Molecular polymorphism Analysis on CD36 Deficiency among Platelet Blood Donors in Shenzhen / 中国实验血液学杂志

OBJECTIVE@#To analyze the molecular polymorphisms of CD36 among 58 blood donors with CD36 deficiency and compare with CD36 positive controls.@*METHODS@#A total of 58 donors with CD36 deficiency during a screening conducted in the laboratory from September 2019 to December 2020 were enrolled as the test group, including 39 males and 19 females, while 120 platelet donors with CD36 positive were randomly selected as the controls, including 76 males and 44 females. All of the subjects were Han nationality. The PCR-SBT method was used to detect coding region of CD36 gene, and molecular mutations were compared with those CD36 positive controls.@*RESULTS@#Among the 58 donors with CD36 deficiency, mutations appears in 32 individuals. The detection rate for type I was 71.43% (5/7), and type II was 51.92% (27/52), while among the 120 controls, mutations appears in 12 donors (10%). In the CD36 antigen-deficient donors, 16 variations were found, in which 329-330 del AC with the highest frequency accounted for 20.69%, followed by 1228-1239 del ATTGTGCCTATT(15.52%) and 1156 C>T(10.34%). Two variations, 198-205 del GATCTTTG and 220 C>T, led to premature termination of translation; four mutations, 329-330 del AC, 560 ins T, 1011-1049 39bp dupl and 1343-1344 ins TCTT, caused translation frame shift; 1228-1239 del ATTGTGCCTATT led to deletion of four amino acids (Ile-Val-Pro-Ile) at sites 410-413 of the peptide chain. The 1140 T>A and 1275 G>A were synonymous mutations, and the other 7 mutations resulted in the substitution of single nucleotide. The platelet expression in the donors of CD36 positive with 329-330 del AC or 1228-1239 del ATTGTGCCTATT mutation (heterozygote) was lower than those CD36 positive individuals without mutations (homozygote).@*CONCLUSION@#Multiple gene mutations in the CD36 coding region may cause CD36 deficiency, and the heterozygous individuals with mutations may lead to CD36 antigen reduction or deletion. Mutation is not detected in 44.83% of CD36 deficient individuals, there may be some other reasons for the CD36 antigen deficiency.

Study on the Relationship between the Level of Soluble HLA-E Molecules in Plasma and Gene Polymorphism and Leukemia / 中国实验血液学杂志

OBJECTIVE@#To explore the relationship between the level of soluble HLA-E (sHLA-E) molecules in plasma and gene polymorphism and leukemia in Shenzhen of China.@*METHODS@#Enzyme-linked immunosorbent assay was used to detect sHLA-E level in plasma of 103 leukemia patients and 113 healthy blood donors. PCR-SBT was used to identify the HLA-E genotype of 73 leukemia patients and 76 healthy blood donors.@*RESULTS@#The level of plasma sHLA-E of 103 leukemia patients was significantly higher than that of 113 healthy blood donors (P<0.001); And the level of plasma sHLA-E in 77 myeloid leukemia patients was also significantly higher (P<0.001). The percentage of patients with plasma sHLA-E concentration of 0-199 ng/ml in leukemia and myeloid leukemia patients was 37.86% and 32.47%, respectively, which was significantly lower than 53.98% of healthy donors, the difference was statistically significant (P<0.05, P<0.01); While, when the plasma sHLA-E concentration was more than 400 ng/ml, the percentage was 33.01% and 36.36%, respectively, which was significantly higher than 13.28% of healthy donors, the difference was also statistically significant (P=0.001, P<0.001). There was no significant difference in the level of plasma sHLA-E among different HLA-E genotypes (P>0.05), whether healthy blood donors or leukemia patients.@*CONCLUSION@#The level of plasma sHLA-E in patients with leukemia (especially myeloid leukemia) is significantly higher than that of healthy blood donors, but different HLA-E genotypes do not affect the level of plasma sHLA-E. A cut-off value for the concentration of plasma sHLA-E (recommended risk value >400 ng/ml) can be set to assess the risk of certain pre-leukemia patients.

