MNS Blood Group System Research Articles

Prevalence and Risk Factors of Alloimmunization in Multi-Transfused Pediatric Patients: A Cross-Sectional Study from a Sub-Himalayan Tertiary Care Hospital in Uttarakhand India

BackgroundPacked red blood cell (PRBC) transfusion is critical in managing pediatric patients with conditions requiring frequent transfusions, such as leukemia, thalassemia, and bone marrow disorders. Alloimmunization, the formation of antibodies against foreign antigens in donor blood, is a significant complication of repeated transfusions. Further, auto/alloimmunization is influenced by multiple factors, including antigenic differences between donor and recipient and the recipient’s immune status. ObjectivesThis study aimed to assess the prevalence and risk factors of auto/alloimmunization among pediatric patients requiring multiple PRBC transfusions in a tertiary care hospital in the sub-Himalayan region of Uttarakhand, India. MethodsA cross-sectional study was conducted on multiply transfused 113 pediatric patients aged 4 months to 18 years who received more than one PRBC transfusion between September 2022 and August 2023. Antibody screening and identification were performed using column agglutination techniques. Statistical analysis was conducted to evaluate associations between demographic, clinical factors, and antibody detection. ResultsAlloimmunization was observed in 5.31% of patients, with the majority developing antibodies against the MNS blood group system. Autoantibodies were more common, detected in 17.7% of patients. Significant associations were found between the history of prior PRBC transfusions and the presence of alloantibodies (p=0.005). Age, gender, and ethnicity did not show a statistically significant association with antibody detection. ConclusionsThe study reveals a relatively higher prevalence of autoimmunization among multi-transfused pediatric patients. The history of PRBC transfusions was a significant risk factor, indicating the need for extended RBC phenotyping and tailored transfusion strategies to reduce alloimmunization risks in these patients. Most patients and blood donors in this region belong to the local Garhwali community. This homogeneity may help explain the lower rate of alloimmunization observed, suggesting a degree of antigenic similarity among the blood donors and the recipients.

“When less is more and more is less” red cell alloimmunization in multitransfused patients attending a medical institution with a newly developed blood center in North India: A multifactorial study

Abstract: INTRODUCTION: Multiple blood transfusions with one or more nonself, genetically mismatched donor red blood cells (RBCs) may result in the production of alloantibodies, complicating future transfusions and increasing patient morbidity. This could be averted if adequate prophylactic measures are implemented in the vulnerable group. Due to the paucity of data in our region, we planned this study to identify the alloimmunization pattern in relation to clinical and demographic patient factors. MATERIALS AND METHODS: A prospective observational study was carried out in a newly developed Medical Institution of National importance in Northern India, for 1 year. The red cell antibody screening and identification were done for 770 patients receiving two or more transfusions. The patient and transfusion-related factors were statistically compared between alloimmunized and nonalloimmunized cases. RESULTS: The overall seroprevalence of RBC alloimmunization among the multi-transfused patients was 4.02% (31/770). Thirty-six alloantibodies were identified in the 31 alloimmunized patients, which comprised 13 different alloantibody specificities. Most of them belonged to the Rh system (38.8%), followed by MNS (25%) and Lewis (27.7%) blood group systems. On Multivariate logistic regression analysis, the highest risk was found to be associated with recipients having more than three transfusions with an odds ratio of 8.4. CONCLUSIONS: The highest alloimmunization risk was found in multi-transfused patients receiving more than three transfusions and with female gender. Rh blood group system was found to be predominating the alloantibody specificity pattern. This highlights the need for the provision of extended Rh (DCcEe) matched packed red cells for susceptible patients.

