Alemtuzumab-induced thyroid eye disease successfully treated with a single low dose of rituximab.

Introduction: Secondary thyroid autoimmunity, especially Graves' disease (GD), frequently develops in patients with multiple sclerosis (MS) following alemtuzumab treatment (ALTZ; anti-CD52). Thyroid eye disease (TED) can also develop, and rituximab (RTX; anti-CD20) is a suitable treatment. Case presentation: A 37-year-old woman with MS developed steroid-resistant active moderate-to-severe TED 3 years after ALTZ, that successfully responded to a single 500 mg dose of i.v. RTX. Before RTX peripheral B-cells were low, and were totally depleted immediately after therapy. Follow-up analysis 4 years post ALTZ and 1 year post RTX showed persistent depletion of B cells, and reduction of T regulatory cells in both peripheral blood and thyroid tissue obtained at thyroidectomy. Conclusion: RTX therapy successfully inactivated TED in a patient with low B-cell count derived from previous ALTZ treatment. B-cell depletion in both thyroid and peripheral blood was still present 1 year after RTX, indicating a likely cumulative effect of both treatments.

Increased Risk of Thyroid Eye Disease Following Covid-19 Vaccination.

CONTEXT: SARS-CoV-2 infection and Covid-19 vaccines have been associated with thyroid disorders. OBJECTIVE: We analyzed the risk of thyroid eye disease (TED) following Covid-19 vaccination. This was a self-controlled case series study at a tertiary referral center for TED. A total of 98 consecutive patients with newly developed (n = 92) or reactivated (n = 6) TED occurring between January 1, 2021, and August 31, 2022, were included. TED was assessed in patients undergoing Covid-19 vaccination. Person-days were defined as exposed if TED occurred 1 to 28 days after vaccination, and unexposed if occurring outside this time window. Conditional Poisson regression models were fitted to calculate incidence rate ratio (IRR) and 95% CI of exposed vs unexposed. Sensitivity analyses were conducted considering different exposed periods, and effect modification by potential TED risk factors. RESULTS: Covid-19 vaccines were administered in 81 people, 25 (31%) of whom developed TED in exposed and 56 (69%) in unexposed periods. The IRR for TED was 3.24 (95% CI 2.01-5.20) and 4.70 (95% CI 2.39-9.23) in patients below 50 years of age. Sex, smoking, and radioiodine treatment did not modify the association between TED and vaccination. TED risk was unrelated to the number of vaccine doses, and progressively decreased over time following vaccination (P trend = .03). CONCLUSION: The risk of TED was significantly increased after Covid-19 vaccination, especially in people below 50 years of age. Possible mechanisms include spike protein interaction with the angiotensin-converting enzyme II receptor, cross-reactivity with thyroid self-proteins, and immune reactions induced by adjuvants. We suggest monitoring of individuals undergoing Covid-19 vaccination, especially if young and at risk for autoimmunity.

SARS-COV-2 specific t-cells in patients with thyroid disorders related to COVID-19 are enriched in the thyroid and acquire a tissue-resident memory phenotype.

