Biomedical subjects

K Tokunaga

Publications and source records attributed to K Tokunaga.

At least 19 recordsLinked to original sources

PubMed2006

HIV-1 Vpr induces ATM-dependent cellular signal with enhanced homologous recombination.

An ATM-dependent cellular signal, a DNA-damage response, has been shown to be involved during infection of human immunodeficiency virus type-1 (HIV-1), and a high incidence of malignant tumor development has been observed in HIV-1-positive patients. Vpr, an accessory gene product of HIV-1, delays the progression of the cell cycle at the G2/M phase, and ATR-Chk1-Wee-1, another DNA-damage signal, is a proposed cellular pathway responsible for the Vpr-induced cell cycle arrest. In this study, we present evidence that Vpr also activates ATM, and induces expression of gamma-H2AX and phosphorylation of Chk2. Strikingly, Vpr was found to stimulate the focus formation of Rad51 and BRCA1, which are involved in repair of DNA double-strand breaks (DSBs) by homologous recombination (HR), and biochemical analysis revealed that Vpr dissociates the interaction of p53 and Rad51 in the chromatin fraction, as observed under irradiation-induced DSBs. Vpr was consistently found to increase the rate of HR in the locus of I-SceI, a rare cutting-enzyme site that had been introduced into the genome. An increase of the HR rate enhanced by Vpr was attenuated by an ATM inhibitor, KU55933, suggesting that Vpr-induced DSBs activate ATM-dependent cellular signal that enhances the intracellular recombination potential. In context with a recent report that KU55933 attenuated the integration of HIV-1 into host genomes, we discuss the possible role of Vpr-induced DSBs in viral integration and also in HIV-1 associated malignancy.

Ataxia Telangiectasia Mutated Proteins↗

PubMed2006

FLT3 is fused to ETV6 in a myeloproliferative disorder with hypereosinophilia and a t(12;13)(p13;q12) translocation.

The FMS-like tyrosine kinase 3 (FLT3) gene, belonging to the receptor tyrosine kinase (TK) subclass III family, plays an important role in normal hematopoiesis and is one of the most frequently mutated genes in hematologic malignancies as well as an attractive target for directed inhibition. Activating mutations of this gene, including internal tandem duplication in the juxtamembrane (JM) domain and point mutations in the TK domain, are found in approximately one-third of patients with acute myeloid leukemia and in a smaller subset of patients with acute lymphoblastic leukemia. We report here that FLT3 may contribute to leukemogenesis in a patient with myeloproliferative disorder and a t(12;13)(p13;q12) translocation through generating a fusion gene with the ETS variant gene 6 (ETV6) gene. ETV6 has been reported to fuse to various partner genes, including TK and transcription factors. Both ETV6/FLT3 and reciprocal FLT3/ETV6 transcripts were detected in the patient mRNA by reverse transcriptase-polymerase chain reaction. At the protein level, however, only ETV6/FLT3 products were expressed. Among them, one retains the helix-loop-helix (HLH) oligomerization domain of ETV6 and the JM as well as TK domain of FLT3. FLT3 receptor in leukemic cells might be inappropriately activated through dimerization by HLH domain of ETV6, which consequently interfered with proliferation and differentiation of hematopoietic cells.

Aged↗

PubMed2006

Association of HLA-DRB10901-DQB10303 haplotype with microscopic polyangiitis in Japanese.

Microscopic polyangiitis (MPA) is a rare and severe form of systemic necrotizing vasculitis associated with myeloperoxidase (MPO)-specific antineutrophil cytoplasmic antibody (ANCA). We previously reported significant association of HLA-DRB1*0901 with MPA. To define the susceptibility loci within the HLA region, we determined the genotypes of HLA-DQB1, DPB1, B and C in 50 patients with MPA and 77 unrelated Japanese controls. In addition to HLA-DRB1*0901, significant association of DQB1*0303 (allele carrier frequencies 50% in MPA, 29.9% in controls, odds ratio 2.35, P = 0.017) was detected. These alleles were in strong linkage disequilibrium (D' = 0.95, r2 = 0.82). Increased frequency was also observed for DPB1*0201, B*15111 and Cw*0303, which was at least partly accounted for by linkage disequilibrium with DRB1*0901 and DQB1*0303. These results indicate that DRB1*0901-DQB1*0303 haplotype represents the primary genetic risk for MPA within the HLA region in Japanese, and provides the basis that future functional studies on the role of HLA in MPA should target DR9, DQ9 and DR53 proteins encoded by this haplotype.

