A novel thyroid stimulating immunoglobulin bioassay is a functional indicator of activity and severity of Graves' orbitopathy

Thyroid stimulating receptor autoantibodies

Thyroid-stimulating hormone receptor autoantibodies (TRAbs) play a crucial role as pathogenic antibodies in both the diagnosis and management of Graves' disease (GD). GD, an autoimmune disease resulting from a combination of genetic and environmental factors, is the most common cause of hyperthyroidism. With advancements in technology for TRAb detection and the availability of automated commercial kits, TRAb has become an essential clinical laboratory marker for the diagnosis of GD, as well as extra-thyroidal manifestations like Graves' ophthalmopathy (GO). This article provides a comprehensive review of TRAb, encompassing its clinical assays along with its significance in the clinical setting.

Redox mechanisms in autoimmune thyroid eye disease

Thyroid eye disease (TED) is an autoimmune condition affecting the orbit and the eye with its adnexa, often occurring as an extrathyroidal complication of Graves' disease (GD). Orbital inflammatory infiltration and the stimulation of orbital fibroblasts, triggering de novo adipogenesis, an overproduction of hyaluronan, myofibroblast differentiation, and eventual tissue fibrosis are hallmarks of the disease. Notably, several redox signaling pathways have been shown to intensify inflammation and to promote adipogenesis, myofibroblast differentiation, and fibrogenesis by upregulating potent cytokines, such as interleukin (IL)-1β, IL-6, and transforming growth factor (TGF)-β. While existing treatment options can manage symptoms and potentially halt disease progression, they come with drawbacks such as relapses, side effects, and chronic adverse effects on the optic nerve. Currently, several studies shed light on the pathogenetic contributions of emerging factors within immunological cascades and chronic oxidative stress. This review article provides an overview on the latest advancements in understanding the pathophysiology of TED, with a special focus of the interplay between oxidative stress, immunological mechanisms and environmental factors. Furthermore, cutting-edge therapeutic approaches targeting redox mechanisms will be presented and discussed.

Peripheral CD3+CD4+ T cells as indicators of disease activity in thyroid eye disease: age-dependent significance

PURPOSE

To provide an in-depth analysis of the association of peripheral lymphocytes and the disease activity of thyroid eye disease (TED).

METHODS

This retrospective study enrolled 65 active TED patients and 46 inactive TED patients. Comparative analyses of peripheral lymphocyte subsets were conducted between active and inactive patients. Subgroup analyses were performed based on sex, age, disease duration, and severity. Correlation analyses explored the associations between lymphocyte subsets and TED activity indicators. Prediction models for TED activity were established using objective indicators.

RESULTS

Significantly elevated levels of CD3+CD4+ T cells were observed in active TED patients compared to inactive patients (P = 0.010). Subgroup analyses further revealed that this disparity was most prominent in females (P = 0.036), patients aged 50 years and younger (P = 0.003), those with long-term disease duration (P = 0.022), and individuals with moderate-to-severe disease (P = 0.021), with age exerting the most substantial impact. Subsequent correlation analysis confirmed the positive association between CD3+CD4+ T cells and the magnetic resonance imaging indicator of TED activity among patients aged 50 years and younger (P = 0.038). The combined prediction models for TED activity, established using objective indicators including CD3+CD4+ T cells, yielded areas under curve of 0.786 for all patients and 0.816 for patients aged 50 years and younger.

CONCLUSIONS

Peripheral CD3+CD4+ T cells are associated with disease activity of TED, especially in patients aged 50 years and younger. Our study has deepened the understanding of the peripheral T cell profiles in TED patients.

Thyroid stimulating immunoglobulin concentration is associated with disease activity and predicts response to treatment with intravenous methylprednisolone in patients with Graves' orbitopathy

Background

Thyroid stimulating immunoglobulins (TSI) play a central role in the pathogenesis of Graves' orbitopathy (GO), while soluble interleukin-2 receptor (sIL-2R) is a marker for T-cell activity. We investigated TSI and sIL-2R levels in relation to thyroid function, disease activity and severity and response to treatment with intravenous methylprednisolone (IVMP) in patients with GO.

Methods

TSI (bridge-based TSI binding assay), sIL-2R, TSH and fT4 levels were measured in biobank serum samples from 111 GO patients (37 male, 74 female; mean age 49.2 years old) and 25 healthy controls (5 male, 20 female; mean age 39.8 years old). Clinical characteristics and response to treatment were retrospectively retrieved from patient files.

Results

Higher sIL-2R levels were observed in GO patients compared to controls (p < 0.001). sIL-2R correlated with fT4 (r = 0.26), TSH (r = -0.40) and TSI (r = 0.21). TSI and sIL-2R concentrations were higher in patients with active compared to inactive GO (p < 0.001 and p < 0.05, respectively). Both TSI and sIL-2R correlated with total clinical activity score (CAS; r = 0.33 and r = 0.28, respectively) and with several individual CAS items. Cut-off levels for predicting active GO were 2.62 IU/L for TSI (AUC = 0.71, sensitivity 69%, specificity 69%) and 428 IU/mL for sIL-2R (AUC = 0.64, sensitivity 62%, specificity 62%). In multivariate testing higher TSI (p < 0.01), higher age (p < 0.001) and longer disease duration (p < 0.01) were associated with disease activity. TSI levels were higher in patients with a poor IVMP response (p = 0.048), while sIL-2R levels did not differ between responders and non-responders. TSI cut-off for predicting IVMP response was 19.4 IU/L (AUC = 0.69, sensitivity 50%, specificity 91%). In multivariate analysis TSI was the only independent predictor of response to IVMP (p < 0.05).

Conclusions

High TSI levels are associated with active disease (cut-off 2.62 IU/L) and predict poor response to IVMP treatment (cut-off 19.4 IU/L) in GO. While sIL-2R correlates with disease activity, it is also related to thyroid function, making it less useful as an additional biomarker in GO.

Preoperative Risk Factors for Proptosis Recurrence After Rehabilitative Orbital Decompression in Graves' Orbitopathy Patients

PURPOSE

Rehabilitative orbital decompression treats disfiguring exophthalmos in patients with Graves' orbitopathy (GO). This study aimed to identify risk factors associated with the postoperative recurrence of proptosis after orbital decompression.

DESIGN

Retrospective, case-control study.

METHODS

This retrospective review included patients with GO who underwent rehabilitative orbital decompression for disfiguring proptosis in an inactive state with a low clinical activity score (0-2) between January 2017 and December 2020 by a single surgeon. Exophthalmos was measured using a Hertel exophthalmometer, and recurrence was defined as an increase of 2 mm or more after decompression during the follow-up period. The association between preoperative variables and proptosis recurrence was analyzed using multivariable logistic regression.

RESULTS

Of the total 217 patients, 11 (5.1%) developed recurrence of proptosis during the follow-up period (range, 3-30; mean, 15.6 months). Univariate logistic regression analysis identified thyroid-stimulating hormone receptor antibody (TRAb) and thyroid-stimulating immunoglobulin (TSI) as significant factors for recurrence, with age, sex, smoking, disease duration, orbital radiotherapy, and total thyroidectomy history being nonsignificant. TRAb remained significant in a multivariate logistic regression analysis (odds ratio, 1.06; P = .014). Receiver operating characteristic curve analysis revealed an area under the curve of 0.86 with a sensitivity of 90.9% and specificity of 82.0% at a TRAb level of 7.96 IU/L.

CONCLUSION

Preoperative TRAb and TSI are valuable markers to predict proptosis recurrence after orbital decompression. These results may help surgeons to decide the optimal timing for orbital decompression to lessen the risk of postoperative recurrence of proptosis.

Presentation of Graves' orbitopathy within European Group On Graves' Orbitopathy (EUGOGO) centres from 2012 to 2019 (PREGO III)

BACKGROUND

Graves' orbitopathy (GO) is subject to epidemiological and care-related changes. Aim of the survey was to identify trends in presentation of GO to the European Group On Graves' Orbitopathy (EUGOGO) tertiary referral centres and initial management over time.

METHODS

Prospective observational multicentre study. All new referrals with diagnosis of GO within September-December 2019 were included. Clinical and demographic characteristics, referral timelines and initial therapeutic decisions were recorded. Data were compared with a similar EUGOGO survey performed in 2012.

RESULTS

Besides age (mean age: 50.5±13 years vs 47.7±14 years; p 0.007), demographic characteristics of 432 patients studied in 2019 were similar to those in 2012. In 2019, there was a decrease of severe cases (9.8% vs 14.9; p<0.001), but no significant change in proportion of active cases (41.3% vs 36.6%; p 0.217). After first diagnosis of GO, median referral time to an EUGOGO tertiary centre was shorter (2 (0-350) vs 6 (0-552) months; p<0.001) in 2019. At the time of first visit, more patients were already on antithyroid medications (80.2% vs 45.0%; p<0.001) or selenium (22.3% vs 3.0%; p<0.001). In 2019, the initial management plans for GO were similar to 2012, except for lid surgery (2.4% vs 13.9%; p<0.001) and prescription of selenium (28.5% vs 21.0%; p 0.027).

CONCLUSION

GO patients are referred to tertiary EUGOGO centres in a less severe stage of the disease than before. We speculate that this might be linked to a broader awareness of the disease and faster and adequate delivered treatment.

Stability of Ocular Alignment After Teprotumumab Therapy in a Cohort of Patients With Thyroid Eye Disease and Baseline Diplopia

BACKGROUND

Teprotumumab is a monoclonal antibody that is effective in treating patients with thyroid eye disease (TED) and has been shown to produce subjective improvements in diplopia in this group. The aims of this study were to evaluate the rate and timing of recurrence/worsening of diplopia after teprotumumab treatment in a cohort of patients with TED presenting with diplopia at baseline.

METHODS

A retrospective chart review of 15 patients with diplopia secondary to TED, treated with teprotumumab, was conducted in a single-center academic institution. The primary outcome was the rate of recurrence/worsening of diplopia after completing teprotumumab. Secondary outcomes include the time to recurrence/worsening of diplopia and clinical activity scores (CAS) to correlate with changes in ocular alignment.