Simultaneous high throughput genotyping of 36 blood group systems using NGS based on probe capture technology

Human blood group antigen has important biological functions, and transfusion of incompatible blood can cause alloimmunization and may lead to serious hemolytic reactions. Currently, serological methods are most commonly used in blood group typing. However, this technique has certain limitations and cannot fully meet the increasing demand for the identification of blood group antigens. This study describes a next-generation sequencing (NGS) technology platform based on exon and flanking region capture probes to detect full coding exon and flanking intron regions of the 36 blood group systems, providing a new high-throughput method for the identification of blood group antigens. The 871 capture probes were designed for the exon and flanking intron sequences of 36 blood group system genes, and synchronization analysis for 36 blood groups was developed. The library for NGS was tested using the MiSeq Sequencing Reagent Kit (v2, 300 cycles) by Illumina NovaSeq, and the data were analyzed by the CLC Genomics Workbench 21.0 software. A total of 199 blood specimens have been sequenced for the 41 genes from 36 blood groups. Among them, heterozygote genotypes were found in the ABO, Rh, MNS, Lewis, Duffy, Kidd, Diego, Gerbich, Dombrock, Globoside, JR, LAN, and Landsteiner-Wiene blood group systems. Only the homozygous genotype was found in the remaining 22 blood group systems. The obtained data in the NGS method shows a good correlation (99.98 %) with those of the polymerase chain reaction-sequence-based typing. An NGS technology platform for 36 blood group systems genotyping was successfully established, which has the characteristics of high accuracy, high throughput, and wide coverage.

Characterization of GYP(B-A-B) hybrid glycophorins among Thai blood donors with Mia-positive phenotypes.

GYPA and GYPB genes encode the antigens of the MNS blood group system carried on glycophorin A (GPA) and glycophorin B (GPB), or on a hybrid molecule of GPA and GPB. GP hybrid variants are created through unequal crossing over and gene conversion, typically from the parent genes GYPA and GYPB. In the present study, we characterized the GYP(B-A-B) hybrid variants among Thai blood donors with Mia-positive phenotypes using PCR-based coupled to DNA sequencing techniques. Altogether, 1,020 samples from Thai blood donors were tested with anti-Mia by conventional tube technique (CTT). Polymerase chain reaction with sequence-specific primer (PCR-SSP) was initially used to differentiate normal GYPB, GYP*Vw and groups of GYP*Hut, GYP*Mur, GYP*Hop, GYP*Bun and GYP*HF alleles. Subsequently, GYP(B-A-B) hybrid variants were investigated using DNA sequencing. Among 1,020 blood donors, 127 (12.45%) were Mi(a+) phenotypes. The comparison Mia typing results between CTT and PCR-SSP were concordant. All Mi(a+) samples were positive with only group of GYP*Hut, GYP*Mur, GYP*Hop, GYP*Bun and GYP*HF alleles by PCR-SSP. Regarding the sequencing results, 115/1,020 (11.27%) donors carried the GYP*Mur, of which 111/1,020 (10.88%) were GYP*Mur/GYPB heterozygotes and the other 4/1,020 (0.39%) donors were GYP*Mur/GYP*Mur homozygotes. The remaining 12 donors included different GYP*Bun-like alleles; 11 of them (1.08%) were GYP*Thai/GYPB heterozygotes, and one (0.10%) was GYP*Thai II/GYPB heterozygotes. With 5.83% (119/2,040) of the total hybrid alleles, GYP*Mur was the predominant allele. The GYP*HF, GYP*Bun, GYP*Hop and GYP*Kip alleles were not observed in this study. Regarding the hybrid GP variants, a consensus of observed prevalent GYP*Mur and GYP*Bun-like alleles, respectively, was identified in the Thai population. The introduction of our strategy has allowed us to identify the zygosity for GYP hybrid variants, particularly GYP(B-A-B) hybrid genes, when antisera are unavailable and lacking adequate phenotypic features to determine GP variants.

The Research of a Large-Scale Analysis Platform for MNS Blood Group Identification Based on Long-Read Sequencing