Alleles↗

PubMed2006

ADAM33 polymorphisms are associated with asthma susceptibility in a Japanese population.

BACKGROUND: Asthma is the most common chronic disorder in childhood, and asthma exacerbation is an important cause of childhood morbidity and hospitalization. Asthma is believed to be a complex disorder involving genetic and environmental factors, and several asthma susceptibility loci have been identified through genome-wide screening. A disintegrin and metalloprotease 33 (ADAM33) was the first asthma susceptibility gene to be discovered by positional cloning in 2002. OBJECTIVE: The aim of the present study was to investigate whether single-nucleotide polymorphisms (SNPs) in ADAM33 are associated with childhood asthma in the Japanese population. METHODS: Twenty-three ADAM33 SNPs were genotyped by fluorescence correlation spectroscopy with the use of DNA from 155 families (538 members) identified through children with atopic asthma. The transmission disequilibrium test (TDT) was performed for family-based association study. RESULTS: TDT revealed that minor alleles of S+1, ST+4, and T2 SNPs were over-transmitted to asthma-affected offspring (P<0.05). According to the haplotype TDT, no haplotype of ADAM33 was transmitted preferentially to asthmatic offspring. CONCLUSION: Our results confirm the involvement of ADAM33 in the development of childhood asthma among the Japanese.

ADAM Proteins↗

PubMed2006

HLA-A, HLA-B, and HLA-DRB1 alleles and haplotypes in Naxi and Han populations in southwestern China (Yunnan province).

The frequencies of the human leukocyte antigen alleles HLA-A, HLA-B, and HLA-DRB1 and the A-B-DRB1, A-B, and B-DRB1 haplotypes were studied in Naxi and Yunnan Han populations using polymerase chain reaction (PCR)-sequence-specific amplification for alleles A and B and a PCR-microtiter plate hybridization method for the DRB1 allele. A total of 8 A, 19 B, and 30 DRB1 alleles were found in the Naxi population, and 15 A, 21 B, and 36 DRB1 alleles were found in Yunnan Han population. The common A-B-DRB1 haplotypes in the Naxi population were A*24-B*15-DRB1*1202, A*11-B*15-DRB1*0405, A*11-B*15-DRB1*1202, A*11-B*38-DRB1*08032, and A*11-B*55-DRB1*0405; the common A-B haplotypes were A*11-B*15, A*11-B*38, and A*24-B*15; and the common B-DRB1 haplotypes were B*15-DRB1*1202, B*38-DRB1*08032, and B*48-DRB1*1201. In the Yunnan Han population, the common A-B-DRB1 haplotypes were A*24-B*15-DRB1*1501, A*24-B*46-DRB1*08032, and A*24-B*15-DRB1*1201; the common A-B haplotypes were A*24-B*15, A*24-B*46, and A*34-B*46; and the common B-DRB1 haplotypes were B*15-DRB1*1501, B*46-DRB1*09012, and B*46-DRB1*1401. Phylogenetic tree and principal component analyzes based on HLA-A, HLA-B, and DRB1 allele frequencies suggested that the Naxi ethnic group belongs to the southern Chinese groups, while the Yunnan Han population is a characteristic population located intermediate between northern and southern Chinese groups, although they live in the southwest of China.

Alleles↗

PubMed2006

Estimation of the species-specific mutation rates at the DRB1 locus in humans and chimpanzee.

