Improvement of meal-related symptoms and epigastric pain in patients with functional dyspepsia treated with acotiamide was associated with acylated ghrelin levels in Japan.

BACKGROUND: The aim of this study is to clarify whether acotiamide and rabeprazole combination therapy can improve clinical symptoms, gastric emptying, and satisfaction with treatment in functional dyspepsia (FD) patients more effectively than acotiamide or rabeprazole monotherapy alone. We also aimed to determine whether acotiamide affects these changes via its effect on gastric emptying and appetite-related hormones such as ghrelin. METHODS: We used Rome III criteria to evaluate upper abdominal symptoms and anxiety by the State-Trait Anxiety Inventory (STAI). Gastric motility was evaluated by the (13) C-acetate breath test. Eighty-one FD patients were treated with acotiamide (300 mg/day) (n = 35), acotiamide (300 mg/day) and rabeprazole (10 mg/day) (n = 28), or rabeprazole (10 mg/day) (n = 18) for a period of 4 weeks and followed after 4 weeks of no treatment. Adenocorticotropic hormone (ACTH), cortisol, leptin and ghrelin levels were measured in all FD patients. KEY RESULTS: Acotiamide and rabeprazole combination therapy significantly improved postprandial distress syndrome (PDS)-like symptoms (p = 0.018, p = 0.04 and p = 0.041, respectively) and epigastric pain (p = 0.024) as wells as STAI-state scores (p = 0.04) compared to rabeprazole monotherapy. Both acotiamide monotherapy, and acotiamide taken in combination with rabeprazole, significantly (p = 0.001 and p = 0.02, respectively) improved satisfaction with treatment, compared to rabeprazole monotherapy. Acotiamide and rabeprazole combination therapy had no significant effect on ACTH and cortisol levels in FD patients. Of interest, acotiamide monotherapy, and acotiamide and rabeprazole combination therapy, significantly (p < 0.0001 and p = 0.018, respectively) increased acylated ghrelin/total ghrelin ratios and significantly (p = 0.04) improved impaired gastric emptying compared to rabeprazole monotherapy. CONCLUSIONS & INFERENCES: Further studies are warranted to clarify how acotiamide treatment improves clinical symptoms in FD patients.

Association of functional GITR gene polymorphisms related to expression of glucocorticoid-induced tumour necrosis factor-receptor (GITR) molecules with prognosis of autoimmune thyroid disease.

The glucocorticoid-induced tumour necrosis factor (TNF)-receptor (GITR) affects the functions of regulatory T (T(reg)) and effector T (T(eff)) cells, but the significance of this phenomenon is still unclear. To examine the association of single nucleotide polymorphisms (SNPs) in the GITR gene with the expression of GITR molecules on T cells and with the pathological conditions in patients with autoimmune thyroid disease (AITD), we examined the frequencies of four candidate SNPs in AITD patients and healthy volunteers by restriction enzyme analysis and direct sequence analyses. We also analysed the GITR expression on peripheral T(reg) and T(eff) cells in AITD patients by three-colour flow cytometry. The CC genotype in the rs3753348 C/G SNP was significantly more frequent in patients with mild Hashimoto's disease (HD) than in those with severe HD [P = 0·0117, odds ratio (OR) = 3·13]. The AA genotype in the rs2298213 A/G SNP was significantly more frequent in patients with mild HD than in patients with severe HD (P = 0·010, OR = 4·43). All patients and healthy individuals had the GG genotype in rs60038293 A/G and rs11466696 A/G SNPs. The proportions of GITR(+) cells in T(reg) and T(eff) cells were significantly higher in AITD patients with the CC genotype of the rs3753348 SNP than in those with the GG genotype (P = 0·004 and P = 0·011, respectively). In conclusion, the rs3753348 C/G SNP in the GITR is associated with HD prognosis and expression on T(reg) and T(eff) cells.

