A single-center retrospective study on the clinical features of thyrotoxic periodic paralysis.

PURPOSE: Thyrotoxic periodic paralysis (TPP) is characterized by muscle paralysis and significant intracellular potassium movement resulting in hypokalemia. Since TPP is a rare condition, only a few studies have explicated the clinical characteristics of patients with this disease. This study aimed to elucidate the clinical characteristics of patients with TPP by comparing them with those with thyrotoxicosis without paralysis (non-TPP) and sporadic periodic paralysis (SPP). METHODS: This was a single-center retrospective cohort study. Clinical data of patients with hyperthyroidism (n = 62) or periodic paralysis (n = 92) who were emergently admitted to our hospital was extracted from the electronic medical records and analyzed. RESULTS: All patients in the TPP group (15 males and 2 females) had Graves' disease, with 14 being newly diagnosed. The average serum potassium level on admission was 2.3±0.75 mEq/L. No significant correlation was observed among serum potassium level, amount of potassium required for normalization, and thyroid hormone levels. The TPP group showed significantly younger age, higher male ratio and body mass index (BMI), and lower serum potassium and phosphorus levels than the non-TPP group, which comprised 36 patients with Graves' disease. No significant differences were observed between the TPP and SPP (n = 11) groups in terms of age, sex, BMI, serum electrolyte levels, potassium requirement for normalization, and recovery time. MAIN CONCLUSIONS: Considering that most patients with TPP have undiagnosed Graves' disease, distinguishing TPP from SPP based on clinical information and course alone is difficult in emergency settings. Therefore, for early detection and launch of specific treatment of Graves' disease, screening for thyroid hormone and anti-thyroid stimulating hormone receptor antibody levels is necessary when treating patients with periodic paralysis.

Triiodothyronine levels in athyreotic pediatric patients during levothyroxine therapy.

Objective: Levothyroxine (LT4) monotherapy is the current recommended approach for treating pediatric patients post-total thyroidectomy (TT) based on the assumption that peripheral conversion of thyroxine (T4) to triiodothyronine (T3) normalizes thyroid hormone levels. In adults, approximately 15% of post-TT patients on LT4 monotherapy have altered T4:T3 ratios with ongoing debate in regard to the clinical impact with respect to health-related quality of life (hrQOL). The ability to normalize T3 and T4 levels on LT4 monotherapy for pediatric patients' post-TT is important but not previously described. This study reports data on T3 levels in athyreotic pediatric patients to determine if a similar cohort of patients exists on LT4 monotherapy targeting normalization of TSH (LT4 replacement) or suppression (LT4 suppression). Methods: Thyroid function tests (TFTs) were retrospectively extracted from medical charts for patients <19 years old who underwent TT for definitive treatment of Graves' disease (GD) or differentiated thyroid cancer (DTC) between 2010-2021. LT4 dosing was selected to normalize the TSH in GD patients (LT4 replacement) or suppress TSH in DTC patients (LT4 suppression). Pre- and post-surgical TSH, T3 and T4 levels were compared. Results: Of 108 patients on LT4 replacement (n=53) or LT4 suppression (n=55) therapy, 94% (102/108) of patients demonstrated T3 levels in the normal range post-TT. However, the majority of patients on LT4 replacement (44/53; 83%) and LT4 suppression (31/55; 56%) displayed post-TT T3 levels in the lower half of the normal range despite 50% (22/44) and 48% (15/31) of these patients, respectively, having post-TT fT4 levels above the upper limit of the normal range. Conclusion: A significant number of pediatric patients do not achieve similar T3 and T4:T3 levels pre- and post-TT. Future multi-center, prospective studies evaluating LT4 monotherapy in comparison to combined LT4/LT3 therapy are warranted to determine the potential clinical impact of altered T3 levels in athyreotic pediatric patients.

Clinical Significance of IgG4 Serum Concentration in Graves' Disease.