To estimate the species-specific mutation rates at the DRB1 locus in humans and chimpanzee, we analyzed the nucleotide sequence of a 37.6-kb chimpanzee chromosomal segment containing the entire Patr-DRB1*0701 allele and the flanking nongenic region and we compared it with two corresponding human sequences containing the HLA-DRB1*070101 allele using the sequence of HLA-DRB1*04011 as an outgroup. Because the allelic pair of HLA-DRB1*070101 and Patr-DRB1*0701 shows the lowest number of substitutions between the two species, it appears that these sequences diverged close to the time of the humans-chimpanzee divergence (6 million years ago). Alignment of the nucleotide sequences for HLA-DRB1*070101 and Patr-DRB1*0701 alleles showed that they share a high degree of similarity, suggesting that the studied chromosomal segments with these sequences have not been subjected to recombination since the humans-chimpanzee divergence. Comparison of the flanking 10.6 kb of nongenic sequences revealed an average of 41.5 and 83 single nucleotide substitutions in humans and chimpanzee, respectively. Thus, the species-specific nucleotide substitution rates in the flanking nongenic region were estimated to be 6.53 x 10(-10) and 1.31 x 10(-9) per site per year in humans and chimpanzee, respectively. Unexpectedly, the estimated rate in humans was twofold lower than in chimpanzee (P < 10(-3), Tajima's relative rate test) and lower than the average substitution rate in the human genome. Because the nucleotide substitution rate in nongenic regions free from selection is expected to be equal to the mutation rate, the estimated substitution rate should correspond to the species-specific mutation rate at the DRB1 locus. Our results strongly suggest that the mutation rate at DRB1 locus differs among species.

Alleles↗

PubMed2006

Differential diagnosis of the infundibular dilation and aneurysm of internal carotid artery: assessment with fusion imaging of 3D MR cisternography/angiography.

Fusion imaging of 3D MR cisternography/angiography was used for the assessment of the vascular bulging finding detected by MR angiography from the viewpoint of the outer wall configuration of the corresponding internal carotid artery depicted by MR cisternography. With a fusion image, useful information was obtained to distinguish an infundibular dilation and enlarged origin of the normal posterior communicating artery from an aneurysm. This imaging technique can be a feasible addition to a noninvasive screening of cerebrovascular lesions with MR angiography alone.

Adult↗

PubMed2005

Absence of an association between the polymorphisms in the genes encoding adiponectin receptors and type 2 diabetes.

AIMS/HYPOTHESIS: Secreted by adipocytes, adiponectin is a hormone that acts as an antidiabetic and anti-atherogenic adipokine. We recently cloned the genes encoding two adiponectin receptors (ADIPOR1 and ADIPOR2). The aim of this study was to examine whether ADIPOR1 and/or ADIPOR2 play a major role in genetic susceptibility to insulin resistance or type 2 diabetes in the Japanese population. METHODS: By direct sequencing and a search of public databases, we identified single nucleotide polymorphisms (SNPs) in ADIPOR1 and ADIPOR2, and investigated whether these SNPs are associated with insulin resistance and type 2 diabetes in the Japanese population. RESULTS: The linkage disequilibrium (LD) in the chromosomal region of ADIPOR1 was almost completely preserved, whereas the LD in ADIPOR2 was less well preserved. None of the SNPs in ADIPOR1 or ADIPOR2 were significantly associated with insulin resistance or type 2 diabetes. No differences in ADIPOR1 or ADIPOR2 haplotype frequencies were observed between type 2 diabetic and non-diabetic subjects. CONCLUSIONS/INTERPRETATION: Genetic variations in ADIPOR1 or ADIPOR2 are unlikely to lead to a common genetic predisposition to insulin resistance or type 2 diabetes in the Japanese population.

Diabetes Mellitus, Type 2↗

PubMed2005

Emergent endovascular treatment of ruptured vertebral artery dissecting aneurysms.

The goal of this study was to evaluate the results of endovascular and surgical treatments for ruptured vertebral artery dissecting aneurysms (VADAs) to determine which treatment is preferable. We evaluated the cases of 25 consecutive patients with ruptured VADAs treated in our institution. From 1992 to 1997, five patients were treated surgically. Since 1998, 20 patients with VADAs have been treated with endovascular therapy. The goal of the treatment was to exclude the aneurysm from the circulation. Among the five patients undergoing surgery, three aneurysms were treated with proximal clipping, one with trapping, and one with dome clipping. None of the patients were treated during the acute stage of rupture. Transient complications occurred in two patients. Of the 20 patients treated through the endovascular approach, 15 were treated within 24 h of rupture, but 12 had rebleeding before treatment. Eighteen aneurysms were occluded, along with the affected vertebral artery (VA), by using detachable coils (internal trapping), and one was occluded with the VA preserved. A stent-assisted occlusion of one aneurysm was done in a patient who had a contralateral hypoplastic VA. In both groups, the outcome of each patient depended greatly on the patient's condition before treatment and whether there was rebleeding. No posttreatment bleeding occurred. All procedures were effective, but endovascular treatment was less invasive and easier to use during the acute stage of subarachnoid hemorrhage. Although this report does not describe a controlled study, we found that endovascular treatment is preferable for treating ruptured VADAs in the acute stage.

