Serological characteristics and molecular mechanism of an individual with p phenotype / 中华医学遗传学杂志

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.

Study of the molecular characteristics of a Bweak phenotype due to a novel c.398T>C variant of the ABO gene / 中华医学遗传学杂志

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.

Analysis of HLA allele-specific antibodies and Eplets in patients with platelet transfusion refractoriness / 中国输血杂志

【Objective】 To analyze the specificity and Eplets of HLA allele-specific antibody in patients with platelet transfusion refractoriness (PTR). 【Methods】 HLA-A and B genotypes were detected by PCR-SBT, and HLA-Ⅰ antibodies in patients′ serum were detected by Luminex single antigen beads coating method. IPD-IMGT/HLA Database was used to find the differential amino acids of allele-specific antibodies, and HLA Eplet database was used to analyze the registry Eplets. 【Results】 HLA allele-specific antibodies were found in 12 out of 82 patients with PTR.After sequence alignment, a total of 18 differential amino acids were found, such as 19E>19K, 166D>116E, 167G>167W and so on. Among these differential amino acids, 16 registry Eplets were retrieved such as 19E>19K, 95I>95L, 113YD>113HD and so on.The amino acid substitution of 166DG>166EW, 70Q>70H, 67S>67Y, 94I>94T, 82LR>82RG, and 211G>211A may form new Eplets that have not been registered.The antigens of A11, A24, B15, B27 and B38 can be further subdivided into HLA narrow specific antigens. 【Conclusion】 It was found that there were HLA allele-specific antibodies in patients with PTR, suggesting that high-resolution typing of HLA-A, B should be carried out for these patients and platelet donors in HLA compatible transfusion of PTR.

Construction and application of platelet virtual matching information system / 中国输血杂志

【Objective】 To construct a platelet digital matching information system (PMIS). 【Methods】 The framework of PMIS was designed and the main functions were developed. The information system was connected with the information modules of clinical application, laboratory testing, blood donation service, blood inventory and distribution. Further, the preliminary application of this system will be carried on in clinical. 【Results】 The PMIS had been successfully developed and 5048 blood donors with HLA and HPA genotypes were registered in the system. A total of 306 patients applied for matching and 16.5% of them received compatible platelet reports immediately from the inventory bloods, with the median waiting time of all matching as 3 days, which was significantly shorter than that of the manual method (3.8±3.1 days vs 5.4±5.4 days). 【Conclusion】 The developed PMIS has realized the whole process management of blood donors and patients, which is helpful to improve the platelet matching level.

Analysis of HLA-Ⅰ antibody specificity and estimation of antigen immunogenicity: 96 patients recieved genotype-matched platelet transfusions / 中国输血杂志

【Objective】 To analyze the specificity of HLA class-Ⅰ antibody in the patients received HLA-matched platelet transfusions and estimate the relative immunogenicity of HLA-Ⅰ antigens. 【Methods】 The samples from 96 patients who suffered from platelet transfusion refractorines(PTR) and applied for transfusion with genotype-matched platelet were collected. The specificity of HLA I antibody was detected by Luminex technique, and the antibody expression level was analyzed according to MFI. The mismatch rate of HLA antigen and relative immunogenicity of the population were estimated according to the allele frequency distribution of HLA-A and B loci as well as the yielding frequency of antibody. 【Results】 HLA-Ⅰ antibodies were detected in all 96 patients, with varied species of antibodies. The average positive yielding rates of antibodies corresponding to HLA-A, -B and -C magnetic bead coated antigens (97 in total) were 0.38, 0.47 and 0.28, respectively. Among the HLA-A and -B loci in the Zhejiang population, HLA-A2, A11, A24 and HLA-B60, B46, B58 were the antigens with higher frequency, and their relative immunogenicity was 0.403, 0.283, 0.342, and 0.100, 0.067, 0.178, respectively. 【Conclusion】 The specificity of HLA-Ⅰ antibodies in PTR patients is different, which confirms that the relative immunogenicity differs by HLA-A and -B antigens.

