Functional outcomes and complications in refractory dysthyroid optic neuropathy management: Experience with 3 different surgical protocols.

INTRODUCTION: Dysthyroid optic neuropathy (DON) is the most severe complication of Graves' orbitopathy (GO) and its management may require decompression surgery. Clear recommendations do not exist about which surgery should be performed and how extended the decompression should be. In this paper we present our experience regarding the management of DON via 3 different surgical protocols: a modified extended orbital apex decompression, a 2 walls decompression (inferior and lateral) and a 3 walls decompression (inferior, lateral and medial) and evaluate the functional outcomes. METHODS: Retrospective evaluation of subjects affected by DON not responding to medical therapy has been performed. All patients were submitted to pre- and post-operative ophthalmologic evaluations and orbital and sinuses CT scan in order to evaluate functional and surgical outcomes. RESULTS: 27 patients were enrolled in the study. Surgical procedures were performed on 42 orbits. A statistically significant post-operative improvement was recorded in visual acuity, proptosis, color vision and fundus oculi evaluation for all groups. No patient developed major or minor complications after surgery. CONCLUSIONS: Extended endonasal approach and 3 walls decompression have been proved effective in the management of DON. The choice between them is done according to degree of proptosis, general status and eye-surface damages.

Beneficial effect of low-dose radioiodine ablation for Graves' orbitopathy: results of a retrospective study.

OBJECTIVE: Graves' orbitopathy (GO) reflects an autoimmune response against antigens expressed by the thyroid and orbital tissues. Elimination of thyroid antigens may be beneficial for GO. Total thyroid ablation (TTA) [thyroidectomy (Tx), followed by 30 mCi of radioiodine] was shown to exert a beneficial effect on GO following intravenous glucocorticoids (ivGC) compared with Tx alone. Here, we investigated retrospectively whether TTA performed with a 15 mCi of radioiodine still maintains advantages over Tx. METHODS: Thirty-two subjects, 13 treated with TTA (performed with 15 mCi of radioiodine) and 19 with Tx alone, all with moderately severe, active GO, treated with ivGC, were studied. The primary objective was the outcome of GO at 24 weeks based on a composite evaluation. RESULTS: The two groups did not differ at baseline in terms of sex, age, smoking habits, TSH, anti-TSH receptor autoantibodies, GO duration and eye features. The proportion of GO responders at 24 weeks was greater in the TTA (61.5%) than in the Tx group (26.3%, P = 0.046). In contrast, GO outcome at 48 weeks did not differ between the two groups (69.2% vs 52.6% of responder in TTA and Tx group, respectively). The outcome of the individual GO features did not differ between the two groups both a 24 and 48 months. CONCLUSIONS: The advantage of total thyroid ablation seems to be a more rapid response for GO to ivGC treatment. Prospective, randomized studies in a larger number of subjects are needed to confirm our findings.

Cepharanthine blocks TSH receptor peptide presentation by HLA-DR3: Therapeutic implications to Graves' disease.

We have previously identified a signature HLA-DR3 pocket variant, designated HLA-DRß1-Arg74 that confers a high risk for Graves' Disease (GD). In view of the key role of HLA-DRß1-Arg74 in triggering GD we hypothesized that thyroid-stimulating hormone receptor (TSHR) peptides that bind to the HLA-DRß1-Arg74 pocket with high affinity represent key pathogenic TSHR peptides triggering GD, and that blocking their presentation to CD4+ T-cells can be used as a novel therapeutic approach in GD. There were several previous attempts to identify the major pathogenic TSHR peptide utilizing different methodologies, however the results were inconsistent and inconclusive. Therefore, the aim of our study was to use TSHR peptide binding affinity to HLA-DRß1-Arg74 as a method to identify the key pathogenic TSHR peptides that trigger GD. Using virtual screening and ELISA and cellular binding assays we identified 2 TSHR peptides that bound with high affinity to HLA-DRß1-Arg74 - TSHR.132 and TSHR.197. Peptide immunization studies in humanized DR3 mice showed that only TSHR.132, but not TSHR.197, induced autoreactive T-cell proliferation and cytokine responses. Next, we induced experimental autoimmune Graves' disease (EAGD) in a novel BALB/c-DR3 humanized mouse model we created and confirmed TSHR.132 as a major DRß1-Arg74 binding peptide triggering GD in our mouse model. Furthermore, we demonstrated that Cepharanthine, a compound we have previously identified as DRß1-Arg74 blocker, could block the presentation and T-cell responses to TSHR.132 in the EAGD model.