Association of functional polymorphisms in promoter regions of IL5, IL6 and IL13 genes with development and prognosis of autoimmune thyroid diseases.

To clarify the association of genetic producibility of interleukin (IL)-5, IL-6 and IL-13, which are secreted by T helper type 2 (Th2), with the development and prognosis of autoimmune thyroid disease (AITD), we genotyped IL5-746C/T, IL6-572C/G and IL13-1112C/T polymorphisms, which are functional polymorphisms in the promoter regions of the genes regulating these cytokines. Fifty-seven patients with intractable Graves' disease (GD), 52 with GD in remission, 52 with severe Hashimoto's disease (HD), 56 with mild HD and 91 healthy controls were examined in this study. The IL13-1112T allele, which correlates with higher producibility of IL-13, was more frequent in patients with GD in remission than in those with intractable GD [P=0·009, odds ratio (OR)=3·52]. The IL5-746T allele, which may correlate with lower levels of IL-5, was more frequent in patients with GD in remission than controls (P=0·029, OR=2·00). The IL6-572G allele carriers (CG and GG genotypes), which have higher producibility of IL-6, were more frequent in AITD patients (P=0·033, OR=1·75), especially in GD in remission (P=0·031, OR=2·16) and severe HD (P=0·031, OR=2·16) than in controls. Interestingly, both allele and genotype frequencies of Th2 cytokine genes were similar between GD and HD patients. In conclusion, functional polymorphisms in the genes encoding Th2 cytokines are associated differently with the development and prognosis of AITD from each other.

Association of functional polymorphisms related to the transcriptional level of FOXP3 with prognosis of autoimmune thyroid diseases.

The severity of Hashimoto's disease (HD) and intractability (or inducibility to remission) of Graves' disease (GD) varies among patients. Forkhead box P3 (FoxP3) is a crucial regulatory factor for the development and function of regulatory T (T(reg) ) cells, and deficiency of the FoxP3 gene (FOXP3) suppresses the regulatory function of T(reg) cells. To clarify the association of the functional polymorphisms of the FOXP3 with the prognosis of GD and HD, we genotyped -3499A/G, -3279C/A and -2383C/T polymorphisms in FOXP3 gene obtained from 38 patients with severe HD, 40 patients with mild HD, 65 patients with intractable GD, in whom remission was difficult to induce, 44 patients with GD in remission and 71 healthy volunteers. The -3279CA genotype was more frequent in patients with GD in remission than in patients with intractable GD, and the -3279AA genotype, which correlates to defective transcription of FOXP3, was absent in patients with GD in remission. The -2383CC genotype was more frequent in patients with severe HD than in those with mild HD. In conclusion, the -3279A/C polymorphism is related to the development and intractability of GD and the -2383CC genotype to the severity of HD.

Association of the -31C/T functional polymorphism in the interleukin-1beta gene with the intractability of Graves' disease and the proportion of T helper type 17 cells.

Interleukin (IL)-1beta is a proinflammatory cytokine and has been implicated in the pathogenesis of several autoimmune diseases. To evaluate the hypothesis that the functional -31C/T polymorphism (rs1143627) in the gene encoding IL-1beta is associated with the intractability and the severity of autoimmune thyroid diseases, we genotyped this polymorphism in 64 patients with intractable Graves' disease (GD), 28 GD patients in remission, 49 patients with Hashimoto's disease (HD) who developed hypothyroidism (severe HD), 28 untreated euthyroid HD patients (mild HD) and 59 healthy volunteers. The -31T allele, which is related to the high producibility of IL-1beta, was significantly more frequent in patients with intractable GD than in those with GD in remission (P = 0.0017; odds ratio 2.8; 95% confidence interval 1.5-5.3), although there was no difference in this frequency between two groups of HD patients. We showed additionally that the proportion of IL-17-producing T helper type 17 (Th17) cells, whose differentiation and proliferation are promoted by IL-1beta, was higher in autoimmune thyroid disease patients with the T allele than in those with CC genotypes. In conclusion, our data indicated that the T allele of -31C/T polymorphism in the IL1B gene was involved in the intractability of GD, and this involvement may arise through the differentiation and proliferation of Th17 cells.

