Immunotherapies for thyroid eye disease

CD20 + T lymphocytes in isolated Hashimoto's thyroiditis and type 3 autoimmune polyendocrine syndrome: a pilot study

BACKGROUND

CD20+ T cells represent up to 5% of circulating T lymphocytes. These cells have been shown to produce higher levels of IL-17A and IFN-γ than those of CD20- T lymphocytes. Some reports described the role of CD20+ T cells in autoimmune disorders such as multiple sclerosis and rheumatoid arthritis possibly due to their ability to produce these inflammatory cytokines. This study is aimed at describing the behavior of CD20+ T lymphocytes in the most frequent autoimmune disorder, i.e., Hashimoto's thyroiditis (HT), presenting isolated or associated to further autoaggressive disorders in a frame of poly-autoimmunity.

METHODS

The study group encompasses 65 HT patients: 23 presenting in isolated form (IT) and 42 with an associated non-endocrine autoimmune disorder [16 with chronic atrophic gastritis (CAG), 15 with nonsegmental vitiligo (VIT), and 11 with celiac disease (CD)]. Twenty healthy donors act as control group (HD). Chronic use of interfering drugs, severe or chronic disorders, and pregnancy and lactation were used as exclusion criteria. Whole blood samples (100 µl) were stained with fluorescent-labeled antibodies (anti-CD45, anti-CD3, anti-CD19, anti-CD16, anti-CD56, anti-CD4, anti-CD8, anti-CD20). Red blood cells were then lysed by adding 1 ml of hypotonic buffer, and samples were acquired on a Flow Cytometer.

RESULTS

CD3+CD8+CD20+ T lymphocytes' percentages, were significantly higher in the whole group of autoimmune patients compared to healthy donors (p = 0.0145). Dividing HT patients based on the type of presentation of autoimmune thyroiditis, CAG group showed the highest percentage of these cells as compared to HD and CD (p = 0.0058). IT patients showed higher percentages of CD3+ CD8+CD20+ cells than those of HD patients although not reaching statistical significance. However, dividing IT group based on thyroid function, hypothyroid patients showed higher CD8+CD20+ cell percentages than those of HD and euthyroid patients (p = 0.0111). Moreover, in IT patients, these cells were negatively correlated with FT4 levels (p = 0.0171; r = -0.4921).

CONCLUSIONS

These preliminary findings indicate that CD8+CD20+ T cells are activated in patients with autoimmune thyroiditis and may behave differently according to the presence of poly-autoimmunity and hypothyroidism.

Efficacy of tocilizumab in patients with moderate-to-severe corticosteroid-resistant thyroid eye disease: a prospective study

PURPOSE

To evaluate the clinical outcomes of intravenous tocilizumab (TCZ) injection in patients with moderate-to-severe active thyroid eye disease (TED).

METHODS

Patients with active and moderate-to-severe TED who did not respond to conventional therapies were treated with TCZ from June 2019 to January 2021. The medical records of the patients were evaluated before the treatment. We analyzed patient demographics, including the duration of Graves' disease and TED, and assessed subjective symptoms, such as diplopia and ocular movement, clinical activity score (CAS), modified NOSPECS score, and exophthalmos before treatment and at 4, 8, 12, and 16 weeks after the first drug injection. Blood tests, including TSH Rc Ab and TS Ab, were performed before treatment and 24 weeks after the first injection. And orbital computed tomography (CT) was performed and Barrett's Index was calculated at baseline and after completion of all injections.

RESULTS

Nineteen completed the scheduled treatment. There were no significant side effects, other than herpes zoster in one case and headache and dermatitis in another. Clinical symptoms before and 16 weeks after the treatment showed mean CAS decreased by 2.4 points, mean modified NOSPECS score decreased by 3.7 points, and mean exophthalmos decreased by 0.4 mm. Diplopia and extraocular muscle limitation improved in ten and remained stationary in five of the 15 patients, who presented with extraocular motility abnormalities. Six of 11 patients who underwent orbit CT showed improvement in muscle size. The mean TSH Rc Ab decreased by 7.5 IU/L and TS-Ab decreased by 162.9%.

CONCLUSION

TCZ can treat active moderate-to-severe TED, showing high drug compliance and reasonable response to inflammation and extraocular motility abnormality.