The objective of this study was to devise a novel approach for determining MNS blood group utilizing long-read sequencing (LRS) and to identify intricate genome variations associated with this blood group system. In this study, a total of 60 blood samples were collected from randomly selected Chinese Han blood donors. The amplification of the full-length sequences of GYPA exon 2-7 (11 kb) and GYPB exon 2-6 (7 kb) was conducted on the blood samples obtained from these 60 donors. Subsequently, the sequencing of these amplified sequences was performed using the PacBio platform. The obtained sequencing data were then compared with the reference sequence of the human genome (GRCh38) utilizing the pbmm2 software, resulting in the acquisition of the haploid sequences of GYPA and GYPB. The serological typing prediction was conducted using the International Society of Blood Transfusion (ISBT) database, while the analysis of SNVs sites was performed using deepvariant v1.2.0 software and reference sequence alignment. A total of 60 samples yielded unambiguous high-quality haplotypes, which can serve as a standardized reference sequence for molecular biology typing of MNSs in the Chinese population. In a total of 60 serological samples, the LRS method successfully identified the M, N, S, and s blood group antigens by analyzing specific genetic variations (c.59, c.71, c.72 for GYPA, and c.143 for GYPB), which aligned with the results obtained through conventional serological techniques. 4 Mur samples that had been previously validated through serology and molecular biology were successfully confirmed, and complete haploid sequences were obtained. Notably, one of the Mur samples exhibited a novel breakpoint, GYP (B1-136-B ψ 137-212-A213-229-B230-366), thereby representing a newly identified subtype. Single molecule sequencing, which eliminates the necessity for PCR amplification, effectively encompasses GC and high repeat regions, enhancing accuracy in quantifying mutations with low abundance or frequency. By employing LRS analysis of the core region of GYPA and GYPB, diverse genotypes of MNS can be precisely and reliably identified in a single assay. This approach presents a comprehensive, expeditious, and precise novel method for the categorization and investigation of MNS blood group system.

Impact of Anti-M on Grouping and Cross Matching: The Challenges Faced in Three Cases

Anti-M, a frequently encountered antibody of the MNS blood group system, is commonly regarded as a naturally occurring saline agglutinin that can occasionally exhibit clinically significant behaviour. Particularly when reactive at 37°C or during the antiglobulin phase, it can complicate pretransfusion testing and patient management in the blood bank. Three distinct cases (2 males. 1 female) in varying clinical scenarios, ranging from surgery to acute coronary syndrome, are described. The present cases presented discrepancies in blood grouping and compatibility testing, highlighting the challenges posed by the presence of Anti-M antibodies that react at or above room temperature and during the antiglobulin phase, thus defying the usual expectations. It is imperative to provide antigen-negative red cells and those that are compatible by an Indirect Antiglobulin Test (IAT) when Anti-M is reactive at 37°C to ensure safe transfusion. Hence, there is a need to underscore the potential clinical implications in transfusion medicine, as well as the nuances of detecting, identifying, and managing the presence of Anti-M antibodies in patients requiring transfusion.

Feasibility and performance of in-house red blood cell reagents to detect unexpected antibodies in immunized patients in Burkina Faso.

In sub-Saharan Africa, antibody detection tests remain inaccessible because of the high cost and limited shelf life of red blood cell (RBC) reagents. This study aimed at investigating the feasibility and performance of locally prepared RBC reagents for antibody detection in Burkina Faso. We conducted an experimental study comparing commercial RBC panels and a local panel prepared from phenotyped blood donors in Ouagadougou, Burkina Faso. Antibody detection testing was performed by the indirect antiglobulin test using a gel card filtration column in a low-ionic-strength solution. Judgment criteria were the concordance rate and the kappa agreement coefficient of results generated by the two panels. A total of 302 blood donors were phenotyped for the major antigens of the RH, KEL, MNS, FY, JK, LE, and P1PK blood group systems. From this pool of donors, we designed an RBC detection panel that was used to screen for unexpected antibodies in 1096 plasma samples from 832 patients with a history of transfusion and 264 recently delivered or pregnant women with no history of blood transfusion. A positive antibody detection test was observed in 8.1 percent of the samples using the local panel versus 6.4 percent with the commercial panels. A total of 23 samples were negative with the commercial panels and positive with the local panel, while the findings were reversed for four samples. The concordance rate was 97.5 percent, and the kappa agreement coefficient was 0.815. Our results suggest that the development of local RBC panels can be an alternative to commercial panels in countries with limited resources. It could also be a cost-effective intervention, mainly for children under 5 years of age, women of childbearing age, and pregnant women, all of whom are most at risk for malaria and sickle cell disease complications. Blood services could develop and implement appropriate strategies to make phenotyped donor pools available for the design of suitable RBC panels.

