Rare Blood Group Research Articles

ANTIGEN FREQUENCY OF KELL, DUFFY, KIDD, MNS AND LUTHERAN BLOOD GROUP SYSTEM IN POPULATION OF NORTH MACEDONIA – TOWARDS RARE BLOOD GROUP REGISTRY

The aim of this study is to perform RBC antigen typing of: Kell, Duffy, Kidd, MNS and Lutheran systems and to calculate antigen and phenotype frequency In 920 blood donors, RBC typing of K, k, Kpa, Kpb, Fya, Fyb, Jka, Jkb, S, s, Lua and Lub antigens was performed using specific monoclonal antisera, antihuman globulin and column agglutination technique with gel cards (BioRad). Antigen and phenotype frequencies were calculated from the statistics module of the donor information system (database for blood donors). The prevalence of Kell antigens is 7.5% for K and 99.94% for k. The phenotype (K+k-) is present in 21 (0.06%) blood donors. The frequency of other clinically significant antigens is as follows: 1.1% (Kpa), 100.0% (Kpb), 60.3% (Jka), 76.2% (Jkb), 65.5% (Fya), 79.5% (Fyb), 59.8% (S), 86.5 (s), 7.2% (Lua) and 92.8% (Lub). The most frequent phenotypes are Jk(a+b+) with 41.5%, Fy(a+b+) with 48.5%, (S+ s+) with 46.3% and Lu(a-b+) with 92.8%. Fy(a-b-) phenotype was detected in 0.21% of blood donors. The estimated RBC antigen frequency in our blood donor population differs from the antigen frequency in different populations. Because of that extended RBC typing is necessary for identifying rare blood group donors within the local population. This strategy enables to meet the needs for RBC transfusion in patients with rare phenotypes and with antibodies against high frequency antigens or multiple antibodies, as well as to prevent RBC alloimmunization in polytransfused patients providing antigen matched RBC.

Comparative analysis of antigen coding genes in 15 red cell blood group systems of Yunnan Yi nationality in China: A cross-sectional study.

IntroductionThere are few analyses of the 15 red blood group system antigen coding genes found in the Yunnan Yi nationality. This has caused many poteintial dangers relating to clinical blood transfusion. In this report, the coding genes and distribution of 15 blood group antigens system in the Yi nationality were tested and compared with those of Han nationality and other ethnic minorities.MethodsThe samples came from the healthy subjects in the first people's Hospital of Qujing, Yunnan Province. Two hundred and three Yunnan Yi and 197 Han nationality individuals were included. Thirty‐three blood group antigens with a low frequency from the 15 blood group systems of Yunnan Yi blood donors were genotyped and analyzed by PCR‐SSP. Sanger sequencing was used to detect A4GALT from the Yunnan Yi nationality. The χ 2 test was used to analyze observed and expected values of gene distribution to verify conformation to the Hardy‐Weinberg equilibrium law. Fisher's exact test was used to analyze gene frequency distribution, and the statistical significance was set at p < 0.05.ResultsThe ABO blood group examination results for the Yi nationality and the local Han nationality in Qujing City, Yunnan Province, showed the majority were type A and type O, while the least prevalent was type AB. RhD+ accounts for more than 98% of the Yi and Han populations. There was a significant difference in ABO blood group antigen distribution between these two nationalities (p < 0.05), but there was no significant difference in the composition ratio of D antigen in the Rh blood group system (p > 0.05). Compared with Tibetan (Tibet), Zhuang (Nanning), and Dong (Guangxi), the gene distribution frequencies of Rh blood group system phenotype CC were significantly lower in the Yunnan Yi nationality (p < 0.05). There were significant differences in six erythrocyte phenotypic antigens in the Yi nationality in Yunnan compared with Han nationality, such as LW(a−b−), JK(a−b+), MMSs, Di(a−b+), Wr(a−b−), and Kp(a−b+) (p < 0.05). There were gene phenotypes with a low frequency in the four rare blood group systems: LW, MNS, Wright, and Colton. Several different mutation types occurred in the P1PK blood group system's A4GALT gene.ConclusionYunnan Yi nationality has a unique genetic background. There are some significantly different distributions of blood group system genes with a low frequency in different regions and groups in China. Multiple mutations in the A4GALT gene of the P1PK blood group system may be related to their environment and ethnic evolution.

Genotyping of the rare Para-Bombay blood group in southern Thailand

IntroductionThe 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. MethodsBlood 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. ResultsThe 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. ConclusionsThe 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.