Selenium in Graves Hyperthyroidism and Orbitopathy.

PURPOSE: To review the in vitro and in vivo studies supporting a role of selenium for the treatment of mild Graves orbitopathy. METHODS: Review of the current literature on the role of selenium in the management of Graves orbitopathy. RESULTS: Graves orbitopathy (GO) is a disfiguring and disabling disorder usually observed in patients with Graves hyperthyroidism, and more rarely in patients with hypothyroid autoimmune thyroiditis or in the absence of overt thyroid dysfunction. Noninvasive treatments include intravenous glucocorticoids and orbital radiotherapy and are generally offered to patients with moderately severe GO. In contrast, patients with mild GO are generally treated only with local measures. Thus, the benefits of intravenous glucocorticoids in mild GO are limited and do not justify the risks that the treatment carries. However, a medical treatment for mild GO is heavily wanted, as a relevant proportion of patients have a significant decrease in their quality of life, and GO can progress into more severe forms. Because of the role of oxidative stress in the pathogenesis of GO, an antioxidant approach has been proposed and the antioxidant agent selenium has been shown to be effective for GO. CONCLUSION: Studies have shown that a 6-month course of sodium selenite can improve the course of mild GO and prevent deterioration when compared with placebo.

Identifying a Small Molecule Blocking Antigen Presentation in Autoimmune Thyroiditis.

We previously showed that an HLA-DR variant containing arginine at position 74 of the DRß1 chain (DRß1-Arg74) is the specific HLA class II variant conferring risk for autoimmune thyroid diseases (AITD). We also identified 5 thyroglobulin (Tg) peptides that bound to DRß1-Arg74. We hypothesized that blocking the binding of these peptides to DRß1-Arg74 could block the continuous T-cell activation in thyroiditis needed to maintain the autoimmune response to the thyroid. The aim of the current study was to identify small molecules that can block T-cell activation by Tg peptides presented within DRß1-Arg74 pockets. We screened a large and diverse library of compounds and identified one compound, cepharanthine that was able to block peptide binding to DRß1-Arg74. We then showed that Tg.2098 is the dominant peptide when inducing experimental autoimmune thyroiditis (EAT) in NOD mice expressing human DRß1-Arg74. Furthermore, cepharanthine blocked T-cell activation by thyroglobulin peptides, in particular Tg.2098 in mice that were induced with EAT. For the first time we identified a small molecule that can block Tg peptide binding and presentation to T-cells in autoimmune thyroiditis. If confirmed cepharanthine could potentially have a role in treating human AITD.

Flexible peptide recognition by HLA-DR triggers specific autoimmune T-cell responses in autoimmune thyroiditis and diabetes.

Autoimmune polyglandular syndrome 3 variant (APS3v) refers to the co-occurrence of autoimmune thyroiditis (AITD) and type 1 diabetes (T1D) within the same individual. HLA class II confers the strongest susceptibility to APS3v. We previously identified a unique amino acid signature of the HLA-DR pocket (designated APS3v HLA-DR pocket) that predisposes to APS3v. We hypothesized that both thyroid and islet peptides can be presented by the unique APS3v HLA-DR pocket, triggering AITD + T1D together. To test this hypothesis we screened islet and thyroid peptides for their ability to bind to the APS3v HLA-DR pocket. Virtual screen of all possible thyroglobulin (Tg), thyroid-stimulating hormone receptor (TSHR), thyroid peroxidase (TPO), insulin (Ins), and glutamic acid decarboxylase 65 (GAD65) peptides identified 36 peptides that bound to this unique pocket. In vitro binding assays using baculovirus-produced recombinant APS3v HLA-DR identified 11 thyroid/islet peptides (of the 36 predicted binders) that bound with high affinity. By immunizing humanized HLA-DR3 mice carrying the APS3v HLA-DR pocket we identified 4 peptides (Tg.1571, GAD.492, TPO.758, TPO.338) that were presented by antigen presenting cells and elicited T-cell response. We conclude that both thyroid and islet peptides can bind to this flexible APS3v HLA-DR pocket and induce thyroid and islet specific T-cell responses. These findings set the stage to developing specific inhibitors of the APS3v HLA-DR pocket as a precision medicine approach to treating or preventing APS3v in patients that carry this genetic HLA-DR pocket variant.