RESULTS

Fifteen patients met the inclusion criteria for this study, and 7 of these had recurrence of diplopia (46.7%). Two patients had worsening of CAS to ≥4, 6 had worsening of CAS to 3, and the other 7 had CAS ≤2 during the follow-up period. The mean follow-up period was 20.4 months (SD 7.2) after completing teprotumumab. The mean time to diplopia recurrence/worsening was 8.8 months (range 6.7-12.2, SD 1.8).

CONCLUSIONS

Patients with TED and baseline diplopia have a substantial rate of recurrence/worsening of diplopia after teprotumumab therapy, suggesting that they may not have stable ocular alignment immediately after treatment. Strabismus surgeons may need to weigh the significant risk of disease relapse when planning optimum timing for surgical correction.

Thyroid Eye Disease: Epidemiology, Natural History, and Risk Factors

BACKGROUND

Thyroid eye disease (TED) is an autoimmune disorder of the orbit and the most frequent extrathyroidal manifestation of Graves' disease but it may rarely occur in euthyroid/hypothyroid patients with chronic autoimmune thyroiditis.

EPIDEMIOLOGY

TED is a relatively infrequent disorder, particularly in its severe forms. Men tend to have more severe TED at an older age. The prevalence of TED is lower than in the past among patients with recent onset Graves' hyperthyroidism, and moderate-to-severe forms requiring aggressive treatments are no more than 5% to 6% of all cases.

NATURAL HISTORY

After an initial inflammatory (active) phase and a plateau phase, TED stabilizes and eventually inactivates (inactive or burnt-out phase) after an estimated period of 18-24 months. Minimal-to-mild TED often remits spontaneously, but complete restitutio ad integrum almost never occurs when TED is more than mild.

RISK FACTORS

Several risk factors contribute to its development on a yet undefined genetic background. Cigarette smoking is the most important of them, but thyroid dysfunction (both hyper- and hypothyroidism), radioactive iodine therapy (if not accompanied by low-dose steroid prophylaxis), elevated thyrotropin receptor antibodies, and, probably, hypercholesterolemia represent relevant modifiable risk factors. Early diagnosis, control and removal of modifiable risk factors, and early treatment of mild forms of GO (local treatment and selenium) may effectively limit the risk of progression to more severe forms.

Case Report of Graves' Disease in a 45-Year-Old Woman Secondary to Herceptin Treatment for Breast Cancer

Graves' disease is the most common cause of thyrotoxicosis and is characterized by ophthalmopathy with proptosis, chemosis, or conjunctival injection; pretibial myxedema; and thyroid acropachy. It is an autoimmune disease that can be genetic or influenced by coexisting environmental factors such as exposure to anticancer drugs, including immune checkpoint inhibitors. The incidence rate of breast cancer is increasing due to rising awareness of risk factors and screening for breast cancer, and the mortality rate is decreasing due to recent advances in cancer treatment. However, there are side effects that are attributed to these treatment modalities, manifesting in various forms in breast cancer survivors, which are reflected in the patient in this case study.

TSHR-based chimeric antigen receptor T cell specifically deplete auto-reactive B lymphocytes for treatment of autoimmune thyroid disease

Graves' disease (GD) is a prominent antibody-mediated autoimmune disorder characterized by stimulating antibodies (TRAb) that target the thyroid-stimulating hormone receptor (TSHR). Targeting and eliminating TRAb-producing B lymphocytes hold substantial therapeutic potential for GD. In this study, we engineered a novel chimeric antigen receptor T cell (CAR-T) therapy termed TSHR-CAR-T. This CAR-T construct incorporates the extracellular domain of the TSH receptor fused with the CD8 transmembrane and intracellular signal domain (4-1BB). TSHR-CAR-T cells demonstrated the ability to recognize and effectively eliminate TRAb-producing B lymphocytes both in vitro and in vivo. Leveraging this autoantigen-based chimeric receptor, our findings suggest that TSHR-CAR-T cells offer a promising and innovative immunotherapeutic approach for the treatment of antibody-mediated autoimmune diseases, including GD.

Application of Multiparameter Quantitative Magnetic Resonance Imaging in the Evaluation of Graves' Ophthalmopathy

BACKGROUND

Assessment of the activity of Graves' ophthalmopathy (GO) is difficult. Existing methods need improvement.

PURPOSE

Investigate the application of multiparametric magnetic resonance imaging (MRI) in GO.

STUDY TYPE

Retrospective.

POPULATION

A total of 235 GO patients (age: 38.8 ± 13.4 years; 90 male; 96 active patients).

FIELD STRENGTH/SEQUENCE

Short-tau inversion recovery (STIR) fast spin echo, multiecho spin echo T2 mapping and 3D T1-weighted fast field echo sequences at 3.0 T.

ASSESSMENT

Two physicians assessed the mean and maximum signal intensity ratio of extraocular muscles to white matter (SIR), T2 relaxation time (T2RT), extraocular muscle area (EMA), fat fraction (FF), retrobulbar fat volume (RFV), and extraocular muscle volume (EMV). Clinical activity score (CAS) ≧ 3 was in active stage.

STATISTICAL TESTS

The optimal cut-off point of diagnostic efficacy was selected using receiver operating characteristic (ROC) curve analysis and evaluated using area under the curve (AUC), compared using Student's t test, analysis of variance or Kruskal-Wallis H test. The correlation used Pearson correlation analysis. The discriminant equation used a binary logistic regression analysis. P < 0.05 was considered statistically significant.

RESULTS

The SIRmean, SIRmax, T2RTmean, T2RTmax, EMA, and EMV in active GO patients were significantly higher than those in inactive and were positively correlated with CAS (r = 0.276, 0.228, 0.438, 0.388, 0.502, and 0333, respectively). The FFmax of active patients was significantly lower than that of inactive patients and was negatively correlated with CAS (r = -0.44). Logistic regression analysis indicated that T2RTmean was independently associated with GO active periods and had good diagnostic performance (area under ROC curve = 0.736, sensitivity 70.7%, specificity 69.3%). T2RTmean ≧ 74.295 could be a diagnostic cut-off for judging GO activity (sensitivity 55.3%).

CONCLUSION

SIR, T2RT, EMV, and FF can quantitatively assess the activity and severity of GO and can potentially provide a basis for clinical judgment and selection of treatment options.

EVIDENCE LEVEL

4.

TECHNICAL EFFICACY

Stage 2.

Prognostic significance of thyroid-stimulating hormone receptor antibodies in moderate-to-severe graves' orbitopathy

Design

Retrospective study.

Purpose

The purpose of this retrospective study was to assess the changes in thyroid-stimulating hormone receptor (TSH-R) antibody levels following treatment in patients with moderate-to-severe and active Graves' orbitopathy (GO) and to investigate the correlation between these antibodies and treatment response.

Methods

The subjects of this study comprised of patients newly diagnosed with moderate-to-severe and active GO within the age range of 19 to 79 years. All participants underwent intravenous methylprednisolone (IVMP) therapy for a duration of 12 weeks. Patients with a clinical activity score (CAS) decrease to or less than 3 and no symptom recurrence for at least 3months after the last dose of IVMP were classified as "Group 1". Those with a CAS equal to or greater than 4 were classified as "Group 2". TSH-R antibody levels were measured prior to and following IVMP treatment and treatment response was evaluated after the completion of IVMP therapy. All patients were monitored for a minimum of 6 months post-treatment, with ocular examinations and laboratory tests at the initial visit being included in the analysis.

Results

The medical records of the 96 patients with GO were retrospectively reviewed. Seventy-five patients (78.1%) were response and 21 (21.9%) were non-responsive to IVMP treatment. A higher TSH-R antibody (TRAb) and thyroid-stimulating antibody (TSAb) following treatment were associated with a high risk of no treatment response (P = 0.017; P = 0.047, respectively). TRAb and TSAb levels before treatment were significantly related to TRAb and TSAb levels after treatment (P < 0.001, respectively). The cut-off values for the prediction of poor treatment response of the TRAb and TSAb before and after treatment were 8.305 IU/L, 5.035 IU/L and 449.5%, 361%, respectively (P = 0.027, P =0.001 and P = 0.136, P = 0.004, respectively).

Conclusion

It was observed that elevated levels of TRAb and TSAb prior to IVMP treatment were positively correlated with post-treatment levels of these antibodies. Furthermore, in cases of non-response to IVMP therapy, a diminished decline in both antibodies was observed, and elevated levels of TRAb and TSAb post-treatment were found to be a significant predictor of poor treatment outcome. Measurement of TRAb and TSAb throughout the course of treatment in moderate-to-severe and active cases of GO may offer valuable insights into treatment prognosis and aid in the decision-making process regarding the potential need for increased IVMP dosage or alternative therapeutic strategies.

A NOVEL MONOCLONAL ANTIBODY DEGRADES THE THYROTROPIN RECEPTOR AUTOANTIBODIES IN GRAVES' DISEASE

OBJECTIVE

Autoantibodies (Ab) against the thyrotropin receptor (TSH-R-Ab) are key mediators for the pathogenesis of Graves' disease (GD). TSH-R-Ab degradation was evaluated using several immunoassays within an exploratory, controlled trial in patients with GD receiving a monoclonal antibody (mAb) targeting the neonatal crystallizable fragment receptor (FcRn).

METHODS

Serial measurements of TSH-R-Ab serum levels were performed using three different binding and cell-based assays in GD patients either on medication or on placebo.

RESULTS

In contrast to placebo where no changes were observed, a 12-week mAb therapy led to an early and significant decrease (> 60%) of the serum TSH-R-Ab serum levels in patients with thyroidal and extra-thyroidal GD, as unanimously shown in all three assays. These marked changes were noted already at week seven post baseline (P<0.0001 for the binding immunoassay and for the luciferase (readout) bioassay. The three TSH-R-Ab binding and bioassays highly correlated in the samples of both study groups (binding immunoassay versus luciferase bioassay r = 0.91, P < 0.001, binding vs. cyclic adenosine monophosphate (cAMP) bioassay, r = 0.86, P < 0.001, luciferase versus cAMP bioassay, r = 0.71, P = 0.006). The serological results correlated with the course of the extra-thyroidal clinical parameters of GD, i.e. clinical activity score and proptosis.

