[Using Next-Generation Sequencing Technology to Confirm the HLA Rare Alleles Detected by PCR-SSOP].

OBJECTIVE: To confirm the HLA genotypes of the samples including 4 cases of magnetic bead probe HLA genotyping result pattern abnormality and 3 cases of ambiguous result detected by PCR sequence-specific oligonudeotide probe (SSOP) method. METHODS: All samples derived from HLA high-resolution typing laboratory were detected by PCR-SSOP. A total of 4 samples of magnetic bead probe HLA genotyping result pattern abnormality and 3 samples of ambiguous result were further confirmed by PCR sequence-based typing (SBT) technology and next-generation sequencing (NGS) technology. RESULTS: A total of 4 samples of magnetic bead probe HLA genotyping result pattern abnormality were detected by PCR-SSOP method. The results of SBT and NGS showed that the HLA-A genotype of sample 1 did not match any known genotypes. NGS analysis revealed that the novel allele was different from the closest matching allele A*31:01:02:01at position 154 with G>A in exon 2, which resulting in one amino acid substitution at codon 28 from Valine to Methionine (p.Val28Met). The HLA-C genotype of sample 2 was C*03:119, 06:02, sample 3 was C*03:03, 07:137, and sample 4 was B*55:02, 55:12. A total of 3 samples with ambiguous result were initially detected by PCR-SSOP method. The re-examination results of SBT and NGS showed that the HLA-B genotype of sample 5 was B*15:58, 38:02, sample 6 was DRB1*04:05, 14:101, and sample 7 was DQB1*03:34, 05:02. Among them, alleles C*03:119, C*07:137 and DRB1*14:101 were not included in the Common and Well-documented Alleles (CWD) v2.4 of the Chinese Hematopoietic Stem Cell Donor Database. CONCLUSION: The abnormal pattern of HLA genotyping results of magnetic probe by PCR-SSOP method suggests that it may be a rare allele or a novel allele, which needs to be verified by sequencing.

[A study of HLA-DPA1 and DPB1 matching status for unrelated donor-recipient pairs matched at allele level for HLA-A, -B, -C, -DRB1 and -DQB1 loci].

OBJECTIVE: To analyze the status of HLA-DPA1 and DPB1 matching for unrelated donor-recipient pairs matched at high-resolution allele level for HLA-A, B, C, DRB1 and DQB1 loci. METHODS: A total of 76 unrelated donor-recipient pairs matching at allele level for HLA-A, B, C, DRB1 and DQB1 loci were subjected to HLA-DPA1 and DPB1 sequence-based typing (SBT). HLA-DPA1and DPB1 matching status at high-resolution allelic level was also analyzed. RESULTS: The allelic identity ratio for single HLA-DPA1 and DPB1 were 17.1% and 9.2%, respectively. HLA-DPA1 and DPB1 allelic identity ratio were both very low. The majority of unrelated donor-recipient pairs (73.7%) had an incompatibility at 1 HLA-DPA1 allele, 9.2% of pairs had an incompatibility at 2 DPA1 alleles. As for the high-polymorphic HLA-DPB1 gene, 57.9% of studied donor-recipient pairs had an incompatibility at 1 HLA-DPB1 allele, almost 1/3 (32.9%) of them were completely incompatible. When HLA-DPA1 and DPB1 genes were analyzed together, the donor-recipient pairs matched at 2/4 was the most common (51.4%), 4/4 allelic complete matched pairs accounted for 5.6%, and 0/4 matched pairs accounted for 8.3%. CONCLUSION: Our results indicated that the ratio of HLA-DPA1 and DPB1 complete match in the unrelated donor-recipient pairs matching at allelic level for HLA-A, B, C, DRB1 and DQB1 loci were very low. The effect of HLA-DPA1 and DPB1 matching status on clinical unrelated stem cell transplantation still needs to be elucidated.

[Study on HLA nucleotide sequence matching in epitope positions among recipient-donor pairs for allogenic hematopoietic stem-cell transplantation].

OBJECTIVE: To analyze the human leukocyte antigens(HLA)-A, -B, -Cw, -DRB1 and DQB1 nucleotide sequences between patients waiting for allogenic hematopoietic stem-cell transplantation (HSCT) and donors in Chinese population, and to establish strategy for maximizing optimal donor selection. METHODS: HLA high-resolution typing in a total of 537 recipient-donor pairs was determined by sequence based typing (SBT) method. The nucleotide BLAST tool was used to compare the nucleotide sequences among recipient-donor pairs. RESULTS: Only 16.20% (88/537) of recipient-donor pairs were found to fully match for nucleotide sequences of all HLA-A,-B,-Cw, -DRB1 and -DQB1 loci. Mismatch rate in single locus were 8.38% in HLA-A, 0.74% in HLA-B, 12.29% in HLA-C, 2.42% in HLA-DRB1, and 2.79% in HLA-DQB1, respectively. Mismatch rate in two or multiple HLA loci was 42.65%. Nonpermissive allele mismatch combinations (A 02:01-A 02:06, A 02:06-A 02:07, Cw 03:04-Cw 15:02, Cw 03:03-Cw 04:01, Cw 03:04-Cw 14:02, Cw 03:03-Cw 08:01, DRB1 04:03:01-DRB1 04:05) were detected in single mismatch HLA locus of recipient-donor pairs, mismatches of B 07:05:01-B 07:06, Cw 07:01:01-Cw 07:06 combinations outside of epitope positions were detected in two recipient-donor pairs. CONCLUSION: Our data suggested that attention should be paid in comparing nucleotide sequences between recipient and donor, and in distinguishing nucleotide sequence mismatches within and outside of the epitope positions. These results could serve as guidelines for donor selection.