VARIABLES AFFECTING THE LONG-TERM OUTCOME OF GRAVES ORBITOPATHY FOLLOWING HIGH-DOSE INTRAVENOUS GLUCOCORTICOID PULSE THERAPY IN PATIENTS NOT TREATED WITH ORBITAL RADIOTHERAPY.

OBJECTIVE: Intravenous (iv) glucocorticoids (GC) (ivGC) are used for active Graves orbitopathy (GO), but factors affecting GO outcome are poorly understood. We performed a retrospective study to investigate the variables affecting GO after ivGC. METHODS: We evaluated 83 consecutive GO patients treated with ivGC but not orbital radiotherapy (ORT) and re-examined them after a median of 47 months. The endpoints were the relationships between GO outcome or additional treatments with age, sex, smoking habits, thyroid volume, thyroid treatment, time since thyroid treatment, antithyroid-stimulating hormone receptor antibodies (TRAb), GO duration, GO features, and follow-up time. RESULTS: GO features improved after treatment, resulting in moderate and marked amelioration in ~75% and ~41% of patients respectively. By multivariate analysis, a moderate GO improvement correlated with diplopia at first observation, which was more severe in responders. A marked GO improvement correlated with time between first and last observation and time after thyroid treatment, which were longer in responders. This likely reflected the combination of an early effect of GC and a late, spontaneous improvement of GO, as shown by analyses of GO outcome at various time points. Additional treatments after ivGC correlated by multivariate analysis with eyelid aperture, diplopia and NOSPECS score (NOSPECS stands for no GO signs [N], only eyelid sign [O], soft tissue involvement [S], proptosis [P], extraocular motility restriction [E], corneal involvement [C], and sight loss [S]) at first observation, which were more severe in responders. CONCLUSION: Our study shows that response to ivGC increases with time, likely reflecting the known tendency of GO to improve spontaneously, and is more pronounced when GO is more severe to begin with, which is associated with more additional treatments. ABBREVIATIONS: ANOVA = analysis of variance CAS = clinical activity score GC = glucocorticoids GO = Graves orbitopathy 131I = radioactive iodine iv = intravenous ivGC = high-dose intravenous glucocorticoid pulse therapy MMI = methimazole OD = orbital decompression ORT = orbital radiotherapy TRAb = antithyroid-stimulating hormone receptor antibodies.

An update on the medical treatment of Graves' hyperthyroidism.

Medical treatment of Graves' hyperthyroidism is based on the use of thionamides; namely, methimazole and propylthiouracil. In the past, methimazole was preferred by European endocrinologists, whereas propylthiouracil was the first choice for the majority of their North American colleagues. However, because of the recent definition of a better side-effect profile, methimazole is nowadays the first choice world while. Although thionamides are quite effective for the short-term control of Graves' hyperthyroidism, a relatively high proportion of patients relapses after thionamide withdrawal. Other possible medical treatments, include iodine and compounds containing iodine, perchlorate, lithium (as an adjuvant in patients undergoing radioiodine therapy), ß-adrenergic antagonists, glucocorticoids, and some new molecules still under investigation. Management of Graves' hyperthyroidism using thionamides as well as the other available medical treatments is here reviewed in detail, with a special mention of situations such as pregnancy and lactation, as well as neonatal and fetal thyrotoxicosis.