Correlation between the quantitative intensity of HLA-Ⅰ gene and its antibody and the clinical transfusion effect of matching platelets / 中国输血杂志

【Objective】 To explore the influence of anti-HLA-Ⅰ with different mean fluorescence intensity (MFI) on the efficacy of HLA-A and -B gene matching platelet transfusion, so as to provide scientific data for clinical platelet gene matching transfusion strategy. 【Methods】 A total of 81 PTR patients had applied for HLA-Ⅰgene matched platelets from the platelet gene database established by our laboratory, and 28 (MFI <5 000) of them needed further avoiding of partial donor-specific antibodies and they were enrolled as the research subjects. According to the platelet MFI value of HLA-Ⅰ antibody-targeting antigen, they were divided into negative transfusion group (MFI <500) (group A) and positive transfusion groups (MFI≥500) ; the latter were further divided into group B (500≤MFI <1 000), group C (1 000≤MFI <3 000) and group D (MFI≥3 000) according to MFI value. Corrected count increment (CCI) in platelet count was used to compare the platelet transfusion effect in 4 groups. 【Results】 Among 28 platelet recipients with MFI <5 000, 19(67.86%) patients successfully received 72 effective transfusions. The first CCI (×109/L) in groups A, B, C and D were 10.27±7.46, 7.58±4.75 (P>0.05), 17.36±7.63 (P>0.05) and -0.77±2.30 (P<0.05), respectively. There was no statistical difference among group A, B and C. 【Conclusion】 The application of HLA-Ⅰ gene matching platelets in PTR patients can adjust the MFI threshold(<2 000) appropriately according to the patient′s condition without compromising the platelet transfusion effect.

Identification of a glycosyltransferase allele associated with Bw subtype and analysis of the protein structure / 中华医学遗传学杂志

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.

Molecular characterization of a recombination allele of ABO blood group / 中华医学遗传学杂志

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.

HLAⅠ-matched transfusion for immune-mediated platelet transfusion refractoriness / 中国输血杂志

【Objective】 To establish the HLA-A, -B genotype-matched transfusion strategy for immune-mediated PTR patients based on donor HLA genotyping database, so as to improve the transfusion efficacy. 【Methods】 The serologic cross-match was used to screen immune PTR primarily. 35 PTR patients screened out were subjected to HLA-match. 24 patients were tested for HLA-A, -B genotyping and antibodies against platelet HLA classⅠ, and then received a total of 83 HLA-typed platelet transfusions, based on patient platelet genotype, donor specific antibody (DSA)(priority), and HLA-A, -B cross-reactive groups (CREGs) principle(lower priority). The other 11 patients received a total of 55 HLA-A/B-matched transfusions according to CREGs principle. The clinical information and transfusion outcome were followed up, and the corrected count increment (CCI) was calculated and statistically analyzed. 【Results】 A total of 453 ABO serological cross-matching tests were performed for 35 PTR patients, with 12.94 tests (453/35) per patient, an average of 4.21 (1908/453) donors per test and positive rate of 69.86% (1333/1908). 23 out 24(95.83%) patients, subjected to HLA class I antibody, were positive and each carried (44.37 ± 22.31) kinds of specific antibodies. According to the fluorescence intensity of the antibody in the patient′s serum, the antibody was strongly positive in 17(73.91%) cases, positive 20(86.96%) and weakly positive 23(100%). After 138 HLA-matched transfusions, the first mean CCI value was 14.08 ± 11.12 (23.95 ± 21.28 h), which was significant higher than 1 hour CCI (>7.5 effective) or 24 hours CCI (> 4.5 effective). The responses of DSA avoidance group (CCI of 1st =15.56±11.00)was significant higher than that of non-DSA avoidance group(CCI of 1st =11.86±12.00)(t=2.045, P<0.05). 49.28% of the patients had one or more non-immune factors during platelet transfusion. 【Conclusion】 The HLA-matched platelet transfusion is feasible to prevent and improve immune-mediated PTR. For patients with multiple blood transfusions and positive platelet antibodies, DSA avoidance and CREGs principle combined transfusion strategy can significantly improve the efficacy of blood transfusion and provide accurate platelet transfusion for the clinical.