[Correlation of killer immunoglobulin-like receptor gene diversity with nasopharyngeal carcinoma in Chinese southern Han population].

The objective of this study was to elucidate the correlation of killer immunoglobulin-like receptor (KIR) gene diversity with nasopharyngeal carcinoma (NPC) in the Chinese southern Han population. KIR genotyping of peripheral blood samples from 67 patients with NPC and 77 randomly-selected healthy controls was performed by PCR-SSP, the relative risk (RR) value was calculated by means of Wolf method. The results showed that the KIR2DL3 gene frequency in NPC patient group was significantly lower than that in healthy controls (χ²>3.84, p < 0.05, RR = 0.08), whereas the KIR2DS5 and KIR2DL5B gene frequencies in patient group were significantly higher than those in healthy controls (χ²>3.84, p < 0.05, RR > 1), the other KIR gene frequencies were no statistically different between two groups. It is concluded that the KIR2DL3, KIR2DS5 and KIR2DL5B genes may be correlated with pathogenesis of NPC in the Chinese southern Han population.

[High through-put genomic DNA isolation technique and its application in HLA genotyping for samples from bone marrow donor program].

This study was aimed to develop and establish an efficient method for high through-put automatically extracting genomic DNA from EDTA-anticoagulated whole blood samples, and to utilize this method in routine rSSO HLA genotyping by luminex flow array assay, the genomic DNA was extracted automatically from 400 microl blood samples by using TECAN DNA workstation and 96-well plate with 2 ml volume per well. The yield and purity of each DNA sample was tested by UV-spectrophotometer, the integrity of these DNA samples were run electrophoresis on the agarose gel. Each DNA sample was subjected to PCR amplification and hybridization using One lambda rSSO HLA-A, -B and -DRB1 commercial kit, the fluorescent intensity for positive bead and negative bead hybridized with HLA-A, -B and -DRB1 PCR products were calculated and analyzed. The results showed that the mean yield and purity (A260/A280) of genomic DNA extracted from 400 microl whole blood samples were 3.217+/-0.715 microg and 1.710+/-0.103 respectively. The molecular weight was more than 15 kb in size and the fluorescent intensity for positive bead hybridized with HLA-A, -B and -DRB1 PCR products of each sample was >600 RFU, however, the fluorescent intensity for negative bead for each sample was <50 RFU. It is concluded that the highly qualified genomic DNA can be extracted automatically from blood samples of marrow-donors by using TECAN DNA workstation, and the extracted DNA samples are suitable for high through-put HLA genotyping by luminex flow array assay and other downstream transplant immunological and molecular biological experiments.

[Demographic characteristics of patients with leukemia waiting for stem cell transplantation in Chinese Marrow Donor Program during 2000 to 2006].

OBJECTIVE: To explore the distributive characteristics for leukemia and to provide scientific reference for its prevention and intervention. METHODS: Microsoft SQL 2005 databases was used to make a mathematical analysis of 3708 patients with leukemia in Chinese Marrow Donor Program (CMDP) from 2000 to 2006. The distributive characteristics were calculated by sex, age and area of patients with leukemia and then compared by constituent ratio and relative ratio statistics method. RESULTS: A total of 3708 cases of leukemia were registered for waiting donor during the period 2000-2006 in CMDP, the age of patients were from 7 months to 69 years, the median age of diagnosis was 24.5 years, standard deviation was 6.7-years-old; males suffered more than females, and the ratio was 1.95: 1 (2451/1257). There were 1202 patients with acute lymphoblastic leukemia (ALL), 1066 with acute myeloid leukemia (AML), 1435 with chronic myeloid leukemia (CML), 5 with chronic lymphoblastic leukemia (CLL), CML was the most common patients. The distributive of 3708 patients with leukemia peak was from 15 to 30 years age group, 542 patients were at the age of 15 years, 559 patients were at the age group above 20 years, 514 patients were at the age above 25, 522 patients were at the age over 30-years-old. ALL patients were accounted for 49.36% (613/1242), AML patients accounted for 27.78% (245/1242), CML patients accounted for 22.78% (283/1242), CLL patients accounted for 0.08% (1/1242) in the age group of under 20 years (childhood group). All subjects were mainly in childhood patients with leukemia; The distributive of patients with leukemia in 30 areas were different, leukemia patients were not registered in one area, 494 patients were at the highest peak, 101 patients were in the median. CONCLUSION: The majority of leukemia patients for waiting stem cell transplantation were registered among children and the adolescents groups, males were suffered more than the females. For children, the major type of leukemia was ALL, being necessary to pay more attention to the education of health, and the precaution of leukemia. The distributive of patients with leukemia for waiting stem cell transplantation was different in 30 areas, and the peak region of leukemia should be in Jiangsu, Guangdong, Shangdong, and Zhejiang provinces.