BACKGROUND: SARS-CoV-2 infections have been associated with the onset of thyroid disorders like classic subacute thyroiditis (SAT) or atypical SAT upon severe COVID disease (COV-A-SAT). Little is known about thyroid anti-viral immune responses. OBJECTIVES: To define the role of T-cells in COV-A-SAT. METHODS: T-cells from COV-A-SAT patients were analyzed by multi-dimensional flow cytometry, UMAP and DiffusionMap dimensionality reduction and FlowSOM clustering. T-cells from COVID-naïve healthy donors, patients with autoimmune thyroiditis (ATD) and with SAT following COVID vaccination were analyzed as controls. T-cells were analyzed four and eight months post-infection in peripheral blood and in thyroid specimen obtained by ultrasound-guided fine needle aspiration. SARS-COV2-specific T-cells were identified by cytokine production induced by SARS-COV2-derived peptides and with COVID peptide-loaded HLA multimers after HLA haplotyping. RESULTS: COV-A-SAT was associated with HLA-DRB1*13 and HLA-B*57. COV-A-SAT patients contained activated Th1- and cytotoxic CD4+ and CD8+ effector cells four months post-infection, which acquired a quiescent memory phenotype after eight months. Anti-SARS-CoV-2-specific T-cell responses were readily detectable in peripheral blood four months post-infection, but were reduced after eight months. CD4+ and CD8+ tissue-resident memory cells (TRM) were present in the thyroid, and circulating CXCR3+T-cells identified as their putative precursors. SARS-CoV-2-specific T-cells were enriched in the thyroid, and acquired a TRM phenotype eight months post-infection. CONCLUSIONS: The association of COV-A-SAT with specific HLA haplotypes suggests a genetic predisposition and a key role for T-cells. COV-A-SAT is characterized by a prolonged systemic anti-viral effector T-cell response and the late generation of COVID-specific TRM in the thyroid target tissue.

Clinical and Visual Outcomes of Dysthyroid Optic Neuropathy After Surgical Orbital Decompression.

Background: Current guidelines suggest high-dose steroids as first-line treatment for dysthyroid optic neuropathy (DON). When steroids fail, decompressive surgery is mandatory. Methods: We conducted a single-center, retrospective cohort study in a tertiary care combined Thyroid-Eye clinic in Milan, Italy. We studied 88 orbits of 56 patients that were submitted to surgical orbital decompression to treat DON from 2005 to 2020. Of these, 33 orbits (37.5%) underwent surgery as first-line treatment for DON whereas the other 55 (62.5%) were decompressed after being unresponsive to very high-dose steroids. Previous orbital surgery, concurrent neurological or ophthalmologic diseases, or incomplete follow-up were considered as exclusion criteria from this study. Surgery was considered successful if no further decompression was needed to preserve vision. Pinhole best corrected visual acuity (p-BCVA), color sensitivity, automated visual field, pupil reflexes, optic disk and fundus appearance, exophtalmometry, and ocular motility were studied before and after surgery (1 week, 1, 3, 6, and 12 months). Activity of Graves' Orbitopathy (GO) was graded using a clinical activity score (CAS). Results: Surgery was successful in 77 orbits (87.5%). The remaining 11 orbits (12.5%) needed further surgery to treat DON definitively. All parameters of visual function improved significantly at follow-up and GO inactivated (CAS <3) within 1 month. At 3 months, all 77 responding orbits had p-BCVA >0.63 whereas all of the 11 non-responding orbits had p-BCVA ≤0.63. Visual field parameters and color sensitivity were not associated with response to surgery. High-dose steroid treatment before surgery was associated with a better response rate (96% vs. 73%; p = 0.004). Balanced decompression was associated with a higher response rate compared with medial wall decompression (96% vs. 80%; p = 0.04). A significant inverse correlation was observed between final p-BCVA and the patient's age (r = -0.42; p = 0.0003). Conclusions: Surgical decompression was found to be a very effective treatment for DON. In this study, all clinical parameters improved after surgery and further intervention was rarely needed.

Endocrine and multiple sclerosis outcomes in patients with autoimmune thyroid events in the alemtuzumab CARE-MS studies.

