OBJECTIVE: To investigate a case of antibodies against high-frequency erythrocyte antigens and elucidate the genetic mechanism underlying the blood group. METHODS: A Lan-negative patient referred to the Zhejiang Blood Center by Quzhou Hospital of Traditional Chinese Medicine in August 2016 was selected as the study subject. A retrospective study was conducted to collect the proband's clinical data. The proband's erythrocyte antigens and unexpected serum antibodies were identified using tube saline and microcolumn agglutination anti-human globulin methods. Antibody specificity was determined by treating erythrocytes with 7 enzymes and 2 chemical reducing agents. Genomic DNA was extracted from the proband's blood sample for whole genome sequencing (WGS) and erythrocyte blood group gene analysis, with validation by Sanger sequencing. Multiple bioinformatics tools were used to analyze the pathogenicity of the variant. The rare blood group and unexpected antibody specificity were comprehensively determined based on the results of serological and genetic testing. This study has been approved by the Zhejiang Provincial Blood Center Medical Ethics Committee(Ethics No.20190201). RESULTS: The proband was a 91-year-old Han Chinese male with prostatitis, cystitis, and malnutrition in conjunct with emaciation. He had a history of multiple erythrocyte transfusions without observable adverse reactions. Prior to the most recent transfusion, major crossmatch agglutination was observed, which prompted antibody identification. Antibodies against high-frequency antigens were detected in the proband's serum, with enzyme and reducing agent treatments ruling out antibody specificities associated with 17 blood group systems, e.g., MNS, LU, KEL. WGS analysis identified 4 525 SNPs and 1 046 INDEL variants among erythrocyte blood group genes. Further screening revealed that the proband had a rare blood group due to a homozygous rs755723161 variant. This variant in the ABCB6 gene (c.459delC) has led to a frameshifting mutation (p.Trp154GlyfsTer96), resulting in the Lan-negative rare blood group with a high-frequency antigen deficiency and the production of IgG anti-Lan antibodies in the serum. CONCLUSION This study has identified anti-Lan alloantibodies in a Lan-negative patient and, for the first time, elucidated the ABCB6 gene variant underlying the Lan-negative rare blood group in the Chinese population.
Humans ; Male ; Blood Group Antigens/immunology* ; Aged, 80 and over ; Retrospective Studies ; ATP-Binding Cassette Transporters

A 90-year-old female patient with novel coronavirus infection, severe pneumonia, and no history of blood transfusion andtransplantation.The mixed appearance phenomenon appeared in the admission blood group identification, and was sent the sample to our laboratory for difficult blood group identification. In the tube saline method, the patient′s red blood cells were positively reacted with 2 monoclonal anti-A and 5 human anti-A reagents.In the microcolumn gel method, the patient′s red blood cells showed 2 positive and 2 negative reactions with monoclonal anti-A and 5 positive and 1 negative reactions with human anti-A. The patient ′s red blood cells showed negative reaction with peanuts in phytohemagglutinin, and positive reaction with double flower lentils, wild soybeans and a string of purples. The patient ′s red blood cells treated with papain showed negative reaction with all monoclonal anti-A reagents, human anti-A and phytohemagglutinin. The patient ′s ABO gene was sequenced as ABO * B.01/O.01.02, but C1GALT1C1 gene mutation was not founded in the gDNA of the whole blood sample.It is speculated that the exposure of Tn antigen on the patient ′s red blood cells leads to red blood cells polyagglutination, resulting in ABO blood group inconsistency.

Objective:To investigate a case of antibodies against high-frequency erythrocyte antigens and elucidate the genetic mechanism underlying the blood group.Methods:A Lan-negative patient referred to the Zhejiang Blood Center by Quzhou Hospital of Traditional Chinese Medicine in August 2016 was selected as the study subject. A retrospective study was conducted to collect the proband′s clinical data. The proband′s erythrocyte antigens and unexpected serum antibodies were identified using tube saline and microcolumn agglutination anti-human globulin methods. Antibody specificity was determined by treating erythrocytes with 7 enzymes and 2 chemical reducing agents. Genomic DNA was extracted from the proband′s blood sample for whole genome sequencing (WGS) and erythrocyte blood group gene analysis, with validation by Sanger sequencing. Multiple bioinformatics tools were used to analyze the pathogenicity of the variant. The rare blood group and unexpected antibody specificity were comprehensively determined based on the results of serological and genetic testing. This study has been approved by the Zhejiang Provincial Blood Center Medical Ethics Committee(Ethics No.20190201).Results:The proband was a 91-year-old Han Chinese male with prostatitis, cystitis, and malnutrition in conjunct with emaciation. He had a history of multiple erythrocyte transfusions without observable adverse reactions. Prior to the most recent transfusion, major crossmatch agglutination was observed, which prompted antibody identification. Antibodies against high-frequency antigens were detected in the proband′s serum, with enzyme and reducing agent treatments ruling out antibody specificities associated with 17 blood group systems, e. g., MNS, LU, KEL. WGS analysis identified 4 525 SNPs and 1 046 INDEL variants among erythrocyte blood group genes. Further screening revealed that the proband had a rare blood group due to a homozygous rs755723161 variant. This variant in the ABCB6 gene (c.459delC) has led to a frameshifting mutation (p.Trp154GlyfsTer96), resulting in the Lan-negative rare blood group with a high-frequency antigen deficiency and the production of IgG anti-Lan antibodies in the serum. Conclusion:This study has identified anti-Lan alloantibodies in a Lan-negative patient and, for the first time, elucidated the ABCB6 gene variant underlying the Lan-negative rare blood group in the Chinese population.