Real-World Experience With Teprotumumab in Patients With Dysthyroid Optic Neuropathy

BACKGROUND

Teprotumumab, an insulin-like growth factor I receptor inhibitory antibody, improved proptosis, diplopia, inflammatory signs/symptoms, and quality of life in patients with active thyroid eye disease (TED) in clinical trials. The trials excluded patients with dysthyroid optic neuropathy (DON). Recently, many case reports and case series have reported the successful use of teprotumumab to treat DON. Here, we review the data from published cases and our clinical experience in treating patients having DON with teprotumumab.

METHODS

A literature search was conducted of patients with DON treated with teprotumumab from January 2020 through September 2022. Data from DON patients from the authors' (M.A.T. and C.A.B.) clinical practice were included. Primary outcome measure was mean (SD) improvements for visual acuity, color vision, and visual fields. Improvements in proptosis and clinical activity score (CAS) and diplopia were compared before and after teprotumumab administration.

RESULTS

Ten observational studies/case reports were identified along with 2 patients in our practice. In all, there were 24 active TED patients with DON (37 eyes) who were treated with teprotumumab. Mean (SD) age was 66.5 (13.6) years and 13 (54%) were females, disease duration ranged from 2 months to >15 years. 22/24 patients had none, minimal improvement or progression of visual loss with intravenous/oral corticosteroids, orbital decompression (n = 9), and orbital radiation (n = 2). There were 2 patients who received teprotumumab as the only therapy. Overall, 88% (21/24) reported improvement in visual acuity after teprotumumab and in 75% (18/24), improvement in vision was observed after just 2 infusions of teprotumumab. Three eyes had decompression surgery in close proximity to teprotumumab infusions and were excluded from analyses. Mean (SD) improvement in visual acuity was 3.73 lines (SD 3.74), range 2-15 lines in 33 eyes. The mean (SD) improvement in the mean deviation on visual field testing in 15 eyes was 5.6 db (3.0 db). Mean (SD) improvement in proptosis was 4.37 mm (SD: 2.11) (20 patients, 32 eyes); and clinical activity score: mean reduction of 5.1 (1.3) for 18 patients. Teprotumumab was well tolerated in all but one patient. Adverse events reported included fatigue, dysgeusia, hearing loss, nausea, hyperglycemia, and muscle spasms.

CONCLUSIONS

Teprotumumab is an effective treatment for DON in our experience and in published cases in whom treatment with steroids, surgery, or orbital radiation was unsuccessful.

Depression- and anxiety-associated disrupted brain structural networks revealed by probabilistic tractography in thyroid associated ophthalmopathy

BACKGROUND

Patients with thyroid-associated opthalmopathy (TAO) have widespread white matter (WM) abnormalities in the emotional and cognitive functional regions. However, the topological representation of these WM abnormalities and the network-level structural aberrations underlying TAO and concomitant affective disorders are still unclear.

METHODS

We used probabilistic diffusion tractography and graph theory to investigate brain network topology in 37 active, 35 inactive TAO patients and 23 healthy controls. Then, we evaluated the partial correlations between network topological metrics and clinical parameters.

RESULTS

For global topology, only active TAO patients exhibited significantly decreased global (Eglob) and local (Eloc) efficiency compared with controls, while no significant difference was observed between active and inactive TAO patients. For regional topology, we found a significantly decreased nodal efficiency in the left orbital superior frontal gyrus (ORBsup), medial orbital superior frontal gyrus (ORBsupmed), hippocampus and amygdala in active TAO patients compared with inactive ones. Intriguingly, Eglob, Eloc, and nodal efficiency of left ORBsup, ORBsupmed, olfactory cortex, gyrus rectus, hippocampus, right parahippocampal gyrus and amygdala had significantly positive correlations with anxiety/depression scores, bilateral exophthalmos and intraocular pressure in active TAO patients, while no significant correlation was observed in inactive TAO patients.

LIMITATIONS

No longitudinal follow-up.

CONCLUSIONS

WM networks of TAO are characterized by decreased local specialization and global integration in the active phase, and decreased nodal efficiency highly related to anxiety and depression in the emotional and cognitive regions. Our findings provide new insight regarding the neurobiological mechanisms of TAO and contribute to the treatment of concomitant affective disorders.

Factors Predicting Long-term Outcome and the Need for Surgery in Graves Orbitopathy: Extended Follow-up From the CIRTED Trial

Graves orbitopathy is both disabling and disfiguring. Medical therapies to reduce inflammation are widely used, but there is limited trial data beyond 18 months of follow-up.

METHODS

Three-year follow-up of a subset of the CIRTED trial (N = 68), which randomized patients to receive high-dose oral steroid with azathioprine/placebo and radiotherapy/sham radiotherapy.