Background: Alemtuzumab is an effective therapy for relapsing multiple sclerosis. Autoimmune thyroid events are a common adverse event. Objective: Describe endocrine and multiple sclerosis outcomes over 6 years for alemtuzumab-treated relapsing multiple sclerosis patients in the phase 3 CARE-MS I, II, and extension studies who experienced adverse thyroid events. Methods: Endocrine and multiple sclerosis outcomes were evaluated over 6 years. Thyroid event cases, excluding those pre-existing or occurring after Year 6, were adjudicated retrospectively by expert endocrinologists independently of the sponsor and investigators. Results: Thyroid events were reported for 378/811 (46.6%) alemtuzumab-treated patients. Following adjudication, endocrinologists reached consensus on 286 cases (75.7%). Of these, 39.5% were adjudicated to Graves' disease, 2.5% Hashimoto's disease switching to hyperthyroidism, 15.4% Hashimoto's disease, 4.9% Graves' disease switching to hypothyroidism, 10.1% transient thyroiditis, and 27.6% with uncertain diagnosis; inclusion of anti-thyroid antibody status reduced the number of uncertain diagnoses. Multiple sclerosis outcomes of those with and without thyroid events were similar. Conclusion: Adjudicated thyroid events occurring over 6 years for alemtuzumab-treated relapsing multiple sclerosis patients were primarily autoimmune. Thyroid events were considered manageable and did not affect disease course. Thyroid autoimmunity is a common but manageable adverse event in alemtuzumab-treated relapsing multiple sclerosis patients.ClinicalTrials.gov Registration Numbers: CARE-MS I (NCT00530348); CARE-MS II (NCT00548405); CARE-MS Extension (NCT00930553).

Gut Microbiome Associated With Graves Disease and Graves Orbitopathy: The INDIGO Multicenter European Study.

CONTEXT: Gut bacteria can influence host immune responses but little is known about their role in tolerance-loss mechanisms in Graves disease (GD; hyperthyroidism caused by autoantibodies, TRAb, to the thyrotropin receptor, TSHR) and its progression to Graves orbitopathy (GO). OBJECTIVE: This work aimed to compare the fecal microbiota in GD patients, with GO of varying severity, and healthy controls (HCs). METHODS: Patients were recruited from 4 European countries (105 GD patients, 41 HCs) for an observational study with cross-sectional and longitudinal components. RESULTS: At recruitment, when patients were hyperthyroid and TRAb positive, Actinobacteria were significantly increased and Bacteroidetes significantly decreased in GD/GO compared with HCs. The Firmicutes to Bacteroidetes (F:B) ratio was significantly higher in GD/GO than in HCs. Differential abundance of 15 genera was observed in patients, being most skewed in mild GO. Bacteroides displayed positive and negative correlations with TSH and free thyroxine, respectively, and was also significantly associated with smoking in GO; smoking is a risk factor for GO but not GD. Longitudinal analyses revealed that the presence of certain bacteria (Clostridiales) at diagnosis correlated with the persistence of TRAb more than 200 days after commencing antithyroid drug treatment. CONCLUSION: The increased F:B ratio observed in GD/GO mirrors our finding in a murine model comparing TSHR-immunized with control mice. We defined a microbiome signature and identified changes associated with autoimmunity as distinct from those due to hyperthyroidism. Persistence of TRAb is predictive of relapse; identification of these patients at diagnosis, via their microbiome, could improve management with potential to eradicate Clostridiales.

Long-term outcome of thyroid abnormalities in patients with severe Covid-19.

Objective: We have previously observed thyroid dysfunction, i.e. atypical thyroiditis (painless thyrotoxicosis associated with non-thyroidal illness syndrome), in patients with severe acute respiratory syndrome coronavirus 2 disease (Covid-19). This study aimed to analyse the evolution of thyroid dysfunction over time. Methods: One hundred eighty-three consecutive patients hospitalised for severe Covid-19 without known thyroid history were studied at hospital admission (baseline). Survivors were offered 12-month longitudinal follow-up including assessment of thyroid function, autoantibodies and ultrasound scan (US). Patients showing US focal hypoechoic areas suggestive of thyroiditis (focal hypoechogenicity) also underwent thyroid 99mTc or 123I uptake scan. Results: At baseline, after excluding from TSH analysis, 63 out of 183 (34%) Covid-19 patients commenced on steroids before hospitalisation, and 12 (10%) showed atypical thyroiditis. Follow-up of 75 patients showed normalisation of thyroid function and inflammatory markers and no increased prevalence of detectable thyroid autoantibodies. Baseline US (available in 65 patients) showed focal hypoechogenicity in 28% of patients, of whom 82% had reduced thyroid 99mTc/123I uptake. The presence of focal hypoechogenicity was associated with baseline low TSH (P = 0.034), high free-thyroxine (FT4) (P = 0.018) and high interleukin-6 (IL6) (P = 0.016). Focal hypoechogenicity persisted after 6 and 12 months in 87% and 50% patients, respectively, but reduced in size. After 9 months, thyroid 99mTc/123I uptake partially recovered from baseline (+28%) but was still reduced in 67% patients. Conclusions: Severe Covid-19 induces mild transient thyroid dysfunction correlating with disease severity. Focal hypoechogenicity, associated with baseline high FT4, IL6 and low TSH, does not seem to be related to thyroid autoimmunity and may persist after 1 year although decreasing in size. Long-term consequences seem unlikely.

