[Establishment of a genotyping method for the junior blood group and identification of a rare blood type with partial DVI.3 and Jr(a-)].

OBJECTIVE: To develop a genotyping method for the Junior blood type and report on a rare blood type with Jr(a-). METHODS: Healthy O-type RhD+ volunteer donors of the Shenzhen Blood Center from January to May 2021 (n = 1 568) and a pedigree with difficult cross-matching (n = 3) were selected as the study subjects. Serological methods were used for proband's blood type identification, unexpected antibody identification, and antibody titer determination. Polymerase chain reaction-sequence specific primer (PCR-SSP) method was used for typing the proband's RhD gene. ABCG2 gene coding region sequencing and a PCR-SSP genotyping method were established for determining the genotypes of the proband and his family members and screening of Jra antigen-negative rare blood type among the 1 568 blood donors. RESULTS: The proband's ABO and RhD blood types were respectively determined as B and partial D (RHDDVI.3/RHD01N.01), Junior blood type Jra antigen was negative, and plasma had contained anti-D and anti-Jra. Sequencing of the ABCG2 gene revealed that the proband's genotype was ABGG201N.01/ABGG201N.01 [homozygous c.376C>T (p.Gln126X) variants], which is the most common Jr(a-) blood type allele in the Asian population. Screening of the voluntary blood donors has detected no Jr(a-) rare blood type. Statistical analysis of the heterozygotes suggested that the allelic frequency for ABCG2*01N.01 (c.376T) was 0.45%, and the frequency of Jr(a-) rare blood type with this molecular background was about 0.2‰. CONCLUSION: A very rare case of partial DVI.3 type and Jr(a-) rare blood type has been identified. And a method for identifying the Junior blood type through sequencing the coding regions of the ABCG2 gene and PCR-SSP has been established.

Naturally occurring anti-PP1PK in a Chinese individual with p phenotype: A case based on compound heterozygosity including one novel allele.

BACKGROUND: The null phenotype in P1PK blood group, known as "p," is extremely rare in the whole world. Individuals of p phenotype spontaneously form anti-PP1PK isoantibody. Here, we report a case of p phenotype with naturally occurring anti-PP1PK isoantibodies in a Chinese individual. STUDY DESIGN AND METHODS: Serology tests, containing alloantibodies screening and identification, were conducted to demonstrate the phenotype in P1PK blood group. The genotype of A4GALT gene was identified by haplotypes separation and sequencing. RESULTS: The serological assay demonstrated the p phenotype of the proband, presenting with 1:64 titer of anti-PP1PK . The sequencing data revealed a compound heterozygote consisting of A4GALT*P1.01 with c.343A>T and a novel allele based on A4GALT*01N.05 with an addition polymorphism c.100G>A. The sequence of the novel allele has been submitted to GenBank and the accession number OM912503 was assigned. CONCLUSION: Our study demonstrates a case of naturally occurring anti-PP1Pk in a Chinese individual with p phenotype, which is based on compound heterozygosity including one novel allele. As the proband is a young lady, monitoring the titer of anti-PP1PK and early initiation of medical intervention are essential after her pregnancy.

Characterization of alternatively spliced transcript variants of glycophorin A and glycophorin B genes in Chinese blood donors.

