Analysis of Human Platelet Antigen-1 System Alloantibodies Using Recombinant GPIIIa Fragments Coupled to Luminex Beads / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To detect platelet anti-HPA-1a and -1b antibodies using recombinant GPIIIa fragments coupled to Luminex beads.</p><p><b>METHODS</b>The sensitivity of 2 techniques, monoclonal antibody specific immobilization of platelet antigen (MAIPA) and Luminex bead assay, was compared using 12 twofold-serial dilutions (from neat to 1 in 2048) of an anti-HPA-1a WHO international standard. The specificity of Luminex assay to identify anti-HPA-1a and -1b antibodies was assessed using 8 negative or positive controls and 36 blinded samples provided by WHO Platelet Workshop.</p><p><b>RESULTS</b>The sensitivity of MAIPA and Luminex bead assay to detect anti-HPA-1a was dilution 1/64 (i.e. 1.56 IU/ml) and far more than dilution 1/2048 (i.e. 0.049 IU/mL), respectively. The Luminex bead assay could specifically identify negative and positive controls of anti-HPA-1a and -1b. All results of 36 blinded samples by Luminex assay were accordant to reference results except one sample which contained high concentration antithetical antibody and resulted in false positive of anti-HPA-1b. Cross-reactivity was also not observed with the samples containing HLA, ABO or other platelet antibodies.</p><p><b>CONCLUSION</b>The Luminex beads coupled with recombinant GPIIIa fragments can be used to detect HPA-1 system antibodies with sufficient sensitivity and specificity, that is suitable for the detection of platelet alloantibodies in clinical alloimmune thrombocytopenia.</p>

Establishment of method detecting CD36 expression on human platelet and its application / 中国实验血液学杂志

The individual with the deficiency of CD36 antigen on platelet displayed the risk of anti-CD36 immune reaction induced by transfusion, which is one of the reasons for platelet transfusion refractoriness (PTR). This study was purposed to detect the expression level of CD36 antigen on platelet by flow cytometry among apheresis platelet donors of Hangzhou area, and the frequency of CD36 deficiency was analyzed. Platelet-rich plasma (PRP) was separated from fresh anticoagulant whole blood by centrifugation, then the platelets were washed and adjusted to 1×10(6). The platelets were incubated with FITC-labeled CD36 and PE-labeled CD41 monoclonal antibodies, then the expression level of CD36 was detected by flow cytometry. The CD36 expression on monocytes for the samples of CD36-deficiency on the platelets was further analyzed. The results showed that 7 samples with CD36 antigen deficiency were found in 192 apheresis platelet donors. The frequency of CD36 deficiency was 3.6% and all of them were typeII deficiency. The significant difference of CD36 antigen expression was observed in the platelet donors of Hangzhou population, among them 59 individuals with low expressed CD36 antigen and 126 individuals with highly expressed CD36 antigen were found according to the geometric mean fluorescence intensity. It is concluded that the CD36 antigen deficient phenotype existed in the population, these data will provide the information for research of the CD36 antigen distribution and help to solve the platelet transfusion refractoriness.

Construction of expression vector from different transcripts of RHD gene / 中国实验血液学杂志

RHD gene has different alternative transcripts. This study was aimed to construct expression vector of normal mRNA, DEL9 and DEL89 transcripts from RHD gene. Total RNA was extracted from Rh(D) positive umbilical blood cells of newborn. Intact RhD cDNA, DEL9 and DEL89 transcripts were obtained by one-step and two-step RT-PCR, respectively. The obtained products were cloned into pCR4 TOPO sequencing vector for choosing the right transcript. RHD gene was amplified again from the sequencing plasmid DNA, and then subcloned into pcDNA3.1/V5-His TOPO expression vector; DEL9 and DEL89 were cloned into the expression vector directly. Gene sequence and direction were identified by sequencing. The results showed that the sequence and direction of target genes were right, thus these 3 different expression vectors were correctly constructed. It is concluded that expression vector is constructed from different transcripts of RHD gene, which lays a foundation for further exploring the membranous protein expression of Rh(D) antigen.