Involvement of functional polymorphisms in the TNFA gene in the pathogenesis of autoimmune thyroid diseases and production of anti-thyrotropin receptor antibody.

The severity of Hashimoto's disease (HD) and intractability of Graves' disease (GD) varies among patients. Severity of HD is associated with the functional +874A/T polymorphism for interferon-gamma, an inflammatory cytokine. To clarify the association between functional polymorphisms in two other inflammatory cytokine genes [tumour necrosis factor (TNF)-alpha and interleukin (IL)-2] and the severity of autoimmune thyroid disease (AITD), we examined the TNF-alpha-1031T/C, TNF-alpha-857C/T and IL-2 -330T/G polymorphisms in genomic DNA samples. We genotyped 41 patients with intractable GD, 34 patients with GD in remission, 41 patients with severe HD, 36 patients with mild HD and 70 healthy controls. The frequency of carriers of TNF-alpha-1031C (CT + CC), which correlates with higher TNF-alpha production, was significantly higher in HD and GD patients than in controls, but was not associated with the severity of HD. In GD patients, the levels of anti-thyrotropin receptor antibody (TRAb) at onset of the disease was higher in patients with the TNF-alpha-857T (CT + TT) genotype, which correlates with higher TNF-alpha production, than in those with the -857CC genotype. We found no differences in the IL-2 -330T/G polymorphism among groups of AITD patients. In conclusion, the functional -1031T/C polymorphism of the TNFA gene is associated with the development of AITD and the functional -857C/T polymorphism is associated with the levels of TRAb in active GD patients.

The +869T/C polymorphism in the transforming growth factor-beta1 gene is associated with the severity and intractability of autoimmune thyroid disease.

The severity of Hashimoto's disease (HD) and the intractability of Graves' disease (GD) vary among patients. To clarify whether the +869T/C polymorphism in the transforming growth factor-beta1 (TGF-beta1) gene, which is associated with TGF-beta1 expression, is involved in the intractability of GD and severity of HD, we genotyped the TGF-beta1 +869T/C polymorphism by polymerase chain reaction-restriction fragment length polymorphism method in genomic DNA samples from 33 patients with HD who developed hypothyroidism before they were 50 years old (severe HD) and 30 untreated, euthyroid patients with HD who were older than 50 years (mild HD). We also examined 48 euthyroid patients with GD who had been under treatment and were still positive for anti-thyrotropin receptor antibodies (intractable GD), 20 euthyroid patients with GD in remission and 45 healthy controls. The frequency of the T allele and the TT genotype were higher in patients with severe HD than in those with in mild HD. In contrast, the frequency of the CC genotype was higher in patients with intractable GD than in patients with GD in remission. In conclusion, the +869T/C polymorphism in the TGF-beta1 gene is associated with the severity and intractability of autoimmune thyroid disease.

Ghrelin prevents development of diabetes at adult age in streptozotocin-treated newborn rats.

