitable to the profiles of patients referred to that laboratory. It should be noted that if an anti-M is found in an M+ patient with negative autocontrol, it is not correct to conclude that there is a "partial M". [ABSTRACT FROM AUTHOR]

Objectives: This study aimed at identifying new ABO alleles from155 unrelated blood samples with potential ABO discrepancy in a Chinese Han population of 835 144 donors. Background: Serological strategies and genotyping are crucial for the precise determination of ABO discrepancy. Methods: Their ABO phenotypes and plasma glycosyltransferase activity were determined by standard forward and reverse typing and dilution tests. The genomic DNA of the ABO gene was amplified by polymerase chain reaction and sequenced. The frequency of ABO subgroup alleles associated with ABO discrepancy was analysed. Results: Serological analysis indicated that 53, 96 and 6 samples with ABO discrepancy were identified in the A, B and O subgroups, respectively. Genetic analysis revealed 12 novel alleles among the 46 associated with serologic ABO discrepancy. The majority of novel alleles was obtained from point mutations or single base insertion in Exons 6 to 7 of the ABO gene. The most frequent alleles were ABO*cisAB.01 (14/53, 26.42%) and ABO*A2.05 (7/53, 13.2%) in the A subgroup and ABO*BA.02 (34/96, 35.42%) and ABO*BEL.11 (15/96, 15.62%) in the B subgroup. Samples with the same ABO subgroup allele displayed different phenotypes, such as ABO*AX.13, ABO*BW.03, ABO*BW.12, ABO*BW.15, ABO*BEL.03, ABO*BEL.10 and ABO*BEL.11. Conclusion: This study identified 12 novel alleles among the 46 associated with serologic ABO discrepancies. ABO genotyping is needed for the accurate evaluation of blood phenotype to improve the safety of blood transfusion. [ABSTRACT FROM AUTHOR]

Anti-A and anti-B antibodies are naturally occurring and develop from exposure to intestinal bacteria after age 4 to 6 months. In the laboratory, strong agglutination with A1 and B cells, or B cells only and A1 cells only, on reverse typing in a healthy person with immunocompetence is expected for patients with ABO types O, A, and B, respectively. However, absent or weak anti-A and anti-B antibodies can be observed in some clinical scenarios, such as patients with immunodeficiencies, newborns, elderly patients, and patients who have recently received bone marrow transplants. In this article, we report the cases of 2 pediatric patients with group O blood type who were receiving total parenteral nutrition (TPN) and disease-specific enteral feeds and who have strong anti-A and absent/weak anti-B. [ABSTRACT FROM AUTHOR]

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., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Elzein et al.)

SUMMARY Aims/Objectives: To investigate the underlying molecular mechanism of the patient's ABO typing discrepancy. Background: ABO typing discrepancy was frequently seen in patients due to different causes. In this study, ABO typing discrepancy was found in a 24‐year‐old man with arthralgia, whose forward ABO grouping was O and reverse ABO grouping was AB. Primary immunodeficiency disease was speculated in this patient, especially X‐linked agammaglobulinemia (XLA). Methods: Immunoglobulins of all isotypes were detected using a specific protein analyser. Lymphocyte subgroups were analysed by flow cytometry. All 19 exons and boundaries of BTK gene were amplified by polymerase chain reaction (PCR), and all PCR products were sequenced by a DNA analyser. BTK protein in the leukocytes and platelets was detected by Western blot. Results: No B lymphocytes could be detected in the peripheral blood of the patient. A novel BTK gene variation, c.817G>T, in the exon 9 of BTK gene was discovered. No BTK protein expression could be detected in the leukocytes and platelets of the patient. Conclusions: XLA could be occasionally discovered by ABO typing discrepancy in some cases because of the deficiency of reciprocal IgM anti‐A and/or anti‐B antibodies in the serum of the patient. Humoral immunodeficiency is one of the causes of ABO typing discrepancy. [ABSTRACT FROM AUTHOR]

