Objective To precisely identify the para-Bombay blood types in cancer patients at our hospital, establish a robust system for the identification of challenging blood types in our laboratory, and provide a foundation for precise transfusion practices. Methods We retrospectively analyzed the blood type results of 91 874 cancer patients from January 1, 2019, to December 31, 2023. Conventional serological methods were used to screen for blood types, and suspected para-Bombay blood types were identified. Further analysis was performed using Pacific Biosciences (PacBio) single-molecule real-time sequencing and Sanger sequencing was used to determine the genotypes of the ABO, FUT1, and FUT2 genes. Results Eight cases of para-Bombay blood type were confirmed through serological and molecular biological methods. The FUT1 genotypes identified were: 5 cases of h1h1 (homozygous mutation 551_552delAG) and 3 cases of h1h2 (compound heterozygous mutations of 551_552delAG and 880_882delTT). The FUT2 genotypes identified were: 2 cases of Se³⁵⁷/Se^{357, 716} and 4 cases of Se³⁵⁷/Se³⁵⁷. Additionally, one sample revealed a novel heterozygous mutation, 818C>T, in exon 7 of the ABO gene, which was confirmed by PacBio sequencing to be located on the O haplotype. Conclusion PacBio sequencing technology demonstrates significant advantages in analyzing the haplotypes of para-Bombay blood type genes. This approach supports the establishment of a robust system for the identification of challenging blood types and provides novel evidence for precise transfusion practices in cancer patients.
Humans ; Neoplasms/genetics* ; Fucosyltransferases/genetics* ; ABO Blood-Group System/genetics* ; Male ; High-Throughput Nucleotide Sequencing/methods* ; Galactoside 2-alpha-L-fucosyltransferase ; Female ; Retrospective Studies ; Genotype ; Middle Aged ; Blood Grouping and Crossmatching/methods* ; Adult ; Mutation ; Aged

OBJECTIVE: To analyze the serological and molecular biological characteristics of 5 patients with cis AB blood group, and to explore the safe transfusion strategy. METHODS: Serological identification of the samples' blood group was performed using anti-A, anti-B, anti-D, anti-A1, anti-H typing reagents and ABO reagent erythrocytes. Molecular biological identification of the samples' blood group was performed using PCR-SSP or gene sequencing. RESULTS: The serological identification results of blood group in 5 patients all showed inconsistent forward and reverse typing, presenting as A₂B₃ or A₂B_w. ABO gene sequencing of samples 1, 2 and 3 showed 261delG in exon 6 and 467C>T, 803G>C in exon 7. The genotypes of samples 1, 2 and 3 were determined to be cisAB/O . PCR-SSP genotyping was performed on sample 4 and 5，and the results were both cisAB/O . CONCLUSION Patients with cisAB alleles have inconsistent serological manifestations, and genetic testing is necessary to ensure the safety and effectiveness of blood transfusion.
Humans ; ABO Blood-Group System/genetics* ; Blood Transfusion ; Blood Grouping and Crossmatching ; Genotype ; Blood Group Antigens/genetics* ; Alleles ; Male ; Female

OBJECTIVE: By analyzing the correlation between genotypes and phenotypes, we explored the impact of the variant c.917T>C (p.L306P) in the ABO*B.01 allele on the expression and function of B-glycosyltransferase (GTB). This study aims to elucidate the molecular mechanisms underlying the occurrence of this subtype. METHODS: The study subjects included a blood donor specimen with incompatible forward and reverse ABO typing results. ABO phenotyping was determined using ABO blood group serology and GTB activity testing. Subsequently, Sanger sequencing and third-generation sequencing based on the PacBio platform were employed to sequence the ABO gene, resulting in the determination of haplotype sequences. Mutations were identified through sequence alignment. An in vitro cell expression system was established to assess the impact of the mutation site on antigen expression. RESULTS: The index case in this study was identified as B subtype with the allelic genotype c.917T>C in ABO*B.01/ABO*O.01.01 , which has not been previously reported. in vitro expression results revealed decreased levels of GTB expression and overall GTB activity in the mutant cells. Furthermore, the expression of the B antigen on the cell membrane was weaker in the mutant cells compared to the wild-type cells. CONCLUSION The p.L306P variation caused by the c.917T>C mutation in the ABO*B.01 allele may be a genetic factor contributing to the reduced expression of B antigens on the surface of red blood cells.
Humans ; ABO Blood-Group System/genetics* ; Alleles ; Genotype ; Mutation ; Glycosyltransferases/genetics* ; Haplotypes ; Phenotype