AIMS/HYPOTHESIS: Ghrelin, a stomach-derived hormone, functions in multiple biological processes, including glucose metabolism and cellular differentiation and proliferation. In this study, we examined whether early treatment with ghrelin can regenerate beta cells of the pancreas in an animal model of diabetes mellitus, the n0-STZ model, in which neonatal rats are injected with streptozotocin (STZ) at birth. METHODS: Following administration of ghrelin to n0-STZ rats from postnatal days 2 to 8, we examined beta cell mass, mRNA expression levels of insulin and of pancreatic and duodenal homeobox 1 (Pdx1) gene, and pancreatic morphology on days 21 and 70. In addition, we investigated the effects of ghrelin on beta cell replication. RESULTS: By day 21, ghrelin treatment increased pancreatic expression of insulin and Pdx1 mRNA in n0-STZ rats. The number of replicating cells was also significantly increased in the ghrelin-treated n0-STZ model. At day 70, n0-STZ rats exhibited hyperglycaemia, despite slight increases in plasma insulin levels. Ghrelin treatment resulted in the improvement of plasma glucose levels, which were associated with normal plasma insulin levels. Pancreatic insulin mRNA and protein levels were significantly increased in ghrelin-treated n0-STZ model animals. CONCLUSIONS/INTERPRETATION: These findings suggest that ghrelin promotes regeneration of beta cells in STZ-treated newborn rats. Thus, early administration of ghrelin may help prevent the development of diabetes in disease-prone subjects after beta cell destruction.

Plasma ghrelin levels in healthy elderly volunteers: the levels of acylated ghrelin in elderly females correlate positively with serum IGF-I levels and bowel movement frequency and negatively with systolic blood pressure.

Aging is associated with a decrease in growth hormone (GH) secretion, appetite and energy intake. As ghrelin stimulates both GH secretion and appetite, reductions in ghrelin levels may be involved in the reductions in GH secretion and appetite observed in the elderly. However, only preliminary studies have been performed on the role of ghrelin in elderly subjects. In this study, we sought to clarify the physiologic implications of the age-related alterations in ghrelin secretion by determining plasma ghrelin levels and other clinical parameters in healthy elderly subjects. Subjects were > or = 65 years old, corresponding to the SENIEUR protocol, had not had a resection of the upper gastrointestinal tract and had not been treated with hormones. One hundred and five volunteers (49 men and 56 women) were admitted to this study (73.4 +/- 6.3 years old). Plasma levels of acylated ghrelin in elderly female subjects positively correlated with serum IGF-I levels and bowel movement frequency and negatively with systolic blood pressure. In elderly men, desacyl ghrelin levels correlated only weakly with bowel movement frequency. These findings suggest that the plasma levels of the acylated form of ghrelin may influence the age-related alterations in GH/IGF-I regulation, blood pressure and bowel motility. These observational associations warrant further experimental studies to clarify the physiologic significance of these effects.

Recombinant monoclonal thyrotropin-stimulation blocking antibody (TSBAb) established from peripheral lymphocytes of a hypothyroid patient with primary myxedema.

Anti-TSH receptor antibodies (TRAbs) have been known to be involved in Graves' disease and primary hypothyroidism. We previously isolated and reconstituted immunoglobulin (Ig) genes of Epstein-Barr virus-transformed B cell clones producing monoclonal TRAbs obtained from Graves' patients. In the present study, we performed a similar experiment using a B cell clone, 32A-5, derived from a patient with primary hypothyroidism. The variable region genes of Ig heavy (H) and light (L) chains were isolated and sequenced from the 32A-5 clone. A significant number of somatic mutations were found in variable regions of H and L chain gene segments. Each pair of H and L chain cDNAs was ligated into an expression vector for IgG1 production and stably introduced into myeloma cells. The transfectants were injected ip into BALB/c mice to yield ample volume of the antibody for following applications. Interactions of recombinant 32A-5 with Graves' sera with varying thyroid-stimulating antibody (TSAb) activities were studied. The recombinant antibody tended to suppress TSAb activities in 10 of 15 Graves' sera, in which four were significantly inhibited. In summary, this is the first study to analyze human monoclonal TSH-stimulation blocking antibodies (TSBAb) at the molecular level. Use of human recombinant monoclonal TSBAb may be an analytical tool for molecular-basis etiology and an alternative therapeutic path for Graves' disease.

Drug-induced neutropenia associated with anti-neutrophil cytoplasmic antibodies (ANCA): possible involvement of complement in granulocyte cytotoxicity.