CONCLUSIONS

Targeting the FcRn markedly reduces the disease-specific TSH-R-Ab in patients with GD. The novel and rapid TSH-R-Ab bioassay improves diagnosis and management of GD patients.

Application of an Interpretable Machine Learning for Estimating Severity of Graves’ Orbitopathy Based on Initial Finding

(1) Background: We constructed scores for moderate-to-severe and muscle-predominant types of Graves’ orbitopathy (GO) risk prediction based on initial ophthalmic findings. (2) Methods: 400 patients diagnosed with GO and followed up at both endocrinology and ophthalmology clinics with at least 6 months of follow-up. The Score for Moderate-to-Severe type of GO risk Prediction (SMSGOP) and the Score for Muscle-predominant type of GO risk Prediction (SMGOP) were constructed using the machine learning-based automatic clinical score generation algorithm. (3) Results: 55.3% were classified as mild type and 44.8% were classified as moderate-to-severe type. In the moderate-to-severe type group, 32.3% and 12.5% were classified as fat-predominant and muscle-predominant type, respectively. SMSGOP included age, central diplopia, thyroid stimulating immunoglobulin, modified NOSPECS classification, clinical activity score and ratio of the inferior rectus muscle cross-sectional area to total orbit in initial examination. SMGOP included age, central diplopia, amount of eye deviation, serum FT4 level and the interval between diagnosis of GD and GO in initial examination. Scores ≥46 and ≥49 had predictive value, respectively. (4) Conclusions: This is the first study to analyze factors in initial findings that can predict the severity of GO and to construct scores for risk prediction for Korean. We set the predictive scores using initial findings.

Pathophysiology of thyroid-associated orbitopathy

Thyroid-associated orbitopathy, the most common extrathyroidal manifestation of Graves' disease, is characterized by orbital inflammatory infiltration and activation of orbital fibroblasts, which mediates de novo adipogenesis, excessive production of hyaluronan, myofibroblast differentiation and ultimately tissue fibrosis. Interactions among T cells, B cells, and orbital fibroblasts result in their activation and perpetuation of orbital inflammation as well as tissue remodelling. T helper 17 cells belong to a newly identified pathogenic CD4+ T cell subset which possesses prominent pro-inflammatory and profibrotic capabilities. Thyroid stimulating hormone receptor/insulin-like growth factor-1 receptor crosstalk and the downstream signalling pathways of both receptors represent the major mechanisms leading to activation of orbital fibroblasts. Thyroid stimulating hormone receptor autoantibody is the disease specific biomarker of great clinical relevance and utility. There is growing evidence that oxidative stress, gut microbiome and epigenetics also play a role in the pathogenesis and their manipulation may represent novel therapeutic strategies.

Using the Random Forest Algorithm to Detect the Activity of Graves Orbitopathy

PURPOSE

The aim of this study is to establish a random forest model to detect active and quiescent phases of patients with Graves Orbitopathy (GO).

METHODS

A total of 243 patients (486 eyes) diagnosed with GO in Beijing TongRen hospital were included in the study. The Clinical Activity Score of GO was regarded as the golden standard, whereas sex, age, smoking status, radioactive I131 treatment history, thyroid nodules, thyromegaly, thyroid hormone, and Thyroid-stimulating hormone receptor antibodies were chosen as predictive characteristic variables in the model. The random forest model was established and compared with logistic regression analysis, Naive Bayes, and Support vector machine metrics.

RESULTS

Our model has a sensitivity of 0.81, a specificity of 0.90, a positive predictive value of 0.87, a negative predictive value of 0.86, an F1 score of 0.85, and an out-of-bag error of 0.15. The random forest algorithm showed a more precise performance compared with 3 other models based on the area under receiver operating characteristic curve (0.92 versus 0.77 versus 0.76 versus 0.75) and accuracy (0.86 versus 0.71 versus 0.69 versus 0.66).

CONCLUSIONS

By integrating these high-risk factors, the random forest algorithm may be used as a complementary method to determine the activity of GO, with accurate and reliable performance.

Clinical relevance of thyroid-stimulating immunoglobulin as a biomarker of the activity of thyroid eye disease

BACKGROUND/OBJECTIVES

Although it has been reported that thyroid-stimulating immunoglobulin (TSI) is associated with the clinical characteristics of thyroid eye disease (TED), there is a paucity of literature regarding the role of TSI in diagnosing active TED. This study investigated the relationship between the level of TSI and the activity of TED and assessed the cut-off value of TSI discriminating active TED from inactive TED.

METHODS

This cross-sectional study included 101 patients with TED. TSI was quantitatively measured with a cell-based bioassay using a chimeric TSH receptor and a cyclic adenosine monophosphate response element-dependent luciferase. The association between TSI and a variety of demographic and clinical features of TED was analysed. Multivariate regression analysis was performed to determine possible independent factors affecting the level of TSI.

RESULTS

TSI level was higher in males than in females (p = 0.023) and smokers than in nonsmokers (p = 0.004). TSI level was inversely correlated with the duration of ocular symptoms (r = -0.295, p = 0.003). The level of TSI was also significantly different when compared to the thyroid function (p = 0.003), TED activity (p < 0.001), and TED severity (p = 0.001). Multivariate regression analysis revealed a significant relationship between TED activity and thyroid function jointly and the TSI level. The cut-off level of TSI for predicting active TED was a specimen-to-reference ratio of 406.7 (p < 0.001, area under the curve = 0.847, sensitivity 77.4%, specificity 81.3%).

CONCLUSIONS

TSI was a functional biomarker strongly associated with TED activity even after being adjusted by other clinical characteristics. Serum TSI level may help identify patients with active TED in clinics.

Thyroid autoantibodies

Thyroid-stimulating hormone (TSH) receptor antibody (TSH-R-Ab or TRAb) testing plays a pivotal role in arriving at the aetiological diagnosis in patients with thyrotoxicosis. A positive test establishes the diagnosis of Graves' disease (GD) while a negative result in conjunction with imaging studies supports other possible aetiologies. In patients with GD, TRAb levels at diagnosis and at the time of withdrawal of antithyroid drugs can identify patients who are unlikely to achieve remission and guide clinical management decisions. We provide an algorithm that incorporates TRAb in the decision-making process for the management of thyrotoxicosis. The utility of TRAb in predicting the risk of fetal and neonatal thyroid dysfunction is established and widely accepted in guidelines. TRAb may also help in the diagnosis of Graves' orbitopathy, especially in euthyroid or hypothyroid patients and its role in guiding its management is evolving as a useful adjunct to the clinical parameters used in making therapeutic decisions.Anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibodies (TgAb) indicate thyroid autoimmunity. The most common use of TPOAb is to identify patients at a higher risk of progression to treatment-requiring hypothyroidism. They also aid the diagnosis of immune thyroiditis and Hashimoto's encephalopathy. Thyroglobulin measurement is used to help guide differentiated thyroid cancer treatment. TgAb is used as an accompanying test with thyroglobulin measurement as its presence can interfere with the thyroglobulin assay. A negative TgAb result reduces the likelihood of, but does not exclude, interference with thyroglobulin assay.

Factors related to steroid treatment responsiveness in thyroid eye disease patients and application of SHAP for feature analysis with XGBoost

INTRODUCTION

The primary treatment for active thyroid eye disease (TED) is immunosuppressive therapy with intravenous steroids. In this study, we attempted to predict responsiveness to steroid treatment in TED patients using eXtreme Gradient Boosting (XGBoost). Factors associated with steroid responsiveness were also statistically evaluated.

METHODS

Clinical characteristics and laboratory results of 89 patients with TED who received steroid treatment were retrospectively reviewed. XGBoost was used to explore responsiveness to steroid treatment, and the diagnostic performance was evaluated. Factors contributing to the model output were investigated using the SHapley Additive exPlanation (SHAP), and the treatment response was investigated statistically using SPSS software.

RESULTS

The eXtra Gradient Boost model showed high performance, with an excellent accuracy of 0.861. Thyroid-stimulating hormone, thyroid-stimulating immunoglobulin (TSI), and low-density lipoprotein (LDL) cholesterol had the highest impact on the model. Multivariate logistic regression analysis showed that less extraocular muscle limitation and high TSI levels were associated with a high risk of poor intravenous methylprednisolone treatment response. As a result of analysis through SHAP, TSH, TSI, and LDL had the highest impact on the XGBoost model.

CONCLUSION

TSI, extraocular muscle limitation, and LDL cholesterol levels may be useful in predicting steroid treatment response in patients with TED. In terms of machine learning, XGBoost showed relatively robust and reliable results for small datasets. The machine-learning model can assist in decision-making for further treatment of patients with TED.

Sphingolipids in thyroid eye disease

Graves' disease (GD) is caused by an autoimmune formation of autoantibodies and autoreactive T-cells against the thyroid stimulating hormone receptor (TSHR). The autoimmune reaction does not only lead to overstimulation of the thyroid gland, but very often also to an immune reaction against antigens within the orbital tissue leading to thyroid eye disease, which is characterized by activation of orbital fibroblasts, orbital generation of adipocytes and myofibroblasts and increased hyaluronan production in the orbit. Thyroid eye disease is the most common extra-thyroidal manifestation of the autoimmune Graves' disease. Several studies indicate an important role of sphingolipids, in particular the acid sphingomyelinase/ceramide system and sphingosine 1-phosphate in thyroid eye disease. Here, we discuss how the biophysical properties of sphingolipids contribute to cell signaling, in particular in the context of thyroid eye disease. We further review the role of the acid sphingomyelinase/ceramide system in autoimmune diseases and its function in T lymphocytes to provide some novel hypotheses for the pathogenesis of thyroid eye disease and potentially allowing the development of novel treatments.

