TSH receptor inhibitory antibody(TBAb) promotes extracellular accumulation of hyaluronic acid in pretibial myxedema primary fibroblasts via PI3K-AKT pathway / 中华内分泌代谢杂志

Objective:Pretibial myxedema (PTM) is a localized myxedema characterized by excessive dermal hya-luronan (HA) deposition and elevated serum TSH receptor antibody (TRAb). In this study, we investigated the effects of TRAb and its subtypes, stimulating antibody [TSAb (M22)] and inhibitory antibody[TBAb (K1-70)], on the synthesis of hyaluronic acid produced by PTM primary dermal fibroblasts.Methods:Normal and PTM dermal fibroblasts were isolated and stimulated with M22, K1-70, and IgG from patients respectively. HA concentration in the supernatant before and after stimulation was tested by ELISA. The protein level and phosphorylation variation of CEMIP, HAS2 and PI3K-AKT pathway were detected by Western blot.Results:IgG from patients (TRAb 8.4 IU/L) significantly stimulated the extracellular accumulation of HA in PTM primary fibroblasts. Similarly, both M22 and K1-70 also upregulated HA level in the supernatant, though K1-70 seemed much more effecitve. After treatment with IgG, M22, and K1-70, the expression of HAS2 increased and the expression of CEMIP decreased; meanwhile, p-PI3K and p-AkT increased. Among them, further study on K1-70, promoting HA production by regulating PI3K-AkT signal pathway could be inhibited by PI3K inhibitor (LY294002).Conclusion:TSAb (M22) and TBAb (K1-70), especially TBAb, increase HAS2 and inhibit CEMIP expression by activating PI3-AKT signaling pathway in PTM fibroblasts, leading to increased extracellular HA level.

Comparison between peak systolic velocity of the inferior thyroid artery and technetium-99m pertechnetate thyroid uptake in differentiating Graves' disease from thyroiditis

ABSTRACT Objectives The differentiation between the various etiologies of thyrotoxicosis, including those with hyperthyroidism (especially Graves' disease [GD], the most common cause of hyperthyroidism) and without hyperthyroidism (like thyroiditis), is an important step in planning specific therapy. Technetium-99m (99mTc) pertechnetate thyroid scanning is the gold standard in differentiating GD from thyroiditis. However, this technique has limited availability, is contraindicated in pregnancy and lactation, and is not helpful in cases with history of recent exposure to excess iodine. The aim of this study was to identify the diagnostic value of the peak systolic velocity of the inferior thyroid artery (PSV-ITA) assessed by color-flow Doppler ultrasound (CFDU) and compare the sensitivity and specificity of this method versus 99mTc pertechnetate thyroid uptake. Subjects and methods We prospectively analyzed 65 patients (46 with GD and 19 with thyroiditis). All patients were evaluated with clinical history and physical examination and underwent 99mTc pertechnetate scanning and measurement of TRAb levels and PSV-ITA values by CFDU. The diagnosis was based on findings from signs and symptoms, physical examination, and 99mTc pertechnetate uptake. Results Patients with GD had significantly higher mean PSV-ITA values than those with thyroiditis. At a mean PSV-ITA cutoff value of 30 cm/sec, PSV-ITA discriminated GD from thyroiditis with a sensitivity of 91% and specificity of 89%. Conclusion Measurement of PSV-ITA by CFDU is a good diagnostic approach to discriminate between GD and thyroiditis, with sensitivity and specificity values comparable to those of 99mTc pertechnetate thyroid uptake.