RESULTS

Data were available at 3 years from 68 of 126 randomized subjects (54%). No additional benefit was seen at 3 years for patients randomized to azathioprine or radiotherapy with regard to a binary clinical composite outcome measure (BCCOM), modified European Group on Graves' Orbitopathy score, or Ophthalmopathy Index.Clinical Activity Score (CAS), Ophthalmopathy Index, and Total Eye Score improved over 3 years (P < .001). However, quality of life at 3 years remained poor. Of 64 individuals with available surgical outcome data, 24 of 64 (37.5%) required surgical intervention. Disease duration of greater than 6 months before treatment was associated with increased need for surgery [odds ratio (OR) 16.8; 95% CI 2.95, 95.0; P = .001]. Higher baseline levels of CAS, Ophthalmopathy Index, and Total Eye Score but not early improvement in CAS were associated with increased requirement for surgery.

CONCLUSION

In this long-term follow-up from a clinical trial, 3-year outcomes remained suboptimal with ongoing poor quality of life and high numbers requiring surgery. Importantly, reduction in CAS in the first year, a commonly used surrogate outcome measure, was not associated with improved long-term outcomes.

Traditional Chinese medicine in thyroid-associated orbitopathy

PURPOSE

Orbital fibroblasts (OF) are considered the central target cells in the pathogenesis of thyroid-associated orbitopathy (TAO), which comprises orbital inflammation, orbital tissue edema, adipogenesis, fibrosis, oxidative stress and autophagy. Certain active ingredients of traditional Chinese medicine (TCM) demonstrated inhibition of TAO-OF in pre-clinical studies and they could be translated into novel therapeutic strategies.

METHODS

The pertinent and current literature of pre-clinical studies on TAO investigating the effects of active ingredients of TCM was reviewed using the NCBI PubMed database.

RESULTS

Eleven TCM compounds demonstrated inhibition of TAO-OF in-vitro and three of them (polydatin, curcumin, and gypenosides) resulted in improvement in TAO mouse models. Tanshinone IIA reduced inflammation, oxidative stress and adipogenesis. Both resveratrol and its precursor polydatin displayed anti-oxidative and anti-adipogenic properties. Celastrol inhibited inflammation and triptolide prevented TAO-OF activation, while icariin inhibited autophagy and adipogenesis. Astragaloside IV reduced inflammation via suppressing autophagy and inhibited fat accumulation as well as collagen deposition. Curcumin displayed multiple actions, including anti-inflammatory, anti-oxidative, anti-adipogenic, anti-fibrotic and anti-angiogenic effects via multiple signaling pathways. Gypenosides reduced inflammation, oxidative stress, tissue fibrosis, as well as oxidative stress mediated autophagy and apoptosis. Dihydroartemisinin inhibited OF proliferation, inflammation, hyaluronan (HA) production, and fibrosis. Berberine attenuated inflammation, HA production, adipogenesis, and fibrosis.

CONCLUSIONS

Clinical trials of different phases with adequate power and sound methodology will be warranted to evaluate the appropriate dosage, safety and efficacy of these compounds in the management of TAO.

A review of TSHR- and IGF-1R-related pathogenesis and treatment of Graves' orbitopathy

Graves' orbitopathy (GO) is an organ-specific autoimmune disease, but its pathogenesis remains unclear. There are few review articles on GO research from the perspective of target cells and target antigens. A systematic search of PubMed was performed, focusing mainly on studies published after 2015 that involve the role of target cells, orbital fibroblasts (OFs) and orbital adipocytes (OAs), target antigens, thyrotropin receptor (TSHR) and insulin-like growth factor-1 receptor (IGF-1R), and their corresponding antibodies, TSHR antibodies (TRAbs) and IGF-1R antibodies (IGF-1R Abs), in GO pathogenesis and the potentially effective therapies that target TSHR and IGF-1R. Based on the results, OFs may be derived from bone marrow-derived CD34+ fibrocytes. In addition to CD34+ OFs, CD34- OFs are important in the pathogenesis of GO and may be involved in hyaluronan formation. CD34- OFs expressing Slit2 suppress the phenotype of CD34+ OFs. β-arrestin 1 can be involved in TSHR/IGF-1R crosstalk as a scaffold. Research on TRAbs has gradually shifted to TSAbs, TBAbs and the titre of TRAbs. However, the existence and role of IGF-1R Abs are still unknown and deserve further study. Basic and clinical trials of TSHR-inhibiting therapies are increasing, and TSHR is an expected therapeutic target. Teprotumumab has become the latest second-line treatment for GO. This review aims to effectively describe the pathogenesis of GO from the perspective of target cells and target antigens and provide ideas for its fundamental treatment.