Association of clinical course with thyroid-stimulating immunoglobulin in Graves’ ophthalmopathy in Mongolians

Graves’ ophthalmopathy (GO) is a complex inflammatory condition affecting the orbit and is often associated with Graves’ disease (GD). This study aims to determine the levels of thyroid-stimulating immunoglobulin (TSI) and thyroid-stimulating hormone receptor autoantibody (TSHR-ab) in the serum of patients with GO, compare it with the GD, and determine whether there is a correlation with the clinical course of GO. The cross-sectional study included 82 patients with GO, 81 patients with GD, and 75 healthy subjects. The ocular manifestations of GO were identified and evaluated by the clinical activity score (CAS) and severity of GO using the European Group of Graves’ Orbitopathy (EUGOGO). TSI and TSHR-ab levels in the serum of participants were determined with ELISA kits and correlated with clinical findings. A total of 238 participant’s data were analyzed. There were 14 patients (17%) with unilateral GO. The most common ocular signs were eyelid retraction 68 (82.3%) and proptosis 61 (74.4%). The mean CAS score was 2.65±1.64 in GO patients and was higher in men than women (P = 0.008). The mean of TSI was 37.95±35.41 in GO, 14.16±15.67 in GD, and 4.33±2.94 in healthy controls (P<0.0001). The TSI was significantly higher in patients with GO than in those with GD (P<0.0001). There were no correlations between TSI and TSHR-ab levels and CAS scores. However, we observed a correlation between the TSI level and the severity of GO (P = 0.023). The area under the ROC curve (AUC) of TSI was 0.933 and selected 14.1 IU/ml was the optimal cutoff value (98.78% of sensitivity, 83.97% of specificity). Our study showed that TSI is significantly related to GO and the severity of GO. Therefore, TSI can be used as a predictor of severe GO to help in prognostication, follow-up and treatment planning.

Current concepts regarding Graves' orbitopathy

Graves' orbitopathy (GO) is an orbital autoimmune disorder and the main extrathyroidal manifestation of Graves' disease, the most common cause of hyperthyroidism. GO affects about 30% of Graves' patients, although fewer than 10% have severe forms requiring immunosuppressive treatments. Management of GO requires a multidisciplinary approach. Medical therapies for active moderate-to-severe forms of GO (traditionally, high-dose glucocorticoids) often provide unsatisfactory results, and subsequently surgeries are often needed to cure residual manifestations. The aim of this review is to provide an updated overview of current concepts regarding the epidemiology, pathogenesis, assessment, and treatment of GO, and to present emerging targeted therapies and therapeutic perspectives. Original articles, clinical trials, systematic reviews, and meta-analyses from 1980 to 2021 were searched using the following terms: Graves' disease, Graves' orbitopathy, thyroid eye disease, glucocorticoids, orbital radiotherapy, rituximab, cyclosporine, azathioprine, teprotumumab, TSH-receptor antibody, smoking, hyperthyroidism, hypothyroidism, thyroidectomy, radioactive iodine, and antithyroid drugs. Recent studies suggest a secular trend toward a milder phenotype of GO. Standardized assessment at a thyroid eye clinic allows for a better general management plan. Treatment of active moderate-to-severe forms of GO still relies in most cases on high-dose systemic-mainly intravenous-glucocorticoids as monotherapy or in combination with other therapies-such as mycophenolate, cyclosporine, azathioprine, or orbital radiotherapy-but novel biological agents-including teprotumumab, rituximab, and tocilizumab-have achieved encouraging results.

Ocular Manifestations Related to Antibodies Positivity and Inflammatory Biomarkers in a Rheumatological Cohort

Purpose

Ocular involvement is frequent in autoimmune diseases and even can be the first manifestation. There are multiple descriptions in the literature around the world regarding this topic. However, we evidenced a lack of studies analyzing the relationship between the ocular manifestations and systemic biomarkers, especially in Latinamerica. Therefore, this study aimed to examine the relationship between the positivity of inflammatory biomarkers and the ocular manifestations in a Colombian cohort of rheumatological patients.

Patients and Methods

We conducted an observational, descriptive, non-comparative cross-sectional study in a rheumatology center, in Bogotá, Colombia, from 2013 to 2019. We calculated a sample size of 797 patients to assess the prevalence of ocular manifestations and inflammatory biomarkers. We performed univariate analyses for categorical and continuous variables and bivariate analyses using the Chi-square and Fisher’s exact test for categorical variables.

Results

Women represented 84% of the population, and the mean age was 54.61± 15.64 years. Of 797 patients, 21.45% reported one or more ophthalmological diagnoses, being keratoconjunctivitis sicca (KCS) the most common (15.93%), followed by uveitis, and cataract (1.38%, each one). Regarding ophthalmological symptoms, 35% presented at least one, being dry eye sensation (DE) the most common (30.86%), followed by ocular pain (2.76%), red eye, and decreased visual acuity (2.63%, each one). The antibodies or inflammatory biomarkers most frequently found were antinuclear antibodies (ANAs) (35.3%), C-reactive protein (28.7%), and rheumatoid factor (27.9%). We found statistical associations between consumption of complement 3, anti-CCP, anti-RO, and anti-LA antibodies with ocular manifestations such as photophobia, DE, conjunctivitis, KCS, uveitis, retinal vasculitis, and maculopathy.

Conclusion

Ocular manifestations are frequently found in patients with positive antibodies and inflammatory biomarkers. Our results suggest antibodies and inflammatory molecules could be biomarkers for ocular manifestations in patients with rheumatological diseases. This study provides the basis for future longitudinal studies.

TSAb/TRAb ratio as a sensitive screening test for active Graves' orbitopathy

OBJECTIVE

Graves' orbitopathy (GO), an extrathyroidal manifestation of Graves' disease, can seriously threaten the patient's quality of life. Given that immunosuppressive treatment during the early active phase of GO has been found to reduce both disease activity and severity, sensitive screening tests are needed.

METHODS

The present study included 86 patients with GO, in whom serum levels of thyroid-stimulating hormone (TSH), free T3, free T4, thyroid-stimulating antibody, TSH receptor antibody, thyroid peroxidase antibody, thyroglobulin, and thyroglobulin antibody were measured within 2 months before magnetic resonance imaging (MRI)for orbit assessment.

RESULTS

The thyroid-stimulating antibody/TSH receptor antibody ratio was able to distinguish MRI results with a correct classification rate of 81%. When focusing on patients without T3 predominant Graves' diseases, the ratio distinguished MRI results at a rate of 92%. Receiver operating characteristic curve analysis revealed a cutoff antibody ratio of 87, which yielded a sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 91%, 95%, 18.2, and 0.0957, respectively, for distinguished MRI results.

CONCLUSIONS

The thyroid-stimulating antibody/TSH receptor antibody ratio is a highly sensitive and specific indicator for active GO, especially in patients without T3 predominance, and serves as a good screening test for active GO in primary care settings.

Differential Diagnosis of Thyrotoxicosis by Machine Learning Models with Laboratory Findings

Differential diagnosis of thyrotoxicosis is essential because therapeutic approaches differ based on disease etiology. We aimed to perform differential diagnosis of thyrotoxicosis using machine learning algorithms with initial laboratory findings. This is a retrospective study through medical records. Patients who visited a single hospital for thyrotoxicosis from June 2016 to December 2021 were enrolled. In total, 230 subjects were analyzed: 124 (52.6%) patients had Graves’ disease, 65 (28.3%) suffered from painless thyroiditis, and 41 (17.8%) were diagnosed with subacute thyroiditis. In consideration that results for the thyroid autoantibody test cannot be immediately confirmed, two different models were devised: Model 1 included triiodothyronine (T3), free thyroxine (FT4), T3 to FT4 ratio, erythrocyte sediment rate, and C-reactive protein (CRP); and Model 2 included all Model 1 variables as well as thyroid autoantibody test results, including thyrotropin binding inhibitory immunoglobulin (TBII), thyroid-stimulating immunoglobulin, anti-thyroid peroxidase antibody, and anti-thyroglobulin antibody (TgAb). Differential diagnosis accuracy was calculated using seven machine learning algorithms. In the initial blood test, Graves’ disease was characterized by increased thyroid hormone levels and subacute thyroiditis showing elevated inflammatory markers. The diagnostic accuracy of Model 1 was 65–70%, and Model 2 accuracy was 78–90%. The random forest model had the highest classification accuracy. The significant variables were CRP and T3 in Model 1 and TBII, CRP, and TgAb in Model 2. We suggest monitoring the initial T3 and CRP levels with subsequent confirmation of TBII and TgAb in the differential diagnosis of thyrotoxicosis.

Advances in the Treatment of Thyroid Eye Disease Associated Extraocular Muscle Myopathy and Optic Neuropathy

PURPOSE OF REVIEW

To review emerging treatments for thyroid eye disease (TED) associated extraocular muscle myopathy and dysthyroid optic neuropathy (DON).

RECENT FINDINGS

Emerging targeted biologic therapies may alter the disease course in TED. Teprotumumab, a type I insulin-like growth factor receptor inhibitor, is the most recent addition to the treatments available for TED-associated extraocular muscle myopathy causing diplopia. Small studies also suggest a potential therapeutic benefit for DON. Various recent studies have also expanded our knowledge on conventional TED therapies. The therapeutic landscape of TED and its sequelae has evolved in recent years. New targeted therapies have the potential to reduce the extraocular muscle and orbital volume expansion which can lead to diplopia and vision loss from optic nerve compression. Longer term efficacy and durability data is needed to determine the role biologics, such as teprotumumab, should play in the treatment of TED patients compared to the current standard of care.