TRAbs at diagnosis may better predict disease severity and relapse in younger patients with Graves' disease / 中华内分泌代谢杂志

Thyrotropin receptor antibodies ( TRAbs) are pathognomonic for Graves' disease. Previous studies have linked serum titers of TRAbs to severity of Graves' disease and likelihood of Graves' disease relapse. However, we know little about factors that may be involved in the impact of TRAbs on Graves' disease patients. In December 2018,"The Journal of Clinical Endocrinology&Metabolism" online published an article [ Bano A, Gan E, Addison C, et al. Age may influence the impact of TRAbs on thyroid function and relapse-risk in patients with Graves' disease. J Clin Endocrinol Metab, 2019,104(5):1378-1385. DOI:10.1210/jc.2018-01738]. With the permission of the original journal, we translated the article into Chinese. This article aimed to investigate the association of TRAbs at diagnosis with thyroid hormones and risk of relapse, and to study the influencing factors on these associations. The results showed that TRAbs at diagnosis were positively associated with circulating thyroid hormone levels and risk of relapse, and these associations were influenced by age, but not by sex, race, smoking or thyroid peroxidase antibody levels. This study indicates TRAbs at diagnosis can better predict severity of elevated thyroid hormone levels and risk of relapse in younger patients with Graves' disease.

Conversion to Graves disease from Hashimoto thyroiditis: a study of 24 patients

ABSTRACT Objective: The conversion of Hashimoto's thyroiditis (HT) to hyperthyroidism due to thyrotropin receptor antibodies is intriguing and considered rare. The contribution of TSH receptor blocking antibodies (TRAb), which may be stimulators (TSAb) or blockers (TBAb), is suspected. We describe clinical and biological variables in a series of patients switching from Hashimoto's thyroiditis to Grave's disease. Subjects and methods: Retrospective case study of 24 patients with Hashimoto's thyroiditis followed during 48 ± 36 months that developed later Graves' disease (GD). These variables were analysed in the hypo and hyperthyroid phase: age, sex, initial TSH, free triiodothyronine (fT3), free thyroxine (fT4), anti-TPO, TBII antibodies, parietal cell autoantibodies, time between hypo and hyperthyroidism, thyroid volume and levothyroxine doses (LT). Results: In HT, mean TSH was 9.4 ± 26.1 UI/L and levothyroxine treatment was 66.2 ± 30.8 µg/day. The switch to GD was observed 38 ± 45 months after HT diagnosis. As expected, we found significant differences on TSH, FT3, FT4 and TBAb levels. Three out of 14 patients had parietal cell autoantibodies. In two of these three cases there was an Helicobacter pylori infection. There were no significant differences between HT and GD groups with respect to thyroid volume. Conclusions: To our knowledge, large series documenting the conversion of HT to GD are scarce. Although rare, this phenomenon should not be misdiagnosed. Suspicion should be raised whenever thyroxine posology must be tapered down during the follow-up of HT patients. Further immunological and genetic studies are needed to explain this unusual autoimmune change.

TSH-receptor antibodies may prevent bone loss in pre- and postmenopausal women with Graves' disease and Graves' orbitopathy

ABSTRACT Objective Thyrotoxicosis is established risk factor for osteoporosis due to increased bone turnover. Glucocorticoids often administered for Graves' orbitopathy (GO) have additional negative effect on bone mineral density (BMD). Our aim was to examine the influence of thyroid hormones, TSH, TSH-receptor antibodies (TRAb) and glucocorticoid treatment on bone in women with Graves' thyrotoxicosis and Graves' orbitopathy (GO). Subjects and methods Forty seven women with Graves' disease, mean age 55.6 ± 12.8 (23 women with thyrotoxicosis and 24 hyperthyroid with concomitant GO and glucocorticoid therapy) and 40 age-matched healthy female controls were enrolled in the study. We analyzed clinical features, TSH, FT4, FT3, TRAb, TPO antibodies. BMD of lumbar spine and hip was measured by DEXA and 10-year fracture risk was calculated with FRAX tool. Results The study showed significantly lower spine and femoral BMD (g/cm2) in patients with and without GO compared to controls, as well as significantly higher fracture risk. Comparison between hyperthyroid patients without and with orbitopathy found out significantly lower spine BMD in the first group (p = 0.0049). Negative correlations between FT3 and femoral neck BMD (p = 0.0001), between FT4 and BMD (p = 0.049) and positive between TSH and BMD (p = 0.0001), TRAb and BMD (p = 0.026) were observed. Fracture risk for major fractures and TRAb were negatively associated (p = 0.05). We found negative correlation of BMD to duration of thyrotoxicosis and cumulative steroid dose. Conclusions Our results confirm the negative effect of hyperthyroid status on BMD. TRAb, often in high titers in patients with GO, may have protective role for the bone, but further research is needed.