Elevated immunoglobulin G4 (IgG4) serum antibodies are an important feature of IgG4-related disease. However, IgG4 antibodies can play a role in autoimmune thyroid disorders. In this study, we aimed to evaluate the impact of serum IgG4 levels on clinical features of Graves' disease (GD). We recruited 60 patients with GD (48 patients without thyroid eye disease, 12 patients with moderate-to-severe Graves' orbitopathy [GO], and 25 healthy control subjects). The prevalence of high IgG4 serum concentration was 4.2% among GD patients without GO and 33.33% in patients with moderate-to-severe GO. The group with GO had significantly higher median IgG4 levels (87.9 mg/dL) than the control group (41.2 mg/dL, P = 0.034) and the GD without GO group (30.75 mg/dL, P < 0.001). Patients with thyroid nodules had lower IgG4 levels than patients without thyroid nodules, but the difference was not statistically significant (35.7 [24.8; 41.53] mg/dL vs. 43 [30.1; 92.7] mg/dL, P = 0.064). IgG4 as a diagnostic tool for moderate-to-severe GO had the following parameters: area under the curve (AUC): 0.851 (P < 0.001), at the cut-off value of 49 mg/dL, negative predictive value: 100%, positive predictive value: 48%, sensitivity: 100%, specificity: 73%. There were no significant differences between the high and normal IgG4 groups in thyroid hormones, antithyroid antibodies, and ultrasound features. Serum IgG4 levels are associated with some of the clinical features of GD and can help in the diagnostic process of the disease. More research is needed to better understand the pathophysiology of IgG4 involvement in GD.

Identification and functionalization of thyrotropin receptor antibodies with different antigenic epitopes.

One of the sensitive markers for autoimmune thyroid disease (AITD) clinical identification is thyroid-stimulating hormone receptor antibodies (TRAbs). To quickly distinguish TRAb with distinct antigenic epitopes, a straightforward and uncomplicated technique has not yet been created. The objective of this study is to search for molecular diagnostic targets for different types of AITD {Graves' disease (GD), Graves' orbitopathy (GO), GD with third-degree goiter [GD(3)], hypothyroidism combined with positive TRAb [HT(TRAb+)]} as molecular diagnostic targets. Following action on thyroid cells, differential genes (DEGs) generated by TRAb with distinct antigenic epitopes were detected and identified by RNA sequencing (RNA-Seq), bioinformatics analysis, and quantitative reverse transcription-polymerase chain reaction (RT-qPCR) in the serum of patients with AITD. Using the 5-ethynyl-2'-deoxyuridine (EdU) assay, the effect of coculturing thyroid cells with different antigenic TRAb epitopes on the cells' capacity to proliferate was investigated. Bioinformatics analysis and RT-qPCR validation identified one GD key gene alpha 2-HS glycoprotein (AHSG), two GO key genes [adrenoceptor alpha 1D (ADRA1D) and H2B clustered histone 18 (H2BC18)], two GD(3) key genes [suppressor of cytokine signaling 1 (SOCS1) and cytochrome b-245 beta (CYBB)], and one HT(TRAb+) key gene (MASP2). Correlation analysis and ROC curves showed that the abovementioned genes could be used as molecular diagnostic targets for different types of AITD. Finally, EdU results showed that TRAb inhibited thyroid cell proliferation in the HT(TRAb+) group compared with the normal control group, whereas the remaining three groups promoted thyroid cell proliferation, with a statistically significant difference (P < 0.05). We identified six key genes for different types of AITD, which have diagnostic value for different types of AITD. Meanwhile, we found that TRAbs with different antigenic epitopes in AITD have different biological functions.NEW & NOTEWORTHY We identified six molecular targets of different types of AITD [GD, GO, GD(3), and HT(TRAb+)], which have diagnostic value for different types of AITD. Meanwhile, we found that TRAb with different antigenic epitopes extracted from the sera of patients with AITD had different biological functions, which also provided a new idea for further research on the mechanism of action of TRAb with different antigenic epitopes in AITD.