Retrospective Analysis of Irregular Antibodies Causing Hemolytic Disease of the Fetus and Newborn in Jiangxi Province

To analyze the characteristics of antibody-specific distribution, laboratory detection results of hemolytic disease of the fetus and neonatal(HDFN) caused by irregular blood group antibodies other than ABO, and its correlation with the clinical situation. The non-ABO-HDFN cases in our hospital from October 2012 to December 2021 were selected as the research objects, and the cases diagnosed with ABO-HDFN in the same period were randomly selected as the control group, and the data of antibody specific distribution, total bilirubin, direct antibodies, maternal history, age of the children, the presence or absence of combined ABO-HDFN, and whether to exchange/transfuse blood were retrospectively analyzed. The characteristics of non-ABO-HDFN in Jiangxi province were analyzed. The detection rate of non-ABO-HDFN in Jiangxi province increased. Among 187 non ABO-HDFN cases, the highest percentage of Rh-HDFN was detected (94.6%). Compared with the control group of ABO-HDFN, the non-ABO-HDFN had higher mean integral value of direct antibody, higher peak total bilirubin, and longer duration. Anti-M-HDFN may have severe disease but the direct antibody weak positive/negative, it was easy missed in clinical and delayed the treatment. There is no correlation between the specificity of irregular antibodies, the sex of the child, the mother's previous childbirth history, the presence or absence of combined ABO-HDFN and the need for blood exchange/transfusion(P>0.05). The irregular antibodies of causing non ABO-HDFN in Jiangxi area are mainly Rh blood group system, followed by MNS blood group system. Understanding the characteristics of HDFN disease, serological features and the correlation with clinical indexes will help to detect and treat non ABO-HDFN in time and reduce the risk of complications.

A hemolysis verified to be induced by anti-meropenem

Incompatibility of blood groups or unexpected antibodies are primary considerations when acute hemolysis occurs during or after transfusion. However, less attention is paid to drug-induced immune hemolytic anemia (DIIHA), which is a rare but potentially life-threatening autoimmune disease. We present the case of a 34-year-old woman (group A, RhD+) who was treated with multiple antibiotics after meningioma resection. As her hemoglobin (Hb) decreased significantly from 109 g/L to 52 g/L without obvious bleeding, a blood transfusion was conducted soon after the medication, during which acute hemolysis occurred. An unexpected antibody, anti-M (MNS blood group system), was identified in the patient. It was confirmed that both the recipient and donor were group A, M antigen negative (M−) with CCDee phenotype, and no agglutination reactivity was observed in major crossmatch by testing the specimens before and after transfusion. Meanwhile, the results of the direct antiglobulin test (DAT) changed from negative to positive. Anti-meropenem, a drug-dependent antibody of meropenem, was detected, and hemolysis resolved after cessation. Anti-meropenem may mainly act through an "immune complex-type" reaction that induces intravascular hemolysis. Notably, the peculiarity of this case was dependent on the occurrence time of the acute hemolysis. Hence, it is necessary to raise awareness of DIIHA in clinical antibiotic treatments.

Long-Read Sequencing in Blood Group Genetics

Background: The key advantages of latest third-generation long-read sequencing (TGS) technologies include the ability to resolve long haplotypes and to characterize genomic regions that are challenging to analyze with short-read sequencing. Recent advancements in TGS technologies have significantly improved accuracy, a crucial requirement for the transition from research to diagnostic applications. Summary: In the field of immunohematology, the adoption of TGS is still in its early stages and published applications are scarce. An undeniable utility of TGS in blood group genomics is the ability to resolve ambiguous genotype-phenotype blood group results. In particular, hybrid genes and other large structural variants, as commonly found in the RHD/CE and MNS blood group systems, cause such discrepant results that can hardly be resolved by conventional methods. Long-read sequencing also greatly aids to generate high-standard reference alleles, establish haplotype sequence databases, or could even serve for high-resolution genotyping of all blood groups in parallel. Additionally, TGS holds the potential to close important knowledge gaps in blood group transcriptomics and epigenetics. Key Messages: The aims of this review were to examine the prospects of TGS technologies within the field of immunohematology and to highlight practical applications. Furthermore, we present a comprehensive overview of the existing and emerging wet-laboratory strategies for data generation, as well as a summary on bioinformatic data analysis methods. Finally, we provide an outlook on anticipated advancements in the near future.