Detection of anti-HLA and anti-MICA in convalescent plasma from individuals recovered from COVID-19 / 中国输血杂志

【Objective】 To analyze the positive rate of antibodies against human leukocyte antigen(HLA)and MHC class I chain-related gene A(MICA) in the convalescent plasma from individuals recovered from COVID-19. 【Methods】 HLA-Ⅰ, -Ⅱ and MICA antibodies were screened simultaneously by Luminex platform. The specificity of HLA-Ⅰ and -Ⅱ antibodies was identified by single antigen reagents.The positive rate of antibody in different groups were compared by Chi-square test. 【Results】 A total of 88 cases of convalescent plasma were collected, among which the positive rates of HLA-Ⅰ, -Ⅱ and MICA antibodies were 18.19%, 19.32% and 10.23%, respectively, and 64 individuals (72.73%) were negative for HLA-Ⅰ and -Ⅱ antibodies. 95 blood donors were randomly selected as the control group, and the positive rate of HLA-Ⅰ, -Ⅱ and MICA antibodies were 8.42%, 13.68% and 10.53%, respectively, and 76 individuals(80.00%) were negative for HLA-Ⅰ and -Ⅱ antibodies. There were no significant difference in the positive rates of HLA-Ⅰ, -Ⅱ and MICA antibodies between convalescent individuals and control group. The specificity of HLA antibody to epitopes was different in each convalescent individual with positive HLA antibodies, and most antibodies were targeted to the epitopes of multiple HLA alleles. 【Conclusion】 A certain proportion of HLA antibody was found in the convalescent plasma of individuals recovered from COVID-19. Therefore, HLA antibody screening is helpful to improve the safety of transfusion.

Expression of ABO blood group antigen on platelets of blood donors / 中国输血杂志

【Objective】 To study the expression level of ABO blood group antigen on the surface of platelets of blood donors. 【Methods】 A total of 506 donors with normal ABO blood group were selected to analyze the ABO antigen on platelets by flow cytometry. Among them, 30 donors were selected to monitor the changes of ABO antigen on platelets during the storage period, and the remaining 476 to analyze the expression difference of ABO antigen among blood donors. 【Results】 The ABO antigen on platelets of each sample fluctuated slightly but was relatively stable over 1~7 days in vitro. According to MFI values, the donors were divided into low-, moderate- and high- expression groups, with the average frequency of 59.6%, 35.5% and 4.9%, respectively. The A and B antigens of blood group AB platelets exhibited a competitive co-expression pattern. 【Conclusion】 Most individuals have low-expression phenotype of ABO antigen on platelets and can be potential platelet donors for ABO-incompatibility transfusion, which is helpful to improve platelets transfusion strategy.

Study of the molecular basis for an individual with Bel variant due to deletion of B glycosyltransferase gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the molecular basis of an individual with Bel variant of the ABO blood group.</p><p><b>METHODS</b>The ABO antigen and serum antibody of the individual were detected by serological method. All coding regions and flanking introns of the ABO gene were amplified with PCR and sequenced bidirectionally. The haplotypes of the individual were analyzed by cloning and sequencing. A three dimensional model of the mutant protein was constructed and analyzed.</p><p><b>RESULTS</b>The individual has expressed a very weak B antigen on its red blood cells by absorption and elution testing, which was identified as a Bel variant phenotype. The heterozygous sites in exon 6 (261del/G) and exon 7 (297A/G, 484del/G, 526C/G, 657C/T, 703G/A, 796C/A, 803G/C, 930G/A) of the coding region of the ABO gene were identified by direct sequencing. Haplotype analysis showed that the individual has carried an O01 allele and a novel B allele. The sequence of the novel B allele was identical to B101 except for a del G at nucleotide position 484 (484delG), which was nominated as B120 by the Blood Group Antigen Gene Mutation Database (dbRBC NCBI). The 484delG mutation of the B allele has led to a reading frame shift and created a premature terminal codon for the glycosyltransferase (GT) enzyme. Prediction of the 3D structure suggested that the GT enzyme has become an incomplete protein only with its N-terminal region.</p><p><b>CONCLUSION</b>The 484delG mutation of the glycosyltransferase B gene has probably abolished or reduced the enzymatic activity and resulted in the Bel variant phenotype.</p>