ABO discrepancies are recognized when the reactions obtained in the forward type do not "match" the reactions obtained in the reverse type. Discrepant results are often caused by a variant ABO gene. Molecular analysis is required to confirm the type of subgroups and discrepancy. In this study ABO genotyping was performed on a series of blood donors and patients to determine their definite blood groups. We examined 100 samples with ABO discrepancies from blood donors and patients referred to Tehran Blood Transfusion Center between October 2015 and August 2016. ABO genotyping was performed on all samples with allele specific PCR for differentiation of A, B and O alleles. Exon 6 and 7 of ABO gene were sequenced to confirm the results. The genotyping of donor/patients samples with discrepant results of ABO blood typing consisted of 61 cases of A2 and A2B, 3 cases of B302 and 4 cases of Aw06. Genotyping of 6 samples that had extra antibody in their serum (AB blood group) confirmed the cell type reaction results. 6 samples that had shown a very weak reaction with anti-AB (similar to O blood group) and had no anti-A in their serum were genotyped as O1O2. Blood group genotyping laboratory provides an efficient service for evaluation of ABO discrepancies and resolve the problems encountered in serology reactions. [ABSTRACT FROM AUTHOR]

SUMMARY: Objective: The aim of our study was to determine the incidence and causes of ABO typing discrepancies among patients and blood donors at our centre. Background: An accurate interpretation of the ABO blood group of an individual is of utmost importance to ensure patient safety and good transfusion practices. Methods: A retrospective observational study was carried out in the Department of Transfusion Medicine in our hospital from March 2013 to December 2015. Records of all patient and blood donor samples were retrieved and analysed for ABO typing discrepancies. Results: In total, 135 853 patient and 62 080 donor samples were analysed for ABO typing discrepancies. The incidence among patients and blood donors was found to be 0·1% (138/135853) and 0·02% (14/62080), respectively. The mean age for patients and blood donors was 48·4 and 29·2 years, respectively. The most common cause of ABO typing discrepancies was due to cold autoantibodies among the patients (50·7%) and blood donors (57%) causing discrepant results in reverse typing. The various other causes of reverse typing discrepancies among patients were weak/missing antibody (25·4%), cold‐reacting alloantibody (4·3%), warm autoantibody (2·2%), anti‐A1 antibody (2·2%), Bombay phenotype (1·5%), transplantation (0·7%) and rouleaux (0·7%), whereas in blood donors, the causes were cold‐reacting antibody (7%) and weak antibody (7%). The major cause of forward typing discrepancies among patients (12·3%) and blood donors (29%) was ABO subgroups. Conclusion: The resolution of ABO typing discrepancy is essential to minimise the chance of transfusion of ABO‐incompatible blood. [ABSTRACT FROM AUTHOR]

"Auto-anti-A1" has been sparsely discussed in the literature. Only few workers in the past depicted such antibody in transfused and nontransfused patients. The current case is probably the first example of auto-anti-A1 in a healthy young blood donor who was typed as ABO Group "A1B." The cold reacting autoantibody in the donor was serologically characterized in details and was found to be nonhemolytic. ABO discrepancy was resolved and the donor was finally typed as "A1B Negative." Therefore, we concluded that auto-anti-A1 may be a rare cause of ABO discrepancy and its resolution is essential to confirm blood group and subsequent blood transfusion management. [ABSTRACT FROM AUTHOR]

Anti M is considered a naturally occurring antibody that is usually active at temperatures below 37°C and is thus of no clinical significance. This antibody, if present in an individual, can lead to a discrepancy between forward and reverse ABO grouping and thus creates diagnostic difficulties for blood bank staff. We report a case of a 58-year-old lady who had an unexpected reaction in reverse grouping due to anti M that posed a problem for us in the interpretation of results of her blood group. We also reviewed the literature to find out the significance of such discrepancy in blood grouping.