Objective:To investigate a case of antibodies against high-frequency erythrocyte antigens and elucidate the genetic mechanism underlying the blood group.Methods:A Lan-negative patient referred to the Zhejiang Blood Center by Quzhou Hospital of Traditional Chinese Medicine in August 2016 was selected as the study subject. A retrospective study was conducted to collect the proband′s clinical data. The proband′s erythrocyte antigens and unexpected serum antibodies were identified using tube saline and microcolumn agglutination anti-human globulin methods. Antibody specificity was determined by treating erythrocytes with 7 enzymes and 2 chemical reducing agents. Genomic DNA was extracted from the proband′s blood sample for whole genome sequencing (WGS) and erythrocyte blood group gene analysis, with validation by Sanger sequencing. Multiple bioinformatics tools were used to analyze the pathogenicity of the variant. The rare blood group and unexpected antibody specificity were comprehensively determined based on the results of serological and genetic testing. This study has been approved by the Zhejiang Provincial Blood Center Medical Ethics Committee(Ethics No.20190201).Results:The proband was a 91-year-old Han Chinese male with prostatitis, cystitis, and malnutrition in conjunct with emaciation. He had a history of multiple erythrocyte transfusions without observable adverse reactions. Prior to the most recent transfusion, major crossmatch agglutination was observed, which prompted antibody identification. Antibodies against high-frequency antigens were detected in the proband′s serum, with enzyme and reducing agent treatments ruling out antibody specificities associated with 17 blood group systems, e. g., MNS, LU, KEL. WGS analysis identified 4 525 SNPs and 1 046 INDEL variants among erythrocyte blood group genes. Further screening revealed that the proband had a rare blood group due to a homozygous rs755723161 variant. This variant in the ABCB6 gene (c.459delC) has led to a frameshifting mutation (p.Trp154GlyfsTer96), resulting in the Lan-negative rare blood group with a high-frequency antigen deficiency and the production of IgG anti-Lan antibodies in the serum. Conclusion:This study has identified anti-Lan alloantibodies in a Lan-negative patient and, for the first time, elucidated the ABCB6 gene variant underlying the Lan-negative rare blood group in the Chinese population.

A 90-year-old female patient with novel coronavirus infection, severe pneumonia, and no history of blood transfusion andtransplantation.The mixed appearance phenomenon appeared in the admission blood group identification, and was sent the sample to our laboratory for difficult blood group identification. In the tube saline method, the patient′s red blood cells were positively reacted with 2 monoclonal anti-A and 5 human anti-A reagents.In the microcolumn gel method, the patient′s red blood cells showed 2 positive and 2 negative reactions with monoclonal anti-A and 5 positive and 1 negative reactions with human anti-A. The patient ′s red blood cells showed negative reaction with peanuts in phytohemagglutinin, and positive reaction with double flower lentils, wild soybeans and a string of purples. The patient ′s red blood cells treated with papain showed negative reaction with all monoclonal anti-A reagents, human anti-A and phytohemagglutinin. The patient ′s ABO gene was sequenced as ABO * B.01/O.01.02, but C1GALT1C1 gene mutation was not founded in the gDNA of the whole blood sample.It is speculated that the exposure of Tn antigen on the patient ′s red blood cells leads to red blood cells polyagglutination, resulting in ABO blood group inconsistency.