Study of the molecular basis of an individual with Aw43 subtype of the ABO blood group / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the molecular basis of an individual with A subtype of the ABO blood group.</p><p><b>METHODS</b>The ABO antigen and serum antibody of the proband and his parents and sister were detected by a serological method. The whole coding regions of the ABO gene were amplified by PCR and subjected to bidirectional sequencing.</p><p><b>RESULTS</b>Red blood cells of the proband showed mixed field agglutination with anti-A but did not agglutinate with anti-B, and his serum did not agglutinate with A and O cells but with B cells. The proband was identified as an Aw phenotype. Heterozygous status of 1A/G, 106G/T, 188A/G, 189C/T, 220C/T, 261G/del, 297A/G, 467C/T, 646A/T, and 681A/G of the coding region of the ABO gene were identified by directly sequencing of the proband. The serological characteristics and nucleotide sequences of the mother were similar to those of the proband. However, the ABO genotypes of his father and sister were B101/O02 and O02/O02. The proband therefore has carried an O02 allele and a novel allele. Compared with A102, the novel allele contains 1A>G, which resulted in translation-initiator code change and was nominated as Aw43 by dbRBC of NCBI.</p><p><b>CONCLUSION</b>An Aw43 subtype has been identified for the first time, which may be attributed to the 1A>G and 467C>T variants on the α1,3-N-acetyl-galactosaminyltransferase gene.</p>

Study of in vitro expression of human platelet ITGB3 gene nonsense mutation c.1476G>A / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the function of a novel nonsense mutation c.1476G>A of ITGB3 gene using an in vitro expression system.</p><p><b>METHODS</b>An eukaryotic expression vector containing ITGB3 c.1476G>A cDNA was generated by site-directed mutagenesis and transformed into E.coli. Plasmid DNA was extracted and sequenced to confirm the target mutations. Wild-type and mutant recombination plasmids were transfected into Chinese hamster ovarian cancer (CHO) cells by nonliposome method, and the stable expression cells were harvested by G418 screening. The ITGB3 gene mRNA transcription and GPIIIa expression level in CHO cells were detected with real-time quantitative PCR, Western blotting and flow cytometry, respectively.</p><p><b>RESULTS</b>The eukaryotic expression vectors of wild ITGB3 cDNA and c.1476G>A mutant were successfully constructed. CHO cells with stable expression were obtained after transfection and screening. Compared with the wild-type transfected cells, the amount of CD61 antigen expression was 37% and mRNA transcription level was only 6% in the mutant-transfected cells. Full length GPIIIa protein was found only in the stably wild-type-transfected cells, but not in mutant-transfected cells by Western blotting analysis.</p><p><b>CONCLUSION</b>The ITGB3 c.1476G>A mutation can decrease the transcription level and further affect GPIIIa synthesis and CD61 antigen expression.</p>

Molecular basis for an individual with rare p phenotype in P1Pk blood group system / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the molecular basis for an individual with rare p phenotype in the P1Pk blood group system.</p><p><b>METHODS</b>Erythrocyte blood group antigens and antibodies in serum were identified in the proband and five family members with a serological method. Coding regions and flanking untranslated regions of the α1,4-galactosyltransferase gene (A4GALT) encoding P1Pk antigens were amplified with polymerase chain reaction and directly sequenced. The haplotypes of A4GALT in the parents of the proband were also analyzed by cloning sequencing.</p><p><b>RESULTS</b>The proband was found with a rare p phenotype with anti-Tja antibody in his serum by serological method. The other family members all had a common P2 phenotype. The results of DNA sequencing showed that a cytosine was inserted at nucleotide position 1026 to 1029 (1026_1029insC) of both alleles of the A4GALT gene in the proband. The mutation has caused a reading frame shift and formed a mutant protein by extending 92 amino acid residues. The other family members were either heterozygous for the insertion or of the wild type at above position.</p><p><b>CONCLUSION</b>The 1026_1029insC mutation of the A4GALT gene is probably responsible for the p phenotype identified for the first time in Chinese population. The individual with the p phenotype possesses anti-Tja antibody.</p>

