Biomedical subjects

Toru Takano

Publications and source records attributed to Toru Takano.

At least 37 records · Page 2Linked to original sources

PubMed2003

Relation between post-partum liver dysfunction and anti-cytochrome 2D6 antibodies.

PROBLEM: Autoimmune thyroid disease frequently aggravates or develops after delivery through the immune rebound mechanism. However, little is known about the post-partum development of autoimmune hepatitis (AIH). METHOD OF STUDY: We examined 18 patients who developed liver dysfunction after delivery or abortion. Serial examinations were performed in 10 of these cases. Anti-cytochrome 2D6(CYP2D6) antibodies, which are liver-specific autoantibodies, were measured using a sensitive radioligand assay. RESULTS: Liver dysfunction developed between 1 and 5 months after delivery and was mild and transient except in one case. One patient developed liver dysfunction after abortion. Eight of 10 patients who underwent serial serologic examinations were positive for anti-nuclear antibodies, but anti-smooth muscle antibodies were positive in only three patients, and were present only at low titer. None of the patients had anti-mitochondrial antibodies. Nine of these 10 cases were diagnosed as definite or probable AIH according to the international scoring system of AIH. Nine of these 10 patients were positive for anti-CYP2D6 antibodies. The increase of anti-CYP2D6 antibodies was slightly delayed compared to increase of aminotransferase. Of the 18 patients who developed liver dysfunction, 15 cases (83.3%) were positive for anti-CYP2D6 antibodies. Of the 77 post-partum control subjects only three (3.9%) had positive antibodies. CONCLUSIONS: Autoimmune hepatitis developed after delivery, similarly to the development of post-partum autoimmune thyroid disease. Measurement of anti-CYP2D6 antibodies by a sensitive radioligand assay could provide information important for the detection of post-partum AIH.

Adult↗

PubMed2003

Blocking-type anti-TSH receptor antibodies and relation to responsiveness to antithyroid drug therapy and remission in Graves' disease.

OBJECTIVE: Antithyroid drugs are effective in some patients with Graves' disease but not in others. The factors responsible for this difference are still unknown. We examined the relationship between the nature of anti-TSH receptor (TSH-R) antibodies and responsiveness to drugs in Graves' disease. PATIENTS: Twenty-eight untreated patients with Graves' disease were treated with thiamazole and followed for up to 13 years. MEASUREMENT: Antithyroid microsomal antibodies (MCHAs) and antithyroglobulin antibodies (TGHAs) were measured by the passive haemagglutination method. Anti-TSH-R antibodies were measured by a radioreceptor assay (TBII), and thyroid-stimulating antibodies (TSAbs) and TSH-stimulation blocking antibodies (TSBAbs) were measured by bioassays using FRTL-5 cells. Blocking antibodies were also measured by the conversion assay. In order to confirm the usefulness of the conversion assay, in vitro experiments using mixtures of TSAb serum and TSBAb serum were performed. RESULTS: In in vitro conversion experiments, the conversion assay sensitively detected coexisting blocking antibodies. TSBAb was found in seven patients and a positive conversion ratio was found in four patients, and, of these, three patients had both antibodies. Finally, eight patients (28.6%) had blocking antibodies and 25 of 28 patients (89.3%) had stimulating antibodies. These patients with blocking antibodies (Group A) responded well initially to antithyroid drugs and showed earlier normalization of the serum T4 level (3.0 +/- 1.2 weeks) than patients without blocking antibodies (Group B, 10.7 +/- 8.5, P < 0.001). Unexpectedly, remission of Graves' thyrotoxicosis was earlier in Group B (5.1 +/- 4.4 years) than in Group A (8.0 +/- 4.3 years, P < 0.05). Other parameters, including serum T4, goitre size, ophthalmopathy, TBII, TSAb, TGHA and MCHA, were not different between the two groups. CONCLUSIONS: Graves' patients with coexisting blocking antibodies initially respond well to thiamazole but are relatively slow to achieve remission. Measurement of blocking antibodies may be useful for selection of treatment options in Graves' disease.

Adult↗

PubMed2003

Increased serum concentration of eosinophil-derived neurotoxin in patients with Graves' disease.