Thyroid findings in pediatric and adult patients with PTEN hamartoma tumor syndrome: A retrospective analysis, and literature review.

PURPOSE: PTEN hamartoma tumor syndrome (PHTS) comprises a group of rare genetic conditions caused by germline mutations in PTEN gene and characterized by development of both benign and malignant lesions in many body tissues. In this study, we aimed to evaluate the incidence of thyroid findings in both adult and pediatric PHTS patients. METHODS: A retrospectively analysis conducted in 19 (13 adult and 6 pediatric) patients with PHTS, all confirmed with genetic testing, observed from 2015 to 2021 at the Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico. RESULTS: We found a thyroid involvement in 12 adult patients (92%): 11 patients had benign lesions (85%) and the remaining developed a follicular thyroid carcinoma (8.3%). The median age at time of the first available record was 30 years. Among benign lesions, multinodular goiter was the most observed finding (10/11, 91%). Only 1 out of 6 (16%) pediatric patients was diagnosed with a thyroid lesion (unifocal lesion in mild lymphocytic thyroiditis) at the age of 8 years. CONCLUSIONS: Thyroid disorders affected nearly all adult PHTS patients, but a much lower proportion of pediatric patients. We discuss about the natural history of thyroid involvement, age of PHTS clinical onset, and optimized surveillance.

Microbiota Alterations in Patients with Autoimmune Thyroid Diseases: A Systematic Review.

Autoimmune thyroid diseases (AITDs) are chronic autoimmune disorders that cause impaired immunoregulation, leading to specific immune responses against thyroid antigens. Graves' disease (GD) and Hashimoto's thyroiditis (HT) are the major forms of AITDs. Increasing evidence suggests a possible role of microbiota alterations in the pathogenesis and progression of AITDs. This systematic review was designed to address the following question: "Is microbiota altered in patients with AITDs?" After screening the selected studies using the inclusion and exclusion criteria, 16 studies were included in this review (in accordance with PRISMA statement guidelines). A meta-analysis revealed that patients with HT showed significantly higher values of diversity indices (except for the Simpson index) and that patients with GD showed significant tendencies toward lower values of all assessed indices compared with healthy subjects. However, the latter demonstrated a higher relative abundance of Bacteroidetes and Actinobacteria at the phylum level and thus Prevotella and Bifidobacterium at the genus level, respectively. Thyroid peroxidase antibodies showed the most significant positive and negative correlations between bacterial levels and thyroid functional parameters. In conclusion, significant alterations in the diversity and composition of the intestinal microbiota were observed in both GD and HT patients.

Case Report: A Novel ARMC5 Germline Mutation in a Patient with Primary Bilateral Macronodular Adrenal Hyperplasia and Hypogammaglobulinemia.