Shared molecular amino acid signature in the HLA-DR peptide binding pocket predisposes to both autoimmune diabetes and thyroiditis.

There is strong genetic association between type 1A diabetes (T1D) and autoimmune thyroid disease (AITD). T1D and AITD frequently occur together in the same individual, a condition classified as a variant of the autoimmune polyglandular syndrome type 3 (APS3). Because T1D and AITD are individually strongly associated with different HLA class II sequences, we asked which HLA class II pocket sequence and structure confer joint susceptibility to both T1D and AITD in the same individual (APS3v). We sequenced the HLA-DR gene in 105 APS3v patients and 153 controls, and identified a pocket amino acid signature, DRß-Tyr-26, DRß-Leu-67, DRß-Lys-71, and DRß-Arg-74, that was strongly associated with APS3v (P = 5.4 × 10(-14), odds ratio = 8.38). Logistic regression analysis demonstrated that DRß-Leu-67 (P = 9.4 × 10(-13)) and DRß-Arg-74 (P = 1.21 × 10(-13)) gave strong independent effects on disease susceptibility. Structural modeling studies demonstrated that pocket 4 was critical for the development of T1D+AITD; all disease-associated amino acids were linked to areas of the pocket that interact directly with the peptide and, therefore, influence peptide binding. The disease-susceptible HLA-DR pocket was more positively charged (Lys-71, Arg-74) compared with the protective pocket (Ala-71, Gln-74). We conclude that a specific pocket amino acid signature confers joint susceptibility to T1D+AITD in the same individual by causing significant structural changes in the MHC II peptide binding pocket and influencing peptide binding and presentation. Moreover, Arg-74 is a major amino acid position for the development of several autoimmune diseases. These findings suggest that blocking the critical Arg-74 pocket might offer a method for treating certain autoimmune conditions.

Effective Inhibition of Thyroid Antigen Presentation Using Retro-Inverso Peptides in Experimental Autoimmune Thyroiditis: A Pathway Toward Immune Therapies of Thyroid Autoimmunity.

Background: Autoimmune thyroid diseases (AITD) represent the most common autoimmune diseases. However, current therapies focus on relieving the symptoms instead of curing AITD, and new therapies to reverse the autoimmune attack on the thyroid are needed. HLA-DRß1-Arg74 is the key HLA class II allele that triggers AITD by presenting pathogenic thyroglobulin (Tg) peptides that activate thyroid self-reactive T cells. We hypothesized that blocking the presentation of Tg peptides to T cells within the HLA-DRß1-Arg74 peptide binding cleft could reverse the autoimmune response to the thyroid in AITD. Methods: The approach we used to block Tg peptide presentation within HLA-DRß1-Arg74 is to design retro-inverso D-amino acid (RID) peptides that have high affinity to the HLA-DRß1-Arg74 peptide binding pocket. Results: By using computational approaches and molecular dynamics simulations, we designed two RID peptides, RT-15 and VT-15, that blocked peptide binding to recombinant HLA-DRß1-Arg74 molecule, as well as T cell activation in vitro. Furthermore, RT-15 and VT-15 blocked in vivo T cell activation by thyroglobulin in humanized NOD-DR3 mice induced with experimental autoimmune thyroiditis. Conclusions: In summary, we discovered two RID peptides that block thyroglobulin peptide binding to HLA-DRß1-Arg74 and their presentation to T cells in AITD. These findings set the stage for a personalized medicine therapeutic approach for AITD patients who carry the DRß1-Arg74 allele. This antigen-specific therapeutic strategy can potentially be extended to other autoimmune diseases.

Insights Into the Role of DNA Methylation and Gene Expression in Graves Orbitopathy.