Although antineutrophil antibodies are thought to be involved in drug-induced neutropenia, neither the precise mechanisms nor the particular antigens on the neutrophil surface have yet been clarified. Recently, we examined a patient with Graves' disease who developed antineutrophil cytoplasmic antibodies (ANCA) after propylthiouracil treatment and exhibited neutropenia. Because several target antigens of ANCA are expressed on the surface of neutrophils, it was suggested that ANCA might contribute to neutropenia. The patient's serum bound specifically to neutrophils and HL-60 cells differentiated into granulocytes, and lysed the HL-60 cells via a complement-mediated mechanism. Furthermore, two representative ANCA antigens, proteinase 3 and myeloperoxidase, significantly inhibited both the binding and cytotoxicity of the serum. Finally, tumour necrosis factor-alpha, which is known to up-regulate cell surface expression of several ANCA antigens, enhanced both the binding and cytotoxicity of the serum. These findings suggest that ANCA induced by propylthiouracil contributed to leucopenia through a complement-mediated mechanism.

Stomach is a major source of circulating ghrelin, and feeding state determines plasma ghrelin-like immunoreactivity levels in humans.

Ghrelin, an endogenous ligand for the GH secretagogue receptor, was isolated from rat stomach and is involved in a novel system for regulating GH release. Although previous studies in rodents suggest that ghrelin is also involved in energy homeostasis and that ghrelin secretion is influenced by feeding, little is known about plasma ghrelin in humans. To address this issue, we studied plasma ghrelin-like immunoreactivity levels and elucidated the source of circulating ghrelin and the effects of feeding state on plasma ghrelin-like immunoreactivity levels in humans. The plasma ghrelin-like immunoreactivity concentration in normal humans measured by a specific RIA was 166.0 +/- 10.1 fmol/ml. Northern blot analysis of various human tissues identified ghrelin mRNA found most abundantly in the stomach and plasma ghrelin-like immunoreactivity levels in totally gastrectomized patients were reduced to 35% of those in normal controls. Plasma ghrelin-like immunoreactivity levels were increased by 31% after 12-h fasting and reduced by 22% immediately after habitual feeding. In patients with anorexia nervosa, plasma ghrelin-like immunoreactivity levels were markedly elevated compared with those in normal controls (401.2 +/- 58.4 vs. 192.8 +/- 19.4 fmol/ml) and were negatively correlated with body mass indexes. We conclude that the stomach is a major source of circulating ghrelin and that plasma ghrelin-like immunoreactivity levels reflect acute and chronic feeding states in humans.

Substantial production of ghrelin by a human medullary thyroid carcinoma cell line.

Ghrelin, an endogenous ligand for the GH secretagogue receptor, is a novel acylated peptide produced in the gastrointestinal endocrine cells as well as neuroendocrine cells in the hypothalamus. The Ser(3) residue of ghrelin is modified by n-octanoic acid, a modification necessary for hormonal activity. Human medullary thyroid carcinoma is known to produce a variety of gastrointestinal and neuroendocrine peptides. In the present study we investigated ghrelin production in the thyroid gland, especially in human medullary thyroid carcinoma. PCR amplification demonstrated prepro-ghrelin gene transcripts in normal human thyroid tissue and two medullary thyroid carcinoma cell lines (human TT cells and rat 6-23 cells), but not in a rat thyroid follicular cell line. TT cells showed the expression of prepro-ghrelin mRNA of about 0.6 kb by Northern blot analysis. Furthermore, production of ghrelin in TT cells was demonstrated by RIA and immunocytochemistry. Accumulation of des-n-octanoyl ghrelin in the cultured medium of the cells was confirmed. Finally, human medullary thyroid carcinoma surgical specimens showed significantly higher des-n-octanoyl ghrelin contents than normal thyroid tissues. In conclusion, we revealed that ghrelin was produced by the human thyroid parafollicular carcinoma cell line, TT cells. These findings suggest that ghrelin is produced in the thyroid C cells as well as in medullary thyroid carcinoma and may provide opportunities to investigate its physiological role in the thyroid gland.