Potential Therapeutic Role of Bone Morphogenic Protein 7 (BMP7) in the Pathogenesis of Graves' Orbitopathy

Purpose

We investigated a role of bone morphogenic protein 7 (BMP7), a member of the TGF-β superfamily on pathogenic mechanism of Graves' orbitopathy (GO). The therapeutic effects of BMP7 on inflammation and fibrosis were evaluated in cultured Graves' orbital fibroblasts.

Methods

Expression of BMP7 was compared in cultured orbital tissue explants from GO (n = 12) and normal control (n = 12) subjects using real-time PCR. Orbital fibroblasts were cultured from orbital connective tissues obtained from GO (n = 3) and normal control patients (n = 3). Cells were pretreated with recombinant human BMP7 (rhBMP7) before stimulation with TGF-β, IL-1β, and TNF-α. Fibrosis-related proteins and inflammatory cytokines were analyzed by Western blotting. The activation of signaling molecules in inflammation and fibrosis was also analyzed.

Results

The expressions of BMP7 mRNA were lower in GO orbital tissues than control. Fibrosis-related proteins, fibronectin, collagen 1α, and α-SMA induced by TGF-β were suppressed by treating rhBMP7, and rhBMP7 upregulated TGF-β induced SMAD1/5/8 protein expression, whereas downregulated SMAD2/3. Increased pro-inflammatory molecules, IL-6, IL-8, and intercellular adhesion molecule-1 (ICAM-1) by IL-1β or TNF-α were blocked by rhBMP7 treatment, and the expression of phosphorylated NFκB and Akt was suppressed by rhBMP7 treatment.

Conclusions

BMP7 transcript levels were downregulated in Graves' orbital tissues. Exogenous BMP7 treatment showed inhibitory effects on the production of profibrotic proteins and proinflammatory cytokines in orbital fibroblasts. Our results provide a molecular basis of BMP7 as a new potential therapeutic agent through the opposing mechanism of profibrotic TGF-β/SMAD signaling and proinflammatory cytokine production.

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.

Thinking inside the box: Current insights into targeting orbital tissue remodeling and inflammation in thyroid eye disease

Thyroid eye disease (TED) is an autoimmune disorder that manifests in the orbit. In TED, the connective tissue behind the eye becomes inflamed and remodels with increased fat accumulation and/or increased muscle and scar tissue. As orbital tissue expands, patients develop edema, exophthalmos, diplopia, and optic neuropathy. In severe cases vision loss may occur secondary to corneal scarring from exposure or optic nerve compression. Currently there is no cure for TED, and treatments are limited. A major breakthrough in TED therapy occurred with the FDA approval of teprotumumab, a monoclonal insulin-like growth factor 1 receptor (IGF1R) blocking antibody. Yet, teprotumumab therapy has limitations, including cost, infusion method of drug delivery, variable response, and relapse. We describe approaches to target orbital fibroblasts and the complex pathophysiology that underlies tissue remodeling and inflammation driving TED. Further advances in the elucidation of the mechanisms of TED may lead to prophylaxis based upon early biomarkers as well as lead to more convenient, less expensive therapies.

Drug safety in thyroid eye disease - a systematic review

INTRODUCTION

The autoimmune-induced thyroid eye disease (TED) is a frequent extrathyroidal manifestation of Graves' disease and less frequently of Hashimoto's thyroiditis. Pathognomonic clinical signs, i.e. exophthalmos, double vision, and inflammation of the orbital tissue cause physical, ophthalmic, and socio-psychological limitations.

AREAS COVERED

PubMed and MeSH database were searched for specific guidelines, randomized controlled trials, prospective clinical studies, systematic reviews and meta-analyses pertaining to the safety profile of currently administered immunosuppressive agents for the treatment of TED. Occurred adverse events (AE), severe AE (SAE), side effects (SE), and severe SE (SSE) were classified according to the standardized medical dictionary for regulatory activities (MedDRA).

EXPERT OPINION

This novel systematic analysis offers an overview of potential AE, SAE and SE for currently recommended immunosuppressive drugs for the treatment of TED. Non-specific, anti-inflammatory drugs and more specific, targeted biologicals are treatment options for active and severe TED. Critical evaluation of the pertinent literature confirms an evidence-based, beneficial efficacy/risk ratio of the current first-line and second-line treatment recommendations endorsed by the European Society of Endocrinology. However, further large, well-conceived trials are mandatory to enhance our knowledge and experience with novel specific small molecules and/or monoclonal antibodies targeting the key autoantigens in TED.

