Practical applications of studies on the TSH receptor and TSH receptor autoantibodies

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.

Characterizing the Interplay of Lymphocytes in Graves' Disease

Graves' disease (GD) is a thyroid-specific autoimmune disease with a high prevalence worldwide. The disease is primarily mediated by B cells, which produce autoantibodies against the thyroid-stimulating hormone receptor (TSHR), chronically stimulating it and leading to high levels of thyroid hormones in the body. Interest in characterizing the immune response in GD has motivated many phenotyping studies. The immunophenotype of the cells involved and the interplay between them and their secreted factors are crucial to understanding disease progression and future treatment options. T cell populations are markedly distinct, including increased levels of Th17 and follicular helper T cells (Tfh), while Treg cells appear to be impaired. Some B cells subsets are autoreactive, and anti-TSHR antibodies are the key disease-causing outcome of this interplay. Though some consensus across phenotyping studies will be discussed here, there are also complexities that are yet to be resolved. A better understanding of the immunophenotype of Graves' disease can lead to improved treatment strategies and novel drug targets.

Establishment and analytical performance of light-initiated chemiluminescence assay method for detecting thyrotropin receptor antibody

Aim: To evaluate double-antibody competitive light-initiated chemiluminescence assay method for detecting the thyrotropin receptor antibody. Materials & methods: The optimal working concentrations of competitive antibody and rTSHR were confirmed by checkerboard titration. Assay performance was assessed by precision, linearity, accuracy, limit of blank and clinical evaluation. Results: The coefficient of variation for repeatability and intermediate precision was 3.9-5.9 and 0.9-1.3%, respectively. The correlation coefficient was 0.999 by least squares linear fitting in linearity evaluation. The relative deviation ranged from -5.9 to 4.1%, and the limit of blank of the method was 0.13 IU/l. Compared with the Roche cobas system (Roche Diagnostics, Mannheim, Germany), the relationship between the two assays was shown to be significantly correlative. Conclusion: The light-initiated chemiluminescence assay method for detecting thyrotropin receptor antibody is a rapid, novel and accurate method for thyrotropin receptor antibody measurement.

Changes in Th9 and Th17 lymphocytes and functional cytokines and their relationship with thyroid-stimulating hormone receptor antibodies at different stages of graves’ disease

Objective

Graves’ disease (GD) is an organ-specific autoimmune disease characterized by the production of thyroid-stimulating antibodies (TSAb). The newly discovered CD4⁺ T helper cells, Th9 and Th17 lymphocytes, have been confirmed to be closely associated with a variety of immune diseases. However, relationships with the onset and development of GD remain unclear. The purpose of this study was to investigate the roles of Th9 and Th17 in the pathogenesis and prognosis of GD.

Patients

We recruited 26 patients with newly diagnosed GD, 45 patients with GD in remission, and 20 healthy individuals.

Measurements

Thyroid function and autoantibodies were evaluated using chemiluminescence immunoassays. Th9 and Th17 cells were analyzed using flow cytometry. The expression of Foxo1, IRF-4, RORc, IL-9, and IL-17 mRNA was examined using real-time PCR, and IL-9 and IL-17 protein levels were measured using enzyme-linked immunosorbent assay.

Results

Th9, Th17, and characteristic cytokines IL-9 and IL-17 in the GD-untreated group were significantly higher than those in the control and remission groups. The above indexes significantly decreased in the remission group, with the levels in the TRAb⁻ remission group being similar to those in the normal group, while in the TRAb⁺ remission group, levels were differentially increased. TRAb titer was positively correlated with the levels of Th9, Th17, and their functional cytokines.

Conclusions

Th9 and Th17 cells may be involved in the pathogenesis and disease outcome of GD, which could provide a new direction for developing immunotherapy for patients with GD.