ABO antibodies occur naturally and usually exist as alloantibodies. They are the most clinically significant in cases of transfusions. However, there are very few reports on auto-anti-A or B. A 58-year-old man visited our hospital for evaluation of an inguinal mass. Blood typing was performed, while preparing the patient for an excisional biopsy. Forward and reverse typing showed a typical AB and A pattern. Results of the direct antiglobulin and unexpected antibody screening tests were negative. The serum did not react with AB3 cells. The biopsy revealed a diffuse large B-cell lymphoma. After completing four cycles of R-CHOP chemotherapy, the patient achieved complete remission. There were no anti-B antibodies found on repeat ABO typing. This report shares our experience on unexpected anti-B antibody findings in a patient with an A1B blood type. To the best of our knowledge, this is the first report of anti-B antibodies in a patient with an A1B blood type in Korea. [ABSTRACT FROM AUTHOR]

Background Serological analysis of ABO blood group has been widely applied in transfusion medicine. However, ABO subgroups with different expression of blood group antigens sometimes cannot be determined by serological methods. Therefore, genotyping is useful to understand the variant ABO phenotypes. Material and Methods Exon 6 to exon 7 and adjacent introns of the ABO gene from a donor with ABO typing discrepancy were amplified and sequenced. Cloning sequencing was also performed to identify the allele. To explore the effect of mutation, three dimensional model of mutant p.Pro234Ala was built and optimized. Results The variant B (c. 700C > G) allele expressed an AweakB phenotype with anti-A in his serum with a ABO*B(A)02/O02 heterozygote genotype. Cloning sequencing confirmed that the c.700C > G single nucleotide polymorphism was associated with a B101 allele. Three dimensional molecular modeling suggested that p.Pro234Ala might affect the conformation of His233, Met266 and Ala268, which were known as critical residues for donor recognition. Conclusion ABO genotyping is needed for correct identification subgroups to improve accuracy evaluation of blood typing and increase the safety of blood transfusion. Alteration of DNA sequence in the ABO gene resulted in amino acid substitutions and led to a weak or missing expression of ABO antigens. [ABSTRACT FROM AUTHOR]

Anti-M antibodies are usually of IgM, appear as cold agglutinins and are clinically insignificant. We are reporting two cases of anti-M in cases of solid tumors where the anti-M caused discrepancy in blood grouping, reacted in coombs phase of crossmatching. Anti-M in first case showed dosage effect. These antibodies can be clinical significant when detected in coombs phase, making M antigen negative coombs compatible unit transfusion imperative. [ABSTRACT FROM AUTHOR]

Abstract: Background: Regional Blood Transfusion Centre (RBTC), GTB Hospital, Delhi is providing safe and quality blood to one third of Delhi population. A discrepancy exists when reactions in forward grouping do not match with reverse grouping or if the previous and current results do not match. Aim: To analyze ABO blood group discrepancies in an algorithmic manner, and to access the incidence and causes of ABO discrepancies among blood donors. Material and methods: Retrospective data of blood donors with blood group discrepancies was recorded in Regional Blood Transfusion Centre (East) Delhi, during a period of 3years from January 2010 to May 2013. DiaMed-ID Card Micro Typing System using Gel Cards (Cressier sur Morat, Switzerland) were used for determination of the ABO/Rh blood groups combined with reverse grouping. A detailed serological workup of these cases was studied for recognition and resolution of the blood group discrepancy. Results: Total number of donors during the study period were 104,010 (30,120; 31,117; 32,173 and 10,600 respectively). Blood group discrepancies were found in 51 cases (0.04%). There were 30 (58.8%) cases with low avidity anti-B Antibodies, 10 (19.6%) cases with weaker expression or subgroups of A, 2 (3.9%) cases with weaker expression or subgroups of B, 5(9.8%) cases with unexpected alloantibodies (Anti-N and Anti-M, Anti-Lea) and one(1.9%) case of Bombay blood group. In 3 cases, discrepancy could not be resolved and were referred to reference laboratory for confirmation by molecular analysis. The most frequent cause of discrepancy in forward grouping was found to be weak A or B antigen expressions and in reverse grouping decreased anti-B titers was most common. Conclusion: All discrepancies reported on ABO cell and serum grouping must be investigated further, so that correct blood group is reported, minimizing the chances of transfusion reaction. A note of caution should be mentioned on the blood group card to prevent ABO incompatibility in case of transfusion. [Copyright &y& Elsevier]