Association between serum vitamin D level and Graves' disease: a systematic review and meta-analysis.

OBJECTIVE: This meta-analysis aims to analyze the relationship between serum vitamin D (VD) levels and Graves' disease (GD). METHODS: We conducted a search for publications on VD and GD in the English language. Our search encompassed databases such as PubMed, Embase, Web of Science, and the Cochrane Library, covering publications available through August 2023. A meta-analysis was performed using Cochrane RevMan 5.4 software. The standardized mean difference (SMD) and 95% confidence interval (CI) were used for outcome calculation. We used R software to test for publication bias. RESULTS: Twelve studies were selected, comprising 937 (22.4%) cases with GD and 3254 (77.6%) controls. The overall meta-analysis revealed that patients with GD are significantly more likely to have low VD levels (SMD = - 0.66; 95% CI: -1.05, - 0.27; p = 0.001) than those in the control group. Egger's test results indicated no publication bias (p = 0.0791). These studies exhibited a high degree of heterogeneity (chi-square = 205.86, p < 0.00001; I2 = 95%). Subgroup analysis was conducted based on assay method, geographic location, and mean age of the case group to explore the heterogeneity sources. Assay methods and geographic locations were identified as potential heterogeneity sources. Based on the mean age, there were no statistically significant differences found in the subgroup analysis of the included studies. CONCLUSION: There is promising evidence that low serum VD levels may increase the risk of GD. Further rigorous and long-term trials are needed to explore the role of VD in the onset and treatment of GD.

Predictive value of bone turnover markers and thyroid indicators for bone metabolism in GD patients after treatment.

Purpose: To investigate the relationship between bone turnover markers (BTMs) and thyroid indicators in Graves' disease (GD) and to further assess predictive value of changes in early stage retrospectively. Methods: We studied 435 patients with GD and 113 healthy physical examiners retrospectively and followed up these two groups of patients after 6 months. We investigated the correlations between BTMs and other 15 observed factors, and analyzed the predictive value of FT3 and FT4 before and after treatment (FT3-P/FT3-A, FT4-P/FT4-A) on whether BTMs recovered. Results: The levels of thyroid hormones and BTMs in GD group were significantly higher than those in control group (P < 0.05) and decreased after 6 months of treatment. FT3, W, Ca and ALP were independent factors in predicting the elevation of OST. Duration of disease, FT3, TSH and ALP were independent factors in predicting the elevation of P1NP. Age, duration of disease, TRAb and ALP were independent factors in predicting the elevation of CTX-1. The AUC of FT3-P/FT3-A and FT4-P/FT4-A for predicting OST recovery were 0.748 and 0.705 (P < 0.05), respectively, and the cut-off values were 0.51 and 0.595. There was no predictive value for P1NP and CTX-1 recovery (P > 0.05). Conclusion: BTMs were abnormally elevated in GD and were significantly correlated with serum levels of FT3, FT4, TRAb, Ca, and ALP. FT3 decreased more than 51% and FT4 dropped more than 59.5% after 6 months of treatment were independent predictors for the recovery of BTMs in GD.

Minor hyperthyroidism with normal levels of thyroid-stimulating hormone receptor antibodies: a case report.

The present report describes for the first time a case of diffuse hyperthyroidism in a 30-year-old female patient who had normal levels of thyroid-stimulating hormone receptor antibodies (TSHR-Ab), slightly elevated plasma levels of thyroid hormones, and slightly increased thyroid blood flow. Seven years before, after severe stress, she had Graves' disease with elevated plasma levels of TSHR-Ab. The patient's recent medical history included mental stress and autonomic dysfunction. This report describes a mild form of hyperthyroidism in terms of elevated plasma levels of thyroid hormones and Doppler ultrasonography data; this condition was first defined as 'minor hyperthyroidism'. The examination data suggest a probable secondary role of the immune system and primary role of the autonomic nervous system in the pathogenesis of Graves' disease.