Eosinophil-derived neurotoxin (EDN) is released after activation and stimulation of eosinophils in allergic disease, which is a T(H)2-predominant condition. We previously reported that Graves' thyrotoxicosis develops or relapses after an attack of allergic rhinitis. In this study, to confirm the relation between Graves' disease and the allergic condition, we determined the serum level of EDN in 30 untreated patients with Graves' disease, 50 patients with Hashimoto's thyroiditis, and 39 normal controls. Compared to the serum level in normal subjects (30.1 +/- 15.6 ng/mL), EDN was increased in untreated patients with Graves' disease (52.4 +/- 27.6 ng/mL), but not in patients with Hashimoto's thyroiditis (thyrotoxic, 30.9 +/- 13.4 ng/mL; euthyroid, 30.0 +/- 11.9 ng/mL; hypothyroid, 23.4 +/- 10.2 ng/mL). A significant correlation was observed between the EDN level and the serum activity of thyrotropin (TSH) receptor antibody (r = 0.541, p < 0.0001). These data suggest that the allergic condition is closely related to Graves' disease and that a T(H)2-type immune response is crucial in the pathogenesis of Graves' disease.

Adult↗

PubMed2003

Association of seasonal allergic rhinitis is high in Graves' disease and low in painless thyroiditis.

Hashimoto's thyroiditis is thought to be a T-helper cell type 1 (TH1)-dependent disease, but it is not clear whether Graves' disease is T-helper cell type 2 (TH2)-predominant or not. TH1-predominant diseases are infrequently and TH2-predominant diseases are frequently associated with allergic diseases. We examined the prevalence of seasonal allergic rhinitis to Japanese cedar pollen, a typical TH2-associated disease, in patients with Graves' disease (n = 126), painless thyroiditis (n = 46) and Hashimoto's thyroiditis (n = 88), and compared them to healthy controls (n = 766). Gender and age distribution were not different among patient groups and healthy controls, except for the higher age of patients with Hashimoto's thyroiditis. The prevalence of seasonal allergic rhinitis was significantly high in patients with Graves' disease (42.9%, p < 0.05) and low in patients with painless thyroiditis (13.0%, p < 0.01) but was not different in patients with Hashimoto's thyroiditis (26.1%) compared to that of healthy controls (32.6%). When patients with painless thyroiditis were included in Hashimoto's thyroiditis group, the prevalence of seasonal allergic rhinitis was 21.6% and significantly different from that of healthy controls (p < 0.05). These data indicate that Graves' disease is TH2 predominant and painless thyroiditis is a TH1-predominant disease. Our findings suggest that the shift from TH2 toward TH1 immunogenesis may be important for achieving earlier remission of Graves' disease.

Adult↗

PubMed2003

Possible induction of Graves' disease and painless thyroiditis by gonadotropin-releasing hormone analogues.

Prolonged administration of gonadotropin-releasing hormone (GnRH) analogues induce a decrease in serum estrogen level, which may aggravate subclinical or mild autoimmune thyroid disease. Two patients developed Graves' thyrotoxicosis in association with an increase in anti-thyrotropin (TSH) receptor antibody activities at 4 months after initiation of buserelin acetate. GnRH analogue therapy was discontinued at the time of diagnosis but it took more than 2 years of methimazole therapy to obtain remission of Graves' disease. Another patient developed painless thyroiditis in association with an increase in antithyroid microsomal antibodies at 4 months after initiation of leuprolide acetate. These results indicate that GnRH analogues possibly induce clinical onset of Graves' thyrotoxicosis or destruction-induced thyrotoxicosis. Clinicians should be aware of this phenomenon. All patients who are to receive GnRH analogue therapy should be examined for antithyroid antibodies and family history of autoimmune thyroid disease, and should be followed accordingly.

Adult↗

PubMed2003

Decreased expression of catalase mRNA in thyroid anaplastic carcinoma.

BACKGROUND: A decreased expression of glutathione peroxidase mRNA, an antioxidant enzyme, was previously observed in thyroid anaplastic carcinomas. METHODS: To clarify the expression of antioxidant-related enzymes in thyroid anaplastic carcinomas, the expression levels of catalase, copper and zinc superoxide dismutase and manganese superoxide dismutase mRNA in 85 benign and malignant thyroid tissues were measured by means of real-time quantitative reverse transcription-polymerase chain reaction. RESULTS: Decreased expression levels of catalase and copper and zinc superoxide dismutase mRNAs, but not manganese mRNA, were observed in five anaplastic carcinomas compared with normal thyroid tissues and differentiated tumors. CONCLUSION: These results suggest the possibility that anaplastic carcinoma cells are more likely to suffer damage by oxygen free radicals than normal thyroid cells or differentiated tumor cells.