Detection of hematopoietic chimera by real-time fluorescent quantitative PCR with erythrocyte Kidd blood group gene / 中国实验血液学杂志

This study was aimed to establish the real-time fluorescent quantitative PCR (RT-qPCR) with erythrocyte Kidd blood group gene for detecting the hematopoietic chimera and to investigate the feasibility of this method. The TaqMan MGB probes and special primers were designed on basis of difference of erythrocyte Kidd blood group alleles, the hematopoietic chimerism was detected by RT-qPCR, the DNA chimerism was simulated by means of dilution of multiple proportions, and the sensitivity analysis was performed. The results showed that the RT-qPCR with erythrocyte Kidd blood group gene could effectively distinguish JK*A and JK*B alleles. There was no significant difference between the theoretic value and the practical measured value by this method (P > 0.05). As 156 donor's cells could be discriminated from 10(4) chimeric cells, this method may effectively detect donor's cells with correlation coefficient 0.998. It is concluded that the established RT-qPCR with erythrocyte Kidd blood group gene shows the feasibility for quantitative detection of hematopoietic chimera, and may be used to quantitatively detect chimera in a certain range.

Study on a novel mutation of B glycosyltransferase gene related with an ABx variant / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the molecular basis of an individual featuring an ABx variant of ABO blood group system.</p><p><b>METHODS</b>Serological assays were used to characterize the erythrocyte phenotypes and salivary ABH secretors. All of the seven exons and flanking introns of ABO glycosyltransferase gene were amplified with polymerase chain reaction (PCR). And the products were sequenced bidirectionally following enzyme digestion. Exons 6 and 7 were also subcloned and analyzed for haplotypes of the ABO gene.</p><p><b>RESULTS</b>Erythrocytes of the proband have expressed a strong A antigen and a weak B antigen, which was identified as a rare ABx variant in addition with other serological features. Nine heterozygous sites in exon 6 (297A/G) and exon 7 (467C/T, 526C/G, 657C/T, 703G/A, 796C/A, 803G/C, 808T/A, 930G/A) of the coding region of the ABO gene were identified. Based on haplotype analysis, one allele was determined as common A102, whilst another was consistent with B101 except for an 808T>A mutation which has resulted in replacement of phenylalanine with isoleucine at position 270 of glycosyltransferase B.</p><p><b>CONCLUSION</b>The 808T>A mutation of the glycosyltransferase B gene may decrease the enzymatic activity and result in the Bx variant.</p>

Molecular mechanism of an individual with weaken B phenotype in ABO blood group / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To elucidate the serological characteristics and molecular mechanism of a blood donor with weaken B antigen.</p><p><b>METHODS</b>The ABO blood group antigens on red blood cells were identified by monoclonal antibodies, the ABO antibodies in serum were detected by standard A, B, O cells and the activity of the B glycosyltransferase was analyzed. The full-length sequence and 5'-untranslated region (5'-UTR) sequence of ABO gene were amplified by polymerase chain reaction (PCR) respectively and direct sequencing. The alternative splicing isoforms of ABO cDNA were obtained by reverse transcription-PCR(RT-PCR) and analyzed with cloning and sequencing techniques. The level of methylation of the CpG island in ABO gene promoter was analyzed by bisulfite sequencing method.</p><p><b>RESULTS</b>The serological characteristic of the donor showed that the B antigen was decreased obviously without anti-B antibodies in serum and the B glycosyltransferase activity was decreased as well. The genotype of the donor was B101/O01 without any other mutations in the full-length coding sequences and splice receptor sites. The nucleotide characteristics of the 5'-UTR was consistent with B101/O01 and no any abnormity was identified in the promoter, enhancer and the negative regulatory sequence regions. The integrative cDNA transcript of ABO gene was obtained and no new splicing isoform was found. Compared with the normal B phenotype, a number of methylated CpG sites were found near the promoter of ABO gene in this sample.</p><p><b>CONCLUSION</b>The methylation in the CpG island of ABO gene promoter region may cause weak expression of the B antigen.</p>

Identification of an ABx09 phenotype of ABO subtype / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the molecular basis for an individual with ABx09 phenotype of ABO subtype.</p><p><b>METHODS</b>The ABO group antigens on red blood cells of the proband were identified by monoclonal antibodies, and the ABO antibody in serum was detected by standard A, B, O cells. The exons 1 to 7 of ABO gene were amplified by polymerase chain reaction (PCR) respectively and the PCR products were sequenced directly. The amplified products for exons 5 to 7 were also cloned by TOPO TA cloning sequencing kit to split the two alleles apart, selected colonies were sequenced bidirectionally for exons 5 to 7 of the ABO gene. The samples of the proband's parents were collected, then serological test of the blood group and sequence analysis for exons 6 and 7 of ABO gene were preformed.</p><p><b>RESULTS</b>Both A and B antigens were detected on red blood cells of the proband and there was anti-B antibody in the serum. There was no G deletion at position 261, while 297AG in exon 6, 467CT, 526CG, 657CT, 703GA, 796CA, 803GC, 889GA and 930GA heterozygote in exon 7 were detected by direct DNA sequencing, which can be assigned for A102Bx09 genotype. After cloning and sequencing, two alleles A102 and Bx09 were obtained. The sequence of Bx09 had one nucleotide changes (G to A) at position 889 compared with that of B101, which resulted in an amino acid change of Glu to Lys at 297 position. The Bx09 in the proband was inherited from her mother by family investigation.</p><p><b>CONCLUSION</b>G to A at nt889 of alpha-1,3 galactosyltransferasegene can result in Bx09 phenotype, with the presence of anti-B antibody in serum.</p>