Clinical Implication of TSH Receptor Antibody Measurement

Autoantibodies directed against the thyrotropin receptor have been well known to be an important pathogenesis of Graves' disease. However, the diagnosis and management of Graves' disease are still mainly dependent on thyroid function itself and clinical manifestation of thyrotoxic patients. That is mainly due to the low sensitivity of early generation of thyrotropin receptor assay methods. The development of sensitive thyrotropin receptor measuring tools through third generation immunometric assay made the diagnosis of Graves' disease with mild hyperthyroidism accurate and convenient for patients. Bioassay to detect thyroid stimulating immunoglobulin is also commercially available nowadays, which theoretically discriminate thyroid stimulating antibodies from thyrotropin receptor-blocking antibodies. Although the use of these serologic markers plays an informative role in accurately diagnosing Graves' disease and predicting the prognosis of disease, consideration of the heterogeneous nature of autoimmunity of Graves' disease and the limitation of indirect antibody assay is also required for proper management of Graves' disease patients. In this review, the clinical usefulness of thyrotropin receptor antibody in various clinical situations of Graves' disease was overviewed.

Development of Thyroid-Associated Ophthalmopathy in Patients Who Underwent Total Thyroidectomy

PURPOSE: To report clinical characteristics of thyroid-associated ophthalmopathy (TAO) in patients who previously underwent total thyroidectomy for thyroid cancer or a benign mass of the thyroid. MATERIALS AND METHODS: Of the patients who were diagnosed with TAO from March 2008 to March 2012, we performed a retrospective chart review on those who had undergone total thyroidectomy for thyroid cancer or a benign mass of the thyroid before the occurrence of ophthalmopathy. RESULTS: Of the 206 patients diagnosed with TAO, seven (3.4%) met the inclusion criteria. The mean age of the subjects was 47.4 years, and all were female. Six patients were diagnosed with papillary thyroid cancer, and one was diagnosed with a benign mass. The duration between total thyroidectomy and onset of TAO ranged from 3-120 months (median 48 months). Ophthalmic manifestations varied among cases. Except for the patient who was diagnosed with a benign mass, all patients showed hyperthyroid status and were under Synthroid hormone treatment at the time of TAO development. Five of these six patients had positive levels of thyroid-stimulating hormone (TSH) receptor autoantibodies. CONCLUSION: TAO rarely develops after total thyroidectomy, and the mechanism of TAO occurrence is unclear. However, most patients showed abnormalities in thyroid function and TSH receptor autoantibodies.

Hipertiroidismo congénito, Reporte de dos casos

Introducción: El hipertiroidismo es una patología tiroidea poco frecuente en neonatos, relacionada con el antecedente materno de enfermedad de Graves, y por lo tanto con el paso transplacentario de inmunoglobulinas estimulantes del receptor de TSH. Presentación de casos: Reportamos dos casos de sexo femenino, que se presentaron en el Hospital Universitario de Santander. El primero de los casos se manifestó en la primera semana; el segundo caso se presentó tardíamente después del primer mes de vida. Los síntomas que presentaron en común fueron taquicardia persistente e hiperactividad. En uno de los casos la presentación clínica fue confundida con una infección bacteriana, debido a la presencia de fiebre. Se confirma el diagnóstico con los niveles de TSH muy suprimidos y T4 libre elevada, al menos al doble del límite superior. Los dos casos observaron medicamentos antitiroideos y propanolol con buena evolución clínica y de laboratorios; no se observamos complicaciones a corto o largo plazo como arritmias o craneosinostosis. Discusión: El hipertiroidismo congénito es una patología poco frecuente y siempre debe ser sospechado en recién nacidos de madres con antecedente de enfermedad de Graves, sus manifestaciones pueden presentarse prenatalmente o postnatalmente, y su diagnóstico y tratamiento deben ser oportunos para evitar secuelas a largo plazo o incluso la muerte.