OBJECTIVE: To analyze the B_el subtype gene mutation and its genetic mechanism in a family line. METHODS: ABO blood groups were identified by serologic tests. ABO genotyping was performed by polymerase chain reaction with sequence-specific primer (PCR-SSP). Sanger sequencing was performed on exons 1-7 of the ABO gene, the flanking intronic region, and exon 7 of the single strand of the gene confirmed the mutation site location. Missense3D software was used to predict the protein structure alteration caused by this mutation. RESULTS: Conventional serologic tests failed to detect erythrocyte B antigen in the proband and her three family members, and only trace amounts of B antigen expression could be detected by the absorption-dispersal test. DNA analysis showed that, on the basis of the normal ABO gene, there was a G>T substitution in the position of exon 7, position 803, which resulted in the change of amino acid 268 from Gly to Val. Further single-stranded sequencing analysis showed that the mutation site was located in the B gene. CONCLUSION In this family line, the proband, her father, her son, and her daughter all have reduced B type glycosyltransferase activity due to the new point mutation (c.803G>T) in exon 7 of the B gene, and the B antigen can only be detected by the absorption-dispersal method, and the point mutation can be stably inherited by offspring.
Point Mutation ; Alleles ; ABO Blood-Group System/genetics* ; Exons ; Introns ; Genotype ; Humans ; Male ; Female ; Glycosyltransferases/genetics*

OBJECTIVE: To identify the blood type of specimens from pregnant patients with difficult-to-type ABO status, and to guide clinical safe blood transfusion. METHODS: The specimens from 36 pregnant patients with suspicious ABO blood group were collected. These specimens were submitted by clinical institutions from various regions to our center's genetic testing platform from January 2021 to December 2022. The blood group phenotypes and genotypes of these specimens were identified by serological method and genetic sequencing. RESULTS: A total of 20 ABO subtypes were detected in the 36 samples, including 10 cases of BA/O, 3 cases of cisAB/O, 2 cases of A/Bw, 1 case of A2/B, 1 case of Aw/B, 1 case of BA/B, 1 case of BA/A, and 1 case of Bw/O. Additionally, 4 cases were identified as para-Bombay blood type, and no specific variations associated with abnormal phenotypes were found in the remaining 12 cases. CONCLUSION ABO subtypes interfere with ABO blood group identification in pregnant patients, and pregnancy status also affects blood group phenotype. Accurate determination of blood group genotype by genetic sequencing technology can guide clinical blood transfusion for pregnant patients, and ensure maternal and infant safety.
Humans ; Female ; Pregnancy ; ABO Blood-Group System/genetics* ; Blood Grouping and Crossmatching ; Blood Transfusion ; Genotype ; Phenotype

OBJECTIVE: Serological and molecular biological analysis of a B(A) subtype family was carried out to explore the underlying mechanism of B(A) subtype and clinical safe blood transfusion strategies. METHODS: The ABO blood type of the proband and her four family members were identified by serological methods, and serological experiments such as anti-H, anti-A1 and absorption-elution tests was added. In addition, the exons 6 and 7 of the ABO gene were sequenced by PCR-SSP (polymerase chain reaction - sequence specific primer). RESULTS: The serological results showed that the agglutination intensity of the proband, her mother and her maternal grandmother was imbalanced during forward typing, showing weak A and strong B antigens, and there were strong H antigens and their intensity were higher than that of normal B type. The results of reverse typing indicated the presence of weak anti-A1 antibodies, and human anti-A was positive in the absorption-elution test. Genetic sequencing revealed a characteristic mutation of c.700 C>G in all three individuals. The sequencing results showed that the proband was B(A)02/B01, her mother was B(A)02/O02, and her maternal grandmother was B(A)02/O01 . According to the compatibility principle, 1.5 units of type O washed red blood cells were transfused intraoperatively, resulting in no adverse reactions. CONCLUSION The c.700 C > G mutation on exon 7 is the molecular basis for the formation of B(A)02, and pedigree analysis shows that the B(A)02 allele was inherited from the proband's maternal grandmother to the proband's mother and then to the proband, showing a stable cis-inheritance pattern rather than a spontaneous mutation. For patients with B(A)02 subtype, type O washed red blood cells and type AB plasma can be transfused according to the principle of compatibility.
Humans ; ABO Blood-Group System/genetics* ; Female ; Blood Transfusion ; Blood Grouping and Crossmatching ; Pedigree ; Male ; Mutation ; Adult ; Exons

OBJECTIVE: To study the characteristics of a novel variant of the α-1,3-N-acetylgalactosaminyltransferase gene in a family through serological and gene sequence analyses of a proband with ABO subtype and her family members. METHODS: Blood samples of the proband and four family members were collected. The ABO phenotypes were detected by serological methods, and the ABO blood group genotyping was performed by fluorescence PCR. Direct sequencing was carried out for exons 1-7 of the ABO gene in the proband and family members, and cloning sequencing was conducted for exons 6 and 7. RESULTS: The serological test showed that the blood group phenotype of the proband was Ael type, and the ABO blood group genotyping result was A/O. Sequencing results indicated that on the basis of the ABO*A1.01 sequence, there were simultaneous variations of c.467C>T and c.664G>A in exon 7 of the A allele, which belonged to a novel variation of the A allele and had been registered in GenBank with the accession number MZ076784.1. Family investigation revealed that the proband, her son and granddaughter all had this novel variation. CONCLUSION On the basis of the ABO*A1.01 sequence, the new variation of the combination of c.467C>T and c.664G>A in exon 7 is a heritable variation. It is speculated that this variation is the cause of the weakened expression of the A antigen.
Humans ; N-Acetylgalactosaminyltransferases/genetics* ; ABO Blood-Group System/genetics* ; Pedigree ; Female ; Genotype ; Male ; Exons ; Alleles ; Phenotype