Graves' Disease: Acquired Cause of a Moderate Increase in Hemoglobin A2 Level.

BACKGROUND: Hyperthyroidism can lead to diverse hematological disorders, such as microcytosis and a mild increase in hemoglobin A2 fraction. METHODS: This study reported a 31-year-old woman of Moroccan origin recently diagnosed with Graves' disease. Her blood tests revealed microcytosis, hypochromia, and a normal ferritin level. A phenotypic analysis of hemo-globin was performed using two techniques: capillary electrophoresis and reversed-phase high performance liquid chromatography. RESULTS: Both techniques indicated a slight increase in hemoglobin A2 level. These results initially suggested het-erozygous beta-thalassemia, eventually correlating with the concurrent presence of Graves' disease, as evidenced by the normalization of hemoglobin A2 level following treatment. CONCLUSIONS: This case highlights the importance of having clinical, biological, and therapeutic data for a relevant interpretation of a phenotypic hemoglobin study.

Neutropenia Occurs More Often Under Carbimazole than Under Methimazole Treatment in Pediatric Graves' Disease Patients.

Background: Agranulocytosis is a rare antithyroid drug treatment (ATD) side effect seen in children suffering from Graves' disease (GD). Neutropenia is a recognized adverse event associated with ATD but has also been reported as pre-treatment neutropenia in GD. Methods: We performed a retrospective cohort study to analyze the longitudinal clinical and biochemical data of 161 pediatric patients with GD who received either methimazole (MMI) or carbimazole (CBZ) as ATD. The inclusion criteria were elevated free thyroxine (fT4 >25 pmol/L), suppressed thyrotropin (TSH <0.05 mlU/mL), and elevated thyrotropin receptor antibodies (TSHRAbs >2.5 IU/L). Absolute neutrophil count (ANC) was used to define neutropenia (ANC <1800/µL) and agranulocytosis (ANC <500/µL). Results: Nine of the 161 patients had neutropenia at diagnosis (ANC: 1348/µL ± 250) without further deterioration under ATD. In this subgroup, we found higher levels of free triiodothyronine (fT3: 31.45 pmol/L ± 3.99) at diagnosis in comparison with those who developed neutropenia (26.29 pmol/L ± 12.96; p = 0.07) and those without neutropenia before and during therapy (23.12 pmol/L ± 13.7; p = 0.003). Thirty-eight patients (23.6%) became neutropenic (ANC: 1479/µL ± 262) while receiving ATD. Neutropenia occurred after a mean of 551.8 (range: 10-1376) days, mostly without further deterioration. Two of these 38 patients developed agranulocytosis and underwent emergency thyroidectomy. The patients with neutropenia were significantly younger (p = 0.031). Neutropenia occurred significantly more often in patients receiving CBZ (50%; n = 20/40) than in those receiving MMI (16.5%; n = 18/110; p = 0.001). The minimum ANC was significantly lower in the CBZ (1971/µL ± 1008) than in the MMI group (2546 ± 959); p = 0.004. Conclusions: Neutropenia occurred significantly more often under CBZ than MMI. As this is potentially due to higher immunogenicity, we suggest that children with GD should be treated with MMI. Frequent measurements of ANC may be needed to detect severe agranulocytosis, although low pre-treatment ANC may not necessarily be a contraindication to ATD treatment. Young age may be potentially associated with an increased risk of reduced ANC. Further investigation is necessary to fully understand risk factors for neutropenia in children with GD.

Methylation levels of the IL10 gene in peripheral blood are related to the intractability of Graves' disease.