Primary bilateral macronodular adrenal hyperplasia (PBMAH) represents an uncommon cause of endogenous hypercortisolism. Since the first description in 2003 in a French cohort, many papers have been published describing families as well as isolated individuals affected with this condition, who were found to harbor a genetic variants in the armadillo-repeat containing 5 (ARMC5) gene, a tumor-suppressor gene with a still unknown role in the disease pathogenesis. Studies in rat models suggested a possible link between ARMC5 damaging variants and the impairment of the cell-mediated immune response, leading to a higher susceptibility to bacterial and viral infections. To our knowledge, we describe the first case of a patient affected by PBMAH with hypogammaglobulinemia and monthly relapsing human herpes simplex viral infections. After the detection of subclinical Cushing's syndrome, a unilateral laparoscopic adrenalectomy was performed. Subsequent genetic analysis of ARMC5 performed on genomic DNA extracted both from the adrenal tissue and lymphocytes revealed a novel somatic frameshift variant in exon 1 (c.231_265del:p.A77Afs*13) and a novel germline variant in exon 6 (c.2436del: p. C813Vfs*104). After adrenalectomy, we observed a significant improvement of clinical features concerning both hypercortisolism and relapsing viral infections, thus suggesting a possible adjuvant role of hypercortisolism on a genetic-based derangement of the immune system.

Expression of Endogenous Putative TSH Binding Protein in Orbit.

Thyroid stimulating antibodies (TSAB) cause Graves' disease and contribute to Graves' Orbitopathy (GO) pathogenesis. We hypothesise that the presence of TSH binding proteins (truncated TSHR variants (TSHRv)) and/or nonclassical ligands such as thyrostimulin (α2ß5) might provide a mechanism to protect against or exacerbate GO. We analysed primary human orbital preadipocyte-fibroblasts (OF) from GO patients and people free of GO (non-GO). Transcript (QPCR) and protein (western blot) expression levels of TSHRv were measured through an adipogenesis differentiation process. Cyclic-AMP production by TSHR activation was studied using luciferase-reporter and RIA assays. After differentiation, TSHRv levels in OF from GO were significantly higher than non-GO (p = 0.039), and confirmed in ex vivo analysis of orbital adipose samples. TSHRv western blot revealed a positive signal at 46 kDa in cell lysates and culture media (CM) from non-GO and GO-OF. Cyclic-AMP decreased from basal levels when OF were stimulated with TSH or Monoclonal TSAB (M22) before differentiation protocol, but increased in differentiated cells, and was inversely correlated with the TSHRv:TSHR ratio (Spearman correlation: TSH r = -0.55, p = 0.23, M22 r = 0.87, p = 0.03). In the bioassay, TSH/M22 induced luciferase-light was lower in CM from differentiated GO-OF than non-GO, suggesting that secreted TSHRv had neutralised their effects. α2 transcripts were present but reduced during adipogenesis (p < 0.005) with no difference observed between non-GO and GO. ß5 transcripts were at the limit of detection. Our work demonstrated that TSHRv transcripts are expressed as protein, are more abundant in GO than non-GO OF and have the capacity to regulate signalling via the TSHR.

Therapy With Different Dose Regimens of Rituximab in Patients With Active Moderate-To-Severe Graves' Orbitopathy.

Background: Immunosuppressive therapy of Graves' orbitopathy (GO) is indicated during the active phase of disease. Intravenous steroids (IVGC) are effective in about 70% of patients, although unresponsiveness or relapse are observed. In previous studies, rituximab (RTX) has been shown to be effective in inactivating moderate-to-severe GO when used early in the disease, but its optimal dosage has never been studied in randomized clinical trials. Aim of this study was to compare the efficacy and safety of different doses of RTX, based on a post-hoc analysis of two open label studies and one prospective trial randomized to IVGC. Methods: of 40 patients (35 women, 5 men), with active moderate-to-severe GO treated with RTX, 14 received a single dose of 100 mg (Group 1), 15 a single dose of 500 mg (Group 2) and 11 two 1000 mg doses, administered one week apart (Group 3). Thyroid function, TSH-receptor antibodies (TRAb) and peripheral CD19+ cells were measured. Primary endpoint was disease inactivation, measured as a decrease of the Clinical Activity Score (CAS) of at least two points. Secondary endpoints were improvement of proptosis, diplopia, quality of life and safety. Results: Baseline CAS decreased significantly in all groups (P<0.0001), independently of GO duration or whether patients had newly occurring or relapsing GO after IVGC. Proptosis did not significantly change. There was an inverse correlation between the Gorman score for diplopia and RTX dose (P<0.01). The appearance score of the GO-QoL improved in Group 1 (P=0.015), and the visual function score, in Group 2 (P=0.04). A reduction of serum TRAb was observed in Group 1 (P=0.002) and Group 2 (P<0.0002), but not in Group 3. CD19+ cell decreased in all groups (P<0.01), independently of the dose. Conclusions: We studied the optimal dosage of RTX in the treatment of active moderate-to-severe GO. In this analysis, we considered the efficacy of RTX in inactivating GO, in changing its natural course, its effect on disease severity and on the patients' quality of life. Based on our clinical findings, and balancing the cost of therapy, a single 500 mg dose regimen is suggested in the majority of patients.