A low dose of ghrelin stimulates growth hormone (GH) release synergistically with GH-releasing hormone in humans.

The synergistic relationship between GH-releasing secretagogue (GHS) and GH-releasing hormone (GHRH) with respect to GH secretion is well known. In the present study, we report a similar relationship between GHRH and ghrelin, a recently identified endogenous ligand for the GHS receptor. In normal male adults, various doses of ghrelin were intravenously administered alone or together with 1.0 microg/kg GHRH. At small doses of 0.08 and 0.2 microg/kg ghrelin, combined administration of the two peptides significantly stimulated GH release in a synergistic manner; the mean GH response values of the two peptide combinations were more than the summed mean GH response values of each peptide alone (P < 0.05). In addition, at 1.0 microg/kg ghrelin, the tendency of the synergistic effect was observed, although the comparison was not statistically significant probably due to a submaximal dose ceiling effect. No synergistic effects with respect to ACTH or prolactin secretion were observed. In conclusion, the synergistic interaction between ghrelin and GHRH was clearly shown and might be useful for a provocation test to diagnose GH deficiency.

Characterization of the secretable ectodomain of thyrotropin receptor produced by the recombinant baculovirus system.

Thyrotropin receptor (TSHR) is a member of the glycoprotein hormone receptor family and an autoantigen of Graves' disease. Various attempts have been made to obtain a large amount of soluble ectodomain of TSHR in insect or mammalian cells, but most of them failed to secrete the overexpressed ectodomain. In the present study, we observed that about one-third of the ectodomain protein (sTSHR-gp), in which the signal peptide of TSHR was replaced by the baculovirus-encoded glycoprotein 67-signal peptide, was secreted into the culture medium and the remainder stayed within cells in the recombinant baculovirus system. Microsequencing the N-terminal of the purified protein confirmed that the baculovirus signal peptide was cleaved at the expected site. Carbohydrate studies using several glycosidases and lectins revealed that the secreted form of the ectodomain had biantennary carbohydrate, whereas the non-secreted form had high-mannose. Moreover, the secreted form of sTSHR-gp exhibited high-affinity ligand binding, whereas the non-secreted form did not show any significant ligand binding. Regarding the interactions of TSHR ectodomains with anti-TSHR antibodies, both the secreted and non-secreted forms of sTSHR-gp, almost completely neutralized the stimulatory and inhibitory anti-TSHR antibody activities. In conclusion, we succeeded in secreting the ectodomain of TSHR into culture medium, which was capable of binding to TSH and neutralizing anti-TSHR antibody activities.

Identification of the peptides that inhibit the function of human monoclonal thyroid-stimulating antibodies from phage-displayed peptide library.

Autoantibodies against TSH receptor (TSHR) are known to be involved in the occurrence of Graves' disease. It is obvious that mapping of epitopes of the autoantibodies found in the patients with Graves' disease is an important step in elucidating possible mechanism of generation of the autoantibodies against TSHR as well as in developing effective diagnostic and therapeutic approaches for Graves' disease. In this report we have identified the peptide sequences that bind to two human monoclonal thyroid-stimulating antibodies (mTSAbs; B6B7 and 101-2) from a disulfide-constrained phage-displayed peptide library. The peptides selected by three rounds of biopanning showed half-maximal inhibitory activities for cAMP synthesis induced by mTSAbs at about 0.1 micromol/L. SPWTLGA and TQWNMQH selected for B6B7 and 101-2, respectively, show specificity for their respective antibodies. This means that different clones of mTSAbs may have different epitopes for TSHR. The IgG of the patient from whom B6B7 was derived binds with specificity to the respective immobilized peptide in an enzyme-linked immunosorbant assay format, and its cAMP generation was also inhibited by selected peptide. It may be possible that the epitopes of TSAbs identified from the phage-displayed peptide library could be used for the classification of different clones of TSAbs present in patients with Graves' disease and for development of drugs to treat Graves' disease.