A rare Pk phenotype caused by a 433 C>T mutation of the β-1,3-N-acetylgalactosyltransferase gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the serological characteristics and molecular mechanism for a rare Pk phenotype of the P1Pk blood group system.</p><p><b>METHODS</b>The blood group of the proband was identified by serological techniques. The coding region and flanking intronic sequences of the β-1,3-N-acetylgalactosyltransferase gene (B3GALANT1) associated with the Pk phenotype were analyzed using polymerase chain reaction sequence-based typing.</p><p><b>RESULTS</b>The proband was identified as having a rare Pk phenotype including anti-P in her serum. The blood group of her daughter and husband showed a P2 phenotype. The nucleotide sequences of the B3GALANT1 gene of her husband and two randomly-chosen individuals were the same as the reference sequence (GenBank AB050855). Nucleotide position 433 C>T homozygous mutation in the B3GALANT1 was found in the proband, which has resulted in a stop codon at amino acid position 145, which may produce a premature protein capable of decreasing or inhibiting the activity of the β -1,3-N-acetylgalactosyltransferase. The nucleotide position 433 C/T heterozygous in the B3GALANT1 was found in her daughter.</p><p><b>CONCLUSION</b>The Pk phenotype resulted from 433 C>T mutation in the B3GALANT1 gene has been identified.</p>

Analysis of erythroid-specific blood group genes using un-mobilized peripheral stem cells cultured in vitro / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze specific expression of blood group genes using nucleated erythroid cells cultured from un-mobilized peripheral stem cells in vitro.</p><p><b>METHODS</b>Hematopoietic stem cells(HSC) bearing the CD34 antigen were isolated from peripheral blood by centrifugation and magnetic beads sorting, followed by suspension culture in vitro. Cells were collected from medium on various stages and analyzed by immunofluorescence. The RNA transcription of RH and ABO blood group genes was analyzed using culture cells on day 12.</p><p><b>RESULTS</b>A total of(3.19±0.13) ×10 (4) CD34+cells were isolated from about 50 mL peripheral blood with a recovery rate of 67.3%±2.7%. The cells amount in erythroid-lineage culture system on day 9 reached a plateau of a 237.1±15.5-fold amplification of the initial cell input. The stem cell-specific CD34 antigen was dropped off, while the erythroid-specific CD235a and CD240D antigens were increased in culture period. RHD/CE and ABO genes can be amplified using RNA extracted from culture cells on day 12, and genotypes of Rh and ABO systems by DNA sequencing were consistent with their serologic phenotypes.</p><p><b>CONCLUSION</b>A method was established to analyze the gene expression of erythroid blood group derived from un-mobilized peripheral stem cells cultured in vitro. It can be used to study the expression of various erythroid-specific genes.</p>