Non-invasive prenatal testing for fetal Ss, Kidd, and CTL2 blood group prediction by multiplex digital droplet PCR.

Some blood groups, such as S and s blood groups in the MNS blood group system, and Kidd and CTL2 blood group systems, can cause severe fetal and newborn alloimmune disorders. Non-invasive prenatal testing (NIPT) to predict fetal blood groups and knowledge of local blood group gene frequency are both important for pregnancy management decisions. Droplet digital PCR (ddPCR) has high specificity and sensitivity in detecting fetal single nucleotide variation. The objective is to predict fetal Ss, Kidd, and CTL2 blood groups using multiplex ddPCR. The gene frequencies of three blood groups were detected by ddPCR in northwest China. This is a prospective study. Cell-free fetal DNA isolated from 26 healthy single pregnant women at different gestational stages was tested with QX200 Droplet Digital PCR. Results were compared with fetal genotypes. DNA samples purified from 20 blood pools containing a total of 1000 donors in northwest China were subjected to ddPCR to detect the gene frequency of three blood groups. Ss, Kidd, and CTL2 blood groups of 26 pregnant fetuses were accurately detected by multiplex ddPCR. The multiplex ddPCR results were consistent with the Sanger sequencing results of 26 fetal blood samples after birth. The gene frequencies of the three blood groups detected by ddPCR were 9.30% for S, 90.70% for s, 48.43% for Jka, 51.57% for Jkb, 66.57% for HNA-3A, and 33.43% for HNA-3B. It is reliable to predict fetal Ss, Kidd, and CTL2 blood groups by multiplex ddPCR. Meanwhile, we designed a simple and efficient method for inferring the gene frequency of three blood groups based on ddPCR.

Immunogenetic Predisposition to SARS-CoV-2 Infection.

Herein, we included 527 individuals from two Hospitals, Chemnitz and University-Hospital Leipzig. In total, 199 were negative for PCR and 328 were positive upon first admission. We used next generation sequencing for HLA-A, B, C, DRB1, DRB345, DQA1, DQB1, DPA1, and DPB1, and in some cases, HLA-E, F, G, and H. Furthermore, we molecularly defined 22 blood group systems comprising 26 genes and 5 platelet antigen genes. We observed a significant enrichment of homozygosity for DQA/DQB in the positive group. Within the negative subjects, HLA-B*57:01, HLA-B*55:01, DRB1*13:01, and DRB1*01:01 were enriched, and in the positive group, homozygosity for DQA/DQB, DRB1*09:01, and DRB1*15:01 was observed. DQA1*01:01, DQA1*02:01, and DQA1*01:03 were enriched in the negative group. HLA-DQB1*06:02 was enriched in the positive group, and HLA-DQB1*05:01 and HLA-DQB1*06:03 were enriched in the negative group. For the blood group systems MNS, RH, LE, FY, JK, YT, DO, and KN, enrichment was seen in both groups, depending on the antigen under observation. Homozygosity for D-positive RHD alleles, as well as the phenotypes M-N+ of the MNS blood group system and Yk(a-) of the KN system, were enriched in the positive group. All of these significances disappeared upon correction. Subjects who carried homozygous HPA-1a were more frequent in the negative group, contrasting with the finding that HPA-1ab was enriched in the positive group.

Racial Disparity in Antibody Against High Prevalence Antigen; Anti-U

Abstract Introduction/Objective Anti-U is an IgG antibody directed against the U antigen, which usually forms after exposure to U antigen via blood transfusion and/or pregnancy. U antigen is located on glycophorin B (GYPB) as part of the MNS blood group system. Approximately 2% of the African American population lacks this antigen, making them prone to developing anti-U. Anti-U can cause hemolytic disease of fetus and newborn (HDFN) and hemolytic transfusion reactions (HTR). Methods/Case Report A 60-year-old African American male underwent aortic valve surgery. The patient was A Pos with a negative antibody screen. During surgery, the patient was transfused with 3 random units of packed red blood cells (PRBCs). The postoperative course was uncomplicated, and the patient was discharged home. 6 months later, the patient was admitted for another procedure and was expected to require blood products. Thus, a type and screen test was ordered, revealing pan reactivity on screening cells. This prompted further investigation. Antibody detection was performed with the solid-phase technique followed by the tube method with Polyethylene glycol (PEG) as an enhancement medium. PEG technique is the next choice of method if the solid phase requires extended antibody work up, which was the case in our patient. PEG tube method successfully identified Anti-U, and the patient's phenotype was confirmed to be U negative. Results (if a Case Study enter NA) N/A. Conclusion It is imperative to stress the importance of racial disparity while investigating antibodies against high prevalence. In our case, our suspicion was high for Anti-U, given that patient was of African American descent. Tube methods with PEG and Solid Phase techniques are usually used for antibody identification. It is recommended that patients with rare antibodies carry an Antibody ID card indicating the rare antibody they have to prevent further exposure.