BACKGROUND AND OBJECTIVES: The molecular basis of MNS blood group variants is not fully clear yet. In this study, we have characterized mRNA variants of GYPA and GYPB genes to reveal whether alternative RNA splicing may cause antigenic diversity of the MNS system. MATERIALS AND METHODS: Total RNA was extracted from peripheral blood of Chinese blood donors and full-length cDNA products were generated. A nested polymerase chain reaction (PCR)-based method was established for fragment amplification and Sanger sequencing. Resulted full-length mRNA sequences were aligned with GYPA or GYPB genomic sequences respectively for exon identification. Amino acid (AA) sequences of GPA and GPB proteins were extrapolated and GYPA-EGFP, GYPB-EGFP fusion genes were generated to monitor subcellular distribution of the encoded glycophorin (GP) proteins. RESULTS: Totally 10 blood samples were analysed. GYPB mRNAs of all the subjects demonstrated frequent exon insertion or deletion whereas this kind of variation was only observed in 3 of 10 GYPA mRNA samples. None of the reported Miltenberger hybrids was detected in any of the mRNA samples. The alternative splicing resulted in changes of AA sequences in N-terminal domains where the MNS antigenic motifs resided; however, subcellular localizations of GP-EGFP fusion proteins showed that the above-mentioned AA changes did not affect cell surface distribution of the encoded GP proteins. CONCLUSIONS: Alternative RNA splicing may influence the antigenic features of GP proteins but not their cell surface distribution. Therefore, GYPA and GYPB mRNA characterization might be an invaluable supplement to serological phenotyping and DNA-based genotyping in MNS blood grouping.

Indirect purification method provides high yield and quality ssDNA sublibrary for potential aptamer selection.

The quality and yield of single-stranded DNA (ssDNA) play key roles in ssDNA aptamer selection. However, current methods for generating and purifying ssDNA provides either low yield due to ssDNA loss during the gel purification process or low specificity due to tertiary structural damage of ssDNA by alkaline or exonuclease treatment in removing dsDNA and by-products. This study developed an indirect purification method that provides a high yield and quality ssDNA sublibrary. Symmetric PCR was applied to generate a sufficient template, while asymmetric PCR using an excessive nonbiotinylated forward primer and an insufficient biotinylated reverse primer combined with a biotin-strepavidin system was applied to eliminate dsDNA, hence, leading to ssDNA purification. However, no alkaline or exonuclease were involved in treating dsDNA, so as to warrant the tertiary structure of ssDNA for potential aptamer SELEX selection. Agarose gel imaging indicated that no dsDNA or by-product contamination was detected in the ssDNA sublibrary generated by the indirect purification method. Purified ssDNA concentration reached 1020±210nM, which was much greater than previous methods. In conclusion, this novel method provided a simple and fast tool for generating and purifying a high yield and quality ssDNA sublibrary.

[Polymorphism of the Full-Length mRNA Sequences of MNS blood group-related genes GYPA, GYPB and GYPE].

OBJECTIVE: The characteristics of the full-length mRNA sequences of MNS blood group-related genes GYPA, GYPB and GYPE were analyzed to understand the polymorphism of MNS blood group genes. METHODS: Anticoagulated blood within 24 h from 500 unpaid blood donors (8 ml each) were randomly selected, and MN, Ss and Mia blood types were identified by serological methods. 5 samples with different combinations of MNS and Mia blood types were randomly selected from 500 samples, and peripheral blood mononuclear cells (PBMC) were isolated by density gradient centrifugation, then total mRNA was extracted. cDNA was prepared by using the reverse transcription kit. The target fragments were amplified by nested PCR, and the full-length mRNA sequences of GYPA, GYPB and GYPE were sequenced after gel cutting and recycling, and the base sequences were analyzed by Oligo 6.0 software. RESULTS: The MN, Ss and Mia phenotypes were detected by serological methods, and there were differences in agglutination intensity of red blood cells (RBC) and anti-Mia serum between different individuals. The full-length mRNA sequences of GYPA, GYPB and GYPE genes in 5 samples of different phenotype combinations were detected. The exon-6 was completely deleted from the GYPA mRNA in 1 sample, and the full-length of GYPA mRNA in the other 4 samples were complete. The exon-2 was completely deleted from the GYPB mRNA in 2 samples, with Mia blood type negative. 2 samples showed complete full-length of GYPB mRNA, with Mia blood type positive. There was base substitution in exon-5 of GYPB mRNA in 1 sample. The full-length of GYPE mRNA was intact in 5 samples. CONCLUSION: MNS blood group related-genes have obvious polymorphism, and the detection of full-length mRNA sequence lays a foundation for the analysis of GYPA, GYPB and GYPE gene structure and in-depth study of MNS blood group antigen expression.