A systematic review of multimodal clinical biomarkers in the management of thyroid eye disease

Thyroid Eye Disease (TED) is an autoimmune disease that affects the extraocular muscles and periorbital fat. It most commonly occurs with Graves' Disease (GD) as an extrathyroidal manifestation, hence, it is also sometimes used interchangeably with Graves' Ophthalmopathy (GO). Well-known autoimmune markers for GD include thyroid stimulating hormone (TSH) receptor antibodies (TSH-R-Ab) which contribute to hyperthyroidism and ocular signs. Currently, apart from radiological investigations, detection of TED is based on clinical signs and symptoms which is largely subjective, with no established biomarkers which could differentiate TED from merely GD. We evaluated a total of 28 studies on potential biomarkers for diagnosis of TED. Articles included were published in English, which investigated clinical markers in tear fluid, orbital adipose-connective tissues, orbital fibroblasts and extraocular muscles, serum, thyroid tissue, as well as imaging biomarkers. Results demonstrated that biomarkers with reported diagnostic power have high sensitivity and specificity for TED, including those using a combination of biomarkers to differentiate between TED and GD, as well as the use of magnetic resonance imaging (MRI). Other biomarkers which were upregulated include cytokines, proinflammatory markers, and acute phase reactants in subjects with TED, which are however, deemed less specific to TED. Further clinical investigations for these biomarkers, scrutinising their specificity and sensitivity on a larger sample of patients, may point towards selection of suitable biomarkers for aiding detection and prognosis of TED in the future.

Thyroid-Stimulatory Antibody as a Predictive Factor for Graves’ Disease Relapse

Introduction: Thyroid-stimulatory antibody (TSAb) assays have been recently optimized, potentially allowing to determine thyrotropin receptor antibodies' (TRAbs) functionality in routine clinical practice. We aimed to determine TSAb's predictive role of relapse at antithyroid drug (ATD) withdrawal in Graves’ disease (GD).

Methods: Retrospective study of GD patients with stable normal thyroid function under low ATD doses that were proposed for withdrawal. Thyroid function tests and TRAb and TSAb levels were obtained at ATD suspension and every three to six months after that, for a minimum of 16 months. Clinical factors associated with GD relapse, such as age at diagnosis, sex, smoking status, thyroid volume, and presence of orbitopathy, were also evaluated.

Results: Thirty-five patients with GD were included for analysis, with a median follow-up period of 24 months, during which 14 patients (40%) relapsed. Relapse was more common in patients with positive TSAb than patients with negative TSAb at ATD withdrawal (79% vs. 33%, p=0.01). Relapse-free survival was shorter in TSAb-positive patients (p=0.01). There were no differences in relapse rates according to TRAb positivity at ATD withdrawal (42.9% vs. 36.4%, p=0.74). We also did not find any differences in relapse rate regarding age, sex, smoking status, thyroid volume, or presence of Graves’ orbitopathy. On multivariate analysis, only TSAb positivity at ATD withdrawal was independently associated with relapse (hazard ratio [HR] 6.63, 95% confidence interval [CI], 1.30-33.7, p=0.02).

Conclusion: At ATD withdrawal, TSAb-positive patients demonstrated a higher risk for GD relapse. Measuring TSAb before ATD suspension, instead of TRAbs, could become an important tool for the clinical management of these patients.

Ocular surface disease in thyroid eye disease: A narrative review

Ocular surface disease (OSD) in the setting of thyroid eye disease (TED) is traditionally thought of as a natural consequence of anatomical changes such as proptosis and corneal exposure. However, a growing body of research suggests that ocular surface inflammation and multi-factorial changes to the homeostasis of the ocular surface contribute substantially to the OSD seen in TED patients. In this paper we review the existing literature which highlights the work and existing theories underlying this new paradigm shift.

Diagnostic Utility of a New Assay for Thyroid Stimulating Immunoglobulins in Graves' Disease and Thyroid Eye Disease

Background: The syndrome of thyrotoxicosis typically relies on radioactive iodine scans for establishing its etiology. Alternatively, the determination of thyrotropin (TSH) receptor antibodies (TRAbs) helps to distinguish Graves' disease (GD) from thyrotoxic thyroiditis. Current assays are impacted by limitations in sensitivity and/or turnaround time. Therefore, we decided to test a new assay for the detection of TSH receptor stimulating antibodies (TSAbs) and compare it with the clinically available assays. Methods: We enrolled 110 individuals in 5 cohorts: patients with incident or recurrent GD (cohort 1); patients with thyroiditis, painless or subacute (cohort 2); patients with Graves' orbitopathy/thyroid eye disease (TED) in cohort 3; patients with Hashimoto's thyroiditis (cohort 4), and a control group of normal volunteers (cohort 5). The patients were tested with the two clinically available assays: Roche Elecsys anti-TSHR assay (ROC-TBII) from Roche Diagnostics and Thyretain™ TSI Reporter BioAssay Kit (QUI-TSI) from Quidel. In addition, the samples were tested with the aequorin TSAb assay (OTS-TSI) provided by Otsuka Pharmaceutical Co., Ltd. (Tokyo, Japan). The data were collected in a cross-sectional manner before initiation of therapy. Results: We had 36 cases of GD, 17 cases of thyroiditis, 27 cases of TED, 10 cases of Hashimoto's thyroiditis, and 20 normal volunteers. OTS-TSI had 100% sensitivity and specificity in distinguishing GD from thyroiditis, identical with QUI-TSI but superior to ROC-TBII (sensitivity 86% and specificity 94.1%). OTS-TSI had 93% sensitivity and 100% specificity for the diagnosis of TED, compared with normal controls. QUI-TSI and ROC-TBII performed similarly in this analysis, demonstrating 82% sensitivity and 100% specificity. The range of detectable values for OTS-TSI was 20-29,000 mIU/L and the turnaround time was ≤6 hours, without the need for cell culture equipment. Conclusions: OTS-TSI performed excellently, though similarly to QUI-TSI, for the differential diagnosis of GD vs. thyroiditis, while being superior in that respect to ROC-TBII. Furthermore, OTS-TSI has superior sensitivity to QUI-TSI and ROC-TBII for TED diagnosis, while retaining high specificity. It has a short turnaround time and avoids the need for cell culture and sterility. Larger studies in U.S. populations are needed for its validation.

Thyroid eye disease: From pathogenesis to targeted therapies

Thyroid eye disease (TED) is the most common extrathyroidal manifestation of autoimmune Graves’ hyperthyroidism. TED is a debilitating and potentially blinding disease with unclear pathogenesis. Autoreactive inflammatory reactions targeting orbital fibroblasts (OFs) lead to the expansion of orbital adipose tissues and extraocular muscle swelling within the fixed bony orbit. There are many recent advances in the understating of molecular pathogenesis of TED. The production of autoantibodies to cross-linked thyroid-stimulating hormone receptor and insulin-like growth factor-1 receptor (IGF-1R) activates OFs to produce significant cytokines and chemokines and hyaluronan production and to induce adipocyte differentiation. In moderately severe active TED patients, multicenter clinical trials showed that inhibition of IGF-1R with teprotumumab was unprecedentedly effective with minimal side effects. The emergence of novel biologics resulted in a paradigm shift in the treatment of TED. We here review the literature on advances of pathogenesis of TED and promising therapeutic targets and drugs.

Clinical value of functional thyrotropin receptor antibodies in Serbian patients with Graves' orbitopathy

PURPOSE

Thyrotropin receptor autoantibodies (TSH-R-Ab) are heterogeneous in their biological function and play a significant role in the pathophysiology of both Graves' disease and Graves' orbitopathy (GO). The clinical significance and utility of determining functional TSH-R-Ab in a Serbian collective were evaluated.

METHODS

91 consecutive patients with GO were included in this study. Total TSH-R-Ab concentration, referred to as TSH-R binding inhibitory immunoglobulins (TBII) was detected using a competitive-binding immunoassay. Stimulating and blocking TSH-R-Ab (TSAb and TBAb) were measured with cell-based bioassays.

RESULTS

Stimulating TSAb activity and TBII positivity were detected in 85 of 91 (93.4%) and 65 of 91 (71.4%) patients with GO (P < 0.001). Blocking TBAb activity was observed in only one patient who expressed dual stimulating and blocking TSH-R-Ab activity. The sensitivity rates for differentiating between clinically active versus inactive and mild versus moderate-to-severe GO were 100% and 100% for TSAb, respectively. In contrast, these were 82% and 87% only for TBII. Seven of eight (87.5%) and one of eight (12.5%) euthyroid patients with GO were TSAb and TBII positive, respectively (P < 0.031). TSAb serum levels significantly predicted GO activity compared to TBII (odds ratio, OR, 95%CI: 3.908, 95%CI 1.615-9.457, P = 0.003; versus 2.133, 0.904-5.032, P = 0.084, univariate analysis; and OR 4.341, 95%CI 1.609-11.707, P = 0.004; versus 2.337, 0.889-6.145, P = 0.085 multivariate analysis).

CONCLUSION

Stimulating TSAb are highly prevalent in patients with GO and show superior clinical characteristics and predictive potential compared to the traditionally used TBII.

Efficacy and Safety of Teprotumumab in Thyroid Eye Disease

Thyroid eye disease (TED; also known as thyroid-associated ophthalmopathy) is an autoimmune condition with disabling and disfiguring consequences. Teprotumumab is the first and only medication approved by the United States Food and Drug Administration for the treatment of TED. We review the efficacy and safety of teprotumumab in TED, highlighting results from the 2 randomized, double-masked, placebo-controlled trials. Post-approval case reports of teprotumumab use in patients with compressive optic neuropathy (CON) and inactive TED were similarly favorable to those from the trials. The preliminarily results of teprotumumab for CON and inactive TED should be investigated in formal clinical trials. Teprotumumab should be avoided in pregnancy. Evidence also suggests that teprotumumab may exacerbate pre-existing inflammatory bowel disease, worsen hyperglycemia, and be associated with hearing impairment. Patients at risk for these adverse events need to be closely monitored with baseline and periodic assessments.