A puerpera with a obstetric history of gravida 2, para 2, underwent blood typing due to the presence of agglutination reactions in her serum against all tested red blood cells. She was found to be blood type O and her RhD phenotype was identified as CcDEe through serological testing. The reaction agglutination intensity between her serum and 26 O-type blood cells from the panel was 2+. Whole genome sequencing was performed, yielding data on 4014 single nucleotide polymorphisms (SNPs) and 958 insertion/deletion (INDEL) loci across 50 genes responsible for encoding blood group systems. Among these, only a single SNP , rs72552713 was predicted to be a highly harmful variant, which is the c.376C>T variation in the ABCG2 gene encoding JR blood group antigen, leading to the premature stop codon (p.Gln126Ter). The c.376C>T variation has been named the ABCG2*01N.01 by the working party on Red Cell Immunogenetics and Blood Group Terminology of International Society of Blood Transfusion. The postpartum woman was found to have the Jr(a-) phenotype. Whole genome sequencing can accurately determine the antigens of blood group systems in some difficult specimens.

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 analyze the serological characteristics and molecular mechanism for an individual with p phenotype. METHODS: An individual with p phenotype upon blood group identification at Jiaxing Blood Center in May 2021 was analyzed. ABO, RhD and P1PK blood groups and irregular antibodies in her serum were identified using conventional serological methods. The encoding region of α1, 4-galactosyltransferase gene (A4GALT) encoding P1 and Pk antigens was analyzed by polymerase chain reaction-sequence-based typing (PCR-SBT). RESULTS: The individual was A group, RhD positive and had a p phenotype of the P1PK blood group system. Anti-PP1Pk was discovered in her serum. Sequencing analysis revealed that she has harbored a homozygous c.343A>T variant of the A4GALT gene. CONCLUSION The homozygous c.343A>T variant of the A4GALT gene probably underlay the p phenotype in this individual.
Female ; Animals ; Blood Group Antigens ; Homozygote ; Phenotype ; Polymerase Chain Reaction ; Sequence Analysis, DNA

OBJECTIVE: To analyze the molecular characteristics of a recombinant allele of the ABO blood group. METHODS: The ABO phenotype was determined with the tube method. The coding regions of the ABO and FUT1 genes were analyzed by PCR-sequence based typing. The ABO alleles of the proband were determined by allele-specific primer sequencing. The full sequences of the ABO gene of the proband and her mother were determined through next generation sequencing. RESULTS: The red blood cells of the proband did not agglutinate with anti-H, and the sequence of the FUT1 gene was homozygous for c.551_552delAG.The proband was thereby assigned as para-Bombay. Bi-directional sequencing also found that she was heterozygous for c.261G/del,467C>T,c.526C>G,c.657C>T,c.703G>A,c.796C>A,c.803G>C and c.930G>A of the coding regions of the ABO gene. Allele-specific primer sequencing also found her to carry a ABO*A1.02 allele and a recombinant allele from ABO*O.01.01 and ABO*B.01. The recombination site was located between nucleotide c.375-269 and c.526, and the allele was maternally derived. CONCLUSION An recombinant allele of the ABO gene has been identified, which has originated from recombination of ABO*O.01.01 with the ABO*B.01 allele.
ABO Blood-Group System/genetics* ; Alleles ; Blood Grouping and Crossmatching ; Female ; Fucosyltransferases/genetics* ; Genotype ; Humans ; Phenotype ; Recombination, Genetic

OBJECTIVE: To explore the molecular basis for an individual with Bw subtype. METHODS: Routine serological reactions were used to determine the surface antigens of erythrocytes and antibodies in serum. PCR-sequence-based typing (PCR-SBT) was used to analyze the coding regions of the ABO gene and erythroid-specific regulatory element in its intron 1. Amplicons for exons 5 to 7 containing the variant site were subjected to TA cloning for the isolation of the haploid and verification of the sequence. The 3D structure of mutant protein was predicted with Pymol software. Changes of amino acid residues and structural stability were also analyzed. RESULTS: Serological assay showed that the individual had weakened B antigen and anti-B antibody in his serum. His genotype was determined as ABO*B.01/ABO*O.01.01. Sequencing of the entire coding region of the ABO gene identified an additional heterozygous c.734C/T variant. No variant was found in the erythroid-specific regulatory element of intron 1. Haploid cloning and isolation has obtained an ABO*O.01.01 allele and a ABO*B.01 allele containing a c.734T variant, which has led to substitution of Thr by Ile at position 245 in the functional center of glycosyltransferase. Based on the 3D structure of the protein, the residues binding with the mutation were unchanged, but the bonding distance between the hydrogens was changed with the amino acid substitution. Meanwhile, the connections with water molecules were increased. CONCLUSION The c.734C>T variant of the GTB gene can lead to an amino acid substitution in the functional center of the enzyme, which in turn may affect the stability of glycosyltransferase B protein and reduceits enzymatic activity.
ABO Blood-Group System/genetics* ; Alleles ; Exons/genetics* ; Genotype ; Glycosyltransferases/genetics* ; Humans ; Male ; Phenotype