Efficacy Profile and Safety of Very Low-Dose Rituximab in Patients with Graves' Orbitopathy.

Background: Rituximab (RTX), a chimeric human-murine anti-CD20 monoclonal antibody, has been used for treatment of active moderate-severe Graves' orbitopathy (GO) since 2004 as second-line therapy in patients unresponsive to intravenous steroids. We conducted an open-label prospective study (EUDRACT 2012-001980-53) in which patients were treated with a single infusion of only 100 mg RTX to analyze the efficacy and safety of this low dose. Methods: Seventeen patients, of whom nine had disease that was unresponsive to intravenous methylprednisolone and eight with newly diagnosed GO, were enrolled. Disease activity was assessed with the clinical activity score (CAS) and severity with a composite ophthalmic score. Long-term surgical treatment and quality of life were also assessed, as well as treatment-related adverse events. Results: Mean baseline CAS was 4.56 ± 0.96 and decreased to 1.25 ± 1.14 at 24 weeks (p = 0.001). Disease inactivation occurred within 24 weeks in >90% of patients and was unrelated to disease duration. Severity improved in about 60% of patients, with no relapses. All patients showed peripheral depletion of CD20+ and CD19+ cells at the end of RTX infusion (60 minutes). Two patients required surgical orbital decompression because of optic neuropathy (ON). Among adverse events observed, there was one patient who developed a cytokine release syndrome. Conclusions: A dose of 100 mg RTX is effective in patients with active moderate-severe GO. Low doses are better tolerated, expose patients to immune suppression for a shorter period of time, and are extremely cost effective, compared with higher doses. This dose, consistently with all other immunosuppressants, does not prevent the progression of GO to dysthyroid ON.

Indications for treatment of subclinical hypothyroidism and isolated hypothyroxinaemia in pregnancy.

Thyroid hormones are essential for maintaining a pregnancy and optimal fetal neurological development. Pregnancy places additional demands on the thyroid axis and around 5% of women who have their thyroid function checked during gestation will have borderline low thyroid function (subclinical hypothyroidism or isolated hypothyroxinemia) identified. These borderline low thyroid states are associated with adverse obstetric and offspring outcomes. Whilst it is well established that overt hypothyroidism requires treatment with levothyroxine, it is less clear whether there is any benefit of treating borderline low thyroid states. This review summarizes the potential indications for treatment of subclinical hypothyroidism and isolated hypothyroxinemia.

CATS II Long-term Anthropometric and Metabolic Effects of Maternal Sub-optimal Thyroid Function in Offspring and Mothers.