Introduction: Hyperthyroidism is a thyroidal pathology infrequent in neonates related with maternal history of Graves' disease, and therefore with the transplacental passage of stimulating TSH receptor immunoglobulins. Case report: We report two female gender cases at Hospital Universitario Santander, one of the two cases became manifest during the first week of life, and the other took longer time after the first month of life, as it can happen. Symptoms in common were persistent tachycardia and hyperactivity; one of the cases was mistaken for bacterial infection arising from fever. Diagnose was confirmed of highly suppressed TSH levels and high Free T4, at least twice the limit level. Both cases were treated for some time with antithyroid drugs and ß-blockers, showing good clinical and lab evolution; no complications like arrhythmias or craneosynostosis were observed. Discussion: Congenital hyperthyroidism is a rare condition and should always be suspected in infants of mothers with Graves' disease, its manifestations may occur prenatally or postnatally, and their diagnosis and treatment should be timely to avoid long-term sequelae or death.

Regulation of TSH Receptor Autoantibodies by a long Non-Coding RNA (Heg) and Cdk1- A Review.

Aims: A substantial part of the genome is transcribed in non-coding RNAs. We review our finding of a long non-coding RNA (designated Heg) in mononuclear cells (MNC) and regulation of TSH receptor autoantibodies (TRAb). Results: The Heg RNA transcript in MNC is negatively correlated with TRAb in patients with early and untreated Graves’ disease. In treated patients and in controls Heg correlated negatively with CD14 mRNA. Transfection studies with fragments of Heg added to MNC (exogenous Heg) decreased CD14 mRNA in MNC and increased gene expression of RIG-I, TLR7 and IFN-γ. Heg is likely to activate TLR7 receptors. CD14 is a co-receptor of TLR7. Decrease in gene expression of CD14 after Heg is a sign of differentiation of MNC to dendritic cells. This may reduce surface expression of CD14, cytokine responses and the responsiveness to TSH receptor antigens. Thus the relationship between TRAb and lnc Heg RNA is most likely explained by receptor crossinterference. Cdk1 mRNA (an index of cell cycle activity) is positively related with TRAb. Cdk1 mRNA and TRAb but not Heg decreased significantly during antithyroid treatment. Cdk1 decreased to values below normal. Conclusion: Thus both Heg RNA and Cdk1 may regulate the level of TRAb but by two different mechanisms.

Correlation between TSH Receptor Antibody Assays and Clinical Manifestations of Graves' Orbitopathy

PURPOSE: To investigate an association between the levels of serum thyroid-stimulating hormone (TSH)-receptor autoantibodies (TRAbs) and Graves' orbitopathy (GO) activity/severity scores, and compare the performance of three different TRAb assays in assessing the clinical manifestations of GO. MATERIALS AND METHODS: Cross-sectional study. Medical records of 155 patients diagnosed with GO between January 2008 and December 2010 were reviewed. GO activity was assessed by clinical activity score (CAS) and severity graded with the modified NOSPECS score by a single observer. Serum TRAb was measured by three different methods: 1st generation thyrotropin-binding inhibitor immunoglobulin (TBII) assay (TRAb1st); 3rd generation TBII assay (TRAb3rd); and biological quantitative assay of thyroid-stimulating immunoglobulin (TSI) using Mc4-CHO cells (Mc4-CHO TSI assay). Results were correlated with scores of activity/severity of thyroid eye disease. RESULTS: All three assays (TRAb1st, TRAb3rd, and Mc4-CHO TSI) yielded results that were significantly positively correlated with CAS (beta=0.21, 0.21, and 0.46, respectively; p<0.05) and proptosis (beta=0.38, 0.34, and 0.33, respectively; p<0.05). Mc4-CHO TSI bioassay results were significantly positively correlated with all GO severity indices (soft tissue involvement, proptosis, extraocular muscle involvement, and total eye score; beta=0.31, 0.33, 0.25, and 0.39, respectively; p<0.05). CONCLUSION: Mc4-CHO TSI bioassay was superior over the two TBIIs in assessing active inflammation and muscle restriction due to GO, whereas TBII assay would be sufficient for evaluation of patients with proptosis.