Adenoma↗

PubMed2003

Increase in serum levels of autoantibodies after attack of seasonal allergic rhinitis in patients with Graves' disease.

BACKGROUND: The prevalence of allergic disease is increasing worldwide, but its influence on the clinical course of autoimmune diseases is unknown. OBJECTIVE: The purpose of this study was to assess the effect of seasonal allergic rhinitis on the clinical course of Graves' disease, which has been considered a Th2-dominant autoimmune disease. METHODS: Ten patients with Graves' disease, who were considered to be in a state of remission or near remission, were serially examined for 18 months starting from August. Five of them had seasonal allergic rhinitis due to Japanese cedar pollen, and the remaining patients had no such allergic disorders. Peripheral eosinophil counts, serum concentrations of cedar-pollen-specific IgE, anti-TSH-receptor antibody, anti-thyroid-peroxidase antibody and antithyroglobulin antibody were assessed at 2- to 4-month intervals. Serum thyroid hormones and TSH levels were also measured to evaluate disease activity. RESULTS: All patients with pollinosis had attacks of allergic rhinitis caused by cedar pollen in early March. Subsequently, peripheral eosinophil counts, pollen-specific IgE activity and serum levels of anti-thyroid-peroxidase and antithyroglobulin autoantibodies markedly increased. Serum levels of anti-TSH-receptor antibody increased in 3 patients in association with an increase in serum thyroid hormones but were always negative in 2 patients. The control patients without pollinosis showed no consistent change of these parameters. CONCLUSIONS: Seasonal allergic rhinitis aggravated the clinical course of Graves' disease and induced an increase in serum antithyroid autoantibody concentrations as well as an increase in pollen-specific IgE concentration. These data suggest that environmental antigens induce not only local allergic reactions, but also stimulate thyroid immune reactions toward Th2 proliferation, and finally aggravate Th2-dependent autoimmune thyroid disease.

Adult↗

PubMed2003

Expression of TRbeta1 mRNAs with functionally impaired mutations is rare in thyroid papillary carcinoma.

A previous study reported the expression of functionally impaired thyroid hormone receptor (TR)beta1 mutants in almost all papillary thyroid carcinomas. To confirm this, we analyzed the sequence of the entire coding region of TRbeta1 cDNAs expressed in 16 papillary carcinomas. Among the 48 clones analyzed, we found no mutations with an amino acid substitution, which represents a clear discrepancy between our findings and those in the previous study. Our findings suggest that the expression of functionally impaired mutants in papillary carcinomas is rare, and they raise a question about the possible role of mutated TRbeta1 in the tumorigenesis of papillary carcinoma.

Adult↗

PubMed2003

No increase of blocking type anti-thyrotropin receptor antibodies during pregnancy in patients with Graves' disease.

Serial changes in serum levels of anti-TSH receptor antibodies were examined during and after pregnancy in six patients with Graves' disease receiving no or minimal maintenance doses of antithyroid drugs. During pregnancy, serum levels of TSH-binding inhibitory Igs (P < 0.001) and thyroid-stimulating antibodies (TSAbs) (P < 0.01) decreased gradually but increased after delivery in all patients. Activities of thyroid-stimulation blocking antibodies (TSBAbs) were lower than the cut-off value in early pregnancy, and values significantly decreased in four patients during pregnancy. The other two patients showed no significant change during pregnancy. In contrast, TSBAb levels increased significantly (P < 0.01) after delivery in all patients. We found that activities of TSH-binding inhibitory Igs, TSAb, and TSBAb decrease during pregnancy and increase after delivery, suggesting that amelioration of Graves' disease during pregnancy is induced by decrease of TSAb but not by the appearance of TSBAb.

Adult↗

PubMed2003

Frequent appearance of autoantibodies against prohormone convertase 1/3 and neuroendocrine protein 7B2 in patients with nonfunctioning pituitary macroadenoma.

Among pituitary disorders having mass effect of the pituitary gland, nonfunctioning pituitary macroadenoma and lymphocytic hypophysitis are difficult to differentiate without histological examination. In order to efficiently distinguish lymphocytic hypophysitis and pituitary tumors, we studied the presence of autoantibodies against prohormone-processing enzymes, prohormone convertase (PC) 1/3, PC2, carboxypeptidase E (CPE), and PC2 regulatory protein, 7B2, by radioligand assay using recombinant human 35S-labeled protein in patients with clinically nonfunctioning pituitary macroadenoma, lymphocytic hypophysitis, and other pituitary diseases. The indexes for anti-PC1/3 antibodies (Ab) were significantly higher in patients with nonfunctioning pituitary macroadenoma than in patients with lymphocytic hypophysitis. Patients positive for either anti-PC1/3 or anti-7B2 Ab were significantly frequent among patients with nonfunctioning pituitary macroadenoma than in other pituitary diseases and healthy controls. None of the patients was positive for anti-PC2 Ab or anti-CPE Ab. These results suggest that autoantibodies against PC1/3 and 7B2 are novel tumor-associated autoantibodies and can be helpful in the diagnosis of clinically nonfunctioning pituitary macroadenoma.