CONTEXT: A role of DNA methylation in Graves orbitopathy (GO) has been proposed. OBJECTIVE: This work aimed to investigate DNA methylation and gene expression in orbital fibroblasts from control and GO patients, under basal conditions or following challenge with an anti- thyrotropin (TSH) receptor antibody (M22) or cytokines involved in GO; to investigate the relationship between DNA methylation and cell function (proliferation); and to perform a methylome analysis. METHODS: Orbital fibroblasts from 6 GO and 6 control patients from a referral center underwent methylome analysis of the whole genome. RESULTS: Global DNA methylation increased significantly both in control and GO fibroblasts on incubation with M22. Expression of 2 selected genes (CYP19A1 and AIFM2) was variably affected by M22 and interleukin-6. M22 increased cell proliferation in control and GO fibroblasts, which correlated with global DNA methylation. Methylome analysis revealed 19 869 DNA regions differently methylated in GO fibroblasts, encompassing 3957 genes and involving CpG islands, shores, and shelves. A total of 119 gene families and subfamilies, 89 protein groups, 402 biological processes, and 7 pathways were involved. Three genes found to be differentially expressed were concordantly hypermethylated or hypomethylated. Among the differently methylated genes, insulin-like growth factor-1 receptor and several fibroblast growth factors and receptors were included. CONCLUSION: We propose that, when exposed to an autoimmune environment, orbital fibroblasts undergo hypermethylation or hypomethylation of certain genes, involving CpG promoters, which results in differential gene expression, which may be responsible for functional alterations, in particular higher proliferation, and ultimately for the GO phenotype in vivo.

Joint genetic susceptibility to type 1 diabetes and autoimmune thyroiditis: from epidemiology to mechanisms.

Type 1 diabetes (T1D) and autoimmune thyroid diseases (AITD) frequently occur together within families and in the same individual. The co-occurrence of T1D and AITD in the same patient is one of the variants of the autoimmune polyglandular syndrome type 3 [APS3 variant (APS3v)]. Epidemiological data point to a strong genetic influence on the shared susceptibility to T1D and AITD. Recently, significant progress has been made in our understanding of the genetic association between T1D and AITD. At least three genes have been confirmed as major joint susceptibility genes for T1D and AITD: human leukocyte antigen class II, cytotoxic T-lymphocyte antigen 4 (CTLA-4), and protein tyrosine phosphatase non-receptor type 22. Moreover, the first whole genome linkage study has been recently completed, and additional genes will soon be identified. Not unexpectedly, all the joint genes for T1D and AITD identified so far are involved in immune regulation, specifically in the presentation of antigenic peptides to T cells. One of the lessons learned from the analysis of the joint susceptibility genes for T1D and AITD is that subset analysis is a key to dissecting the etiology of complex diseases. One of the best demonstrations of the power of subset analysis is the CTLA-4 gene in T1D. Although CTLA-4 showed very weak association with T1D, when analyzed in the subset of patients with both T1D and AITD, the genetic effect of CTLA-4 was significantly stronger. Gene-gene and genetic-epigenetic interactions most likely play a role in the shared genetic susceptibility to T1D and AITD. Dissecting these mechanisms will lead to a better understanding of the etiology of T1D and AITD, as well as autoimmunity in general.

Molecular amino acid signatures in the MHC class II peptide-binding pocket predispose to autoimmune thyroiditis in humans and in mice.

Hashimoto's thyroiditis (HT) is associated with HLA, but the associated allele is still controversial. We hypothesized that specific HLA-DR pocket-sequence variants are associated with HT and that similar variants in the murine I-E locus (homologous to HLA-DR) predispose to experimental autoimmune thyroiditis (EAT), a classical mouse model of HT. Therefore, we sequenced the polymorphic exon 2 of the HLA-DR gene in 94 HT patients and 149 controls. In addition, we sequenced exon 2 of the I-E gene in 22 strains of mice, 12 susceptible to EAT and 10 resistant. Using logistic regression analysis, we identified a pocket amino acid signature, Tyr-26, Tyr-30, Gln-70, Lys-71, strongly associated with HT (P = 6.18 x 10(-5), OR = 3.73). Lys-71 showed the strongest association (P = 1.7 x 10(-8), OR = 2.98). This association was seen across HLA-DR types. The 5-aa haplotype Tyr-26, Tyr-30, Gln-70, Lys-71, Arg-74 also was associated with HT (P = 3.66 x 10(-4)). In mice, the I-E pocket amino acids Val-28, Phe-86, and Asn-88 were strongly associated with EAT. Structural modeling studies demonstrated that pocket P4 was critical for the development of HT, and pockets P1 and P4 influenced susceptibility to EAT. Surprisingly, the structures of the HT- and EAT-susceptible pockets were different. We conclude that specific MHC II pocket amino acid signatures determine susceptibility to HT and EAT by causing structural changes in peptide-binding pockets that may influence peptide binding, selectivity, and presentation. Because the HT- and EAT-associated pockets are structurally different, it is likely that distinct antigenic peptides are associated with HT and EAT.