Analysis of anti-M antibody status and blood transfusion strategy in Hunan, China.

By analyzing the detection rate of anti-M antibody in patients with the MNS blood group system in the Hunan area, we aimed to explore its clinical significance and blood transfusion strategy. We retrospectively analyzed the clinical data of patients who had been confirmed to contain anti-M antibodies through serological methods such as the saline tube method and cassette anti-human globulin method. Irregular antibody screening tests had been applied to 94,452 patients, from which 652 results were positive. Among those positive patients, 93 cases were positive for anti-M antibodies, accounting for 14.26% of the positive rate of irregular antibodies; 11 cases had a blood transfusion history, accounting for 11.8%; 59 cases had a pregnancy history, accounting for 63.4%; and 2 cases had a transplant history, accounting for 2.2%. The patients with anti-M antibodies included 23 pregnant woman, accounting for 24.7%, and 19 tumor patients, accounting for 20.4%. A total of 66 cases were immunoglobulin M (IgM) + immunoglobulin G (IgG) class, accounting for 71.0%, 26 cases were IgM class, accounting for 28.0%, and 1 case was IgG class, accounting for 1.0%. The detection rates of anti-M antibody in the Hunan area and unexpected antibodies in literature reports are mainly related to a pregnancy history, and the type of antibody is predominantly IgM + IgG class. The clinical significance of anti-M antibody cannot be ignored, and three media should be used for cross-matching of blood wherever possible to ensure the safety of blood transfusion.

Laser incubation for the rapid detection of red cell alloantibodies in human blood samples.

Pre-transfusion antibody screening requires the detection and identification of immunoglobulin G (IgG) antibodies against red blood cells (RBCs). Using the indirect antiglobulin test (IAT), plasma-RBC solutions are incubated at 37°C in gel cards, typically by heating block technology. Here, we apply the newly developed laser incubation method to detect RBC alloantibodies in the plasma from human donors. Donated human plasma samples (N=128) containing clinically significant IgG antibodies directed against Rh (D, C, c, Cw and E), Kell (K and Kpa ), Duffy (Fya and Fyb ), Kidd (Jka ) and MNS (S) blood group system antigens were tested by the indirect antiglobulin test (IAT). Samples were heated to 37°C by infrared laser (980 nm) for incubations of up to 5min. Samples were also incubated in a heating block for comparison. When heating by laser, the presence of an alloantibody is detected after only a 1-min incubation for 96% of samples. No samples required longer than 3min of laser incubation in order to detect the antibody. For all samples, incubation by laser gave the same or stronger result within 5min. No samples required longer than 5min to achieve an equivalent result to that of the 5-min heating block incubation. The laser was not found to damage cells or antibodies. Laser incubation provides comparable results in shorter time frames than the heating block. Laser incubation can rapidly detect even very weak antibodies.