Relationship between Serum Thyroid-stimulating Hormone Receptor Autoantibodies and Activity and Severity of Thyroid Eye Disease

Purpose: To study the relationship between the levels of serum thyroid-stimulating hormone (TSH)-receptor autoantibodies (TRAbs) and thyroid eye disease (TED) activity and severity scores.Methods: A cross-sectional study was performed. The medical records of 315 patients diagnosed with TED between March 2014 and December 2019 were reviewed. The clinical activity score (CAS) was used to assess TED activity and a modified NOSPECS score was used for severity grading. The serum TRAb level was measured using two assays: a TSHR binding inhibitory immunoglobulin (TBII) assay and thyroid stimulating immunoglobulin (TSI) bioassay.Results: The TBII and TSI assay results were significantly positively correlated with the CAS (R = 0.113 and 0.211, respectively; p < 0.05), modified NOSPECS score (R = 0.173 and 0.316, respectively; p < 0.05), and proptosis (R = 0.136 and 0.167, respectively; p < 0.05). Both assays demonstrated significant differences in the level of TRAb between patients with and without compressive optic neuropathy or corneal epithelial defects.Conclusions: The levels of TRAbs according to both TBII and TSI assays showed significant correlations with clinical signs of corneal involvement, optic neuropathy, and TED activity and severity.

Characteristics of Diabetic and Nondiabetic Patients With Thyroid Eye Disease in the United States: A Claims-Based Analysis

OBJECTIVE

Thyroid eye disease (TED) is a debilitating autoimmune disease characterized by ocular and periorbital tissue inflammation, proptosis, and visual impairment. The known risk factors for TED include radioactive iodine therapy, female sex, and smoking. The risk factors for severe TED include hyperthyroidism, male sex, smoking, and diabetes; however, little is known about how diabetes mellitus (DM) influences TED. This claims-based analysis examined TED characteristics in patients with and without diabetes.

METHODS

Symphony database (2010-2015 U.S. claims) was mined for patients with ≥1 Graves' disease diagnosis code and ≥1 TED-associated eye code, including proptosis, strabismus, diplopia, lid retraction, exposure keratoconjunctivitis, and optic neuropathy (ON). DM status was determined based on type 1 or type 2 diabetes coding. Sight-threatening TED was defined as ≥1 ON or exposure keratoconjunctivitis code.

RESULTS

A total of 51 220 patients were identified. Of them, 2618 (5.1%) and 12 846 (25.1%) had type 1 and type 2 DM, respectively. Patients with and without DM had similar characteristics, but patients with DM were more often men (type 1: 30.3%, type 2: 28.7% vs no DM: 20.5%; both P < .001) and older at the first TED code. In patients with DM, strabismus (25.4%, 22.6% vs 19.9%) and diplopia (38.6%, 37.9% vs 29.9%) occurred more often but proptosis occurred less often (42.3%, 46.3% vs 58.5%; all P < .001). Sight-threatening TED occurred more often in patients with DM because of higher ON rates.

CONCLUSION

Patients with TED and DM may have more extraocular muscle involvement. Furthermore, the higher prevalence of severe TED stemmed from higher ON rates, possibly associated with diabetes-related vasculopathies. These hypothesis-generating data warrant further exploration.

Correlation between Thyroid-stimulating Antibody Level Change and Extraocular Muscle Thickness Change in Thyroid Eye Disease

Purpose: To investigate the changes in extraocular muscle thicknesses by variations in the thyroid stimulating antibody (TSAb) level in patients with thyroid eye disease (TED).Methods: A total of 67 TED patients were enrolled. They were divided into two groups: an experimental group with clinically significant elevated TSAb levels (≥140 IU/L) and a control group (TSAb <140 IU/L). All of the lateral, medial, superior, and inferior rectus muscle thicknesses were measured with the aid of anterior segment optical coherence tomography (OCT). The average thicknesses for both eyes were recorded for each patient based on the values measured at the ends of the muscles (which become vertically thinner from the points of tendon attachment). We measured changes in TSAb levels and extraocular muscle thicknesses after two follow-up periods and sought correlations among these parameters.Results: At the initial visits, the inferior rectus muscle thickness was positively correlated with the TSAb level in the experimental group (p = 0.045, r = 0.478). None of the medial, superior, or lateral rectus muscle thicknesses were so correlated. On follow-up, the variation in TSAb level correlated negatively with changes in lateral rectus muscle thickness (p = 0.038, r = -0.357). The superior rectus muscle thickness tended to be negatively correlated with the TSAb level, but statistical significance was not attained (p = 0.146, r = -0.669). The thicknesses of the inferior and superior rectus muscles did not change over time.Conclusions: In TED patients, TSAb variations seem to reflect the extent of periorbital tissue edema, thus correlating negatively with especially lateral rectus muscle thickness changes.

Diagnostic accuracy of Immulite® TSI immunoassay for thyroid-associated orbitopathy in patients with recently diagnosed Graves' hyperthyroidism

PURPOSE

The Immulite® thyroid stimulating immunoglobulin (TSI) immunoassay is a relatively new commercial assay that has shown good diagnostic accuracy in Graves' hyperthyroidism (GH). However, its clinical utility in thyroid-associated orbitopathy (TAO) is less clear. The purpose of this study was to assess the diagnostic accuracy of the Immulite® TSI immunoassay for TAO and investigate the associations between TSI and other clinical measures.

METHODS

One hundred and forty patients that had been diagnosed with GH within the previous 12 months were recruited. Identification and grading of TAO were performed at enrolment and serum samples were analysed using the Immulite® TSI immunoassay.

RESULTS

Of the 140 participants recruited, 75 (53.6%) had TAO. Age, sex and time since GH diagnosis were similar between those with and without TAO (p ≥ 0.300). TSI level tended to decrease with increasing time from GH diagnosis (Spearman's ρ - 0.28, 95% CI - 0.43, - 0.12). TSI levels were higher among those with than those without TAO (median 4.0 vs. 2.7 IU/L, respectively, p = 0.037). There was no correlation between TSI level and inflammatory index score (ρ = 0.14, 95% CI - 0.03, 0.30) or clinical severity (p = 0.527) among those with TAO. TSI level showed poor diagnostic accuracy for TAO (area under the receiver operating characteristic curve 0.60, 95% CI 0.51, 0.70).

CONCLUSIONS

Although Immulite® TSI level was higher in the presence of TAO, it showed poor diagnostic accuracy and no correlation with clinical markers of TAO severity or activity.

Thyroid-related ophthalmopathy development in concurrence with growth hormone administration

BACKGROUND

Thyroid stimulating hormone (TSH) receptor and local infiltrate lymphocytes have been considered as major pathological factors for developing thyroid-related ophthalmopathy. Overexpression of insulin-like growth factor-I (IGF-I) receptor has emerged as a promising therapeutic target for refractory patients. However, the relationship between activation of growth hormone (GH)/IGF-I receptor signaling and development or exacerbation of thyroid ophthalmopathy has not been elucidated. Herein we describe a case that provides further clarification into the association between thyroid-related ophthalmopathy and GH/IGF-I receptor signaling.

CASE PRESENTATION

A 62-year-old Japanese female diagnosed with thyroid-related ophthalmopathy was admitted to Kurume University Hospital. She had received daily administration of GH subcutaneously for severe GH deficiency; however, serum IGF-I levels were greater than + 2 standard deviation based on her age and sex. She exhibited mild thyrotoxicosis and elevation in levels of TSH-stimulating antibody. Discontinuation of GH administration attenuated the clinical activity scores of her thyroid-related ophthalmopathy. Additionally, concomitant use of glucocorticoid and radiation therapies resulted in further improvement of thyroid-related ophthalmopathy. The glucocorticoid administration was reduced sequentially, followed by successful termination. Thereafter, the patient did not undergo recurrence of thyroid-related ophthalmopathy and maintained serum IGF-I levels within normal physiological levels.

CONCLUSIONS

We describe here a case in which development of thyroid-related ophthalmopathy occurred upon initiation of GH administration. GH/IGF-I signaling was highlighted as a risk factor of developing thyroid-related ophthalmopathy. Additionally, aberrant TSH receptor expression was suggested to be a primary pathophysiological mechanism within the development of thyroid-related ophthalmopathy. Physicians should be aware of the risks incurred via GH administration, especially for patients of advanced age, for induction of thyroid-related ophthalmopathy.

Prognostic factors of restrictive myopathy in thyroid eye disease

To investigate the prognostic factors of extraocular muscle restriction in patients with thyroid eye disease (TED), 65 patients with TED and restrictive myopathy were evaluated. Demographics, clinical activity score (CAS), smoking status, thyroid disease status, thyroid hormone status, thyroid autoantibody status, orbital computed tomography (CT) scan at initial presentation, and treatment regimens were assessed. The movements of the most severely affected extraocular muscles were categorized into five grades. The patients were divided into the improved and the not-improved group based on the improvement in the limitation of the extraocular muscle excursion (LOM) throughout the follow-up, and the groups were compared using clinical factors. The mean LOM significantly improved from 2.3 ± 1.1 to 1.7 ± 1.2 after 1 year of follow-up. The excursion of the most restricted muscle improved in 32 patients but not in 33 patients during the follow-up. The initial concentration of the thyroid-stimulating antibody (TSAb) was significantly lower in the improved (229.3 ± 114.1) than in the not-improved group (345.0 ± 178.6) (P = 0.02) Age, sex, smoking status, CAS, thyroid status, and muscle thickness on the CT scan did not significantly differ in the groups. This study showed that the initial concentration of TSAb is a factor affecting the recovery of restrictive myopathy.