[Analysis of HLA haplotype frequency and linkage disequilibrium in patients with acute lymphoblastic leukemia from Northern Chinese Han].

OBJECTIVE: To analyze the difference between the frequencies of HLA-A-B, B-DRB1 and A-B-DRB1 haplotype, as well as their linkage disequilibrium pattern in patients with acute lymphoblastic leukemia(ALL) and healthy controls from Northern Chinese Han. METHODS: The frequencies of HLA-A-B, B-DRB1, A-B-DR haplotypes and linkage disequilibrium were estimated by Expectation Maximization method based on the genotypes of 643 patients with ALL and 2 0359 unrelated healthy donors, and the statistical significance between the two groups were estimated by chi-square test. Linkage disequilibrium was analyzed with population genetic methods. RESULTS: The most common HLA-A-B, B-DRB1, and A-B-DR haplotypes were A30-B13, A2-B46, A33-B58, B13-DR7, B46-DR9, B52-DR15, B58-DR17, A30-B13-DR7, A33-B58-DR17 and A1-B37-DR10 in both groups. The frequencies of A30-B13, A2-B46, A33-B44, B13-DR7, A30-B13-DR7 and A2-B46-DR9 haplotypes and linkage disequilibrium value were significantly decreased (P<0.05) in the patient group than that in the control group. On the other hand, the frequencies of A2-B52, A31-B61, A24- B8, B60-DR9, B27-DR4, B52-DR14, B44-DR17, B27-DR12 and A11-B27-DR12 haplotypes and linkage disequilibrium value were significantly increased (P<0.05) in the patient group than that in the control group. CONCLUSION: There are some common and positive linkage disequilibrium haplotypes in both the ALL patients and the healthy donors in Northern Chinese Han. Interestingly, some haplotypes and their linkage disequilibrium patterns had significantly different distributions between the two groups. The study provided basic data for the relationship of ALL and HLA haplotype and for finding the HLA-A, B, DR matching donors.

[Study on the correlation between acute lymphoblastic leukemia and HLA genes in southern China Han population].

To study the correlation between acute lymphoblastic leukemia (ALL) and HLA-A, B and DRB1 gene in southern Chinese Han population and to investigate the susceptible HLA gene to ALL, a total of 4707 healthy volunteer bone marrow donors from southern Chinese Han population were used as a control group, 201 patients diagnosed as patient group from southern Han individuals were genotyped at HLA-A, B and DRB1 loci by PCR-SSP, PCR-SSOP and SBT. HLA allele frequency and its distribution of ALL patient group were compared with the control group by using chi(2) test, and calculated the statistic value of relative risk (RR), pathogenicity score (EF) and preventive score (PF). The results showed that in comparison with the control group, the gene frequence of HLA-A26, B56 and DR9 increased significantly, but the gene frequence of HLA-A30, A33 and B58 allele frequency decreased significantly for patients with ALL. It is concluded that HLA-A26, B56 and DR9 gene have a high correlation with ALL and seem to contribute the genetic susceptibility to ALL in southern Chinese Han populations. However, HLA-A30, A33 and B58 gene seem to have protective role for southern Han individuals suffered from ALL.

[Study of HLA polymorphism in the 6965 Han bone marrow registry donors].

OBJECTIVE: To analyze human leukocyte antigen (HLA) polymorphism and search for new alleles in Chinese Han population bone marrow registry donors. METHODS: DNA-based HLA genotyping methods were used including PCR-SSP, BST and molecular cloning. RESULTS: A total of 6965 unrelated donors, 4707 from South China origin and 2258 from north, were typed for HLA-A, B, and DRB1 loci. Seventy-two specificities of HLA alleles were identified. The HLA-A25, A34, A74, B41, B42, B53, B73 and B81 that were rarely reported in previously Chinese population studies were identified in this study. Estimation of gene frequency indicated that the blank gene frequency was less than 0.2% for HLA-A, 0.25% for HLA-B and 0.70% for HLA-DRB1 loci. Three novel alleles were identified and officially assigned by the World Health Organization (WHO) Nomenclature Committee as A*0253N, A*1114 and B*5610. CONCLUSION: Large-scale DNA-based HLA genotyping used in bone marrow registry donors is highly accurate and reliable for estimating gene frequency and searching for new alleles. The discrepancy of HLA gene distribution between South and North China Han population showed the necessity of setting the more regions in South and North China to screen the bone marrow registry donors for bone marrow transplant.