FREQUENCIES OF PREDICTED MIA ANTIGEN AMONG SOUTHERN THAI BLOOD DONORS

Background: The Mia antigen (MNS7) of the MNS blood group system is clinically important in Asian populations. Anti-Mia has been implicated in hemolytic transfusion reactions and hemolytic disease of the fetus and newborn in Thai populations. However, data of this antigen frequency among southern Thais remains unknown.
 Objective: This study aimed to determine and predict Mia antigen frequencies among southern Thai blood donors and to estimate the risk of alloimmunization among Thais.
 Methods: A cross-sectional study was conducted. Altogether, 400 southern and 500 central Thai blood samples were genotyped for GYP(B-A-B) and GYP(A-B-A) MNS hybrids using polymerase chain reaction with sequence-specific primer (PCR-SSP).
 Results: Among them, 19 of 400 (4.45%), and 28 of 500 (9.33%) were positive with the set of GP. Hut, GP.HF, GP.Mur, GP.Hop, and GP.Bun. No GP.Vw phenotype was found among southern and central Thais. The predicted Mi(a+)frequency among southern Thais was significantly lower than among central and northern Thais (p<0.05). Its frequency was similar to Vietnamese, Taiwanese, and Southern Han Chinese populations (p>0.05) but significantly differed from Indonesian, Filipino, and Chinese (Guangzhou) populations (p<0.05). The risk of Mia alloimmunization among southern Thais was significantly lower than among both Thai groups (p<0.05).
 Conclusion: This constitutes the first study to report Mi(a+) frequencies among southern Thais, supporting the estimation risk of alloimmunization and providing transfusion safety among Thai populations.

Glycophorins and the MNS blood group system: a narrative review

: The MNS blood group system, International Society of Blood Transfusion (ISBT) 002, is second after the ABO system. GYPA and GYPB genes encode MNS blood group antigens carried on glycophorin A (GPA), glycophorin B (GPB), or on variant glycophorins. A third gene, GYPE, produce glycophorin E (GPE) but is not expressed. MNS antigens arise from several genetic mechanisms. Single nucleotide variants (SNVs) contribute to the diversity of the MNS system. A new antigen SUMI (MNS50), p.Thr31Pro on GPA has been described in the Japanese population. Unequal crossing-over and gene conversion are the mechanisms forming hybrid glycophorins, usually from parent genes GYPA and GYPB. GYPE also contributes to gene recombination previously only described with GYPA. Recently, however, GYPE was shown to recombine with GYPB to form a GYP(B-E-B) hybrid. A GYP(B-E-B) hybrid allele encodes a mature GP(E-B) molecule expressing a trypsin-resistant M antigen but no S/s. Another novel glycophorin GP.MOT has been described carrying Mia, Mur, MUT, and KIPP antigens. GP.MOT is encoded by a GYP(B-A) hybrid allele. Newly reported cases of haemolytic transfusion reaction (HTR) or haemolytic disease of the fetus and newborn (HDFN) due to antibodies to MNS antigens is a constant reminder of the clinical significance of the MNS system. In one HDFN case, anti-U and anti-D were detected in an Indian D–, S–s–U– mother. The S–s–U– phenotype is rare in Asians and Caucasians but it is more commonly found in the African populations. Several types of novel GYPB deletion alleles that drive the S–s–U– phenotype have been recently described. Two large GYPB deletion alleles, over 100 kb, were identified as the predominant alleles in the African population. The use of advanced DNA sequencing techniques and bioinformatic analysis has helped uncover these large gene-deletion variants. Molecular typing platforms used for MNS genotyping are also discussed in this review. In conclusion, this review considers currently recognised MNS antigens and variants, new hybrid alleles and GYPB gene deletion alleles as well as clinical case studies. These new discoveries contribute to our understanding of the complexity of the MNS system to guide decision-making in genetic analysis and transfusion medicine.

Frequencies of MNS Blood Group Antigens and Phenotypes in Southwestern Saudi Arabia.

PurposeKnowledge of the prevalence of blood group antigens in a given population is important for the prevention of hemolytic reactions. The MNS blood group system (002) has four polymorphic antigens—M, N, S, and s. Anti-S and anti-s antibodies may result in immediate and delayed hemolytic transfusion reactions, and hemolytic disease of the fetus and newborn may occur. The present study investigated the frequencies of the main antigens and phenotypes of the MNS blood group system.Subjects and MethodsWe randomly obtained 149 samples from anonymous Saudi blood donors living in Jazan Province. Serotyping was conducted using a gel card to investigate (M, N, S, and s) antigens and phenotypes.ResultsThe frequencies of MNS antigens were as follows: M = 89.26%, N = 51.67%, S = 61.07%, and s = 82.55%. Regarding the MNS phenotypes, nine phenotypes were observed in the study population. The most common phenotype was M+N–S+s+ (n = 36, 24.16%), in contrast to the least common phenotype M+N–S–s– (n = 1, 0.67%). The prevalence of the MNS phenotypes in the current study population was highly and significantly different from that in Europeans (P = 0.044) and African Americans (P = 0.000).ConclusionIn summary, this study reports the frequencies of the MNS antigens and phenotypes in Jazan Province, Saudi Arabia. The most common phenotype was M+N–S+s+, whereas the least observed phenotype was M+N–S–s–. The outcomes of this study may assist the blood banks in Jazan Province to establish an extended phenotyping protocol including the MNS antigens, in particular S and s antigens, to preclude any alloimmunization events.