Identification of susceptibility loci for autoimmune thyroid disease to 5q31-q33 and Hashimoto's thyroiditis to 8q23-q24 by multipoint affected sib-pair linkage analysis in Japanese.

Autoimmune thyroid disease (AITD), including Graves' disease (GD) and Hashimoto's thyroiditis (HT), is caused by multiple genetic and environmental factors. The clinical and immunological features of GD and HT are distinct; however, there are multiplex families with both GD and HT, and cases in which GD evolves into HT. Thus, there may be specific susceptibility loci for GD or HT, and common loci controlling the susceptibility to both GD and HT may exist. A genome-wide analysis of data on 123 Japanese sib-pairs affected with AITD was made in which GD- or HT-affected sib-pairs (ASPs) were studied to detect GD- or HT-specific susceptibility loci, and all AITD-ASPs were used to detect AITD-common susceptibility loci. Our study revealed 19 regions on 14 chromosomes (1, 2, 3, 5, 6, 8, 9, 10, 11, 12, 13, 15, 18 and 22) where the multipoint maximum LOD score (MLS) was >1. Especially, chromosome 5q31-q33 yielded suggestive evidence for linkage to AITD as a whole, with an MLS of 3.14 at D5S436, and chromosome 8q23-q24 yielded suggestive evidence for linkage to HT, with an MLS of 3.77 at D8S272. These observations suggest the presence of an AITD susceptibility locus at 5q31-q33 and a HT susceptibility locus at 8q23-q24.

Simultaneous onset of type 1 diabetes mellitus and painless thyroiditis following acute pancreatitis.

A 24-year-old female suffered from acute pancreatitis, followed by simultaneous onset of painless goiter, elevation of thyroid hormones and diabetic ketoacidosis. Two months later, her insulin secreting function was severely decreased and positive for anti-GAD and anti-islet cell antibodies, whereas the serum glucagon level was normal, suggesting an autoimmune-related destruction specifically of beta cells. In addition, the initial hyperthyroid state was followed by a hypothyroid phase which later recovered to an euthyroid state, suggesting an initial destruction of thyroid cells. Because anti-thyroidal antibodies were positive, it is likely that the thyroidal destruction was also autoimmune-related. This case implies common pathogenic mechanisms in the autoimmunity related destruction of beta cells and thyroid cells.

[Association study on candidate loci of susceptible genes of autoimmune thyroid diseases in a Japanese population].

Autoimmune thyroid diseases(AITD), which include Graves' disease(GD), Hashimoto's thyroiditis(HT), primary hypothyroidism with blocking-type anti-thyrotropin receptor antibody and idiopathic myxedema, are believed to be a multifactorial disease with a significant genetic and environmental component. Several genetic factors associated with AITD susceptibility have been tentatively identified, including the HLA genes and the cytotoxic T lymphocyte associated-4(CTLA-4) gene. More recently, as part of a genome scan, five additional chromosomal locations, i.e., chromosome 5, 8, 9, 15 and X, have recently been reported in a Japanese population. In the present study, in order to confirm evidence obtained by the genome scan, we performed an association study regarding these five candidate loci identified as regions where susceptible genes of AITD exist. Five microsatellite markers, which are located in these loci, were genotyped in a set of 487 unrelated Japanese AITD patients and 218 Japanese controls. Markers located in chromosome 5, 15 and X showed association in AITD patients with significant increase in particular alleles (p < 0.01), while markers in chromosome 8 and 9 did not consistently show significant association. These findings partly support evidence by the previous genome scan that attempted to identify loci of susceptible genes of AITD in a Japanese population; presence of an AITD susceptibility locus at 5q31-33 was suggested. Genotyping using other markers located in these loci would be helpful not only to confirm regions of AITD susceptible genes but also to narrow the regions.