Teprotumumab: The Dawn of Therapies in Moderate-to-Severe Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is a potentially sight-threatening ocular disease. About 3-5% of patients with TAO have severe disease with intense pain, inflammation, and sight-threatening corneal ulceration or compressive optic neuropathy. The current treatments of TAO are often suboptimal, mainly because the existing therapies do not target the pathogenesis of the disease. TAO mechanism is unclear. Ocular fibrocytes express relatively high levels of the functional TSH receptor (TSHR), and many indirect evidences support its participation. Over expression of insulin-like growth factor-1 receptor (IGF-IR) in fibroblasts, leading to inappropriate expression of inflammatory factors, production of hyaluronic acid and cell activation in orbital fibroblasts are also possible mechanisms. IGF-1R and TSHR form a physical and functional signaling complex. Inhibition of IGF-IR activity leads to the attenuation of signaling initiated at either receptor. Teprotumumab (TMB) is a human immunoglobulin G1 monoclonal antibody, binding to IGF-IR. Recently two TMB clinical trials had been implemented in TAO patients, indicating dramatic reductions in disease activity and severity, which approved its use for the treatment of TAO in the US. This review summarizes the treatments of TAO, focusing on the pathogenesis of IGF-1R in TAO and its application prospects.

Updates on the understanding and management of thyroid eye disease

Thyroid eye disease (TED) is a complex disease associated with myriad clinical presentations, including facial disfigurement, vision loss, and decreased quality of life. Traditionally, steroid therapy and/or radiation therapy were commonly used in the treatment of active TED. While these therapies can help reduce inflammation, they often do not have a sustainable, significant long-term effect on disease outcomes, including proptosis and diplopia. Recent advances in our understanding of the pathophysiology of TED have shifted the focus of treatment toward targeted biologic therapies. Biologics have the advantage of precise immune modulation, which can have better safety profiles and greater efficacy compared to traditional approaches. For instance, the insulin-like growth factor-1 receptor (IGF-1R) has been found to be upregulated in TED patients and to colocalize with the thyroid-stimulating hormone receptor (TSHR), forming a signaling complex. Teprotumumab is an antibody targeted against IGF-1R. By inhibiting the IGF-1R/TSHR signaling pathway, teprotumumab may reduce the production of proinflammatory cytokines, hyaluronan secretion, and orbital fibroblast activation in patients with TED. Due to promising phase II and III clinical trial results, teprotumumab has become the first biologic US Food and Drug Administration (FDA)-approved for the treatment of TED. In addition, there are currently ongoing studies looking at the use of antibodies targeting the neonatal Fc receptor (FcRn) in various autoimmune diseases, including TED. FcRn functions to transport immunoglobulin G (IgG) and prevent their lysosomal degradation. By blocking the recycling of IgG, this approach may dampen the body's immune response, in particular the pathogenic IgG implicated in some autoimmune diseases. Advances in our understanding of the pathophysiology of TED, therefore, are leading to more targeted therapeutic options, and we are entering an exciting new phase in the management of TED. This review will cover recent insights into the understanding of TED pathophysiology and novel treatment options as well as ongoing studies of new potential treatment options for TED.

Cytokines as Targets of Novel Therapies for Graves' Ophthalmopathy

Graves' disease (GD) is an organ-specific autoimmune disorder of the thyroid, which is characterized by circulating TSH-receptor (TSH-R) stimulating antibodies (TSAb), leading to hyperthyroidism. Graves' ophthalmopathy (GO) is one of GD extra-thyroidal manifestations associated with the presence of TSAb, and insulin-like growth factor-1 receptor (IGF-1R) autoantibodies, that interact with orbital fibroblasts. Cytokines are elevated in autoimmune (i.e., IL-18, IL-6) and non-autoimmune hyperthyroidism (i.e., TNF-α, IL-8, IL-6), and this could be associated with the chronic effects of thyroid hormone increase. A prevalent Th1-immune response (not related to the hyperthyroidism per se, but to the autoimmune process) is reported in the immune-pathogenesis of GD and GO; Th1-chemokines (CXCL9, CXCL10, CXCL11) and the (C-X-C)R3 receptor are crucial in this process. In patients with active GO, corticosteroids, or intravenous immunoglobulins, decrease inflammation and orbital congestion, and are considered first-line therapies. The more deepened understanding of GO pathophysiology has led to different immune-modulant treatments. Cytokines, TSH-R, and IGF-1R (on the surface of B and T lymphocytes, and fibroblasts), and chemokines implicated in the autoimmune process, are possible targets of novel therapies. Drugs that target cytokines (etanercept, tocilizumab, infliximab, adalimumab) have been tested in GO, with encouraging results. The chimeric monoclonal antibody directed against CD20, RTX, reduces B lymphocytes, cytokines and the released autoantibodies. A multicenter, randomized, placebo-controlled, double-masked trial has investigated the human monoclonal blocking antibody directed against IGF-1R, teprotumumab, reporting its effectiveness in GO. In conclusion, large, controlled and randomized studies are needed to evaluate new possible targeted therapies for GO.