Adenoma↗

PubMed2003

Practical treatment with minimum maintenance dose of anti-thyroid drugs for prediction of remission in Graves' disease.

Although many researchers have reported clinical and laboratory parameters for prediction of remission in Graves' disease during or after anti-thyroid drug therapy, there is no reliable one to assure the complete remission. We prospectively examined a practical therapy with minimum maintenance dose of anti-thyroid drugs for prediction of remission in Graves' disease. Fifty-seven patients with Graves' disease were treated with anti-thyroid drugs at the initial dose of 30 mg/day of methimazole (MMI) or 300 mg/day of propylthiouracil (PTU). Then, doses were gradually decreased, and finally discontinued when the patients were able to maintain euthyroid (normal FT4 and TSH) for at least 6 months with the minimum maintenance dose (MMI 5 mg every other day or PTU 50 mg every other day). After discontinuation of drugs, FT4, FT3, TSH and TSH-binding inhibitory immunoglobulin (TBII) were measured every one to two months for the first 6 months and every 3-4 months for the next 18 months to confirm continuous remission. After 2 years of drug cessation, 46 (81%) of 57 patients were in remission and the other 11 patients had relapsed into thyrotoxicosis. At the time of drug discontinuation, the serum concentration of FT4, FT3 and TSH, titers of anti-thyroglobulin antibodies and anti-thyroid microsomal antibodies, goiter size were not different between the remission and relapse groups. At the time of drug cessation, the activities of TBII and thyroid-stimulating antibodies (TSAb) overlapped between the two groups, although they were significantly lower in the remission group than in the relapse group (p<0.01). Forty percent (4/10) of TBII positive patients and 71% (23/32) of TSAb positive patients continued to be in remission. On the other hand, thyrotoxicosis relapsed in 5 (11%) of 47 TBII negative and 2 (8%) of 25 TSAb negative patients. These data indicate that minimum maintenance therapy to keep euthyroid (normal FT4 and TSH) for 6 months is a practical measure for 81% prediction of remission in Graves' disease. The measurement of TBII or TSAb gave little additional information for predicting remission.

Adult↗

PubMed2003

Anti-alpha-enolase antibodies in pituitary disease.

A previous study reported a high prevalence of autoantibodies to alpha-enolase in lymphocytic hypophysitis and these antibodies efficiently distinguished lymphocytic hypophysitis from pituitary tumors. To confirm this, we examined autoantibodies to alpha-enolase in patients with lymphocytic hypophysitis (n = 17), pituitary non-functioning adenoma (n = 13), other pituitary diseases (n = 17) and other autoimmune diseases (n = 30), and compared to healthy controls (n = 46). Autoantibodies were found in 41.2%, 46.2%, 23.5%, 20.0% and 4.3%, respectively. Our findings indicate that detection of anti-alpha-enolase antibodies is not suitable for specific diagnosis of lymphocytic hypophysitis.

Adenoma↗

PubMed2003

[Aspiration biopsy RNA diagnosis].

Recent advances in molecular-based techniques, especially RNA analyses such as differential display, serial analysis of gene expression(SAGE) and DNA arrays, have enabled us to detect the specific changes in mRNA in cancer tissues rapidly and easily. We have established a new method of preoperative molecular-based diagnosis of thyroid carcinomas, one of the most common cancers in females. This technique, Aspiration Biopsy RNA Diagnosis, ABRD, allows us to perform preoperative RNA analysis of the tumors by extracting RNA from tumor cells obtained by fine needle aspiration biopsies(FNABs). For example, by ABRD detection of oncofetal fibronectin or calcitonin mRNA in FNABs, three types of thyroid carcinomas, papillary, anaplastic and medullary carcinomas, were accurately diagnosed preoperatively without the help of cytological or pathological examinations by a skillful pathologist. Further, by real-time monitoring RT-PCR measuring the expression levels of these cancer-specific mRNAs, a fully automated system was established. Because ABRD can be performed without any severe invasion to the patients, in the near future, when more reliable systems of quantitative RNA analysis are developed, ABRD will probably become one of the standard tests for preoperative diagnosis of cancer.