OBJECTIVE: The molecular biology of alleles of ABO blood group A_el and B_el subtype from two samples was analyzed to explore the effect of mutations on the structure of glycosyltransferase. METHODS: The ABO phenotypes were identified by serological techniques, then exons 6 and 7 of ABO gene were amplified and sequenced, combined with haplotype analysis to determine the genotypes. Finally, homology modeling of the mutated A/B glycosyltransferase were conducted by Modeller software and the effect of mutations on the spatial structure was analyzed by PyMol software. RESULTS: The serological phenotypes of the two samples were A_el and B_el, and their genotypes were ABO*AW.37/ABO*O.01.01 and ABO*BEL.03/ABO*O.01.01, respectively. The three-dimensional structure modeling of the protein showed that, compared to the wild-type glycosyltransferase, two hydrogen bonds between the side chain of p.Glu314 and surrounding amino acid disappeared in the p.Lys314Glu mutant GTA; the hydrogen bonds between the side chain of p.Trp168 and surrounding amino acid also disappeared, and the hydrogen bond between the main chain of p.Trp168 and p.Gly165 was shortened to 3.3 Å in the p.Arg168Trp mutant GTB. CONCLUSION Mutations in exon 7 of ABO gene c.940A>G and c.502C>T are keys to the formation of AW.37 and BEL.03 alleles, resulting in decreased expression of A and B antigens, respectively.
ABO Blood-Group System/classification* ; Humans ; Genotype ; Mutation ; Alleles ; Glycosyltransferases/genetics* ; Exons ; Haplotypes ; Phenotype ; Models, Molecular

OBJECTIVE: To explore the molecular mechanism for an individual with Bweak subtype. METHODS: Serological methods were used to identify the proband's phenotype. In vitro enzyme activity test was used to determine the activity of B-glycosyltransferase (GTB) in her serum. The genotype was determined by PCR amplification and direct sequencing of exons 5 to 7 and flanking sequences of the ABO gene. T-A cloning technology was used to isolate the haploids. The primary physical and chemical properties and secondary structure of the protein were analyzed with the ProtParam and PSIPRED software. Three software, including PolyPhen-2, SIFT, and PROVEAN, was used to analyze the effect of missense variant on the protein. RESULTS: Serological results showed that the proband's phenotype was Bweak subtype with anti-B antibodies presented in her serum. In vitro enzyme activity assay showed that the GTB activity of the subject was significantly reduced. Analysis of the haploid sequence revealed a c.398T>C missense variant on the B allele, which resulted in a novel B allele. The 398T>C variant has caused a p.Phe133S substitution at position 133 of the GTB protein. Based on bioinformatic analysis, the amino acid substitution had no obvious effect on the primary and secondary structure of the protein, but the thermodynamic energy of the variant protein has increased to 6.07 kcal/mol, which can severely reduce the protein stability. Meanwhile, bioinformatic analysis also predicted that the missense variant was harmful to the protein function. CONCLUSION The weak expression of the Bweak subtype may be attributed to the novel allele of ABO*B.01-398C. Bioinformatic analysis is helpful for predicting the changes in protein structure and function.
Female ; Animals ; ABO Blood-Group System/genetics* ; Phenotype ; Genotype ; Exons ; Alleles

Objective To investigate the effect of blood group serology and polymerase chain reaction with sequence-specific primers (PCR-SSP) on identification and genotyping of ambiguous ABO blood group. Methods Eighty suspicious ABO blood group samples were identified by serology and polymerase chain reaction with sequence-specific primers (PCR-SSP). The final blood group type and the strategy of the transfusion of each case were determined according to the results of serology and PCR-SSP. Results 40 cases were confirmed to be subtypes, and the remaining 40 cases were normal types with weakened antigens or missing antibodies due to other reasons. The results of molecular genetic blood group typing based on PCR-SSP were 41 cases of subtypes (There were 3 discrepancies between two methods: one was Ael identified by serological methods, while its gene type was O2O2; one was common type O, while its gene type was BO1; one was type A, while its gene type was AB.) and 39 cases of normal ones. Conclusion Genotyping technology combined with serological typing has an important significance in identification of ABO blood groups.
ABO Blood-Group System/genetics* ; Genotype ; Polymerase Chain Reaction ; Antibodies ; DNA Primers