Medical treatment in thyroid eye disease in 2020

Thyroid eye disease (TED) affects 25% of patients with Graves' hyperthyroidism, where 1 in 20 patients has active, moderate-to-severe disease that will require medical treatment for reducing TED activity and severity. Intravenous corticosteroid has been the mainstay of treatment for active moderate-to-severe TED. With improved understanding of the pathophysiology of TED, immunotherapy targeting different molecular pathways including T cells, B cells, cytokines and cell surface receptors have been investigated in randomised clinical trials. This review provides an overview of the current advances in medical treatment including teprotumumab, tocilizumab, rituximab and mycophenolate and the indications for their use in the management of active, moderate-to-severe TED.

TSH/IGF1 receptor crosstalk: Mechanism and clinical implications

Increasing evidence of interdependence between G protein-coupled receptors and receptor tyrosine kinase signaling pathways has prompted reevaluation of crosstalk between these receptors in disease and therapy. Investigations into thyroid-stimulating hormone (TSH) and insulin-like growth factor 1 (IGF1) receptor crosstalk, and its application to the clinic have in particular shown recent progress. In this review, we summarize current insights into the mechanism of TSH/IGF1 receptor crosstalk. We discuss evidence that crosstalk is one of the underlying causes of TSHR-based disease and the feasibility of using combinations of TSH receptor and IGF1 receptor antagonists to increase the therapeutic index for the treatment of Graves' hyperthyroidism and Graves' ophthalmopathy.

Glucocorticoids in Graves' orbitopathy: mechanisms of action and clinical application

BACKGROUND

Graves' orbitopathy (GO) is the most frequent extrathyroidal manifestation of the autoimmune Graves' disease. GO significantly impacts quality of life and has a psycho-social morbidity. Inflammation and swelling of the orbital tissue often leads to proptosis, diplopia, and decrease of visual acuity. Due to the inflammatory background of the disease, glucocorticoids (GC) have been used as a first-line treatment for decades.

METHODS

PubMed and MeSH database were searched for original articles, clinical trials, reviews, and meta-analyses published between 1 January 2000 and 31 March 2020 and pertaining to both the mechanism of action and immunological effects of GC as well as to the treatment of GO by GC. The publications were evaluated according to their setting and study design.

RESULTS

GC act through genomic (trans-activation and trans-repression) and rapid non-genomic mechanisms. GC in general, and the intravenous (IV) administration of GC in particular, markedly decrease the activity and number of the most potent antigen-presenting dendritic cells. According to the internationally acknowledged European Thyroid Association Guidelines for the management of GO, weekly IVGC application over 12 weeks is recommended as first-line treatment for patients with active and severe GO. The daily and cumulative dose should be tailored according to clinical severity, for example, 4.5 g of IV methylprednisolone for the inflammatory component versus 7.5 g in the presence of diplopia and severe proptosis. Fast and significant improvements in orbital symptoms and signs are noted in 65-70% of patients. Long-term experience over decades, and worldwide availability at low cost, underline the clinical and therapeutic relevance of GC. Adverse events are rarely severe, dose-dependent, and usually reversible, hence easy to handle by medical investigators. Oral GC application on a daily basis is characterized by high bioavailability but reduced efficacy and increased toxicity.

CONCLUSION

IVGC still represents the standard of care in active/severe GO. Innovative biologicals, like monoclonal antibodies targeting the thyrotropin/Insulin-like growth factor-1 receptors or pro-inflammatory cytokines (e.g., Interleukin-6) should be compared with standard GC treatment with respect to short- and long-term efficacy, safety, costs, and global availability.