CONTEXT AND OBJECTIVES: The Controlled Antenatal Thyroid Screening Study I (CATS-I) was a randomized controlled trial investigating the effects of levothyroxine therapy for suboptimal gestational thyroid function (SGTF), comparing outcomes in children of treated (SGTF-T) with untreated (SGTF-U) women during pregnancy. This follow-up study, CATS-II, reports the long-term effects on anthropometric, bone, and cardiometabolic outcomes in mothers and offspring and includes a group with normal gestational thyroid function (NGTF). DESIGN & PARTICIPANTS: 332 mothers (197 NGTF, 56 SGTF-U, 79 SGTF-T) aged 41.2±5.3 years (mean±SD) and 326 paired children assessed 9.3±1.0 years after birth for (i) body mass index (BMI); (ii) lean, fat, and bone mass by dual-energy X-ray absorptiometry; (iii) blood pressure, augmentation index, and aortic pulse-wave-velocity; and (iv) thyroid function, lipids, insulin, and adiponectin. The difference between group means was compared using linear regression. RESULTS: Offspring's measurements were similar between groups. Although maternal BMI was similar between groups at CATS-I, after 9 years (at CATS-II) SGTF-U mothers showed higher BMI (median [interquartile ratio] 28.3 [24.6-32.6] kg/m2) compared with NGTF (25.8 [22.9-30.0] kg/m2; P = 0.029), driven by fat mass increase. At CATS-II SGTF-U mothers also had higher thyroid-stimulating hormone (TSH) values (2.45 [1.43-3.50] mU/L) than NGTF (1.54 [1.12-2.07] mU/L; P = 0.015), since 64% had never received levothyroxine. At CATS-II, SGTF-T mothers had BMI (25.8 [23.1-29.8] kg/m2, P = 0.672) and TSH (1.68 [0.89-2.96] mU/L; P = 0.474) values similar to NGTF mothers. CONCLUSIONS: Levothyroxine supplementation of women with SGTF did not affect long-term offspring anthropometric, bone, and cardiometabolic measurements. However, absence of treatment was associated with sustained long-term increase in BMI and fat mass in women with SGTF.

New insights into the pathogenesis and nonsurgical management of Graves orbitopathy.

Graves orbitopathy, also known as thyroid eye disease or thyroid-associated orbitopathy, is visually disabling, cosmetically disfiguring and has a substantial negative impact on a patient's quality of life. There is increasing awareness of the need for early diagnosis and rapid specialist input from endocrinologists and ophthalmologists. Glucocorticoids are the mainstay of treatment; however, recurrence occurs frequently once these are withdrawn. Furthermore, in >60% of cases, normal orbital anatomy is not restored, and skilled rehabilitative surgery is required. Clinical trials have shown that considerable benefit can be derived from the addition of antiproliferative agents (such as mycophenolate or azathioprine) in preventing deterioration after steroid cessation. In addition, targeted biologic therapies have shown promise, including teprotumumab, which reduces proptosis, rituximab (anti-CD20), which reduces inflammation, and tocilizumab, which potentially benefits both of these parameters. Other strategies such as orbital radiotherapy have had their widespread role in combination therapy called into question. The pathophysiology of Graves orbitopathy has also been revised with identification of new potential therapeutic targets. In this Review we provide an up-to-date overview of the field, outline the optimal management of Graves orbitopathy and summarize the research developments in this area to highlight future research questions and direct future clinical trials.

The antigenic link between thyroid autoimmunity and breast cancer.

The association between breast cancer and benign thyroid disorders, in particular thyroid autoimmunity, has been debated for decades. Autoantibodies to thyroid peroxidase, the hallmark of thyroid autoimmunity, have a higher prevalence among patients with breast cancer compared with the general population. Furthermore a correlation between their positivity and a better prognosis of breast cancer was found in several independent small-scale studies, even if such observation was not confirmed in a subsequent retrospective study conducted on the largest patient cohort to date. The thyroid and mammary glands present several biological similarities, therefore the hypothesis of an immune response to shared thyroid/breast antigens could in part explain the association between thyroid autoimmunity and breast cancer. The sodium iodide symporter is expressed in both glands, however it seems unlikely to be the key common antigen, considering that autoantibodies targeting it are rare. Instead thyroid peroxidase, one of the major thyroid autoantigens, is also expressed in breast tissue and therefore represents the main antigenic link between thyroid autoimmunity and breast cancer. Furthermore lactoperoxidase, an enzyme of the same family that shares structural similarities with thyroid peroxidase, is expressed in neoplastic breast cells and is responsible for the cross-reactivity with some autoantibodies to thyroid peroxidase. Novel strategies for the diagnosis and treatment of breast cancer might take advantage of the antigenic link between thyroid and breast tissues.