Effect of α -1,2 fucosyltransferase gene 682A> G and 547_552delAG mutations on the activity of fucosyltransferase / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the effect of α -1,2 fucosyltransferase (FUT1) gene 682A> G and 547_552delAG mutations on the expression of FUT1 mRNA and activity of α -1,2 fucosyltransferase.</p><p><b>METHODS</b>Recombinant expression vectors of FUT1 682A> G and FUT1 547_552delAG were constructed and transfected into COS-7 cells for stable expression screening. Expression of FUT1 mRNA was determined using real-time quantitative PCR. The activity of FUT1 was measured with high-performance liquid chromatography.</p><p><b>RESULTS</b>Stably transfected COS-7 cells with wild type FUT1, FUT1 682A> G and FUT1 547_552delAG were respectively obtained. The FUT1 mRNA level of transfected cells with 682A> G and 547_552delAG recombination vectors have measured 101.69% and 102.79% compared with that of wild type FUT1 transfected cells. A specific protein band with about 46 kD was confirmed in the 682A> G transfected cell lysates by SDS-PAGE electrophoresis and Western blotting with 6× His Tag antibody. Similar protein was not identified in the 547_552delAG cells lysates. Enzymes activity of FUT1 682A> G has measured 61.01% compared with wild type FUT1 protein, whilst the activity of FUT1 547_557delAG was completely abolished.</p><p><b>CONCLUSION</b>FUT1 682A> G and 547_552delAG mutations do not affect the transcript efficiency, although various mutations have different impact on the enzyme's activity.</p>

A rare p phenotype caused by a 26-bp deletion in α 1,4-galactosyltransferase gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To delineate serological features and genetic basis for a rare p phenotype of P1Pk blood group system found in a Chinese individual.</p><p><b>METHODS</b>Serological assaying was carried out for a proband with unexpected antibody found in his serum using specific antibodies and panel cells. Coding regions and flanking introns of α 1,4-galactosyltransferase gene (A4GALT) associated with the p phenotype were screened with polymerase chain reaction and DNA sequencing.</p><p><b>RESULTS</b>A rare p phenotype of the P1Pk blood group system has been identified with red blood cells from the proband, whose serum contained anti-Tja antibody which can agglutinate and hemolyze with other common red blood cells. Other members of the proband's family were all normal with P1 or P2 phenotype. DNA sequencing has identified in the proband a homozygous 26 bp deletion at position 972 to 997 of the A4GALT gene. The deletion has caused a shift of the reading frame, resulting in a variant polypeptide chain with additional 83 amino acid residues compared with the wild-type protein. Other family members were either heterozygous for above deletion or non-deleted.</p><p><b>CONCLUSION</b>A 26 bp deletion at position 972 to 997 of the A4GALT gene has been identified in a Chinese individual with p phenotype.</p>

Molecular basis of the B(A)phenotype and its pedigree analysis / 中华检验医学杂志

Objective To investigate the serological characteristics and molecular basis of the B (A)phenotype in ABO blood group and provide the data for clinical transfusion of individuals with B(A) phenotype.Methods The ABO group antigens on red cells of the proband,family members and donors were identified by monoclonal antibodies and the ABO antibodies in sera were detected by the standard A,B,O cells.The compatibility testing for the proband and donors was detected by salted test,polybrene test and antiglobulin test.The coding region of exon 6 to exon 7 in ABO gene was amplified by polymerase chain reaction(PCR) and the PCR products were sequenced.The haplotypes of proband were analyzed by cloning and sequencing.Results It was showed that both A and B antigens were detected on red cells of the proband and her two family members,and there was anti-A_1 antibody in their sera.The serological phenotype of the samples are identified as the A_2B.DNA sequencing showed 261 G/del,297A/G,526C/G,657C/T,700C/G,703G/A,796C/A,803G/C,930G/A heterozygotes in exon 6 to exon 7.It can be deduced that genotype in the proband is B(A)_(02)/O_(01).The genotypes of her mother and grandmother-in-law were B(A)_(02)/B_(101) and B(A)_(02)/O_(01),respectively.After cloning and sequencing,two alleles B(A)_(02) and O_(01) in proband was showed.B(A)_(02) has snigle nucleotide change(700 C>G),which resets replacement of proline with alanine at position 234.Two donors with phenotype A_2B were identified as genotype B(A)_(02)/O_(01) and A_(208)/B_(101),respectively.The results of crossmatch testing is in accordane between the proband and two donors and there was no clinical adverse reaction after transfusion.Conclusions 700C>G in α-1,3galactosyltransferase allele(B allde)can result in B(A)phenotype in individuals with the phenotype of A_2B.The donors in the transfusion for the individuals with B(A) phenotype should include individuals with A_2B phenotype.