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T Akaza

Publications and source records attributed to T Akaza.

At least 19 recordsLinked to original sources
PubMed2002

HLA class II allele and haplotype frequencies in Koreans based on 107 families.

We have investigated the distribution of HLA class II alleles and haplotypes in 107 Korean families (207 parents and 291 children) for the HLA-DRB1, DRB3/B4/B5, DQA1, DQB1 and DPB1 loci. Numbers of alleles observed for each locus were DRB1: 25, DQA1: 14, DQB1: 15, and DPB1: 13. Only two to three alleles were observed for the DRB3 (*0101, *0202, *0301), DRB4 (*0103, * 0103102 N), and DRB5 (*0101, *0102) loci. These alleles showed strong associations with DRB1 alleles: DRB3*0101 with DRB1*1201, *1301 and *1403; DRB3*0301 with DRB1*1202 and *1302; DRB3*0202 with DRB1*0301, *1101, *1401 and *1405; DRB5*0101 and *0102 were exclusively associated with DRB1*1501 and *1502, respectively. The seven most common DRB1-DQB1 haplotypes of frequencies > 0.06 accounted for 52% of the total haplotypes. These haplotypes were exclusively related with the seven most common DRB1-DRB3/B4/B5-DQA1-DQB1 haplotypes: DRB1*1501-DRB5*0101-DQA1*0102-DQB1*0602 (0.085), DRB1*0405-DRB4*0103-DQA1*0303-DQB1*0401 (0.082), DRB1*09012-DRB4*0103-DQA1*0302-DQB1*03032 (0.082), DRB1*0101-DQA1*0101-DQB1*0501 (0.075), DRB1*0701-DRB4*0103-DQA1*0201-DQB1*0202 (0.065), DRB1*0803-DQA1*0103-DQB1*0601 (0.065), and DRB1*1302-DRB3*0301-DQA1*0102-DQB1*0604 (0.065). When these haplotypes were extended to the DPB1 locus, much diversification of haplotypes was observed and only one haplotype remained with a frequency of > 0.06: DRB1*0405-DRB4*0103-DQA1*0303-DQB1*0401-DPB1*0501 (0.062). Such diversification would have resulted from cumulated events of recombination within the HLA class II region, and the actual recombination rate observed between the HLA-DQB1 and DPB1 loci was 2.3% (10/438 informative meioses, including 2 recombinants informative by analysis of TAP genes). Comparison of the distribution of DRB1-DQB1 haplotypes with other populations revealed that Koreans are closest to Japanese people. However, Koreans share a few haplotypes with white people and Africans, which are rare in Japanese: DRB1*0701-DQB1*0202 and DRB1*1302-DQB1*0609. The results obtained in this study will provide useful information for anthropology, organ transplantation and disease association studies.

Alleles↗
PubMed2002

Polymorphisms in TNFA and TNFR2 affect outcome of unrelated bone marrow transplantation.

Effects of polymorphisms in TNFA and TNFR2 on the outcome of 462 cases of unrelated bone marrow transplantation (uBMT) were studied retrospectively. Four alleles of TNFA (U01-U04) distinguished by polymorphism in the upstream region, -1031 (T/C), -863 (C/A) and -857 (C/T), and two alleles of TNFR2 (196M/196R) distinguished by polymorphism at codon 196 were determined. Transplantation involving TNFA-U02- and/or U03-positive donors and/or recipients resulted in a higher incidence of graft-versus-host disease (GVHD) of grade III-IV (P < 0.05 for donor type, P < 0.01 for recipient type) and a lower relapse rate than that involving TNFA-U01 homozygous recipients and/or donors (P < 0.025 for donor type, P < 0.01 for recipient type). These results include the HLA mismatching effect due to linkage disequilibirium of TNFA with HLA loci. However, the effects were also observed in HLA-A, -B and -DRB1 allele-matched transplantation. Transplantation from TNFR2-196R-positive donors exhibited a higher incidence of severe GVHD (P < 0.05) and tendency for a lower relapse rate than that from TNFR2-196M homozygous donors. TNFR2-196R of recipient origin had no effect on GVHD but increased the relapse rate (P < 0.025). These results suggest that TNFA and TNFR2 typings are helpful for predicting uBMT outcome and for preventing severe complications at an early stage.

Adult↗
PubMed2001

Allele frequency of HLA-B39 in the Japanese population and identification of a novel B39 allele, B*3923.