Clinical Value of a Rapid Fully Automated Thyroid Autoantibody Assay in the Diagnosis and Management of Graves Disease

The most common cause of hyperthyroidism is Graves disease (GD) which is characterised by the presence of autoantibodies which binds to the TSH receptor (TRAb). Recently, a rapid, fully automated electrochemiluminescent immunoassay ElecsysAnti-TSHR for detection of autoantibodies to TSH receptor was made available for routine clinical use. The objective of this study is to evaluate this assay and to determine the sensitivity, specificity and cut-off value. Interassay and total imprecision (CV) were determined at 3.78-7.02 IU/L and 13.5-21.2 IU/L respectively. A total of 124 samples which comprised of 46 GD, seven Hashimoto thyroiditis (HD), 11 non autoimmune nodular goitre (NAG), 2 thyroid cancers (Ca) and 58 normal controls were retrospectively analysed to determine the sensitivity, specificity and cut-off value. Inter-assay CV’s were 2.4% at a concentration of 3.90 IU/L (range: 3.78-7.02 IU/l) and 0.8% at 20.80 IU/L (range:13.5-21.2 IU/l). Total imprecision was 3.8% at a concentration of 3.80 IU/L (range:13.5-21.2 IU/l) and 1.0% at 20.8 IU/L (range:13.5-21.2 IU/l). The ROC analysis of patients with GD, other thyroid disorders and normal controls revealed that the highest sensitivity (94%) and specificity (98%) were seen at cut-off value of 1.69 IU/L. Positive predictive value (PPV) and negative predictive value (NPV) was 95% and 94% respectively. At this derived cut-off value of 1.69 IU/L, we found that the sensitivity of TRAb positivity within the group of 29 newly diagnosed GD patients was 94%. Our results demonstrate that this fully automated assay with testing time of 27 minutes has high sensitivity in detecting GD and high specificity for discriminating other thyroid disease and represent major improvement in the diagnosis and management of patients with thyroid diseases.

The single nucleotide polymorphisms in the intron 1 of TSHR gene were associated with Graves' disease / 中华内分泌代谢杂志

Objective To investigate the association between single nucleotide polymorphisms in the intron 1 of thyroid stimnulating hormone receptor gene (TSHR) and Graves' disease (GD) in the Chinese Han population from Linyi city,Shandong Province.Methods A total of 1759 GD patients and 1740 control subjects were recruited for genotyping in TSHR intron 1 with genome-wide association study (GWAS) and Taqman probe technique.At the same time,serum thyroid hormone and TSH receptor antibody (TRAb) levels of patients were determined.Results Five SNPs were selected for further replication.The rs12101261 _T was significantly associated with GD risk ( OR=1.257,95％CI 1.137-1.390,P =8.23 × 10-6 ). Logistic regression identified that rs12101261 was an independent susceptibility locus of GD ( P=1.61 × 10-3 ).Furthermore,rs12101261 _T was strongly associated with GD ( OR =1.317,95％ CI 1.171-1.481,P=4.14× 10-4 ) in TRAb positive patients,but no association in TRAb negative patients ( OR=1.056,95％ CI 0.892-1.251,P=0.524 ).Serum TRAb concentration showed remarkable difference among three genotype groups of rs12101261.Conclusions Five SNPs in TSHR intron 1 are associated with GD.rs12101261 contributes to increased GD risk independently and is associated with serum TRAb level.

TSHR gene intron 1 region polymorphism and its relationship with Graves' disease / 中华内分泌代谢杂志