The prognosis of autoimmune thyroid diseases (AITDs), including Hashimoto's disease (HD) and Graves' disease (GD), is difficult to predict. DNA methylation regulates gene expression of immune mediating factors. Interleukin (IL)-10 is a Th2 cytokine that downregulates inflammatory cytokines produced by Th1 cells. To clarify the role of methylation of the IL10 gene in the prognosis of AITD, we evaluated the methylation levels of two CpG sites in the IL10 promoter using pyrosequencing. The methylation levels of the -185 CpG site of the IL10 gene were related to age and GD intractability in GD patients. Furthermore, the C carrier of the IL10-592 A/C polymorphism was related to low methylation levels of the -185 CpG site. The methylation levels of the IL10-185 CpG site of the IL10 gene were related to the intractability of GD and were lower in individuals with the C allele of the IL10-592 A/C polymorphism.

Causality of blood metabolites and metabolic pathways on Graves' disease and Graves' ophthalmopathy: a two-sample Mendelian randomization study.

OBJECTIVES: There is ample that metabolic dysregulation is involved in Graves' disease (GD) and Graves' ophthalmopathy (GO). Recent studies have identified numerous metabolites associated with GD and GO. However, the causal impact of metabolites on GD and GO remains to be investigated. METHODS: This two-sample Mendelian randomization (MR) analysis investigated the causal relationships between 486 blood metabolites and GD and GO. Sensitivity analysis was also performed to examine heterogeneity and pleiotropy. RESULTS: MR analysis showed that 9 and 13 metabolites were associated with GD and GO, respectively, each meeting the nominal significance criteria (inverse variance weighted, p < 0.05). Additionally, four metabolic pathways were identified for each condition using network-based MetaboAnalyst 5.0. CONCLUSIONS: The metabolites and pathways discovered in this study could serve as circulating metabolic biomarkers for clinical screening and prevention of GD and GO. They can be also used for further studies on the mechanisms and drug targets in GD and GO.

Risk of recurrence at the time of withdrawal of short- or long-term methimazole therapy in patients with Graves' hyperthyroidism: a randomized trial and a risk-scoring model.

PURPOSE: In Graves' disease, administration of low-dose methimazole for more than 60 months induces higher remission rates compared with the conventional duration of 12-18 months. However, the risk of recurrence and its predictors beyond 48 months of drug withdrawal are not known. The aims of this study were to determine the risk of recurrence during 84 months after withdrawal of short- or long-term methimazole therapy and a risk stratification for recurrence of hyperthyroidism. METHODS: A total of 258 patients were treated with methimazole for a median of 18 months and randomized to discontinuation of the drug(conventional short-term group; n = 128) or continuation of the treatment up to 60-120 months(long-term group; n = 130). Patients were followed for 84 months after methimazole withdrawal. Cox proportional hazards modeling was performed to identify factors associated with relapse and develop a risk-scoring model at the time of discontinuing the treatment. RESULTS: Hyperthyroidism recurred in 67 of 120(56%) of conventionally-treated patients versus 20 of 118(17%) of those who received long-term methimazole treatment, p < 0.001. Age, sex, goiter grade, triiodothyronine, thyrotropin, and thyrotropin receptor antibodies were significant predictors of recurrence in both "conventional" and "long-term" groups but free thyroxine just in the "long-term" group. The risk-scoring model had a good discrimination power (optimism corrected c-index = 0.78,95%CI = 0.73-0.82) with a range of 0-14 and sensitivity of 86% and specificity of 62% at the risk-score of eight. CONCLUSION: A relapse-free state was achieved in 83% of patients with Graves' hyperthyroidism 84 months after cessation of long-term methimazole treatment which could be predicted by some significant predictors in a simple risk-scoring system.

IgG4 serum levels in Graves' orbitopathy.