A new HLA-B39 allele, B*3923, was found in the Japanese population. Compared with B*39022, the new allele had a single point mutation at position 503 in exon 3 with an amino acid substitution, Gln144Arg. To determine B39 allele frequency in Japanese, 275 B39-positive samples from 3277 Japanese individuals were examined by polymerase chain reaction using microtitre plate hydribization (PCR-MPH) and single-strand conformation polymorphism (PCR-SSCP). The frequency of B*3923 was estimated to be 0.4% in B39 alleles of the Japanese population. B*3923 was found in samples from four Japanese individuals, all of whom have DRB1*1406.

Asian People↗
PubMed2001

The origin of Minnan and Hakka, the so-called "Taiwanese", inferred by HLA study.

The Minnan and Hakka people groups, the so-called "Taiwanese", are the descendants of early settlers from the southeast coast of China during the last few centuries. Genetically they showed affinities to southern Asian populations, as determined by phylogenetic trees and correspondence analysis calculated from HLA allele frequencies. This corresponds historically with the fact that they are the descendants of the southeast coastal indigenous population (Yueh) of China and should therefore not be considered as descendants of "pure" northern Han Chinese. A33-B58-DRB1*03 (A33-Cw10-B58-DRB1*03-DQB1*02), the most common HLA haplotype among "Taiwanese", with a haplotype frequency of 6.3%, has also been found to be the most common haplotype among Thai-Chinese and Singapore Chinese, two other populations also originating from the southeast coast of China. These observations suggests that this haplotype is the most well-conserved ancient haplotype of the Yueh.

Alleles↗
PubMed2001

Polymorphisms in the coding region of mtDNA and effects on clinical outcome of unrelated bone marrow transplantation.

The entire protein-coding region was divided into 45 fragments, separately amplified and analyzed for polymorphism by the PCR-SSCP (single-strand conformation polymorphism) method. The effect of polymorphism mismatching on the clinical outcome of unrelated bone marrow transplantation was studied to clarify whether products from mtDNA become minor antigens. Variability in PCR-SSCP pattern combinations of the 45 fragments suggests that each individual has a different polymorphism combination in the protein-coding region if all the coding regions were compared at the nucleotide sequence level. Nonsynonymous polymorphisms were found at relatively high frequency in MTATP8 and MTND3. Both the polymorphisms with and without substitution matched the peptide-binding motifs of HLA-A*0201. The effects of the polymorphism matching were retrospectively analyzed in 340 recipients transplanted with HLA-A, -B, -DRB1 allele-matched bone marrow from unrelated donors. There were no effects of polymorphism matching on the incidence of acute GVHD and cumulative disease-free survival. These results suggest that polymorphisms which generate peptides, with and without substitutions, that bind the same HLA molecule hardly influence GVHD because the difference between the HLA-peptide complexes is minute.

Bone Marrow Transplantation↗
PubMed2001

E variants found in Japanese and c antigenicity alteration without substitution in the second extracellular loop.

BACKGROUND: The molecular basis of E variants in the Japanese population is poorly understood. In this study, molecular analysis of E variants detected in Japanese by serologic methods was carried out. STUDY DESIGN AND METHODS: E variants from healthy Japanese blood donors were screened by serologic analysis using E MoAbs. Fifteen E variant samples were divided into three types--EFM, EKH, and EKK-on the basis of patterns of reactivity with five distinct E antibodies. The entire coding region of the Rh cDNAs from the E variant samples was analyzed by sequencing. RESULTS: Although the Rh cDNA sequences of the three types were different from each other, those of the EFM-type variants (RHEFM) had a partial DNA exchange in exon 5 between the RHCE and RHD genes, generating an RHcE variant (Gln233Glu, Met238Val). The cDNA of EKH-type variants (RHEKH) exhibited a point mutation (G461C) in exon 3 of the RHcE allele that resulted in an Arg154Thr substitution in the third external loop of the RhcE peptide. The EKK-type variant (RHEKK) carried a hybrid gene structure characterized by replacement of exons 1-3 (or 2-3) of the RHCE gene with those of the RHD gene. The RHD gene of a person possessing an E variant of the EKK type was also a hybrid gene, D-cE(2-3)-D or cE(1-3)-D (RHDKK). The E variants of types EKH and EKK showed weak c antigenicity. CONCLUSION: In serologic screening of 140,723 Japanese blood donors, 15 were found to possess E variants (0.011%). A new RHCE variant, RHEKH, was identified. On the basis of the variants found in this study, the c antigenicity seemed to be determined not only by Pro-103 but also by the structure of the third extracellular loop or the amino acids contained in it.