C742T mutation of α1, 3 N-acetyl-D-galactosaminyltransferase gene is responsible for A2 subgroup / 中国实验血液学杂志

The objective of this study was to analyze the molecular genetic basis for 2 individuals with A2B phenotype of ABO subtype. The ABO group antigens on red blood cells were identified by monoclonal antibodies and the ABO antibodies in serum were detected by the standard A, B, O cells. The exon 5 to exon 7 coding region of ABO gene was amplified by polymerase chain reaction (PCR) and the PCR product was sequenced directly after the enzymes digested. The amplified product was also cloned by TOPO TA cloning sequencing kit to split the 2 alleles apart and chosen colonies were sequencing bidirectionally for exon 6 to 7 of ABO gene. The results showed that both A and B antigen were identified on red blood cells of the individuals and there was anti-A1 antibody in their serum. There was no 261G deletion and showed 297A/G, 467C/T, 526C/G, 657C/T, 703G/A, 742C/T, 796C/A, 803G/C, 930G/A heterozygotes by direct DNA sequencing. After cloning and sequencing, it was obtained the B101 and one novel A allele. The novel allele has one nucleotide change at 742 position C to T compared with A102, which results in an amino acid Arg to Cys at 248 position and was nominated as A213. It is concluded that C742T mutation of the α1, 3 N-acetyl-D-galactosaminyl-transferase gene can lead to A2 phenotype and with anti-A1 antibody in serum.

Study on polymorphism of membrane glycoprotein genes related to human platelet alloantigens / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the polymorphisms of platelet membrane glycoprotein genes related to human platelet alloantigen (HPA)-1 to 17w.</p><p><b>METHODS</b>The DNA segments of platelet membrane glycoprotein genes related to HPA-1 to 17w were amplified using author's designed primers. The amplification products were purified and directly sequenced to identify the HPA genotype and glycoprotein gene polymorphisms.</p><p><b>RESULTS</b>Thirteen new single nucleotide polymorphisms (SNPs) and a micro-satellite sequence were found in the glycoprotein genes from the 112 random samples, in which two SNPs (1333G/A and 1960G/A) in ITGB3 gene result in two amino acid change (V419M and E628K) on glycoprotein GPIIIa.</p><p><b>CONCLUSION</b>New variants in platelet membrane glycoprotein genes were identified, which may lead to structure change of platelet membrane glycoprotein and affect the accuracy of partial HPA genotyping method.</p>

Cloning and sequence analysis of 5'untranslated region of human ABO gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To clone and investigate the polymorphism of the 5'-untranslated region (5'-UTR) of the human ABO gene, in order to provide the basis for exploring the transcriptional regulation of the human ABO histo-blood group genes.</p><p><b>METHODS</b>ABO phenotypes of 30 unrelated healthy blood donors were determined by serological technique, their genotypes were analyzed by sequencing the exons 6 and 7 of the ABO gene. Nearly 5 kb of the 5'-UTR of ABO gene was obtained by PCR amplification and sequencing was performed bidirectionally. Haplotypes of samples with heterozygous sites in the 5'-UTR of ABO gene were separated and analyzed after cloning.</p><p><b>RESULTS</b>Twenty polymorphic sites were identified in these samples where ABO genotypes were consistent with serological phenotypes. It included sixteen nucleotide sequence variations, one 8 bp deletion, one 6 bp deletion/insertion, one 36 bp insertion and one 43 bp repeats. Among them, 11 were novel polymorphic sites. Seven different haplotypes of 5'-UTR of ABO gene were defined to the cis/trans linkage of those mutations.</p><p><b>CONCLUSION</b>There were polymorphisms in the 5'-UTR of ABO gene and the nucleotide sequences near the proximal promoter were conservative.</p>