Adult↗

PubMed2005

Endovascular treatment for elderly patients with ruptured aneurysm.

We report our results of endovascular treatment for elderly patients with ruptured aneurysm and discuss the indication for treatment. One hundred and thirty four consecutive patients with ruptured aneurysm treated in our institute during the last 4 years were retrospectively evaluated. Fifty eight patients were included in group A (over 70 years old), and 76 patients in group B (under 69 years old). In both groups, the outcome was strongly related to the preoperative Hunt & Kosnik grade. However, significant risk factors (i.e. pneumonia, rupture of extracranial aneurysm) which make prognosis poor were more common in group A. Group A showed poor outcome in grade III patients, although there were no outcome differences between the two groups in patients of other grades. Endovascular treatment for elderly patients with ruptured aneurysms seemed to be useful. Their outcome was strongly related to their preoperative condition. General risk factors should be evaluated before treatment, especially in elderly patients. Patients with low Hunt & Kosnik grade seem to be most suitable for endovascular treatment. On the other hand, outcome of patients with poor preoperative grade was worse despite the less invasive nature of endovascular treatment. An improvement of outcome in grade III patients is desirable.

Adult↗

PubMed2005

Evidence for natural selection in the HAVCR1 gene: high degree of amino-acid variability in the mucin domain of human HAVCR1 protein.

The family of genes encoding T-cell immunoglobulin and mucin-domain containing proteins (Tim), which are cell-surface molecules expressed in CD4(+) T helper cells, has important roles in the immune system. Here, we report three unusual patterns of genetic variation in the human hepatitis A virus cellular receptor 1 gene (HAVCR1) that are similar to patterns observed in major histocompatibility complex loci. First, levels of polymorphism in exon 4 of HAVCR1 were exceptionally high in humans (nucleotide diversity (pi)=45.45 x 10(-4)). Second, nonsynonymous substitutions and insertion/deletion variants were more frequent than synonymous substitutions in that exon (10 out of 12 variants). The rate of the mean number of nucleotide substitutions at nonsynonymous sites to synonymous sites at HAVCR1-exon 4 is >1 (P(A)/P(S)=1.92 and pi(A)/pi(S)=2.23). Third, levels of divergence among human, chimp, and gorilla sequences were unusually high in HAVCR1-exon 4 sequences. These features suggest that patterns of variation in HAVCR1 have been shaped by both positive and balancing natural selection in the course of primate evolution. Evidence that the effects of natural selection are largely restricted to the mucin domain of HAVCR1 suggests that this region may be of particular evolutionary and epidemiological interest.

Base Sequence↗

PubMed2004

Allogeneic peripheral blood stem cell transplantation from two- or three-loci-mismatched related donors in adult Japanese patients with high-risk hematologic malignancies.

With the increasing frequency of haploidentical transplantation, it is becoming more important to establish the degree of HLA mismatch that can be accepted. We retrospectively analyzed clinical data of 50 adult Japanese patients with high-risk hematologic malignancies who underwent allogeneic peripheral blood stem cell transplantation (PBSCT) from two- or three-loci-mismatched related donors with HLA class I and II gene disparities in the graft-versus-host direction. They were treated at 20 transplant centers between 1996 and 2002. In all, 18 patients received unmanipulated PBSC, while 32 received purified CD34+ blood cells. Conventional (n=31) or reduced-intensity (n=19) conditioning regimens were used. Of the 39 patients (78%) who survived for > or =28 days after transplant, 37 (95%) achieved neutrophil engraftment, while graft failure and rejection occurred in two of 39 (5%) and three of 37 (8%) patients, respectively. Stepwise Cox regression analysis revealed a significantly lower incidence of grades II-IV acute GVHD in patients receiving purified CD34+ cells (hazard ratio 0.32; 95% CI 0.12-0.84; P=0.022). By 1 year post transplant, 28 patients (56%) had died of transplant-related problems, including infectious complications (30%). Although the number of patients is small, our data suggest that transplant-related problems, particularly infectious complications, are major obstacles to the success of this therapy.

Adolescent↗

PubMed2004

Association of Fcgamma receptor IIb polymorphism with susceptibility to systemic lupus erythematosus in Chinese: a common susceptibility gene in the Asian populations.