Amino Acid Substitution↗
PubMed2000

Heterogeneity of Taiwan's indigenous population: possible relation to prehistoric Mongoloid dispersals.

Taiwan's 9 indigenous tribes (Tsou, Bunun, Paiwan, Rukai, Atayal, Saisiat, Ami, Puyuma, Yami) are highly homogeneous within each tribe, but diversified among the different tribes due to long-term isolation, most probably since Taiwan became an island about 12,000 years ago. Homogeneity of each tribe is evidenced by many HLA-A,B,C alleles having the world's highest ever reported frequencies, e.g. A24 (86.3%), A26 (18.8%), Cw10 (36.8%), Cw7 (66%), Cw8 (32.1%), B13 (27.9%), B62 (37.4%), B75 (18%), B39 (53.5%), B60 (33.3%), and B48 (24%). Also, all of these tribes have HLA class I haplotype frequencies greater than 10%, with A24-Cw7-B39 in Saisiat (44.5%) being the highest, suggesting Taiwan's indigenous tribes are probably the most homogeneous ( the "purest") population in the world. A24-Cw8-B48, A24-Cw10-B60 and A24-Cw9-B61 found common to many Taiwan indigenous tribes, have also been observed in Maori, Papua New Guinea Highlanders, Orochons, Mongolians, Inuit, Japanese, Man, Buryat, Yakut, Tlingit, Tibetans and Thais. These findings suggest Taiwan's indigenous groups are more or less genetically related to both northern and southern Asians. Principal component analysis and the phylogenetic tree (using the neighbor-joining method) showed close relationship between the indigenous groups and Oceanians. This relationship supports the hypothesis that Taiwan was probably on the route of prehistoric Mongoloid dispersals that most likely took place along the coastal lowland of the Asian continent (which is under the sea today). Cultural anthropology also suggests a relationship between Taiwan's indigenous tribes and southern Asians and to a lesser extent, northern Asians. However, the indigenous groups show little genetic relationship to current southern and northern Han Chinese.

Alleles↗
PubMed2000

Identification of a novel HLA-B46 allele, B*4602, in Japanese.

The B*4602 was identified in a healthy Japanese donor. The B46 variant antigen differed serologically from B46. The nucleotide sequence of B*4602 differed from that of B*4601 by a single base (from A to G) at position 293 in exon 2. The substitution changed the amino acid Asp at position 74 to Gly. The gene frequency of B*4602 in the Japanese population is extremely low. The presumed haplotype of B*4602 was HLA-A2-Cw1-B*4602-DRB1*09. This is the first report of polymorphism of the B46 antigen.

Alleles↗
PubMed2000

Polymorphisms of RhD(Va) and a new RhD(Va)-like variant found in Japanese individuals.

BACKGROUND AND OBJECTIVES: Red cell type RhD(Va) lacks epD1 and 5 and is encoded by hybrid RHD-CE(5)-D alleles. We analyzed RhD(Va) and RhD(Va)-like samples in Japanese blood donors. MATERIALS AND METHODS: Ten RhD(Va) samples lacked epD1 and 5 and 3 RhD(Va)-like variants also lacked, epD2 and a part of 6/7. We identified the full-length nucleotide sequences of the complementary DNA (cDNA) synthesized from 4 samples: 3 of type D(Va) and the 4th a D(Va)-like variant. RESULTS: Although their sequences differed from each other, all the substitutions were exclusively in exon 5. Three D(Va) samples had hybrid RHD-CE(5)-D alleles, but the D(Va)-like variant had a unique nucleotide substitution with a single amino acid change, E233K. Exon 5 of the genomic DNA from all 13 samples was analyzed by sequencing. No other sequences were identified. CONCLUSION: All RhD(Va) and RhD(Va)-like variants had the substitution for E233. E233 seems to be a determinant of epD1 and 5. A new category of RhD variant, DYO, was identified.

Amino Acid Substitution↗
PubMed1999

Polymorphism in RANTES chemokine promoter affects HIV-1 disease progression.