Para-Bombay phenotype caused by combined heterozygote of two bases deletion on fut1 alleles / 中国实验血液学杂志

This study was purposed to investigate the molecular basis of a para-Bombay phenotype for screening and identification of rare blood group. ABO and H phenotypes of the proband were identified by serological techniques. The exon 6 to exon 7 of ABO gene and full coding region of α-1,2-fucosyltransferase (fut1) gene of the proband were analyzed by polymerase chain reaction and direct sequencing of the amplified fragments. The haplotype of compound heterozygote of fut1 was also identified by cloning sequencing. The results indicated that a rare para-Bombay phenotype was confirmed by serological techniques. Two deletion or insertion variant sites near nucleotide 547 and 880 were detected in fut1 gene. The results of cloning sequence showed that one haplotype of fut1 gene was two bases deletion at 547-552 (AGAGAG→AGAG), and another one was two bases deletion at position 880-882 (TTT→T). Both two variants caused a reading frame shift and a premature stop codon. It is concluded that a rare para-Bombay phenotype is found and confirmed in blood donor population. The molecular basis of this individual is compound heterozygote of two bases deletion on fut1 gene which weaken the activity of α-1, 2-fucosyltransferase.

Analysis of alpha-1,2-fucosyltransferase gene mutations in a Chinese family with para-Bombay phenotype / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the molecular genetic basis of para-Bombay phenotype in a Chinese family.</p><p><b>METHODS</b>ABO and H phenotypes of the proband and his pedigree were characterized by serological techniques. The exons 6 and 7 of the ABO gene and full coding region of alpha-1,2-fucosyltransferase (FUT1) gene of the pedigree were analyzed by polymerase chain reaction and direct sequencing of the amplified fragments. The haplotypes of compound heterozygote of the FUT1 gene were also analyzed by cloning sequencing.</p><p><b>RESULTS</b>Three para-Bombay phenotypes were identified in nine family members by serological technology. Three heterozygous variants (35C/T, 235G/C and 682A/G) were found in FUT1 gene of the proband, and the hapotype of FUT1 gene was h(235C)/h(35T+628G)according to the cloning sequencing. The alleles h(235C)and h(35T+628G) caused G79R, A12V and M228V amino acid substitutions in alpha-1,2-fucosyltransferase, respectively.</p><p><b>CONCLUSION</b>A novel 235G>C mutation of FUT1 gene which was associated with para-Bombay phenotype was found in the Chinese pedigree.</p>

Molecular basis of a new O61 allele in ABO blood group / 中国实验血液学杂志

Objective of this study was to explore the molecular basis of a new O61 allele in ABO blood group. The ABO group antigens on red cells of the blood samples were identified by monoclonal antibodies and the ABO antibody in serum was detected by the standard A, B, O red cells. The coding region sequences of exon 5 to exon 7 in ABO gene were amplified by polymerase chain reaction (PCR) and the amplification products were purified with double enzyme digestion and directly sequenced for exon 6 and 7. The diploid of the individual with B phenotype was separated into its haploid components with a haplotype specific extraction method. The exons 6 to 7 of the two single ABO haplotypes were then amplified and sequenced separately. The results indicated that 3 samples had mutation at 743 site in total 417 individuals, in which 2 individuals were with O phenotype and 1 individual was with B phenotype. The DNA sequencing of exon 6 and 7 in 2 samples with O phenotype showed 261G deletion and 743G/C heterozygotes. The DNA sequencing of exon 6 and 7 in the sample with B phenotype showed 261G/deletion and 297A/G, 526C/G, 743G/C, 657C/T, 703G/A, 796C/A, 803G/C, 930G/A heterozygotes. After separating of the 2 single strands in the B sample with haplotype specific extraction, an O and B101 allele were identified after sequencing. The novel allele was submitted to the Blood Group Antigen Gene Mutation database and is named as O61. It is concluded that 743G>C is a novel mutation in exon 7 of ABO and a novel O61 allele with 743G>C has been identified.