Objective To investigate the association between the six single nucleotide polymorphisms ( SNP),named as rs179247,rsl2101261,rs2284722,rs4903964,rs2300525,rsl7111394 in the intron 1 of thyroid stimulating hormone receptor gene (TSHR) and Graves' disease (GD).MethodsThe genotypes of the six SNPs were genotyped by Taqman probe technique on Fluidigm EP1 platform in 618 GD patients and 646 control subjects.Meanwhile,TSH receptor antibodies (TRAb) of the patients were determined.ResultsAmong the six SNPs,five S NPs were strongly associated with GD,with the most signals at rs179247_G,rs12101261_C,rs4903964 _G (P=2.85×10-10,OR=1.73,95％CI1.46-2.05;P=1.74×10-10,OR=1.73,95％CI 1.46-2.05;P=2.24×10-10,OR=1.69,95％ CI 1.44-1.99 ).The results of logistic regression analysis indicated that rs12101261 and rs4903964 were main susceptibility loci of GD in the intron 1 of TSHR.rs179247_G,rs1210126 1_C,and rs4903964_G were associated with subset of the GD patients with positive TRAb (P=4.24× 10-13,p=5.48× 10-13,P =3.89×10-12 ).Conclusionrs179247,rs12101261,and rs4903964 in TSHR intron 1 were significantly associated with GD in the Chinese Han population from Bengbu city.rs12101261 and rs4903964 were the major susceptibility SNPs associated with GD.TSHR gene may play a main role of susceptibility gene in the subset of GD patients with persistent positive TRAb.

Immune effect of propylthiouracil and methimazole in the treatment of Graves' disease / 中华内分泌代谢杂志

ObjectiveTo observe the changes in TSH receptor antibody (TRAb) and soluble intercellular adhesion molecule-1 ( sICAM-1 ) levels after treatment of propylthiouracil ( PTU ) and methimazole( MMI ) in patients with Graves' disease (GD). MethodsOne hundred and six cases of clinically diagnosed patients with GD were divided into PTU and MMI groups( each group, n =53 ). The patients in two groups were regularly followed for 36 months. TRAb and sICAM-1 were measured with ELISA method. Results( 1 ) The general data of two groups were not significantly different before treatment( all P＞0. 05 ). ( 2 ) There was no difference in TRAb positive rates between two groups before treatment. The clinical remission rates between PTU and MMI groups showed no difference (83.02％ vs88.68％ ). The cure rate was higher in MMI group than in PTU group( 58.49％ vs 37.74％, P＜ 0. 05 ). (3) There existed significant differences in TRAb levels determined before and 6, 12, 24,30, and 36 months after treatment( all P＜0. 01 ), being gradually decreased with time( F=275.48 ,P＜0.01 ). TRAb levels between two groups were significantly different( F=5.86, P＜0. 05 ). (4) sICAM-1 levels at 36 months after treatment compared with the baseline in both groups were statistically different (P＜0. 01 ), but no difference was found between two groups.ConclusionsBoth PTU and MMI improve the immune status of patients with GD,and the immunosuppressive effect of methimazole is more evident.

Association of TSHR gene intron 1 polymorphisms with Graves′ disease / 中华内分泌代谢杂志

Objective To investigate the association between polymorphisms of thyroid-stimulating hormone receptor(TSHR)gene intron 1(rs179247, rs12101261)and Graves′ disease(GD)in the China Han population from Xuzhou city, Jiangsu Province. Methods Total 1 066 GD patients and 1 107 control subjects were recruited for genotyping by Taqman probe technique on Fluidigm EP1 platform. Meanwhile, serum concentrations of thyroid hormone and TSH receptor antibodies(TRAb)were determined. Results The rs179247_A, rs12101261_T were significantly associated with GD risk(OR=1.35, 95%CI 1.19-1.54, P=5.92×10-6; OR=1.32, 95%CI 1.16-1.50, P=2.22×10-5). Logistic regression identified that rs179247 was an independent susceptibility locus of GD. Serum TRAb concentration showed a significant difference(P=0.015)among rs179247_AA, AG, and GG genotypes. Conclusion rs179247 and rs12101261 in TSHR intron 1 are both associated with GD, and rs179247 may contribute risk to GD independently. The polymorphism is associated with TRAb, but not with serum concentration of thyroid hormones, age of onset, diffused thyroid goiter, ophthalmic signs, and relapse.

Analysis of factors affecting the prognosis of patients with Graves' disease treated with antithyroid drugs / 中华内分泌代谢杂志

A total of 96 patients with Graves'disease(GD)were followed for one and half years to observe the effect of antithyroid drugs(ATD)treatment.Serum TRAb,total iodine concentration and CD80 mRNA expression of peripheral blood monouclear ceils were measured.Logistics regression analysis was conducted with the combination of above parameters.Those GD patients with high level of TRAb,positive family history of GD, increased expression of CD80 and early age of onset were more inclined to relapse after ATD treatment.