OBJECTIVE: IgG4-related disease (IgG4-RD) can involve many organs, including thyroid and orbital tissues. A link between IgG4, Graves' disease (GD) and Graves' orbitopathy (GO) has been proposed, but results are conflicting. Here we investigated the possible association between IgG4 and GO. METHODS: Retrospective investigation in 297 patients with Graves' disease (GD), 152 with GO. PRIMARY OUTCOME: prevalence of IgG4 ≥ 135 mg/dL (cut-off for IgG4-RD). SECONDARY OBJECTIVES: (1) serum IgG4 concentrations; (2) IgG4/IgG ratio; (3) prevalence of IgG4/IgG ratio ≥ 8.0%; (4) relationship between IgG4 and eye features; (5) relationship between IgG4 and anti-TSH receptor antibodies (TRAbs). RESULTS: Because GO patients had lower FT3 concentrations, we evaluated the main objectives in the second and third FT3 quartiles subpopulation, in which there were no relevant differences between patients with (n = 81) or without GO (n = 67) for baseline parameters. Within this population, the prevalence of IgG4 levels ≥ 135 mg/dL did not differ between patients without and with GO (17.9% vs 17.3%). No difference was observed concerning IgG4 concentrations, prevalence of IgG4/IgG ≥ 8.0%, and IgG4/IgG ratio. There was no relationship between IgG4 and eye features and no correlation between IgG4 levels and TRAb was found. CONCLUSIONS: Our results suggest that, within GD, there is no relationship between serum IgG4 and GO.

Transition from Hashimoto thyroiditis to Graves's Disease: an unpredictable change?

PURPOSE: Hashimoto thyroiditis and Graves's disease are two related autoimmune disorders, representing the leading causes of hypothyroidism and hyperthyroidism. Autoimmune hypothyroidism is generally irreversible but very rarely, some patients would shift to hyperthyroidism. The aim of the study was to seek for possible clinical predictors of the transition from hypo to hyperthyroidism in patients with Hashimoto thyroiditis and to outline their clinical phenotype. METHODS: Twelve patients with overt autoimmune hypothyroidism who had at least one transition from hypothyroidism to autoimmune hyperthyroidism were compared with 294 consecutive patients with autoimmune hypothyroidism and 69 consecutive patients with autoimmune hyperthyroidism that accessed the outpatient clinic over six months. Demographic, hormonal data and autoantibodies titers were compared. RESULTS: Prevalence of smoking habit was significantly higher in switchers compared to controls. Switchers showed a significantly higher prevalence of personal and familial history of non-thyroidal autoimmune disorders. TSH levels were significantly lower in the switcher group during the hypothyroid phase and levothyroxine dose required was lower. TSH concentrations were significantly lower while free fT4 and free fT3 values were higher in GD patients compared to switchers during the hyperthyroid phase despite comparable TRAb levels. Prevalence and type of hyperthyroid symptoms and orbitopathy were similar between switchers and GD group. Mean dose of anti-thyroid drugs was significantly higher in GD patients compared to switchers. No differences were observed in the remission rate from hyperthyroidism between the two groups, despite switchers showed a significantly lower time-to-remission. CONCLUSIONS: Conversion of Hashimoto Thyroiditis towards Graves' disease is a rare phenomenon which can occur almost at any time after the development of autoimmune hypothyroidism. Our findings suggest active surveillance of hypothyroid patients who require frequent reduction of levothyroxine during follow up and testing for TSHR antibodies in these patients.

Pre- and Post-treatment Serum BAFF Levels and BAFF Gene Polymorphisms in Patients with Graves' Disease.