Quantitative chimerism analysis of regulatory T cell subsets based on immunomagnetic sorting / 中国实验血液学杂志

The aim of study was to explore the feasibility of quantitative chimerism analysis of regulatory T (Treg) cells using immune sorting coupling short tandem repeat (STR) method. 14 sets of artificial chimera samples were prepared by mixed lymphocytes according to different proportion. The CD4(+)CD25(+) Treg cells were harvested by negative and positive selection of immunomagnetic beads, then the STR polymorphisms of 16 loci in sorted Treg cells was analyzed. The results showed that the DNA amount extracted from sorted Treg cells was fit for STR detection. All STR alleles specific for recipient or donor could be detected and the quantitative results were consistent with theoretic values in over 10% recipient chimeras. But only partial recipient alleles could be detected and the quantitative results were different from theoretic values in less then 1% recipient chimeras. It is concluded that a quantitative chimerism analysis of Treg cell based on immune sorting is established. The sensitivity and accuracy for chimera detection are 1% to 10%, and this method can be used to monitoring hematopoietic chimerism following allogeneic hematopoietic stem cell transplantation.

In vitro expression activity of α-(1,2) fucosyltransferase with 35C > T and 682A > G mutations / 中国实验血液学杂志

In order to explore the effects of 35C > T and 682A > G mutations on the activity of alpha-(1,2) fucosyltransferase, the coding region of fut1 gene was amplified by polymerase chain reaction (PCR) from genomic DNA. PCR product was ligated into expression vector using TOPO TA cloning kit to obtain the recombinant plasmids. The recombinant plasmids were transfected into COS-7 cells by liposome method. After screening by using G418, H antigen expression on the COS-7 was tested by flow cytometry and fut1 mRNA was detected by real-time PCR. The results indicated that three kinds of recombinant plasmids pcDNA3.1/V5-His-wild (35C + 682A), pcDNA3.1/V5-His-35T and pcDNA3.1/V5-His-35T-682G were successfully constructed. After transfection, the H antigen expressed on membrane of COS-7 cells at the second day, with the maximum level of expression at the fourth day. When compared with pcDNA3.1/V5-His-wild transfected cells, the H antigen expression level of the 35T and 682G + 35T recombinant plasmids in the transfected cells was 52.7% and 13.3% on the fourth day, respectively. Although the level of fut1 mRNA decreased with prolonging of time, the mRNA expressed on the pcDNA3.1/V5-His-35T-682G transfected cells reached to 14% of the wild plasmids on the first day. It is concluded that 682A > G mutation obviously reduces the activity of alpha-(1,2) fucosyltransferase, while 35C > T mutation leads to partial reduction of H antigen in vitro expression.

Molecular genetic analysis of a new B112 allele of ABO blood group / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the molecular genetic basis for a new B112 allele of ABO blood group and the pedigree of the proband.</p><p><b>METHODS</b>The ABO group antigens on red cells of the proband were identified by monoclonal antibodies. The ABO antibody in serum was detected by using standard A, B and O cells. The exons 5-7 of ABO gene for the proband was amplified by polymerase chain reaction and the amplified products were digested with double enzymes and sequenced for exons 6 and 7. A magnetic bead-based, haplotype specific extraction was used to separate the diploid sample of the proband into its haploid components. The exons 6 and 7 of the two single ABO haplotypes were then amplified and sequenced separately. The samples of the parents of the proband were collected, and the blood group serological test and sequence analysis for exons 6 and 7 of ABO gene were performed.</p><p><b>RESULTS</b>The serum characteristic of the proband was consisted with the normal B phenotype. The DNA sequencing of exons 6 and 7 showed 261G/del, 297A/G, 526C/G, 559C/T, 657C/T, 703G/A, 796C/A, 803G/C and 930G/A heterozygotes and was assigned for B/O genotype. After separation of the two single strands of the proband with haplotype specific extraction, a B112 and an O01 allele were identified after sequencing. The B112 allele had one nucleotide change (C to T) at position 559 compared with B101, which resulted in an amino acid change at position 187 (Arg to Cys). The B112 in the proband was identified to inherit from his mother after pedigree analysis, the ABO blood group serological characteristics and sequences of exons 6 and 7 of the mother were identical to that of the proband.</p><p><b>CONCLUSION</b>A novel B112 allele of ABO group system with 559C>T was identified. It had normal B antigen expression, suggesting that Arg118Cys of alpha-1, 3 galactosyltransferase did not affect its enzyme activity.</p>

Molecular basis for real RhD negative and RhDel phenotypes in Yiwu population of Zhejiang Province in China / 中国实验血液学杂志

This study was purposed to investigate the molecular basis for RhD negative phenotype in Yiwu population in Zhejiang Province of China. The RhD negative samples were screened by saline agglutination test in blood donors. Some real RhD negative and RhDel phenotypes were identified using anti-human globulin test and absorbtion elution test. Ten exons of RHD gene in these samples were amplified by PCR-SSP, and positive exons were DNA sequenced. The results indicated that 30 real RhD negative and 8 RhDel phenotypes were identified in 38 initial RhD negative samples. Ten exons were complete negative in 28 real RhD negative samples and only exon 1, 2 and 10 were positive in 2 real RhD negative samples amplified by PCR. All 10 exons in 8 RbDel samples were positive and a DNA variant (1227G > A) was found in 8 RhDel samples. It is concluded that all exons are absence in most real RhD negative phenotypes, and the partial exons absence is also found in some real negative phenotypes among Yiwu population in Zhejiang province of China. The G to A mutation at position 1227 is found in all RhDel phenotypes.