• ABO discrepancy is more frequently discovered in patients than in blood donors. • ABO subgroup is a major reason for weak/missing red cell reactivity. • The cis-AB phenotype is one of the major causes of ABO discrepancy in Koreans. • Hematopoietic transplantation is a major reason for mixed-field red cell reactivity. • Weak/missing serum reactivity is the highest cause of ABO discrepancy in patients. 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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

Bombay blood group is a rare phenotype that is characterized serologically by absence of H, A and B antigens on red cell surface and presence of corresponding antibodies in the serum. We report a case of 45-year old patient having Bombay blood group phenotype who experienced an acute reaction due to transfusion of mismatched blood unit. [ABSTRACT FROM AUTHOR]

Abstract: ABO discrepancy refers to incongruence between the results of red cell and serum groupings. One such case is described here; the discrepant results of whose routine ABO grouping led to the diagnosis of common variable immunodeficiency. There was no reaction in the reverse grouping of a young patient presenting with recurrent bacterial infections, pointing towards an absence of antibodies in the serum. Diagnosis was made on the basis of markedly decreased serum immunoglobulin levels and by serum protein electrophoresis showing scanty gamma regions. [Copyright &y& Elsevier]

Examines the importance of a patient's medical history in finding solutions for ABO blood typing problems. Cause of blood transfusion complications; Instance wherein a direct antiglobulin test and an elution should be performed; Reason behind the difficulty in obtaining a medical history.

Abstract A 54-year-old male patient was admitted with low-grade intermittent fever not associated with chills. The cell grouping of the patient sample showed O Rh D positive and serum grouping as B, with a discrepancy to be resolved. Series of immunohematological workup was performed to rule out the discrepancy. Reviewing the past proxy history revealed that the patient blood group was B Rh D positive. Bone marrow aspirate showed hypercellularity with increased myelopoiesis and markedly suppressed megakaryopoiesis giving an impression of acute myeloid leukemia and was confirmed by flow cytometry. Based on the current results and past history the blood group of the patient was confirmed to be B Rh D positive with loss of B and H antigens expression on the red cell surface due to underlying leukemia. Correlating the lab results with the clinical details and the case history is an important step in resolving blood grouping discrepancy. [ABSTRACT FROM AUTHOR]

The 547G>A polymorphism demonstrates significant allelic competition in people who harbor the B306 allele. We have performed the full sequencing of ABO gene in family members and measured their serum glycosyltransferase activity for demonstrating the cause of allelic competition. Genetic study including two regulatory regions and exon 1, and exons 2-7 of ABO gene demonstrated c.547G>A in exon 7 of the proband and her second son. The ABO genotype of the proband, husband, first son, and other son was ABO*A102/ABO*B306, ABO*A105/ABO*O02, ABO*A102/ABO*O02, and ABO*B306/ABO*O02 respectively. Serum glycosyltransferse B activity in the proband and her second son was lower than in normal B controls. We infer that allelic competition in the the 547G>A carrying individuals is associated with reduced activity of glycosyltransferase B., (© 2016 by the Association of Clinical Scientists, Inc.)

ABO discrepancy refers to an inconsistency between red cell and serum typings and has various causes, including hypogammaglobulinemia. IgM deficiency is a rare disorder that may accompany several conditions such as infection and autoimmune disorders. Here, we describe a case of IgM deficiency discovered during the evaluation of an ABO discrepancy in a 16-yr-old Korean boy. ABO blood grouping showed that while his cell type was O+, serum typing detected only anti-A (3+). Anti-B was not detectable at room temperature but was graded at 1+ at 4℃. ABO genotyping revealed an O/O genotype. His serum IgG, IgA, and IgM concentrations were 770 mg/dL (reference range: 800-1,700 mg/dL), 244 mg/dL (reference range: 100-490 mg/dL), and 13.5 mg/dL (reference range: 50-320 mg/dL), respectively. He was diagnosed with acute osteomyelitis on the basis of clinical presentation and imaging studies. The symptoms gradually improved within 3 weeks of treatment. However, the ABO discrepancy and IgM deficiency persisted even 6 months after recovery and lymphocyte subset analysis revealed CD19+ B cell deficiency. To the best of our knowledge, IgM deficiency detected by ABO discrepancy in a patient with acute osteomyelitis has not been reported before.