The association of Fcgamma receptor (FcgammaR) polymorphisms with systemic lupus erythematosus (SLE) has been demonstrated in various populations; however, the results have been inconsistent. We recently identified a single-nucleotide polymorphism encoding a non-synonymous substitution, Ile232Thr (I232T), of FCGR2B and its association with SLE in Japanese and in Thais. Multiple functional FcgammaR genes with polymorphisms (FCGR2A, FCGR2B, FCGR3A, and FCGR3B) cluster in 1q23, and some of them are in linkage disequilibrium (LD). To differentiate contributions from multiple-linked loci, comparison of different populations may provide useful information. In this study, we analyzed the above four FCGR polymorphisms of the Chinese patients and controls for the association with SLE. FCGR2A-H131R, FCGR2B-I232T, FCGR3A-F176V, and FCGR3B genotypes were determined in 167 Chinese patients with SLE and 129 healthy controls. Association was examined using case-control analysis. Allele frequencies of FCGR2B-232T and FCGR3A-176F were significantly increased in SLE [odds ratio (OR) = 1.67 and OR = 1.41, respectively]. Interestingly, while these alleles had a tendency of positive LD in the controls, FCGR2B-232T was in positive association with FCGR3A-176V in SLE, suggesting that these two alleles were associated with SLE in an independent manner. Comparison between SLE with and without nephritis indicated significant association of FCGR2B-232T with nephritis (OR = 2.65). When the present results were combined with our previous data on the Japanese and the Thais using meta-analytic methods, highly significant and independent association was observed for FCGR2B and FCGR3A genotypes. These results strongly suggested that FCGR2B is a common susceptibility factor to SLE in the Asians.

Adult↗

PubMed2004

Molecular polymorphism of ABO blood group gene in Austronesian and non-Austronesian populations in Oceania.

A number of archeological, linguistic, and genetic studies have been carried out on the peopling of the Pacific, while the origin of Polynesians or the Lapita people is still open to debate. The Lapita people are believed to have populated the Bismarck Archipelago more than 3600 years ago. However, their Melanesian descendants still living in the Bismarck Archipelago have not been genetically clarified yet. To address this question, polymorphism of the ABO blood group gene was investigated in the following three populations who are considered to be almost free from recent admixtures: (i) Balopa islanders as Austronesian (AN)-speaking Melanesians living in the northwestern end of the Bismarck Archipelago; (ii) Gidra as non-Austronesian (NAN)-speaking Melanesians in southwestern lowlands of Papua New Guinea; and (iii) Tongan living in Ha'apai island as AN-speaking Polynesians. Interestingly, there were marked differences in allele frequencies of ABO*A101 and ABO*A102 among the three populations. The allele frequencies of ABO*A101 and ABO*A102 were 7.9 and 19.3% in Balopa, 23.2 and 0.0% in Gidra, and 2.9 and 25.0% in Tongan. Both phylogenetic and correspondence analyses suggested that Balopa was more close to Tongan than to Gidra and that Balopa was genetically placed between Tongan and Asian populations. Our results imply that Balopa may be Melanesian descendants of the Lapita people who populated the Bismarck Archipelago.

ABO Blood-Group System↗

PubMed2004

Centrosome hyperamplification and chromosomal damage after exposure to radiation.

OBJECTIVE: In order to elucidate the effects of radiation on centrosome hyperamplification (CH), we examined the centrosome duplication cycle in KK47 bladder cancer cells following irradiation. METHODS: KK47 cells were irradiated with various doses of radiation and were examined for CH immunostaining for gamma-tubulin. RESULTS: Nearly all control cells contained one or two centrosomes, and mitotic cells displayed typical bipolar spindles. The centrosome replication cycle is well regulated in KK47. Twenty-four hours after 5-Gy irradiation, approximately 80% of irradiated cells were arrested in G2 phase, and at 48 h after irradiation, 56.9% of cells contained more than two centrosomes. Laser scanning cytometry performed 48 h after irradiation showed the following two pathways: (1) unequal distribution of chromosomes to daughter cells, or (2) failure to undergo cytokinesis, resulting in polyploidy. With mitotic collection, M-phase cells with CH could be divided into G1 cells with micronuclei and polyploidal cells. Fluorescence in situ hybridization analysis showed clear signs of chromosomal instability (CIN) at 48 h after irradiation. The present study had two major findings: (1) continual duplication of centrosomes occurred in the cell cycle-arrested cells upon irradiation, leading to centrosome amplification; (2) cytokinesis failure was due to aberrant mitotic spindle formation caused by the presence of amplified centrosomes. Abnormal mitosis with amplified centrosomes was detected in the accumulating G2/M population after irradiation, showing that this amplification of centrosomes was not caused by failure to undergo cytokinesis, but rather that abnormal mitosis resulting from amplification of centrosomes leads to cytokinesis block. CONCLUSION: These results suggest that CH is a critical event leading to CIN following exposure to radiation.