A novel M142T mutation in the B glycosyltransferase gene associated with B3 variant in Chinese / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the molecular genetic basis of the B3 variant of ABO blood group system with mixed-field hemagglutination in Chinese.</p><p><b>METHODS</b>Serological techniques were performed to characterize the erythrocyte phenotype of two discrepant samples. A sequential agglutination method and 13 short tandem repeat (STR) loci were tested to exclude the possibility of exogenous or endogenous DNA chimera. Mutations in exons 6 and 7, including partial intron of the ABO gene, were screened by polymerase chain reaction and DNA sequencing. Haplotypes of the two individuals were also analyzed by sequencing.</p><p><b>RESULTS</b>A mixed-field hemagglutination of RBCs with anti-B and anti-AB antibodies was detected in the two unrelated individuals. Exogenous ABO-incompatible RBC transfusion and endogenous genetic chimera were excluded by sequential agglutination method and STR. The ABO phenotypes of the two individuals were classified as A1B3 according to the ABO subgroup definition. The sequence region from intron 5 to 3'-UTR of the B allele was identical to that of ABO*B101 allele, except for a T to C substitution at nucleotide position 425 in exon 7. This substitution resulted in an amino acid change of M142T in the B glycosyltransferase.</p><p><b>CONCLUSION</b>A novel B allele with 425T>C substitution resulting in B3 subgroup was identified in two Chinese individuals.</p>

Identification of the hemolytic transfusion reaction caused by lewis antibody using serological and molecular biological methods / 中国实验血液学杂志

To analyse the reason for one case of hemolytic transfusion reaction, antibodies in a patient's serum were identified using panel cells and Le (a-b-) phenotype cells, patient phenotype was identified by using anti-Le(a) and anti-Le(b) blood grouping reagents and the entire coding region of FUT3 gene was amplified by PCR and sequenced directly. The results showed that both IgM anti-Le(a) and anti-Le(b) antibodies were detected in patient's serum. Red cells was typed as Le (a-b-) phenotype and the FUT3 genotype was homozygote for non-functional le(59, 508) alleles. In conclusion, anti-Le(b) antibody can result in hemolytic transfusion reaction, FUT3 gene is homozygous for le(59, 508) allele resulting in Le (a-b-) phenotype.

Effect of prefreezing parameters on human platelet cryopreservation / 中国实验血液学杂志

This study was aimed to investigate the effect of prefreezing parameters such as freezing rate, annealing, rate, annealing temperature, holding time in annealing before lyophilization on lyophilized platelets by orthogonal tests. The recovery rate, the morphological and ultrastructural changes, the activation and aggregation of lyophilized platelet after rehydratation were detected by cytometer, scan electron microscopy, flow cytometry and aggregation reaction on thrombin, respectively, and complex evaluation was carried out. The results showed that the recovery rate of lyophilized platelets was 91% - 53.5% at different conditions of lyophilization, the size and shape of ice crystals in lyophilized platelets of different test groups were not similar, the expression and distribution of platelet activation markers (PAC-1 and CD62p) after rehydration were relatively similar to fresh platelets, expression rate of PAC-1 was lower (0.03% - 0.22%), meanwhile there were differences of CD62p expression levels between different groups. The optimal theoretic composition of prefreezing conditions obtained on basis of platelet recovery rate was A(2)B(1)C(1)D(3), i.e, first, suspensions of platelets on the program control cooling apparatus were lyophilized with a rate of 20 degrees C/min and maintained at -40 degrees C for 2 hours, then the annealing was conducted at -30 degrees C for 0.5 hours with a heating rate of 1.5 degrees C/min; finally, the freeze-drying program was carried out to the end. It is concluded that the freezing rate, annealing rate, annealing temperature and holding time of annealing all impact on the recovery of lyophilized platelets. The preservation qualities of lyophilized platelets were affected by the various combinations of prefreezing parameters.