RANTES (regulated on activation normal T cell expressed and secreted) is one of the natural ligands for the chemokine receptor CCR5 and potently suppresses in vitro replication of the R5 strains of HIV-1, which use CCR5 as a coreceptor. Previous studies showed that peripheral blood mononuclear cells or CD4(+) lymphocytes obtained from different individuals had wide variations in their ability to secrete RANTES. These findings prompted us to analyze the upstream noncoding region of the RANTES gene, which contains cis-acting elements involved in RANTES promoter activity, in 272 HIV-1-infected and 193 non-HIV-1-infected individuals in Japan. Our results showed that there were two polymorphic positions, one of which was associated with reduced CD4(+) lymphocyte depletion rates during untreated periods in HIV-1-infected individuals. This mutation, RANTES-28G, occurred at an allele frequency of approximately 17% in the non-HIV-1-infected Japanese population and exerted no influence on the incidence of HIV-1 infection. Functional analyses of RANTES promoter activity indicated that the RANTES-28G mutation increases transcription of the RANTES gene. Taken together, these data suggest that the RANTES-28G mutation increases RANTES expression in HIV-1-infected individuals and thus delays the progression of the HIV-1 disease.

Base Sequence↗
PubMed1999

Tolerance of NK and LAK activity for HLA class I-deficient targets in a TAP1-deficient patient (bare lymphocyte syndrome type I).

NK cells recognize target cells that lack HLA class I molecules and lyse them, according to the 'missing self' hypothesis. It was previously reported that a TAP2-deficient patient with an HLA class I-deficiency, had a normal number of NK cells but that the lymphocytes of this patient had lost their NK activity against K562 cells. In this study, we investigated the HLA class I-recognizing NK receptor expressions and the NK and LAK activities of the lymphocytes of a TAP1-deficient patient. The patient had a normal number of NK cells. Although the lymphocytes showed LAK activity against class I expressing targets following IL-2, IL-12 and IL-15 stimulation for 3 days, neither NK nor LAK activity against targets lacking class I molecules was induced. The NK cells of the patient expressed class I-recognizing NK receptors, although the percentages of such cells were low. However, no differences were observed in the expression levels of inhibitory and activating NK receptors between lymphocytes of the patient and those of healthy controls, suggesting that the modulation of the NK receptor expression is not primarily responsible for this tolerance. These results also suggest that the lymphocytes of the patient are defective in the recognition of class I-deficient target cells in order to promote the induction of self tolerance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Cell surface expression of HLA-E molecules on PBMC from a TAP1-deficient patient.

It was recently revealed from studies on TAP-deficient cell lines that HLA-E molecules are associated with nonamer peptides derived from certain HLA class I leader sequences and are expressed on the cell surface in a TAP-dependent manner. We have previously reported a homozygous TAP1 gene mutation in a HLA class I-deficient patient. In the present report, we demonstrate HLA-E molecule expression on the surface of the peripheral blood mononuclear cells (PBMC) of the TAP1-deficient patient. The HLA-E expression level on the monocytes of the patient was as high as that in healthy donors, whereas the HLA-E expression level on the lymphocytes of the patient was slightly lower. On the other hand, HLA-E expression was not detected on KMW-B2 cells, an Epstein-Barr virus (EBV)-transformed B-cell line derived from the lymphocytes of the TAP1-deficient patient. These data suggest the existence of TAP-dependent and -independent pathways for the surface expression of HLA-E molecules.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Probability of finding HLA-matched unrelated marrow donors for Koreans and Japanese from the Korean and Japan Marrow Donor Programs.

This study was performed to assess the probability of finding HLA-matched donors for Korean and Japanese patients from unrelated marrow donor registries of both countries. A simulation study of donor search was carried out using the donor pools of the Korean Marrow Donor Program (KMDP) with 10,244 and the Japan Marrow Donor Program UMDP) with 53,411 HLA-A, -B, -DR typed donors. The records of a total of 184 actual Korean patients and 1,302 simulated Japanese patients were searched and A, B, DR-matched donors were found for 28% of Korean and 76% of Japanese patients from the KMDP and JMDP pools, respectively. Of those patients who could not find matched donors in the registry of their own country, 30% of Koreans could find matched donors in the JMDP and 10% of Japanese in the KMDP pools. It can be concluded that future international collaboration between Korea and Japan would be very effective for unrelated bone marrow transplantations.

Asian People↗
PubMed1999

Diversity of HLA-B17 alleles and haplotypes in East Asians and a novel Cw6 allele (Cw*0604) associated with B*5701.