Biopsy, Needle↗

PubMed2003

Autoantibodies against muscarinic cholinergic receptor in chronic fatigue syndrome.

The disturbance of the central nervous system and immunological abnormalities have been suggested in patients with chronic fatigue syndrome (CFS). We focused on immunological abnormalities against neurotransmitter receptors in CFS. Using a sensitive radioligand assay, we examined serum autoantibodies to recombinant human muscarinic cholinergic receptor 1 (CHRM1), mu-opioid receptor (OPRM1), 5-hydroxytryptamine receptor 1A (HTR1A), and dopamine receptor D2 (DRD2) in patients with CFS (n=60) and results were compared with those in patients with autoimmune disease (n=33) and in healthy controls (n=30). The mean anti-CHRM1 antibody index was significantly higher in patients with CFS (p<0.0001) and autoimmune disease (p<0.05) than that in healthy controls, and positive reaction was found in 53.3% of patients with CFS. Anti-OPRM1 antibodies, anti-HTR1A antibodies, and anti-DRD2 antibodies were found in 15.2, 1.7, and 5.0% of patients with CFS, respectively. Anti-nuclear antibodies were found in 56.7% (34/60) of patients with CFS, but anti-nuclear antibody titers did not correlate with the activities of the above four autoantibodies. The patients with positive autoantibodies to CHRM1 had a significantly higher mean score (1.81) of 'feeling of muscle weakness' than negative patients (1.18) among CFS patients (p<0.01). Higher scores on 'painful node', 'forgetfulness', and 'difficulty thinking' were also found in CFS patients with anti-CHRM1 antibodies but did not reach statistical significance. In conclusion, autoantibodies to CHRM1 were detected in a large number of CFS patients and were related to CFS symptoms. Our findings suggested that subgroups of CFS are associated with autoimmune abnormalities of CHRM1.

Adult↗

PubMed2002

Decreased expression of glutathione peroxidase mRNA in thyroid anaplastic carcinoma.

Our recent study using serial analysis of gene expression show the decreased expression of glutathione peroxidase (GPx), an antioxidant enzyme, in an anaplastic carcinoma. To clarify the expression of GPx in various kinds of thyroid tumors, the expression levels of GPx mRNA in 79 benign and malignant thyroid tissues were measured by means of real-time quantitative reverse transcription-polymerase chain reaction. A decreased expression of GPx mRNA was observed in all of five anaplastic carcinomas and some of the papillary carcinomas. A molecular-based therapy which produces O(2) radical may be considered as an alternative choice for the treatment of anaplastic carcinomas.

Carcinoma↗

PubMed2002

Simple and practical parameters for differentiation between destruction-induced thyrotoxicosis and Graves' thyrotoxicosis.