Predicting the Course of Graves' Orbitopathy Using Serially Measured TSH-Receptor Autoantibodies by Automated Binding Immunoassays and the Functional Bioassay

The aim of the study was to investigate the use of serial measurements of TSH-receptor autoantibodies (TRAb) with the newest available assay technology to predict the course of Graves' Orbitopathy (GO) during the first 24 months from disease onset. Serial serum samples from patients with GO (103 mild/135 severe) were collected between 2007 and 2017 and retrospectively analyzed. The course of GO were classified into mild/severe 12 months after manifestation (severe: NOSPECS≥5; mild<5). TRAb were measured with automated binding immunoassays (IU/l): TRAb Elecsys (Cobas, Roche), TRAb bridge assay (IMMULITE, Siemens), and a cell-based bioassay (percent of specimen to reference ratio - SRR%) (Thyretain, Quidel). Variable cut off levels of measured TRAb were calculated at specificity of 90% from receiver operator curve (ROC) analysis for several timepoints during the course of GO. To select one: 5-8 months after first GO symptoms, which is the timepoint for usual referals for treatment mild course could be predicted at cut offs of 1.5 IU/l (Elecsys), 0.8 IU/l (Immulite) and 402% SRR (Thyretain) and the risc of severe course has to be anticipated if TRAb are above 11.6 IU/l (Elecsys), 6.5 IU/l (Thyretain), and 714% SRR (Thyretain). The Thyretain bioassay showed the highest diagnostic sensitivity (using the commercial cut off's) over the entire follow up period. TRAb measurements during the 24-month follow up of GO provide added value to the GO clinical activity and severity scores and should be used especially in the event of an unclear decision-taking situation with regard to therapy.

A cyclic peptide significantly improves thyroid function, thyrotropin-receptor antibodies and orbital mucine /collagen content in a long-term Graves' disease mouse model

BACKGROUND

BALB/c mice which received long-term immunizations of adenovirus (Ad) expressing thyrotropin receptor A-subunits (TSHR) developed stable Graves' disease (GD). TSHR-derived cyclic peptide 19 (P19) was identified as effective therapy in this model.

METHODS

In Ad-TSHR mice, we investigated shorter disease intervals up to 4 months for histological alterations of the orbits, fine tuning of anti-TSHR antibodies (Ab) and free thyroxine (fT4) hormone levels by using novel detection methods in an independent laboratory. Therapy (0.3 mg/kg P19 or vehicle) was given intravenously after the fourth Ad-TSHR immunization (week 11) and continued until week 19.

RESULTS

Thyrotropin binding inhibitory immunoglobulins (TBII, bridge immunoassay), blocking (TBAb) and stimulating (TSAb) TSHR-Ab (both cell-based bioassays) and serum levels of fT4 were significantly elevated at week 11 in Ad-TSHR-immunized mice versus none in control mice. For the first time, TSAb, TBAb, and thyroperoxidase-Ab were detected in 17 of 19, 12/19 and 6/19 Ad-TSHR immunized mice, respectively at week 21. Also, for the first time, this study showed that P19 treatment markedly reduced serum TBII (p < 0.0001), serum fT4 (p = 0.02), and acidic mucins and collagen content in the orbital tissue of Ad-TSHR-immunized mice.

CONCLUSION

P19 significantly improved thyroid function, confirming previous results in an independent second laboratory. A relevant shift of anti-TSHR antibody subpopulations in response to P19 therapy may help explain its immunological effects. Moreover, P19 exerted a beneficial effect on mucine and collagen content of orbital tissue. Hence, P19 offers a potential novel therapeutic approach for GD and associated orbitopathy.

IgG4 as a Biomarker in Graves' Orbitopathy

Immunoglobulin G4-related disease (IgG4-RD) is a chronic inflammatory disorder associated with fibrosis and abundant tissue lymphoplasmacytic infiltrations. It typically affects the pancreas, the salivary glands, and the retroperitoneal space. However, it might also involve multiple other organs, including the orbit and the thyroid. Recent studies have suggested that IgG4 plays a role in the pathophysiology of autoimmune thyroid diseases. This ultimately led to the establishment of new clinical entities called IgG4-related thyroid disease and thyroid disease with an elevation of IgG4. The aim of this paper is to describe the pathophysiological, histopathological, and clinical features of Graves' Disease (GD) and Graves' Orbitopathy (GO) with elevated IgG4 levels. Multiple studies have demonstrated higher IgG4 serum concentrations in GD patients than in healthy euthyroid controls. Depending on the studied population, elevated serum IgG4 levels occur in 6.4-23% (average: 10.3%) of all patients with GD, 8.3-37.5% (average: 17.6%) of patients with GO, and 0-9.8% (average: 5.4%) of patients with GD without GO, while GO patients comprise 37.5-100% (average: 65.8%) of all GD patients with elevated IgG4 levels. Characteristic features of GD with elevated IgG4 levels include lower echogenicity of the thyroid gland on ultrasound examination, peripheral blood eosinophilia, higher prevalence of orbitopathy, and better response to antithyroid drugs with a tendency to develop hypothyroidism when compared to patients with GD and normal levels of IgG4. Typical signs of GO accompanied by increased concentration of IgG4 include younger age at diagnosis, and more severe course of the disease with a higher Clinical Activity Score (CAS).. We strongly recommend considering the diagnosis of GO with elevated IgG4 in patients with an established diagnosis of GD, elevated serum IgG4 levels, and clinical features of ophthalmic disease overlapping with those of IgG4-related orbital disease.

Thyrotropin receptor antibodies and Graves' orbitopathy

CONTEXT AND PURPOSE

The thyrotropin receptor (TSHR) is the key autoantigen in Graves' disease (GD) and associated orbitopathy (GO). Antibodies targeting the TSHR (TSHR-Ab) impact the pathogenesis and the course of GO. This review discusses the role and clinical relevance of TSHR-Ab in GO.

METHODS

Review of the current and pertinent literature.

RESULTS

GO is the most common extrathyroidal manifestation of GD and is caused by persistent, unregulated stimulation of TSHR-expressing orbital target cells (e.g. fibroblasts and pre-adipocytes). Serum TSHR-Ab and more specifically, the stimulatory Ab (TSAb) are observed in the vast majority of patients with GD and GO. TSHR-Ab are a sensitive serological parameter for the differential diagnosis of GO. TSHR-Ab can be detected either with conventional binding immunoassays that measure binding of Ab to the TSHR or with cell-based bioassays that provide information on their functional activity and potency. Knowledge of the biological activity and not simply the presence or absence of TSHR-Ab has relevant clinical implications e.g. predicting de-novo development or exacerbation of pre-existing GO. TSAb are specific biomarkers of GD/GO and responsible for many of its clinical manifestations. TSAb strongly correlate with the clinical activity and clinical severity of GO. Further, the magnitude of TSAb indicates the onset and acuity of sight-threatening GO (optic neuropathy). Baseline serum values of TSAb and especially dilution analysis of TSAb significantly differentiate between thyroidal GD only versus GD + GO.

CONCLUSION

Measurement of functional TSHR-Ab, especially TSAb, is clinically relevant for the differential diagnosis and management of GO.

Correlation between serum anti-TSH receptor autoantibodies (TRAbs) and the clinical feature of Graves' orbitopathy

BACKGROUND

Graves' orbitopathy (GO) is the most common extrathyroidal manifestation of Graves' disease (GD). Several studies support the involvement of TSH receptor autoantibodies (TRAbs) in the pathogenesis of GO, and a correlation between GO features and TRAbs has been reported, but not confirmed by all studies. Thus, we conducted a cross-sectional investigation to determine whether there is a correlation between TRAbs and the clinical features of GO in an initial phase of the eye disease.

METHODS

Ninety consecutive patients with untreated GO (67 women and 23 men, age 48.9 ± 12.6 years) were included. Patients who had received treatments other than anti-thyroid drugs for hyperthyroidism or lubricants for GO were excluded. All patients underwent an endocrinological and ophthalmological evaluation, the latter including exophthalmometry, measurement of eyelid width, clinical activity score (CAS), visual acuity, assessment of diplopia, and NOSPECS score. TRAb levels were measured by a third-generation competitive immunoassay.

RESULTS

There was a statistically significant, direct correlation between serum TRAb levels and CAS by linear regression analysis (R = 0.278, P = 0.007). The correlation was confirmed by a multiple regression analysis (R = 0.285; P = 0.006) including age and FT3 levels, which also correlated with CAS. There were no relationships between TRAbs and exophthalmometry, eyelid aperture, degree of diplopia, visual acuity, and NOSPECS score.

CONCLUSIONS

The levels of TRAb in subjects with a recent-onset, untreated GO are directly correlated with the clinical activity of the disease, confirming a possible role of these antibodies in the pathogenesis of GO.

Antithyroid drugs in Graves' hyperthyroidism: differences between "block and replace" and "titration" regimes in frequency of euthyroidism and Graves' orbitopathy during treatment

PURPOSE

Whereas antithyroid drugs (ATD) are the preferred treatment modality for Graves' hyperthyroidism (GH), there is still controversy about the optimal regimen for delivering ATD. To evaluate whether 'Block and Replace' (B + R) and 'Titration' (T) regimes are equivalent in terms of frequency of euthyroidism and Graves' Orbitopathy (GO) during ATD therapy.

METHODS

A prospective multicentre observational cohort study of 344 patients with GH but no GO at baseline. Patients were treated with ATD for 18 months according to B + R or T regimen in line with their institution's policy.

RESULTS

Baseline characteristics were similar in both groups. In the treatment period between 6 and 18 months thyrotropin (TSH) slightly increased in both groups, but TSH was on average 0.59 mU/L (95% CI 0.27-0.85) lower in the B + R group at all time points (p = 0.026). Serum free thyroxine (FT4) remained stable during the same interval, with a tendency to higher values in the B + R group. The point-prevalence of euthyroidism (TSH and FT4 within their reference ranges) increased with longer duration of ATD in both groups; it was always higher in the T group than in the B + R group: 48 and 24%, respectively, at 6 months, 81 and 58% at 12 months, and 87 and 63% at 18 months (p < 0.002). There were no significant differences between the B + R and T regimens with respect to the fall in thyrotropin binding inhibiting immunoglobulins (TBII) or thyroid peroxidase antibodies (TPO-Ab). GO developed in 15.9% of all patients: 9.1 and 17.8% in B + R group and T group, respectively, (p = 0.096). GO was mild in 13% and moderate-to-severe in 2%.