Maternal Cold-Reacting Immunoglobulin G Anti-M of MNS Blood Group System Causing Hemolytic Disease of the Fetus.

Several cases of the hemolytic disease of the fetus and newborn (HDFN) caused by immunoglobulin G (IgG) anti-M antibodies have been reported, in which almost all the HDFN-associated anti-M were warmly reacting. Here we report two cases of severe HDFN associated with cold-reacting IgG anti-M. In both cases, pregnancy was terminated, in weeks 33 and 23 respectively, due to a diagnosis of fetal growth retardation (FGR). To our knowledge, these are the most severe HDFN cases caused by cold-reacting IgG anti-M.

[Genotyping of Duffy Blood Group by Microchip Capillary Electrophoresis].

OBJECTIVE: To explore a method for rapidly screening the Duffy blood group genotypes and to establish an information bank of rare blood type donors. METHODS: The microfluidic capillary electrophoresis system and PCR-SSP method were used to analyze the Duffy genotype of 3 936 unrelated O-type blood donors in our center from December 2014 to September 2018. The serologic identification and typing of other blood type system phenotypes for FYa-negative specimen were performed. The Fy (a-b-) specimen was sequenced for genotyping. RESULTS: The phenotypes of FYa-negative specimens were consistent with the genotyping results of the microfluidic capillary electrophoresis system. The results of Duffy phenotyping in 3 936 specimens were follows: Fy (a+b-) 3 564 (90.54%), Fy(a+b+) 353 (8.97%), Fy(a-b+) 18 (0.46%), Fy (a-b-) 1 (0.03%). The gene frequency was FY*A (95.03%), FY*B (4.94%), and FY*Null (0.03%). The bank of rare blood types of 19 FYa-negative specimens was established. CONCLUSION: Microfluidic capillary electrophoresis system is suitable for Duffy blood group genotyping screening. It can be used to establish a bank of rare blood type, so as to solve the problem of urgent blood transfusion in patients with rare blood type, and to improve blood transfusion safety.

DNA sequence analysis and Jk blood group genotype-phenotype assessment.

BACKGROUND: The Kidd (JK) blood group is critical for clinical blood transfusion. Various methods for Jk typing have been commonly used, including urea hemolysis, serological test, and genotyping. However, the application of molecular methods has so far been restricted to selected samples and not been applied to the population-scale analysis. METHODS: One hundred eighty-three blood samples, containing 174 samples collected from voluntary blood donors of Chinese Han individuals, together with 3 Jk (aw+b-) and 6 Jk (a-b-) samples, were investigated by standard serology urea hemolysis test and Sanger-sequencing. Complete coverage of exons 4-11 and intron-exon borders have been sequenced. RESULTS: We report the frequencies of three SNPs in exon 4, 7, and intron 9. Besides, sequence analysis revealed the simultaneous DNA variants of intron 7 (-68) and exon 9 (838) found in all samples, suggesting the co-inheritance of these SNPs-taking the observed SNPs frequencies into account. Further, we discuss the potential of the sequencing technique for high-resolution genotyping. CONCLUSIONS: The described sequencing method for Jk exons delivers a genotyping technique for Jk molecular characterization. According to the co-inheritance of these DNA variants in intron 7 (-68) and exon 9 (838), and their regularity linkage with Jk phenotypes, these two sites offer a potential sequencing target for rapid and far more simplified Jk typing that can supplement routine serology and urea hemolysis tests.

[Allele Frequency and Distribution of Single Nucleotide Polymorphisms in Promoter Region of Gene Encoding the Kidd Blood Group Antigens].