BACKGROUND: B cell activating factor (BAFF), a crucial factor for B cell survival and differentiation, has been linked to several autoimmune conditions. The aim of this study was to evaluate the association of BAFF gene's polymorphisms with its serum levels and to assess their effect on Graves' disease (GD) susceptibility and presentation. METHODS: Sixty-two GD patients and 152 healthy controls have been enrolled to investigate BAFF rs9514827 (-2841 T/C), rs1041569 (-2701 T/A) and rs9514828 (-871 C/T) gene's polymorphism by PCR-RFLP and serum BAFF level's kinetics under medical treatment by ELISA. RESULTS: Median serum BAFF level at baseline was significantly higher in GD patients (841.7 pg/ml [685.23-1058.32]) comparatively to controls (495.75 pg/ml [383.17-595.7]), p = 7.29 E-25. A ROC curve was used to assess BAFF performances in GD diagnosis and revealed an AUC of 94.9% [0.919-0.979], p = 7.29 E-25. At a cutoff value of 654.9 pg/ml of BAFF at baseline, the sensitivity and the specificity were, respectively, 83.9% and 90.8%. BAFF level was significantly increased in smoking patients (1079.55 pg/ml [875.35-1203]) comparatively to nonsmokers (746.95 pg/ml [643.2-915.7]), p = 3.1 E-5. While -2841 T/C and -2701 T/A genotypes and alleles frequencies were similar between patients and controls, the -871*T allele was significantly more prevalent in patients (0.613) than in controls (0.477); p = .01, OR [95% CI] = 1.73 [1.13-2.65]. The three studied polymorphisms were not associated with serum BAFF level at baseline. CONCLUSION: Serum BAFF level is significantly increased in GD especially in smoking patients. rs9514828 - 871*T allele might be a susceptibility variant for GD.

Low levels of serum IL-39 are associated with autoimmune thyroid disease.

BACKGROUND: Interleukin (IL)-39 is a novel member of IL-12 cytokine family, but its role in autoimmune thyroid diseases (AITD) is unclear. The aim of the present study was to determine serum levels of IL-39 in Hashimoto's thyroiditis (HT) and Graves' disease (GD) patients. METHODS: A total of 48 patients with HT, 50 patients with GD, and 45 healthy controls (HCs) were recruited for this study. Levels of serum IL-39 were determined by ELISA. RESULTS: Compared with HC group, levels of serum IL-39 in patients with HT (p < 0.05) and GD (p < 0.01) were drastically reduced. Among patients with HT, serum IL-39 levels had a positive correlation with white blood cell count (WBC) count and free triiodothyronine level. Among patients with GD, the levels of IL-39 in serum were positively correlated with WBC count and C-reactive protein levels. CONCLUSIONS: IL-39 may be a new potential predictor for patients with HT and GD.

A rapid homogenous bioassay for detection of thyroid-stimulating antibodies based on a luminescent cyclic AMP biosensor.

Graves' disease (GD) is an autoimmune disease caused by antibodies to the thyroid stimulating hormone receptor (TSHR). The FDA-cleared Thyretain™ TSI bioassay is a highly specific method to detect thyroid stimulating antibodies (TSAb/TSI) in the blood of patients with autoimmune thyroid disease (AITD), particularly GD. To simplify the workflow of this bioassay and to support a semi-quantitative result, we have generated a stable CHO-K1 cell line expressing both a chimeric TSH receptor (TSHR-Mc4) and a luciferase-based homogeneous cAMP biosensor (GS luciferase). Here, we describe a rapid, real-time, homogenous bioassay (Turbo™ TSI Bioassay) to directly assess the functional activity of TSI and produce results in International Units of IU/L. The Turbo™ TSI bioassay works by measuring changes in the intracellular cAMP level induced by a G-protein coupled receptor (G-PCR) signaling cascade which is triggered by the binding of TSI to the TSHR. Upon binding to cAMP, the GS luciferase reporter is activated through conformational changes and generates light that can be measured in intact cells with a luminometer. The LoD and LoQ of the assay were determined to be 0.016 IU/L and 0.03 IU/L, respectively and the preliminary assay cutoff was determined to be 0.024 IU/L by ROC analysis using the Thyretain™ TSI bioassay results as reference. The analytical performance of the Turbo™ TSI bioassay is comparable to the Thyretain™ TSI bioassay as evidenced by similar EC50 values for a TSHR stimulating monoclonal antibody (M22). The specificity of the Turbo™ TSI bioassay was demonstrated by showing no response to a high concentration of a human monoclonal TSHR blocking antibody (K1-70). The precision of the assay was excellent with an overall within-laboratory precision <15% CV. When testing 198 clinical samples, the positive and negative percent agreement between the Turbo™ TSI and the Thyretain™ TSI bioassays were 98.7% and 93.5%, respectively. While both bioassays yield equivalent analytical and clinical performances, the Turbo™ TSI bioassay is much simpler to perform. It does not require cell culture, sample dilution, washing or cell lysis steps, resulting in a dramatically reduced turnaround time from about 21 h to 60 min. In addition, the same cell line showed its capability of detecting thyroid blocking antibodies (TBAb/TBI) in a competitive format. The Turbo™ TSI bioassay is user-friendly and is a very promising advancement to aid the diagnosis of autoimmune thyroid disease (AITD).