ABO gene editing for the conversion of blood type A to universal type O in Rhnull donor-derived human-induced pluripotent stem cells.

The limited availability of red cells with extremely rare blood group phenotypes is one of the global challenges in transfusion medicine that has prompted the search for alternative self‐renewable pluripotent cell sources for the in vitro generation of red cells with rare blood group types. One such phenotype is the Rhnull, which lacks all the Rh antigens on the red cell membrane and represents one of the rarest blood types in the world with only a few active blood donors available worldwide. Rhnull red cells are critical for the transfusion of immunized patients carrying the same phenotype, besides its utility in the diagnosis of Rh alloimmunization when a high‐prevalence Rh specificity is suspected in a patient or a pregnant woman. In both scenarios, the potential use of human‐induced pluripotent stem cell (hiPSC)‐derived Rhnull red cells is also dependent on ABO compatibility. Here, we present a CRISPR/Cas9‐mediated ABO gene edition strategy for the conversion of blood type A to universal type O, which we have applied to an Rhnull donor‐derived hiPSC line, originally carrying blood group A. This work provides a paradigmatic example of an approach potentially applicable to other hiPSC lines derived from rare blood donors not carrying blood type O.

Molecular genetic analysis reveals a novel B variant allele at the ABO locus

BackgroundWhen discrepancies in ABO blood typing emerge, ABO subgroups should be considered. Serological procedures such as the adsorption-elution test, the salivary ABH inhibition test, and the antiA1 (lectin) saline technique might be employed. These serological approaches, however in rare blood types are difficult to understand. As a result, a dependable and cost-effective approach for determining ABO subgroups is of special relevance. Methodologyfor this purpose, DNA sequencing is most reliable solution for accurate results. Exon 1 to 7 5′ 3’ UTR and intron 6 of ABO gene of a Chinese individual was sequenced because the laboratory was unable to determine the blood group by traditional method. ResultsThe analysis of the blood showed weak B antigens on their surface. Gene sequencing results revealed a novel B allele, that has one novel identified nucleotide difference from T to C at nucleotide 425. ConclusionThe results reported novel B allele which cannot be confirmed by conventional serological methods. Owing to the peculiarity of ABO blood types of inheritance, findings on the incidence and molecular causes of rare blood groups in the Chinese population have substantial therapeutic implications and are worthy of additional investigation in the future.

Rare Blood Groups in ABO, Rh, Kell Systems - Biological and Clinical Significance.

Background: The frequency of ABO, Rh and Kell blood group antigens differs among populations of different ethnic ancestry. There are low-frequency antigens (<1%) and high-frequency antigens (>90%). A rare blood group is defined as the absence of a high-frequency antigen in the general population, as well as absence of multiple frequent antigens within a single or multiple blood group systems. Aim: To perform red blood cell typing and to calculate the antigen and phenotype frequencies, in order to identify rare blood group donors within the clinically most important АВО, Rh and Kell systems. Material and Methods: АВО, Rh (D, C, E, c, e) and Kell (K) antigen typing was performed using specific monoclonal sera and microplate technique, while Cellano (k) typing was performed with a monoclonal anti-k, antihuman globulin and column agglutination technique. Weak ABO subgroups were determined using the absorption elution method or molecular genotyping (PCR-SSP). Results: ABO antigen frequency is: A (40.89%), O (34.22%), B (16.97%), AB (7.92%) and weak ABO subgroups (0, 009 %). The established genotypes were AxO1 (0, 0026%) and AxB (0, 001%). Rh antigen frequency is: D (85.79%), C (71.7%), c (76.0%), E (26.0%) and е (97.95%). The most common Rh pheno-type is the DCcee (32.7%) while the rarest phenotype is the DCCEE phenotype (0. 003%). The prevalence of K and k antigen is 7.5% and 99.94%, respectively. The frequency of the rare phenotype K+k- is 0.06%. Conclusion: Large scale phenotyping of blood group antigens enables the identification of blood donors with rare blood groups for patients with rare phenotypes or with antibodies to high-frequency antigens and to frequent antigens within one or more blood group systems.

Impact of societal and legal context on the blood supply of African-ancestry populations in Western countries: A review of practices and the French example.