OBJECTIVE: To study the single nucleotide polymorphisms (SNPs) in promoter region of the Jk gene and its allele frequency as well as distribution characteristics in the Chinese Han nationality population. METHODS: 127 blood samples containing 8 Jk(a-b-) and 119 samples (as control) taken randomly from voluntary blood donors of Chinese Han nationality persons in Shenzhen Blood Center were collected. The Kidd phenotypes were identified by using the serologic test and urea hemolysis test; the Jk promoter, exon 1-11 region and respective flanking area were amplified and sequenced, then the sequence information was analyzed. RESULTS: 8 Jk(a-b-) samples all carried JkB/JkB allele which belongs to 2 kind of Jknull genotypes commonly observed in Chinese Han nationality population. 6 IVS5-1g>a and 2 896G>A were found in 8 Jk(a-b-) samples. Besides, all Jk(a-b-) samples were homozygous for JkB/JkB allele. Three SNPs-110(rs900974), -160(rs1484877) and -258(rs1484878) in promoter region of the Jk gene were found and sequenceds calculation of allele and genotype frequencies showed that the result accorded with Hardy-Weinberg equilibrium, indicating that the population in this study possesses representative characteristics of the Chinese Han nationality population. CONCLUSION: The polymorphism of the Jk gene occurs in promoter region. This study calculates the allele frequencies of three SNPs-110(rs900974), -160(rs1484877) and -258(rs1484878) in promoter region of the Jk gene, and shows their distribution characteristics in distinct Kidd phenotypes. These findings provide the basic foundation for further population genetics research.

Haemolytic disease of fetus and newborn caused by ABO antibodies in a cisAB offspring.

ABO hemolytic disease of fetus and newborn (ABO-HDFN) occurs almost exclusively in infants of blood group A or B who are born to group O mothers because IgG anti-A or -B occurs more commonly in group O than in group A or B individuals. We report a case of clinically significant ABO-HDFN where the mother was blood group O with elevated IgG anti-A and anti-B titers and delivered a child with an A2B phenotype. This unusual ABO constellation between mother and infant was based on the inheritance of a rare ABO allele encoding for a glycosyltransferase capable of synthesizing both A and B antigens. Because both anti-A and anti-B antibodies may have been involved in hemolysis in this case, it may be relevant to consider the cisAB phenomenon when monitoring ABO-incompatible pregnancies and births.

Molecular polymorphism of O alleles in the Chinese Han population.

The ABO blood group system is the most important in transfusion medicine. O blood group is common in Chinese Han people, but the distribution of various O alleles is unknown. Sequences of exon6 and exon7 of the O allele at the ABO gene locus were studied in 100 individuals of the O phenotype randomly selected from the Chinese Han population. Some samples, when required, were cloned and sequenced spanning exon6 and exon7. Eight O alleles were found in the Chinese population. Most have the 2 common O01 or O02 alleles. The allele frequency of ABO*O01 was 0.47, and that of ABO*O02 was 0.495. One individual was found to have O05 allele. Five alleles were found to differ from all alleles reported to date. Four of these alleles differed from either the O01 allele (1 out of 4) or O02 allele (3 out of 4) by 1 point mutation at A468G, G489A, T526C, or T1104G. The fifth allele differed from the O01 allele since it does not have nt261G deletion but has C467T mutation. This novel allele occurred in 2 individuals. O genetic analysis suggests that the O01 allele prevails, with O1v accounting for about 97% of these in the Chinese Han population. The O03 allele that has been shown to occur with a frequency of <5% in other populations was not detected. But the novel O allele without 261G deletion has been found in Chinese for the first time. Surely more O alleles will be found in the Chinese population.

[Study on ABO gene polymorphism in Uighur nationality in Xinjiang of China].

OBJECTIVE: To study the distribution of ABO gene polymorphism in Uighur population in Xinjiang area of China. METHODS: DNA was extracted from 160 Uygur unrelated donorso blood and PCR-sequence specific primer analysis was performed. Some difficult samples were further directly sequenced. RESULTS: Six alleles were detected in a population of 160 Uighur individuals, the gene frequencies of which were 0.2062(A101), 0.0563(A102), 0.0156(A201), 0.0031(A205),0.1875(B01),0.5312(O01), respectively. CONCLUSION: The characteristics for AB gene structure of Xinjiang Uighur suggests that genetic polymorphism is distinguished between Xinjiang Uighur nationality and Chinese Han nationality, and both of them have discrepancy and confluent characters.