Establishment of a large-scale bi-directional sequencing and genotyping platform for MICA gene exons 2 to 4 / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To establish a stable and large-scale bi-directional sequencing platform for genotyping MICA gene exons 2 to 4, and to analyze single nucleotide polymorphisms(SNP) of the region.</p><p><b>METHODS</b>Primers for particular alleles of MICA gene exons 2 to 5 were designed. Optimal conditions for PCR amplification and sequencing reaction were explored. A commercialized one-way sequencing kit for MICA allele was used as a parallel control. Four samples carrying a MICA *010 allele were subjected to cloning and haplotype sequencing.</p><p><b>RESULTS</b>Results of MICA allele typing of 100 samples for a parallel control group were confirmed by the establish method. Twenty-two SNP in MICA gene exons 2 to 4 were detected in Chinese population. Two novel allelic sequences were accepted by GenBank and IMGT/HLA database and officially named as MICA*065 and MICA*066 by the WHO Nomenclature Committee. A novel SNP in MICA gene intron 3 was discovered, with allelic sequence submitted to GenBank and IMGT/HLA database.</p><p><b>CONCLUSION</b>The bi-directional sequencing genotyping platform may be applied for large-scale study of MICA allelic polymorphisms, tissue typing, organ transplantation and disease research.</p>

Genetic polymorphism of Chinese Zhuang population at HLA-Cw locus by sequence based typing / 中国实验血液学杂志

Thirst study was purposed to explore the genetic polymorphism of Chinese Zhuang population at HLA-Cw locus by sequence based typing (SBT). A total of 150 unrelated blood samples from Chinese Zhuang population were subjected to sequencing at exon 2, 3 and 4 of HLA-Cw gene in both directions by using SBT technique established by our laboratory. The purified products of sequencing reaction were run by means of electrophoresis on the ABI 3730 DNA Sequencer and the assignment of HLA-Cw genotype was accomplished by using the Assign 3.5 software. The consensus sequence at exon 2, 3 and 4 of HLA-Cw gene for each sample was imported into the Assign 3.5 software. The results showed that 33.33% of tested samples could obtain an unique genotype, genotype in 63.33% of tested samples with ambiguous results could be assigned by ruling out the rare alleles according to the NMDP Rare Allele List File; however, the final genotype in rest 3.33% of the detected samples could be defined when subjected to further confirmatory testing by PCR-SSP. In this detection 16 HLA-Cw alleles were identified, the common alleles with a frequency of > 10% were Cw*0304 > Cw*0102 > Cw*0801 > Cw*0702. The value for gene diversity (GD) was 0.9297, The frequency for Cw*01, 03, 07, 08, 12, 14 (Cw 1 allele group) and Cw*02, 04, 05, 06, 15, 16, 17, 18 (Cw 2 allele group) was 0.8967 and 0.1032, respectively, which indicated that the Cw 1 allele group is the dominant ligand for KIR in Chinese Zhuang population. 51 genotypes were determined and the distribution of genotype frequency was in line with Hardy-Weinberg principle. It is concluded that the obtained HLA-Cw allele frequency and its distribution characteristics of Chinese Zhuang population can provide valuable data in the studies of anthropology and the association of HLA-Cw with disease.