In Western countries, blood supply agencies encounter impediments in providing blood groups defined as rare or of interest, notably for sub-Saharan African ancestry (SSAA) recipients. To establish warning levels and anticipate future blood needs, an estimate of the current carriers of rare blood groups, both potential patients or donors, is crucial but complex. Indeed, if the strict needs can be estimated in medical terms, the modalities of blood product collection must be considered from an interdisciplinary perspective, at the interface of biological data and social norms. Here, we aim to understand how legal choices and a set of representations of otherness may influence the supply of rare blood for SSAA populations. After examining these issues, considering different norms and limits that govern French society, we compare this data with those of four Western countries facing the same difficulties (United States, United Kingdom, Italy and the Netherlands). This work began as part as the reflections of Social Lab, an institutional programme created by the French Blood Establishment (EFS). How can we effectively improve the qualitative blood coverage for SSAA populations? There is no unique solution, but there are many more or less effective answers. Comparison across countries reveals a strong influence of the socio-political histories and ethical choices before technical and medical considerations. We consider that an institutional policy is required to resolve recruitment issues of SSAA donors sustainably. Lastly, we introduce a working group called the EFS Social Lab, which aims to set up a monitoring mechanism for donors and societal trends to make blood donation effective.

Percentage Expression of Lewis B, Rh-e, N and ABO Antigens in descents of Bonny Kingdom, River, State, Nigeria.

Introduction: The presence of rare blood group antibodies in the blood of donors/recipients stimulate red cell alloimmunization and constitute a major cause of transfusion related reaction after a compatible ABO cross match, yet remain one of the less routinely assessed prior to blood donation and transfusion in Nigeria. This cross-sectional study was carried out among indigenes of Bonny kingdom in Rivers State Nigeria to access the percentage expression of Lewis B, Rh-e, N and ABO antigens in descent of Bonny Kingdom Rivers State Nigeria. Materials and Methods:- One hundred and twenty (120) apparently healthy subjects consisting of sixty (60) females and sixty (60) males aged between 18-50 years all indigenes of Bonny Kingdom were recruited by structured questionnaire for the study. 4mls of venipuncture blood was aseptically collected from each participant into vacutainer bottle containing 0.5 mL of 1.2 mg/mL dipottasium ethylenediaminetetraacetic acid anticoagulant and a 5% cell suspension was prepared and used to determine the various blood groups antigens using the standard tube Agglutination technique. Results: Results obtained shows a total of 94.1% (113) of the participants expressed Rh-e antigen, 45.8% (55) male and 48.3% (58) females. 7.5% (9) of the participants expressed the N antigen, 3.3% (4) male and 4.2% (5) females. 4.2% (5) of the study population expressed Lewis B antigen, 2.5% (3) males and 1.7% (2) female. The ABO system showed 68.5% (79) O blood group, 29.1% (35) male and 36.7% (44) female. 22(18.3%) typed for A blood group, 11.6% (14) male and 6.7% (8) female. For B blood group 14.2% (17) persons were typed, 7.5% (9) male and 6.7% (8) female while 1.6% (2) persons were typed as AB and they are all females. Conclusion: Rh-e phenotype occurred highest among the study participants. The proportion of the population without the expression of these antigens of the blood group tested has the potential to be alloimmunized during blood transfusion and develop antibodies, some of which can be responsible for transfusion reactions and haemolytic disease of the new born. This study has provided baseline data on the distribution of some blood group antigens in the Bonny Kingdom of Rivers State in Nigeria. Based on the finding in this study, it is recommended that Rh-e grouping be carried out on pregnant mothers, blood donors and recipients before transfusion; while Lewis B and N blood groups may be subjected to expansive population testing.

Frequency of A2 Blood Group among A Blood Group

Background: Transfusion medicine is an important branch in the field of medicine and patient care. Prior knowledge and identification of subgroups of ABO blood group system is important in blood transfusion, inheritance pattern, genetics and disease susceptibility. Getting right donor in right time in right place is sometime a challenge in patient care. So proper blood typing is mandatory. Still now there is no data on frequency of rare A2 blood group in Bangladesh Armed Forces as well as in Bangladesh. Aim: To see the frequency of A2 blood group among ABO blood groups in Bangladesh Armed forces and Bangladesh. Materials and Methods: A total of 200 patients with blood group A irrespective of age and sex were included in this retrospective study and the study was carried out in the Department of Transfusion Medicine Armed Forces Institute of Pathology (AFIP), Dhaka Cantonment, Dhaka, Bangladesh from 01 June 2021 to 30 June 2021. Blood grouping was performed by slide method and Anti-A1 reagent is used to differentiate blood group A1 from blood group A2. Results: Among 200 A blood group individual 198 were typed as A1 (99%) and 02 were typed as A2 (01%). Among those two one had anti A1 antibody while other didn’t have. Conclusion: A2 is a rare subtype of A blood group. Care should be taken during routine ABO grouping especially in cases of discrepancies or mix-field or weak positive reactions in A blood group.