[Molecular genetic analysis of FUT1 and FUT2 gene in para-Bombay Chinese: a novel FUT1 allele is identified].

OBJECTIVE: Molecular genetic analysis of FUT1 and FUT2 gene was performed for seven Chinese Han individuals serologically typed as para-Bombay. METHODS: Seven DNA samples were studied by polymerase chain reaction and then by direct sequencing. Molecular cloning sequencing was done for an individual with a novel FUT1 allele. Family segregation analysis of the novel FUT1 allele was done to explore whether the allele was responsible for the fucosyltransferase defects of H. RESULTS: The FUT1 genotypes of seven para-Bombay individuals were h1h1 (four individuals), h2h2 (two individuals), h328hnew (one individual), alleles h1 lost one of the three AG repeats located at the nucleotides 547-552 of the FUT1 gene, h2 lost two of the three T repeats located at the nucleotides 880-882, h328 (nt328G>A) was a missense mutation, all of them were known mutations, while allele hnew deleted GGTATTCCGCATCACCCTGCCCGTGCTGGCCCC at nt360-400, total 33 bases, and the frame-shift mutation was not previously reported. The segregation of the hnew allele in his family showed that his father genotype was Hh328, and his mother was Hhnew, while two brother were h328hnew. The FUT2 genotypes of seven para-Bombay individuals were Se357 Se357 (three individuals), Se357 Se357,385 (three individuals), Se357,716Se357,716(one individual), the functional Se357(nt357C>T), Se716(nt716G>A) and the weakly functional Se385(nt385A>T) were known. The seven para-Bombay individuals carried at least one copy of a functional FUT2 allele was consistent with their secretor status. CONCLUSION: A novel FUT1 allele was identified in a para-Bombay Chinese individual, which was responsible for the inactivation of the FUT1-encoded enzyme activity.

[Molecular genetic analysis of Diego blood group Dia and Dib in Chinese Han population].

OBJECTIVE: To study the molecular genetic background of Diego blood group in Chinese Han population. METHODS: A total of 2990 blood samples from unrelated blood donors were phenotyped for Dia and Dib by serological method. Twenty randomly selected samples of Di(a-b+) type and all of the samples of rare Di(a+b-) phenotype by screening were genotyped by PCR-SSP and direct DNA Sequencing. RESULTS: Of the 2990 samples identified by serological method, 2821 were Di(a-b+), 167 were Di(a+b+) and 2 were Di(a+b-). All of the 20 randomly-selected samples with Di(a-b+) phenotype were DI2DI2 homozygote by PCR-SSP genotyping, with nucleotide C at nt position 2561 in exon 19 by direct sequencing of the DI gene. The 2 samples of rare Di (a+b-) phenotype were both the DI1DI1 homozygote, with nucleotide T at nt position 2561 in exon 19. CONCLUSION: Our results indicate that the expression of Dia and Dib antigens in Chinese Han population most likely result from a single nucleotide T to C substitution at nucleotide position 2561 in exon 19 of the DI gene, which subsequently leads to an amino acid 854 change from Pro to Leu.

[Establishment and Application of a Method for Determination of Glycosyltransferase Activity].

OBJECTIVE: To establish a method for determination of glycosyltransferase and to explore the enzyme A, B glycosyltransferase activity in human serum so as to lay the foundation for the determination of enzyme level and enzyme activity. METHODS: The glycosyltransferase activity kit was used to draw phosphate standard curves in our laboratory. The A and B glycosyltransferase activity were determined by the standard curves. RESULTS: The standard curves (y=2671.3x-0.596 R2=0.9998) for determing glycosyltransferase activity suitable for use in our laboratory were drawn. At the same time the method was set up for determination of A, B glycosyltransferase in human serum. CONCLUSION: The establised method of the determination of glycosyltransferase is suitable for common type of enzyme activity and suitable for the A, B glycosyltransferase in human serum.