Molecular blood group screening in Omani blood donors.

Blood group genotyping has been used in different populations. This study aims at evaluating the genotypes of common blood group antigens in the Omani blood donors and to assess the concordance rate with obtained phenotypes. Blood samples from 180 Omani donors were evaluated. Samples were typed by serological methods for the five blood group systems MNS, RH (RHD/RHCE), KEL, FY and JK. Samples were genotyped using RBC-FluoGene vERYfy eXtend kit (inno-train©). Predicted phenotypic variants for 70 red blood cell antigens among the MNS, RH (RHD/RHCE), KEL, FY, JK, DO, LU, YT, DI, VEL, CO and KN blood group systems were assessed. Simultaneous phenotype and genotype results were available in 130 subjects. Concordance rate was >95% in all blood group systems with exception of Fy(b+) (87%). Homozygous GATA-1 mutation leading to erythroid silencing FY*02N.01 (resulting in the Fy(b-)ES phenotype) was detected in 81/112 (72%) of genotyped samples. In addition, discrepant Fyb phenotype/genotype result was obtained in 14/112 samples; 13 of which has a heterozygous GATA-1 mutation and one sample with a wild GATA genotype. D and partial e c.733C>G variants expressing the V+VS+ phenotype were found in 22/121 (18.2%) and 14/120 (11.7%) of the samples, respectively. Di(a-b+), Js(a-b+), Yt(a+b-) and Kn(a+b-) genotype frequencies were 99.4%, 95.8%, 91.9% and 97.7%, respectively. In conclusion, we report a high frequency of FY*02N.01 allele due to homozygous c.-67T>C GATA-1 single-nucleotide variation. This is the first study reporting the detailed distribution of common and rare red cell genotypes in Omani blood donors.

Frequencies of glycophorin variants and alloantibodies against Hil and MINY antigens in Japanese.

Antigens of the MNS blood group system are expressed on the red blood cell (RBC) membrane on glycophorin A (GPA) and glycophorin B (GPB) or on hybrid molecules of GPA and GPB. This study investigated the distribution of glycophorin variants and alloantibodies against Hil and MINY among Japanese individuals. Mi(a+) or Hil+ RBCs were screened using an automated blood grouping machine (PK7300) with monoclonal anti-Mia or polyclonal anti-Hil. Glycophorin variants were defined by serology with monoclonal antibodies against Mia , Vw, MUT and Mur, and polyclonal antibodies against Hil, MINY and Hop + Nob (KIPP). The glycophorin variants were further confirmed by immunoblotting and Sanger sequencing. Alloanti-Hil and alloanti-MINY in the plasma were screened using GP.Hil RBCs in an antiglobulin test. The specificity of anti-Hil or anti-MINY was assessed using GP.Hil (Hil+MINY+) and GP.JL (Hil-MINY+) RBCs. The GP.HF, GP.Mur, GP.Hut, GP.Vw, GP.Kip and GP.Bun frequencies in 1005594 individuals were 0·0357%, 0·0256%, 0·0181%, 0·0017%, 0·0009% and 0·0007%, respectively. GP.Hil was found in as four of the 13546 individuals (0·0295%). Of 137370 donors, 10 had anti-Hil (0·0073%) and three had anti-MINY (0·0022%). Glycophorin variants were relatively rare in Japanese individuals, with the major variants being GP.HF (0·0357%), GP.Hil (0·0295%) and GP.Mur (0·0256%). Only one example of anti-MINY was previously reported, but we found three more in this study.