INCIDENCE OF ABSENCE OF H ANTIGEN IN AN INDIVIDUAL IN CENTRAL INSTITUTE OF INDIA

Bombay blood group is a rare blood group in which there is the absence of H antigen and presence of anti-H antibodies. At the time of blood grouping, this blood group mimics O blood group due to the absence of H antigen, but it shows incompatibility with O group blood during cross matching. Serum grouping or reverse grouping are essential for confirmation of the diagnosis. Patients carrying this blood group can receive blood only from a person with this blood group. Reported cases of General surgery department with Bombay blood group. The transfusion support of such cases is still a challenge in the country like India where prevalence of Bombay blood group is extremely rare and due to which individual having this Bombay group faces difficulty at times of need.

Determination of C,c,E and e Antigens Section Prevalence in Rh D Negative Individuals: Is it Good Exercise with Utilities in Clinical Blood Transfusion Practices?

Introduction: Besides D antigen, C,c,E and e antigens of Rh blood group system are the most important antigens involved in alloimmunisation. The prevalence of C,c,E and e antigens in Rh D negative individuals in local population has many utilities in transfusion medicine practice. Aim: To determine the prevalence of C,c,E and e antigens in Rh D negative individuals. Materials and Methods: This prospective observational study was performed at Bhanumati clinical laboratory, Navsari, Gujarat, India, from January 2020 to January 2022. A total of 270 Rh D negative samples irrespective of ABO blood group status were typed for C,c,E and e antigen using monoclonal reagents from two different manufacturers using conventional tube technique. The most likely phenotype and genotype were determined using reference textbooks. Possibility of weak D in these 270 samples was ruled out using polyspecific Antihuman Globulin Reagent performing test for weak D antigens. Results were analysed using Excel spread sheet. Results: Prevalence of C,c,E, and e antigen in the 270 Rh D negative samples were, C (17, 6.29%), c (267, 98.88%), E (1, 0.37%) and e (270, 100%). Most probable genotypes were dce/ dce(rr), dCe/dce(r’r), dCe/dCe(r’r’) and dcE/dce(r’’r). Conclusion: Data obtained of C,c,E and e antigen prevalence in Rh D negative individuals is having varied utilities in blood transfusion services such as formulating rare blood group registry, preparing in house screening and panel red cells, and maintaining inventory of rare blood group units using freezing technology, if available.

Simplified art of balloon pulmonary valvuloplasty: Does the presence of mild supravalvular pulmonary stenosis preclude successful balloon pulmonary valvuloplasty?

We present a case of successful balloon pulmonary valvuloplasty (BPV) in a 37-year-old female with severe valvular pulmonary stenosis with peak gradient of 82 mmHg with history of exertional presyncope. The crux of our case was that patient also had associated mild supravalvular pulmonary stenosis which did not preclude a successful BPV outcome. The patient had rare Bombay negative blood group, and the requisite units were not available across all the blood banks in the state to subject the patient for surgical correction. Although the art of BPV is dying among budding young interventionists, this simple procedure is as good as surgical pulmonary valvotomy so far as the immediate and late outcome is concerned and the presence of mild supravalvular pulmonary stenosis does not preclude a successful outcome. Our case is a unique illustration of feasibility of successful balloon pulmonary valvuloplasty in the presence of associated mild supravalvular stenosis.

Molecular characterization of rare D--/D-- variants in individuals of Indian origin.

Rh antigens are critical in haemolytic disease of the foetus and newborn (HDFN). The D-- phenotype is a rare blood group characterised by the lack of expression of C, c, E and e antigens at the surface of red blood cells because of mutations in both RHCE alleles inactivating the expression of a "normal" protein. The aim of the study was to determine the molecular basis of D-- individuals of Indian origin. Ten Rh D-positive postnatal women who had produced antibodies against all Rh antigens, except D, leading to HDFN and foetal loss, were investigated. Extensive serological and molecular (polymerase chain reaction [PCR] using sequence-specific primers), quantitative multiplex PCR of short fluorescent fragments (QMPSF), and Sanger sequencing analyses were carried out. Serological testing with anti-C, anti-c, anti-E, and anti-e reagents showed absence of the four antigens in all ten index cases, as well as in three siblings. Flow cytometry indicated absence of these antigens with a typical exalted expression of the D antigen, thus confirming the rare D-- phenotype. Molecular analysis by QMPSF suggested homozygous CE-D hybrid alleles causing the D-- phenotype: RHCE-D(3-9)-CE (n = 11), RHCE-D(3-8)-CE (n=1), and RHCE-D(2-6)-CE (n=1). For the first time, we report the molecular basis of the D-- phenotype in the Indian population. Identification and characterisation of RHCE-null variants by molecular methods can help resolve transfusion-related problems in these individuals. Family studies of index cases helped to identify rare blood donors and offer counselling to females of child-bearing age on the complications involved in such pregnancies.