Crosstalk Between cAMP and Phosphoinositide System in Signal Transduction Pathways Through TSH Receptor / 대한내분비학회지

BACKGROUND: TSH stimulates both the adenyl cyclase and phospholipase C (PLC) pathways by binding to a single cell surface receptor that is coupled to G protein, and we examined crosstalk between these two signaling pathways. METHODS: FRTL-5 rat thyroid cells were grown in 6H medium, then incubated with 5H medium before the stimulation. Then cells were incubated for 24 hours with 5H mix containing 1 mCi/L myo-(2-N-3H) inositol. After pretreatment of 100 microM Rp-cAMP, 100 microM forskolin, 50 nM staurosporine, or 100 nM PMA (phorbol-12-myristate-13-acetate), TSH were added in different experiments. After 30 min at 37 degrees C, cells were disrupted and IP formation was determined. RESULTS: Stimulation with 100 microU/mL TSH resulted in a 1.65 fold increase in IP generation. In pursuing the possibility that the two post-receptor events might be linked in some way, we examined the effect of exogenously administrated Rp-cAMP, protein kinase A antagonist, and forskolin, a direct stimulant of protein kinase A, on IP generation achieved at a dose of 100 microU/mL TSH. The pretreatment of 100 M Rp-cAMP at a concentration sufficient to inhibit protein kinase A enhanced TSH-induced IP production. This effect of Rp-cAMP was dose-dependent. Forskolin attenuatedTSH-stimulated increases in phosphatidylinositide turnover. PMA, a protein kinase C (PKC) activator and staurosporine, a PKC inhibitor did not affect TSH-induced IP generation. CONCLUSION: These data suggested that activation of adenylate cyclase/cAMP post-receptor signalling casacde, which results in the protien kinase A activation, has an inhibitory effect on IP turnover activated by TSH.

Clinical Applications of TSH Receptor Antibodies in Thyroid Diseases

The cloning and sequencing of thyroid-stimulating hormone (TSH) receptor (TSHR), combined with advances in molecular techniques, have facilitated the understanding of the interaction of the TSHR antibodies (TSHRAbs) with the TSHR at the molecular level and have allowed the delineation of their clinical role. TSHRAbs in vivo are functionally heterogeneous; the stimulating TSHRAbs cause hyperthyroidism and diffuse goiter in patients with Graves' disease, whereas, the blocking TSHRAbs cause hypothyroidism in some patients with autoimmune hypothyroidism and are the cause of transient neonatal hypothyroidism. Measuring TSHRAbs has potential clinical implications in differential diagnosis of Graves' disease, predicting the outcome of Graves' disease after antithyroid drug treatment, and predicting the fetal/neonatal hyperthyroidism or neonatal hypothyroidism. The existence of epitope heterogeneity in a patient, i.e., of stimulating TSHRAbs with epitopes other than on the N-terminal region of the extracellular domain, is significantly associated with favorable long-term clinical response to antithyroid drug treatment. Measuring these subtypes for thyroid-stimulating antibody (TSAb) has potential clinical impli-cations, for example, in predicting responsiveness to treatment in untreated patients with Graves' disease.

Clinical significance of classification of Graves' disease according to the characteristics of TSH receptor antibodies