Establishment of an assay for cloning and sequencing the full-length HLA-Cw gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To establish a reliable assay for cloning and sequencing the full-length HLA-Cw gene.</p><p><b>METHODS</b>In this study, a fragment of 4.5 kb full-length HLA-Cw gene was amplified using the self-designed PCR primer pair by long template PCR, purified PCR products was cloned into the pGEM-Teasy plasmid vector and the plasmid DNA isolated from positive clones was subjected to haplotype sequencing by both directions. A total of 12 samples having been previously-genotyped by PCR sequence-based-typing (PCR-SBT) were amplified by using the TaKaRa LA Taq and Stratagene Pfu polymerase, respectively. PCR products of full length HLA-Cw gene were subjected to cloning and sequencing and the obtained haplotype sequence were compared with the PCR-SBT results.</p><p><b>RESULTS</b>The specific target fragment of HLA-Cw gene could be amplified and the full-length HLA-Cw allele sequence covering from nucleotide position -962 in 5'untranslated region (5'-UTR) to nucleotide position 3576 in downstream area of 3'-UTR region could be obtained using our method. The results of cloning and sequencing analysis indicated that the Stratagene Pfu polymerase had better fidelity than the TaKaRa LA Taq polymerase in this experiment. By comparing the sequences of Cw*07020101 with Cw*010201, 11 SNPs as well as 2 insertions/deletions in nt-962--284 of 5'-UTR, and 11 SNPs as well as 1 insertion/deletion in nt3067-3576 downstream of 3'-UTR were identified.</p><p><b>CONCLUSION</b>Our results indicate that the technique for cloning and sequencing full-length HLA-Cw gene has been established, it has a broad application in full-length HLA-Cw gene polymorphism study and the regulation and expression of HLA-Cw gene.</p>

Identification of a novel allele HLA-DRB1*1218 / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify a novel human leukocyte antigen (HLA) allele by cloning and sequence-based typing in Chinese population, and analyzing the sequence of the introns 1 and 2.</p><p><b>METHODS</b>The routine HLA-A, -B, -DRB1 low resolution genotyping for stem cell donor from Guangdong province was performed with polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSOP). An unknown HLA-DRB1 allele was initially detected by HLA typing. Genomic DNA of the proband was amplified by using HLA-DRB1 locus group-specific primer, the amplified product was cloned, sequenced, and compared to the closest DRB1*120201 allele and the closest intron sequence of the DRB1*030101 allele.</p><p><b>RESULTS</b>The sequencing results showed that a normal DRB1*080302 and a novel DRB1*1218 variant allele were identified. The sequence of the novel allele has been submitted to GenBank (FJ481086). The novel allele had 1 nucleotide substitution of the closest matching allele HLA-DRB1*120201 at nt262(G-->C) in exon 2,resulting in an amino acid change from Glu(GAG)-->Gln (CAG) at codon 59.The intron 2 sequence is identical between the novel HLA-DRB1*1218 and DRB1*030101, but there are 12 nucleotides substitution in intron 1.</p><p><b>CONCLUSION</b>A novel HLA allele was confirmed by cloning and sequence-based typing in Chinese. It was officially designated as HLA-DRB1*1218 by WHO Nomenclature Committee.</p>

An analysis of the reason for HLA-C allele dropout in five samples by sequence-based typing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the possible reason for HLA-C allele dropout in routine sequence-based typing (SBT) and improve the accuracy of HLA-C SBT test.</p><p><b>METHODS</b>A total of 620 randomly selected samples from healthy voluntary blood donors in Shenzhen were typed at HLA-C locus by sequence-based typing using the AlleleSEQR HLA-C plus sequence-based typing kit. Samples with no full match result were subjected to cloning and haplotype sequencing of the full-length HLA-C gene. If no novel mutations were found, samples were then retyped, using our self-designed PCR primer pair and PCR conditions replacing the AlleleSEQR HLA-C PCR reagents in the PCR set-up procedure so as to analyze the potential reasons for causing abnormal SBT result.</p><p><b>RESULTS</b>In the 620 samples typed at HLA-C locus using the AlleleSEQR HLA-C SBT commercial kit, 5 samples with no full match result were identified. The closest genotype showed one nucleotide mismatch with many different allele groups at different nucleotide position. Based on the PCR-SBT nucleotide sequence, heterozygous nucleotides were determined only in exon 4, whereas the nucleotides in exon 2 and 3 were all homozygotes. The results showed that HLA-Cw*0706 allele dropout existed in all the 5 samples with abnormal SBT results initially identified by AlleleSEQR HLA-C SBT kit, no novel mutation was found.</p><p><b>CONCLUSION</b>The results indicate that the PCR primer pair incompatible with DNA template may result in allele dropout in HLA-C SBT test. Based on the characterization of HLA-C full-length, it is essential to develop HLA-C SBT kit suitable for Chinese population in the future.</p>