A patient with probable rare blood Group B(A) phenotype

A patient with probable rare blood Group B(A) phenotype

The Future of Red Cell Transfusion Lies in Cultured Red Cells

AbstractBlood is a very important resource for healthcare-based services and there has been a consistently increasing demand for it in most parts of the world. Poor volunteer-based collection system, high-risk of transfusion-transmitted infections, and emergence of new pathogens as evident from the ongoing Coronavirus Disease 2019 (COVID-19) pandemic are potential challenges to the global healthcare systems. It is imperative to explore safe and reliable alternatives to red cell transfusions. Ex vivo culture of red cells (cRBCs) from different sources such as hematopoietic stem cells (HSCs), pluripotent stem cells, and immortalized progenitors (e.g., BELA-2 cells) could revolutionize transfusion medicine. cRBC could be of great diagnostic and therapeutic utility. It may provide a backup in times of acute shortages in patients with rare blood groups, and in cases with multiple antibodies or sickle cell anemia. The CRISP-Cas9 system has been used to develop personalized, multi-compatible RBCs for diagnostic reagents and patients with multiple allo-antibodies. cRBC could be practically feasible for pediatric patients, who require small quantities of red cell transfusions. cRBC produced under good manufacturing practice (GMP) conditions has been reported to survive in human blood circulation for more than 26 days. Recently, a phase I randomized controlled clinical trial called RESTORE was initiated to assess the survival and recovery of cRBCs. However, feasible technological advancement is required to produce enough cRBCs for clinical use. It is crucial to identify sustainable sources for large-scale production of clinically useful cRBCs. Although the potential cost of one unit of cRBC is extrapolated to be around US$ 8000, it is a life-saving product for patients having rare blood groups and is a “ready to use” source of phenotype-matched, homogenous young red cells in emergency situations.

Molecular genotyping of Indian blood group antigens amongst regular voluntary blood donors of Surat city, Gujarat, India

BackgroundThere is paucity of data related to the prevalence of the rare blood group antigens amongst South Gujarat blood donor population due to unavailability and high cost of antisera. Therefore it is difficult to screen donors for such rare antigens by gold standard haemagglutination assay. The single nucleotide polymorphism (SNPs) of Ina and Inb antigens is the base of the PCR based detection methods that help to detect these alleles in regular voluntary blood donors. Materials & methodsBlood samples of 200 unrelated regular voluntary blood donors wee collected. DNA was extracted using phenol-chloroform method and genotyped for Indian (Ina/IN*01, Inb/IN*02) blood group alleles by Sequence Specific PCR. Ina antigen positivity was confirmed by serology test. ResultsFour donors were found heterozygous for Ina antigen i.e. In (a + b+) by SS-PCR and their Ina positivity were confirmed by in-house polyclonal Anti-Ina reagent. SS-PCR was standardized using known heterozygous sample of a blood donor. The frequency of Ina antigen (2.0 %) was higher than Caucasians, lower than Iranians and Arabs while comparable to those reported among Indians of Mumbai city. ConclusionIn absence or unavailability of antisera particularly for low frequency alleles like Ina, such PCR based method would be extremely helpful to prepare rare donor registry by screening blood donors’ at large scale. Red cells of Ina positive donors can be used as in-house reagent red cells for screening and identification of corresponding antibody.

The Usefulness of Rare Blood Group Systems in the Risk Determination for Severe COVID-19.

The newly identified human coronavirus was named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), based on a detailed analysis of clinical manifestation. It was reported that blood type O individuals were less likely to become infected by SARS-CoV, while blood type A individuals have an increased risk of severe illness. The Forssman antigen, or Forssman glycolipid synthase (FS), was first described in 1911 by John Frederick Forssman. Blood type A/B glycosyltransferases (AT/BTs) and Forssman glycolipid synthase (FS) are encoded by the evolutionarily related ABO (A/B alleles) and GBGT1 genes. In this article, based on published studies about the pathogenesis of the COVID-19, we hypothesize the possible relationship between the COVID-19 infection and rare blood type systems, such as the Forssman antigen system.