BACKGROUND: It has been widely accepted that the epitope(s) and/or functional characteristics of thyrotropin receptor antibodies (TSHRAb) from Graves' patients are heterogenous among patients. However, the clinical significance of such heterogeneity has not been systematically evaluated yet. We were to elucidate and find the clinical significance of heterogeneity for TSH receptor antibodies in Graves' disease. METHODS: We measured stimulating TSHRAb (TSAb) activities using CHO-hTSHR cells, FRTL-5 cells and chimeric receptor expressing cells (Mc1 + 2 and Mc2), specific blocking TSHRAb (TSBAb) activities using Mc2 cells and TBII activities using porcine thyroid membrane in 136 patients with untreated hyperthyroid Graves' disease. RESULTS: Based on various TSHRAb activities from each patient, the patients could be categorized into 7 subgroups by cluster analysis; 1) Group 1 (n = 41) was characterized by moderate TSAb activities both in CHO-hTSHR cells and in FRTL-5 cells, typical TSAb epitope, rare blocking antibodies and high TBII activities. 2) Group 2 (n = 16) was characterized by the presence of blocking TSHRAb in most patients, albeit the other characteristics were the same as those in Group 1. 3) Group 3 (n = 19) patients had low TSAb activities both in CHO-hTSHR cells and in FRTL-5 cells, seldom had blocking TSHRAb, but they had high TBII activities. 4) Group 4 (n = 30) could be categorized as 'mild disease' group, as they had low activities in all kinds of TSHRAb assay and had low antimicrosomal antibody activities. 5) Group 5 (n = 14) was characterized by moderate TSAb activities with atypical epitope(s), rare blocking TSHRAb and moderate TBII activities. 6) Group 6 (n = 10) patients had very high TSAb activities with typical epitopes, seldom blocking TSHRAb and low TBII activities. 7) Group 7 (n = 6) was characterized by very high TSAb activities with atypical epitopes and high TBII activities. Pretreatment serum thyroid hormone level was low only in group 4 patients compared to the other 6 groups (p < 0.05). The size of goiter was significantly larger in those in group 1 and group 3 (p < 0.05) compared to the other 5 groups. The prevalence of clinically significant ophthalmopathy was higher in group 2 patients than the other 6 groups (50% vs. 27.5%, p = 0.06). Among 6 kinds of TSHRAb activities, only the blocking TSHRAb activity was significantly associated with the presence of ophthalmopathy in multivariate analysis. CONCLUSION: These results suggest that the differences in epitopes for TSAb or the presence of blocking TSHRAb is not a major factor in determining the degree of thyrotoxicosis in Graves' disease. Although the pathogenic mechanism is not clear yet, we suggest that patients with ophthalmopathy have different TSHRAb repertoire from those without ophthalmopathy in Graves' disease.

A Clinical Study of Subacute Thyoidits / 대한내과학회지

OBJECTIVES: Subacute thyroiditis is a nonsuppurative inflammation of thyroid gland and is probably caused by a cytopathic virus. Typical clinical symptoms and features of subacute thyroiditis vary widely during the course of illness. It has a clinical course, evolving from hyperthyroidism through a temporary hypothyroidism to recovery. However, the final outcome of this disease remains unpredictive in some patients. Permanet hypothyroidism occurs infrequently. METHODS: Thirty-three patients proven to have subacute thyroiditis at the Ewha Womans University Hospital from September 1993 to November 1995 were studied. We analyzed their clinical features, laboratory findings, and duration of recovery to cha- racterize the course of the disease. RESULTS: 1) Total 33 patients were studied: 31 patients were female and 2 patients were male. Their mean age was 42.6+/-8.3 years old. The peak months were August through October in this study. 2) Initial mean ESR was 73.0+/-35.2mm/hr, mean T3 was 217.3+/-73.9ng/dl, mean T4 was 15.2+/-8.5microgram/ dl, and TSH was 0.06+/-0.09microIU/ml. The positive rates of antithyroglobulin and anitmicrosomal antibodies were 31% and 6% respectively, and TSH receptor antibody was elevated in one patient. 3) In the thyroid scan, 91% showed both lobes nonvisualisation, and 9% showed one lobe nonvisualization. Radioactive iodine uptake(RAIU) at 24 hour was 2.4+/-3.3%. 4) With the predisolone therapy, 90% of patients completely recovered, 57% of these patients had no hypothyroid phase and remaining 33% of them had hypothyroid phase during course of the disease. Three of the patients had permanent hypothyroidim. 5) The average duration of recovery was 3.2+/-1.4 months and it has no correlation with initial thyroid hormone levels, antithyroid antibodies and duration of steroid administration. CONCLUSION: There was no historical, physical, laboratory findings that help us predict those patients likely to have an exacerbation of the disease.