Low serum interleukin-38 levels in patients with Graves' disease and Hashimoto's thyroiditis.

BACKGROUND: Autoimmune thyroid disease (AITD) mainly includes Graves' disease (GD) and Hashimoto's thyroiditis (HT), which is caused by individual genetics, autoimmune dysfunction, and a variety of external environmental factors. Interleukin (IL)-38 is involved in a wide range of autoimmune diseases, but little is known about IL-38 expression in AITD. METHODS: Fifty patients with GD, 50 with HT, and 50 healthy controls (HC) were enrolled in this study. Basic information of the participants was obtained through a physical examination. Immunological data were obtained by an automatic chemiluminescence immunoanalyzer. C-reactive protein (CRP) concentrations and the white blood cell count were measured. Serum IL-38 levels were determined by an enzyme-linked immunosorbent assay. RESULTS: Serum IL-38 levels were significantly lower in the GD and HT groups than in the HC group (both p < 0.01). Serum CRP concentrations were significantly lower in the HT group than in the HC group (p < 0.05). Receiver operating characteristic curve analysis showed that the area under the curve was 0.7736 (p < 0.01) for IL-38 and 0.7972 (p < 0.01) for IL-38 combined with CRP in the GD group. In the HT group, the area under the curve was 0.7276 (p < 0.01) for IL-38 and 0.7300 for IL-38 combined with CRP (p < 0.01). CONCLUSIONS: The results suggest that serum IL-38 level is a potential new diagnostic biomarker in patients with GD and HT.

High prevalence of thyroid hormone autoantibody and low rate of thyroid hormone detection interference.

OBJECTIVE: Thyroid hormone autoantibody (THAb) is a common antibody in autoimmune disease and can interfere with the detection of thyroid hormone (TH). There was no research reporting the prevalence of THAb in Chinese and the rate of THAb interfering with TH detection. METHODS: We collected 114 patients with autoimmune thyroid disease (AITD) (Hashimoto's thyroiditis, 57 cases; Graves' disease, 57 cases), 106 patients with nonthyroid autoimmune diseases (NTAID), and 120 healthy subjects. According to the presence or absence of thyroid antibodies, patients with NTAID were divided into two groups: NTAID-AITD and NTAID groups. Radioimmunoprecipitation technique was used to detect THAb in all subjects. TH was detected on Abbot and Roche platforms in patients with positive THAb. RESULTS: The prevalence of THAb was 22.8% in Hashimoto's thyroiditis and 45.6% in Graves' disease. The prevalence of THAb in AITD group was lower than that in NTAID or NTAID-AITD groups (34.2% vs. 61.5%, p = 0.014; 34.2% vs. 71.3%, p < 0.01). Among total 98 patients with positive THAb, TH levels of 9 patients were falsely elevated (9.18%). CONCLUSION: The prevalence of THAb in AITD patients was lower than that in NTAID patients. Although THAb had a high frequency in various autoimmune diseases, the prevalence of THAb interfering with TH detection was only 9.18%.