CONCLUSION

The prevalence of biochemical euthyroidism during treatment with antithyroid drugs is higher during T compared to B + R regimen. De novo development of GO did not differ significantly between the two regimens, although it tended to be higher in the T group. Whether one regimen is clinically more advantageous than the other remains unclear.

Tear-Derived Exosome Proteins Are Increased in Patients with Thyroid Eye Disease

Exosomes contain proteins, lipids, RNA, and DNA that mediate intercellular signaling. Exosomes can contribute to the pathological processes of various diseases, although their roles in ocular diseases are unclear. We aimed to isolate exosomes from tear fluids (TF) of patients with Thyroid eye disease (TED) and analyze the exosomal proteins. TFs were collected from eight patients with TED and eight control subjects. The number of TF exosomes were measured using nanoparticle-tracking analysis. The expression of specific proteins in the purified exosome pellets were analyzed using a Proteome Profiler Array Kit. Cultured normal orbital fibroblasts were incubated with TF exosomes from patients with TED and control subjects, and changes in inflammatory cytokine levels were compared. TF exosomes from TED patients showed more exosomes than the control subjects. The expression levels of exosomal proteins vitamin D-binding (VDB) protein, C-reactive protein (CRP), chitinase 3-like 1 (CHI3L1), matrix metalloproteinase-9 (MMP-9), and vascular adhesion molecule-1 (VCAM-1) were significantly increased in patients with TED, compared to those of controls. Orbital fibroblasts exposed to TF exosomes from patients with TED showed significantly higher levels of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1) production than those treated with control TF exosomes. Specific proteins showed higher expression in exosomes from TED patients, implying that they may play keys roles in TED pathogenesis.

The prognostic value of thyroid-stimulating immunoglobulin in the management of Graves' disease

BACKGROUND

The bioassay of thyroid-stimulating immunoglobulin was reported to have a similar performance to the commonly used thyroid-stimulating hormone binding inhibition assay, also known as thyroid receptor antibody assay. The normal reference range of thyroid receptor antibody levels indicates the withdrawal of anti-thyroid drugs in the recent clinical guidelines.

METHODS

A prospective, longitudinal observational study was conducted to evaluate the prognostic value of thyroid-stimulating immunoglobulin in patients with Graves' disease.

RESULTS

A total of 77 patients with Graves' disease treated with anti-thyroid drugs were in a continuous follow-up until 1 year after anti-thyroid drugs discontinuation. Commercial kits of thyroid-stimulating immunoglobulin and M22-thyroid-stimulating hormone binding inhibition assay were used and compared. Thyroid-stimulating immunoglobulin was all negative in healthy controls, Hashimoto thyroiditis, and subacute thyroiditis. Thyroid-stimulating immunoglobulin value was highest in untreated patients with Graves' disease (p < 0.001). Under anti-thyroid drugs treatment, thyroid-stimulating immunoglobulin value decreased gradually. A total of 21 patients had positive thyroid-stimulating immunoglobulin at the end of treatment. According to clinical fate of patients with Graves' disease after withdrawal of anti-thyroid drugs, thyroid-stimulating immunoglobulin value and positivity in patients with relapse were significantly higher than that reported in patients with remission (p = 0.001, p < 0.001). After adjustment for age, gender, initial thyroid receptor antibody, initial thyroid-stimulating immunoglobulin, and thyroid receptor antibody at the end of treatment, the odds ratio of positive thyroid-stimulating immunoglobulin for the risk of relapse was 33.271 (95% confidence interval: 4.741-233.458, p < 0.001) and odds ratio of quantitative thyroid-stimulating immunoglobulin was 1.009 (95% confidence interval: 1.002-1.015, p < 0.001).

CONCLUSION

Thyroid-stimulating immunoglobulin is a good predictor of relapse in patients with Graves' disease treated with anti-thyroid drugs. It might be safer to discontinue anti-thyroid drugs when thyroid-stimulating immunoglobulin and thyroid receptor antibody were both negative.

Current Knowledge on Graves' Orbitopathy

(1) Background: Graves' orbitopathy (GO) is an autoimmune inflammation of the orbital tissues and the most common extra-thyroid symptom of Graves' disease (GD). Mild cases of GO are often misdiagnosed, which prolongs the diagnostic and therapeutic process, leading to exacerbation of the disease. A severe course of GO may cause permanent vision loss. (2) Methods: The article presents an analysis of GO-its etiopathogenesis, diagnostics, current treatment and potential future therapeutic options based on a review of the currently available literature of the subject. (3) Results: Current treatment of the active GO consists predominantly in intravenous glucocorticoids (GCs) administration in combination with orbital radiotherapy. The growing knowledge on the pathogenesis of the disease has contributed to multiple trials of the use of immunosuppressive drugs and monoclonal antibodies which may be potentially effective in the treatment of GO. Immunosuppressive treatment is not effective in patients in whom a chronic inflammatory process has caused fibrous changes in the orbits. In such cases surgical treatment is performed-including orbital decompression, adipose tissue removal, oculomotor muscle surgery, eyelid alignment and blepharoplasty. (4) Conclusions: Management of GO is difficult and requires interdisciplinary cooperation in endocrinology; ophthalmology, radiation oncology and surgery. The possibilities of undertaking a reliable assessment and comparison of the efficacy and safety of the therapeutic strategies are limited due to the heterogeneity of the available studies conducted mostly on small group of patients, with no comparison with classic systemic steroid therapy. The registration by FDA of Teprotumumab, an IGF1-R antagonist, in January 2020 may be a milestone in future management of active GO. However, many clinical questions require to be investigated first.

A Novel Long-Term Graves' Disease Animal Model Confirmed by Functional Thyrotropin Receptor Antibodies

INTRODUCTION

A novel long-term murine model for Graves' disease (GD) using repeated, long-term immunizations with recombinant adenovirus expressing the extracellular A-subunit of the human thyrotropin receptor (Ad-TSHR) was applied to evaluate the functional anti-TSHR-antibody (TSHR-Ab) profile.

METHODS

BALB/c mice received 7 immunizations with either 10¹⁰ plaque-forming units of Ad-TSHR or control Ad-GFP. Naïve (nonimmuized native) mice were also studied. Three 3-weekly immunizations were followed by 4-weekly boosts until the 7th immunization. Blocking (TBAb) and stimulating (TSAb) TSHR-Ab were measured with bioassays. Assay cut-offs for TBAb/TSAb were at 34% inhibition and a specimen-to-reference ratio (SRR) of 140%.

RESULTS

Nineteen (8 Ad-TSHR-, 4 Ad-GFP-immunized, and 7 native) mice were investigated. All native mice were negative for TSHR-binding inhibitory immunoglobulins (TBII) prior to immunization. Native and Ad-GFP mice were negative in weeks 17 and 27 for TBII and TBAb/TSAb. In native mice, the free thyroxine (fT4) levels (median [25th percentile; 75th percentile]) were in the upper normal range (1.2 ng/mL [1.1; 1.6]) prior to immunization, at weeks 17 (2.2 ng/mL [2.1; 2.4]) and 27 (1.4 ng/mL [1.1; 1.7]), respectively. In contrast, in Ad-TSHR-immunized mice, fT4 values were markedly increased at weeks 17 (4.4 ng/mL [3.9; 6]) and 27 (4.5 ng/mL [4.2; 6]) compared to those in Ad-GFP mice (2 ng/mL [1.8; 2.1] and 1.4 ng/mL [1.1; 1.6]), respectively (p = 0.0008, p = 0.001). In contrast, at week 17, in Ad-TSHR mice, the mean TBII, TBAb, and TSAb levels were 40 IU/L (40; 40); 62% inhibition (38; 69), and 116% SRR (97; 185), respectively; at week 27, they were 40 IU/L (39; 40); 65% inhibition (34; 80) and 95% SRR (63; 187), respectively. Three serum samples from Ad-TSHR mice (38%) demonstrated dual TBAb/TSAb positivity.

CONCLUSIONS

TBAb/TSAb were highly prevalent in Ad-TSHR-immunized mice, thus confirming the successful establishment of a novel, long-term murine model for GD. All TBAb- and TSAb-positive Ad-TSHR-immunized mice were TBII-positive. Thus, the binding immunoassay did not differentiate between TSHR-Ab functionality.

Management of Graves Thyroidal and Extrathyroidal Disease: An Update

CONTEXT

Invited update on the management of systemic autoimmune Graves disease (GD) and associated Graves orbitopathy (GO).

EVIDENCE ACQUISITION

Guidelines, pertinent original articles, systemic reviews, and meta-analyses.

EVIDENCE SYNTHESIS

Thyrotropin receptor antibodies (TSH-R-Abs), foremost the stimulatory TSH-R-Abs, are a specific biomarker for GD. Their measurement assists in the differential diagnosis of hyperthyroidism and offers accurate and rapid diagnosis of GD. Thyroid ultrasound is a sensitive imaging tool for GD. Worldwide, thionamides are the favored treatment (12-18 months) of newly diagnosed GD, with methimazole (MMI) as the preferred drug. Patients with persistently high TSH-R-Abs and/or persistent hyperthyroidism at 18 months, or with a relapse after completing a course of MMI, can opt for a definitive therapy with radioactive iodine (RAI) or total thyroidectomy (TX). Continued long-term, low-dose MMI administration is a valuable and safe alternative. Patient choice, both at initial presentation of GD and at recurrence, should be emphasized. Propylthiouracil is preferred to MMI during the first trimester of pregnancy. TX is best performed by a high-volume thyroid surgeon. RAI should be avoided in GD patients with active GO, especially in smokers. Recently, a promising therapy with an anti-insulin-like growth factor-1 monoclonal antibody for patients with active/severe GO was approved by the Food and Drug Administration. COVID-19 infection is a risk factor for poorly controlled hyperthyroidism, which contributes to the infection-related mortality risk. If GO is not severe, systemic steroid treatment should be postponed during COVID-19 while local treatment and preventive measures are offered.

CONCLUSIONS

A clear trend towards serological diagnosis and medical treatment of GD has emerged.