A Diagnostic Model With IgM Autoantibodies and Carcinoembryonic Antigen for Early Detection of Lung Adenocarcinoma

Immunoglobulin M (IgM) autoantibodies, as the early appearing antibodies in humoral immunity when stimulated by antigens, might be excellent biomarkers for the early detection of lung cancer (LC). We aimed to develop a multi-analyte integrative model combining IgM autoantibodies and a traditional tumor biomarker that could be a valuable and powerful auxiliary diagnostic tool and might improve the accuracy of early detection of lung adenocarcinoma (LUAD). A customized protein array based on cancer driver genes was constructed and applied in the discovery cohort consisting of 68 LUAD patients and 68 normal controls (NCs); 31 differentially expressed IgM autoantibodies were identified. The top 5 candidate IgM autoantibodies [based on the area under the receiver operating characteristic curve (AUC) ranking], namely, TSHR, ERBB2, survivin, PIK3CA, and JAK2, were validated in the validation cohort using enzyme-linked immunosorbent assay (ELISA), which included 147 LUAD samples, 72 lung squamous cell carcinoma (LUSC) samples, 44 small cell lung carcinoma (SCLC) samples, and 147 NCs. These indicators presented diagnostic capacity for LUAD, with AUCs of 0.599, 0.613, 0.579, 0.601, and 0.633, respectively (p < 0.05). However, none of them showed a significant difference between the SCLC and NC groups, and only the IgM autoantibody against JAK2 showed a higher expression in LUSC than in NC (p = 0.046). Through logistic regression analysis, with the five IgM autoantibodies and carcinoembryonic antigen (CEA), one diagnostic model was constructed for LUAD. The model yielded an AUC of 0.827 (sensitivity = 56.63%, specificity = 93.98%). The diagnostic efficiency was superior to that of either CEA (AUC = 0.692) or IgM autoantibodies alone (AUC = 0.698). Notably, the accuracy of this model in early-stage LUAD reached 83.02%. In conclusion, we discovered and identified five novel IgM indicators and developed a multi-analyte model combining IgM autoantibodies and CEA, which could be a valuable and powerful auxiliary diagnostic tool and might improve the accuracy of early detection of LUAD.

2022 European Thyroid Association Guideline for the management of pediatric Graves' disease

Hyperthyroidism caused by Graves' disease (GD) is a relatively rare disease in children. Treatment options are the same as in adults - antithyroid drugs (ATD), radioactive iodine (RAI) or thyroid surgery, but the risks and benefits of each modality are different. The European Thyroid Association guideline provides new recommendations for the management of pediatric GD with and without orbitopathy. Clinicians should be alert that GD may present with behavioral changes or declining academic performance in children. Measurement of serum TSH receptor antibodies is recommended for all pediatric patients with hyperthyroidism. Management recommendations include the first-line use of a prolonged course of methimazole/carbimazole ATD treatment (3 years or more), a preference for dose titration instead of block and replace ATD, and to avoid propylthiouracil use. Where definitive treatment is required either total thyroidectomy or RAI is recommended, aiming for complete thyroid ablation with a personalized RAI activity. We recommend avoiding RAI in children under 10 years of age but favor surgery in patients with large goiter. Pediatric endocrinologists should be involved in all cases.

Thyroid Eye Disease, Teprotumumab, and Hearing Loss: An Evolving Role for Otolaryngologists

Teprotumumab is a human monoclonal antibody and IGF-1R (insulin-like growth factor 1 receptor) inhibitor approved for treatment of thyroid eye disease in adults. Recent clinical trials have demonstrated side effects, notably hearing loss, in the treatment cohort as compared with the placebo cohort. These unexpected otologic side effects may be understood through a mechanistic understanding of IGF-1 (insulin-like growth factor 1). As otolaryngologists who historically play a significant role in the multidisciplinary treatment of thyroid disease and its associated complications, we should be aware of and monitor the otologic side effects of teprotumumab. Clinicians who prescribe teprotumumab should strongly consider monitoring patients' hearing with an audiologist and otolaryngologist.