Molecular red cell genotyping of rare blood donors in South Africa to enhance rare donor-patient blood matching.

BackgroundMolecular red cell genotyping is devoid of serology limitations such as the scarcity of rare antisera and the possibility of inconclusive results due to biological interferences. Blood incompatibility can result in immune transfusion reactions such as haemolytic transfusion reactions or haemolytic disease of the foetus and newborn.ObjectiveThe study aimed to use molecular red cell genotyping to identify rare blood group donors among South African blood donors.MethodsRed cell genotyping data were extracted retrospectively from the BIDS XT genotyping software in the Immunohaematology Reference Laboratory from January 2015 to August 2016. The ID CORE XT genotyping assay was used to identify the single nucleotide polymorphisms of 10 blood groups system alleles in 150 donors. Associations between the resultant genotypes and predicted phenotypes, ABO group, RhD type, race group and gender were studied.ResultsSignificant red cell genetic variability was noted among the numerous South African donor genotypes identified in this study. Genotyping further confirmed the presence of at least one of the 16 rare genotypes in 50 donors. Group O Black donors were associated with two rare blood types, while several other rare blood types were found only in White donors, supporting an association between ABO/Rh subtype, race group and rare blood types.ConclusionTargeted screening of donors for antigen-negative rare blood units for patients should be done to reduce the risk of haemolytic transfusion reactions and haemolytic disease of the foetus and newborn.

Two novel alleles on Fucosyltransferase 2 from northern Thai para‐Bombay family and computational prediction on mutation effect

Major characteristics of the para-Bombay phenotype are the absence of ABH antigens on red blood cells due to fucosyltransferase 1 (FUT1) gene mutation and the presence of these antigens in body secretions due to the active fucosyltransferase 2 (FUT2) gene. An ABO blood group discrepancy can be identified via serological testing, and additional tests can be performed for confirmation. This study aimed to resolve the ABO discrepancy and report two novel alleles on the FUT2 gene in northern Thai para-Bombay families. Twelve blood samples were collected from five suspected para-Bombay donors and their families. Nucleotide sequences of ABO, FUT1, and FUT2 were analyzed by polymerase chain reaction-sequence-based typing. Bioinformatics tools were used to predict the effect of suspected novel FUT2 alleles. All samples exhibited normal ABO alleles, concordant with serological test results. FUT1 exhibited three known variants (c.328G>A, c.424C>T, and c.658C>T). Although FUT2 exhibited two known variants (c.357C>T and c.385A>T), two novel alleles were observed. One allele consisted of c.98A>G, c.101T>G, and c.357C>T with predicted normal transferase activity, whereas the other consisted of c.357C>T and c.617T>C with predicted abnormal enzyme activity. Two novel alleles in FUT2 were reported among the affected para-Bombay individuals of northern Thai families. The c.617T>C variant caused an amino acid change from valine to alanine at position 206, predicted to be an inactive FUT2 enzyme. Inheritance of this variant with the recessive FUT1 allele may lead to inheritance of the rare Bombay blood group in the progeny.

Genotyping for Dombrock blood group alleles in Northern Pakistani blood donors.

Abstract Genotyping can be used to identify rare blood group antigens and to solve suspected blood group discrepancies, particularly when serologic methods are limited. Unfortunately, only a few such studies have been performed in Pakistan. The present study was conducted to determine the frequency of Dombrock blood group alleles by genotyping samples from blood donors from the north of Pakistan. Blood samples were taken with consent from 300 blood donors; DNA was extracted and tested for DO*01 and DO*02 alleles by sequence-specific primer polymerase chain reaction (PCR-SSP), followed by gel electrophoresis. Allele frequencies were calculated. The observed and expected genotype frequencies were compared using the χ 2 test. The allele frequencies for DO*01 and DO*02 were 0.40 and 0.60, respectively. Genotype frequencies were in Hardy-Weinberg equilibrium. This study in Pakistani blood donors provides Dombrock blood group allele frequencies by PCR-SSP. This approach is efficient and economical and can be applied in developing countries. The findings can contribute to the development of in-house red blood cell panels, identification of rare blood types, and establishment of a national rare blood donor program.