Blotting, Western↗

PubMed2004

Reliability and validity of DESIGN, a tool that classifies pressure ulcer severity and monitors healing.

OBJECTIVE: This study reviews the validity and reliability of DESIGN, a tool for classifying pressure ulcer severity and monitoring progression towards healing. Only the tool's healing progression component was evaluated. METHOD: Inter-rater reliability was evaluated by calculating the agreement rate of scores, based on eight photos of pressure ulcers and six actual ulcers, made by a panel of seven nurses. Validity was assessed, using the same eight photos, by comparing DESIGN scores with those made using the validated Pressure Sore Status Tool (PSST). RESULTS: The DESIGN inter-rater reliability results showed a high correlation of r = 0.98 for the photos and r = 0.91 for the real-life patients with pressure ulcers, respectively, for all seven raters based on total scores. For validity, a correlation greater than 0.91 was found between the DESIGN and PSST scores. CONCLUSION: Based on our results, DESIGN was found to have both high inter-rater reliability and high validity among the seven nurses who quantitatively evaluated the wound-healing progress of the pressure ulcers in this study.

Humans↗

PubMed2003

Spiral versus J-shaped coils for neurovascular embolisation-an in-vitro study.

Our purpose was to compare the characteristics of J-shaped detachable platinum coils with those of spiral coils in in-vitro vascular models. J-shaped coils consist of distal semicircular and proximal straight segments, the latter extending for most of the length of the coil. Spiral coils have a helical shape memory and are thus limited in expansion. In in-vitro silicone vascular models simulating intracranial aneurysms and dural arteriovenous fistulae, we compared J-shaped and spiral coils with regard to ease of delivery, anchoring and folding patterns, and stability in various types of vascular lumen. Delivery and retrieval were comparable. In large and irregular aneurysms and venous sinuses, J-shaped coils could form a more complex basket which conformed to the shape of the vascular cavity. The J-shaped coil was always in contact with the vessel wall. In wide-necked aneurysms, coil protrusion was more frequent with J-shaped coils, while spiral coils tended to stay compact and circular. Arteries were occluded in a shorter segment with spiral coils. J-shaped coils were safe and superior for large and irregular aneurysms or sinuses. Spiral coils were preferable for spherical aneurysms and segmental occlusion of arteries.

Angiography↗

PubMed2003

Association of Fcgamma receptor IIb and IIIb polymorphisms with susceptibility to systemic lupus erythematosus in Thais.

We recently reported association of a newly identified polymorphism of Fcgamma receptor (FcgammaR) IIb, I232T, with systemic lupus erythematosus (SLE) in Japanese. To date, information on FcgammaR genotypes and their association with SLE is limited in South-east Asian populations. To gain further insight into the role of FcgammaR polymorphisms in the genetic predisposition of SLE, association of FcgammaRIIa-H131R, IIb-I232T, IIIa-F176V and IIIb-NA1/NA2 (HNA-1a/1b) polymorphisms with SLE was analyzed in the Thai population, using case-control association analysis. FcgammaRIIb-232T/T and IIIb-NA2/NA2 genotypes were associated with SLE with the odds ratio of 2.55. Genotype relative risk analysis revealed significant association of IIb-232T/T and IIIb-NA2/NA2, and a tendency of association of the IIIa-176F/F genotype. Moreover, carriers of FcgammaRIIa-131R were significantly increased in patients with lupus nephritis. Significant linkage disequilibrium was present among FcgammaRIIb, IIIa and IIIb, and two-locus analyses suggested that the tendency of association of FcgammaRIIIa could derive from linkage disequilibrium with IIb and IIIb. These results provided evidence that FcgammaR polymorphisms may be an important predisposing factor also in Thais in a complex manner.

Adolescent↗