OBJECTIVE: Differentiation of destruction-induced thyrotoxicosis from Graves' thyrotoxicosis is important for selection of therapy. It is, however, often difficult to make this distinction without measurement of radioactive iodine uptake. We searched for simple and practical parameters that might allow differentiation between the two entities. PATIENTS: One hundred and eleven untreated patients with thyrotoxicosis (69 Graves' disease, 21 painless thyroiditis, 21 subacute thyroiditis) and 45 normal controls were examined. MEASUREMENTS: Serum levels of free T4 (FT4) and free T3 (FT3) were measured by radioimmunoassay, and anti-TSH receptor antibodies (TBII) were measured by radioreceptor assay. Peripheral leucocyte counts and the percentages of eosinophils and monocytes were measured using an automated leucocyte differential system. RESULTS: Peripheral eosinophils were significantly higher in Graves' disease (3.54 +/- 4.18%, P < 0.05) and lower in subacute thyroiditis (1.08 +/- 1.03%, P < 0.001) than in normal controls (2.26 +/- 1.33%). Peripheral monocytes were significantly higher in painless thyroiditis (6.87 +/- 2.85%, P < 0.01) than that in normal controls (4.63 +/- 2.14%). In comparison between groups, FT3 was higher with Graves' disease (20.55 +/- 10.29 pmol/l) than both painless thyroiditis (11.59 +/- 8.22 pmol/l, P < 0.001) and subacute thyroiditis (15.27 +/- 8.63 pmol/l, P < 0.05). The eosinophil to monocyte (Eo/Mo) ratio, FT3/FT4 ratio and Eo/Mo ratio multiplied by FT3 (pmol/ml) (Eo/Mo.FT3) were calculated and compared in these three disease groups. The Eo/Mo ratio, FT3/FT4 ratio and Eo/Mo.FT3 were significantly higher in patients with Graves' thyrotoxicosis (0.782 +/- 0.759, 0.399 +/- 0.089, 16.7 +/- 23.5 pmol/l, respectively) than in those with painless thyroiditis (0.259 +/- 0.157, 0.304 +/- 0.072, 2.43 +/- 1.49 pmol/l, respectively) and subacute thyroiditis (0.234 +/- 0.241, 0.335 +/- 0.057, 2.98 +/- 3.51 pmol/l, respectively). Twenty-two of 24 (91.7%) thyrotoxic patients with Eo/Mo < 0.2 had destruction-induced thyrotoxicosis (painless or subacute thyroiditis). Twenty-two of 28 (78.6%) thyrotoxic patients with FT3/FT4 < 0.3 had destruction-induced thyrotoxicosis. Thirty-six of 42 (85.7%) thyrotoxic patients with Eo/Mo.FT3 < 4.5 had destruction-induced thyrotoxicosis. The Eo/Mo ratio, FT3/FT4 ratio and Eo/Mo.FT3 were found to be similarly useful for differentiation between the two types of thyrotoxicosis. All thyrotoxic patients with TBII > or = 20% had Graves' disease and 76.4% of patients with TBII < 20% had destruction-induced thyrotoxicosis. CONCLUSION: The Eo/Mo ratio, FT3/FT4 ratio, and Eo/Mo.FT3 are simple, practical parameters and were as effective as TBII for differentiation of destruction-induced thyrotoxicosis (painless or subacute thyroiditis) from Graves' thyrotoxicosis. Eo/Mo < 0.2 and/or Eo/Mo.FT3 < 4.5 in untreated thyrotoxic patients are laboratory signals of destruction-induced thyrotoxicosis, and if these are determined, the radioactive iodine uptake test can be omitted for differential diagnosis of these two types of thyrotoxicosis.

Adolescent↗

PubMed2002

Quantitative analysis of thymosin beta-10 messenger RNA in thyroid carcinomas.

BACKGROUND: Genes that are differentially expressed in benign and malignant tissues are important for the establishment of molecular-based diagnosis of carcinomas. Our recent study on the gene expression profile of thyroid carcinomas revealed an increased expression of thymosin beta-10 mRNA. METHODS: To confirm this, we measured the expression levels of thymosin beta-10 mRNA in 84 thyroid benign and malignant thyroid tissues, including five anaplastic carcinomas, by means of real-time quantitative reverse transcription-polymerase chain reaction. RESULTS: We found an increased expression of thymosin beta-10 mRNA in thyroid carcinomas, especially in anaplastic carcinomas. Expression levels of thymosin beta-10 mRNA relative to thyroglobulin mRNA in anaplastic carcinomas were greatly increased compared with those in differentiated carcinomas. CONCLUSION: These results suggest the usefulness of the quantitative measurement of thymosin beta-10 mRNA in molecular-based diagnosis of thyroid anaplastic carcinomas, but not of differentiated carcinomas.

Biomarkers, Tumor↗

PubMed2002

Fas and Fas ligand gene mutations in Hashimoto's thyroiditis.

To clarify whether Fas and Fas ligand (FasL) mutations are involved in the pathogenesis of Hashimoto's thyroiditis (HT), we examined the open reading frame of Fas and FasL in 21 cases. Mutations of Fas and FasL genes were detected in 8 (38.1%) and 1 (4.8%) of 21 cases, respectively. All but one of the Fas mutations were frameshift mutations, which affect the cytoplasmic region (death domain) known to be involved in apoptotic signal transduction and thus could be loss-of-function mutations. FasL mutation in one case was a 46-bp deletion from nucleotide 349 to 394, which corresponded to exon 2. Lack of exon 2 results in a frameshift, which generates a stop codon at residue 128. This mutant encodes the protein that contains only a part of the intracellular domain, thus the abnormal protein might not be expressed on the cell surface. The cells with Fas mutations were confined to the mantle zone and the germinal center, as determined by microdissection methods. These findings suggest that the cells with Fas mutations might accumulate in those areas and might be involved in the pathogenesis of Hashimoto's thyroiditis.

Aged↗