The distribution of HLA-B17 alleles and their association with HLA-A, -C and -DRB1 alleles were investigated in seven East Asian populations Japanese, South Korean, Chinese-Korean, Man, Northern Han, Mongolian and Buryat populations). The B17 alleles were identified from genomic DNA using group-specific polymerase chain reaction (PCR) followed by hybridization with sequence-specific oligonucleotide probes (SSOP). In all of these East Asian populations, except Japanese and Chinese-Koreans, B*5701 was detected and strongly associated with A*0101, Cw*0602 and DRB1*0701. In contrast, B*5801 was detected in all the seven populations and strongly associated with A*3303, Cw*0302, DRB1*0301 and DRB1*1302. The A*3303-Cw*0302-B*5801-DRB1*1302 haplotype was observed in South Korean, Chinese-Korean, Buryat and Japanese populations, while A*3303-Cw*0302-B*5801-DRB1*0301 was predominantly observed in the Mongolian population. A similar haplotype, A*0101-Cw*0302-B*5801-DRB1*1302, was observed in the Buryat population. A novel Cw6 allele, Cw*0604, was identified in the Man population. This Cw allele was observed on the haplotype A*0101-B*5701-DRB1*0701. Thus, we confirmed, at the sequence level, that the common haplotypes carrying B*5701 and B*5801 have been conserved and shared in East Asian populations.

Alleles↗
PubMed1999

Significant association of a single nucleotide polymorphism in the tumor necrosis factor-alpha (TNF-alpha) gene promoter with human narcolepsy.

Narcolepsy is a sleep disorder in which multiple factors, including environmental and genetic factors, are involved. A genetic factor strongly associated with the disorder has been found in the human leukocyte antigen (HLA) class II region: the haplotype, DRB1*1501-DQB1*0602, predisposes to narcolepsy. No susceptibility genes other than the HLA-haplotype have been found. In this paper, we performed an association study of the tumor necrosis factor-alpha (TNF-alpha) gene located in the HLA class III region with human narcolepsy, in which we examined the known single-nucleotide polymorphisms (SNPs) in the promoter region in 49 narcoleptic patients, who were all positive for DRBI*1501, and 111 healthy control individuals. The results indicated that the frequency of the genotype at position -857 (-857SNP) was significantly different between the patients and controls, and the allele frequencies of 857SNP revealed that the frequency of -857T was significantly increased in the patients as compared with that in the controls (P=0.0068). In addition, haplotypes presumed from HLA-DRB1, -857SNP and HLA-B loci suggested that -857T was mainly associated with DRB1 alleles other than DRB1*1501: the significant increase in frequency of -857T in the patients was not caused by allelic association with DRB1*1501. Therefore, it is conceivable that the TNF-alpha with 857T was associated with narcolepsy independently of the strong association of DRB1*1501 with the disorder. Altogether, the data presented here lead us to propose that TNF-alpha could be a new susceptibility gene in human narcolepsy.

Alleles↗
PubMed1999

Human platelet alloantigen (HPA)-5a/b mismatch decreases disease-free survival in unrelated bone marrow transplantation.

Matching of human platelet alloantigen (HPA) systems 2-6 was retrospectively investigated in 715 unrelated bone marrow transplantations. Of the five HPA systems studied, HPA-5 mismatching was found to have a significant effect on the disease-free survival rate of recipients following transplantation in the HLA-A, -B, -C, and -DR allele-matched donor-recipient pairs. The effect of the HPA-5 mismatch was most significant in the recipient group possessing the HLA haplotype A*2402-B*5201, which is a highly frequent haplotype among the Japanese population. However, the probability of development of acute graft-versus-host disease (GVHD) was not increased significantly by the HPA-5 mismatching. These findings suggest that the HPA-5 mismatching decreases the recipient's survival by a mechanism different from that in the case of mismatching of minor antigens found often in transplant recipients developing GVHD.

Antigens, Human Platelet↗
PubMed1999

Possible association of human leucocyte antigen DR1 with delayed sleep phase syndrome.

The study investigated the human leucocyte antigen (HLA), types A, B and DR, of 42 patients with delayed sleep phase syndrome (DSPS) and compared the frequencies of the antigens with those in 117 healthy controls. The comparison revealed that the gene frequencies and positivities of HLA-A, -B and -DR, except for DR1, had no significant differences between the patients and controls. The frequency of HLA-DR1 was increased in the DSPS patients as compared with that in the healthy controls (P = 0.0069 in positivity). Although the corrected P-value (0.069) for multiple comparisons almost reached the significance level, the results indicated a possible association of the HLA-DR1 antigen with DSPS. This study suggests that there are genetic predispositions to DSPS.

Adolescent↗