Statins for Graves' orbitopathy (STAGO): a phase 2, open-label, adaptive, single centre, randomised clinical trial.

BACKGROUND: A protective action of statins on development of Graves' orbitopathy suggests that statins might be used for treatment of the disease. We aimed to assess the efficacy of the addition of a statin, atorvastatin, to intravenous glucocorticoids (ivGCs) on Graves' orbitopathy outcomes in patients with hypercholesterolaemia. METHODS: We did a randomised, open-label, phase 2, adaptive, clinical trial at a single, tertiary, referral hospital in Pisa, Italy. Patients with moderate-to-severe, active Graves' orbitopathy, with a low-density lipoprotein cholesterol concentration between 2·97 and 4·88 mmol/L were eligible for inclusion. Patients were randomly assigned (1:1) in 11 blocks of eight, using a computer-based system, to the ST group or the NST group. The ST group received ivGCs (methylprednisolone 500 mg once a week for 6 weeks followed by 250 mg once a week for an additional six weeks) for 12 weeks and oral atorvastatin (20 mg once a day) for 24 weeks. The NST group only received the ivGC regimen. Patients were unmasked to group allocation; however, the ophthalmological investigator was masked to randomisation. The primary endpoint was the Graves' orbitopathy outcome (composite evaluation of exophthalmos, clinical activity score, eyelid aperture, and diplopia) at 24 weeks in the modified intention-to-treat (ITT) population (patients who attended the week 12 visit). Patients were considered responders when at least two of the following criteria were fulfilled in the most affected eye, without worsening in any of the same measures in both eyes: (1) reduction in exophthalmos of 2 mm or more, with no increase by 2 mm or more in the other eye; (2) reduction of clinical activity score by two or more points; (3) reduction in eyelid aperture by 2 mm or more, with no increase by 2 mm or more in the other eye; and (4) disappearance or improvement (change from constant to inconstant, intermittent, or absent, or from inconstant to intermittent or absent) of diplopia, and (5) improvement in visual acuity by 0·2 decimals or more. The trial is registered with EUDRACT, 2018-001317-33, and ClinicalTrials.gov, NCT03110848. FINDINGS: Between June 1, 2020, and Nov 30, 2020, 119 patients were screened for inclusion, of whom 88 (74%) patients were enrolled and randomly assigned to one of the two treatment groups (44 [50%] to the ST group and 44 [50%] to the NST group). Eight (9%) patients did not attend the 12 week visit; 80 (91%) patients (18 [23%] men and 62 [78%] women) were included in the modified ITT population (41 [51%] in the ST group and 39 [49%] in the NST group]. The proportion of Graves' orbitopathy composite evaluation responders at 24 weeks was higher in the ST group (21 [51%] of 41 patients) than the NST group (11 [28%] of 39 patients; attributable risk 0·23 [95% CI 0·02-0·44]; p=0·042). 26 adverse events occurred in 21 (24%) of 88 patients in the safety population. One (2%) of 44 patients in each group required treatment discontinuation, with no serious adverse events and no difference between groups. INTERPRETATION: Addition of oral atorvastatin to an ivGC regimen improved Graves' orbitopathy outcomes in patients with moderate-to-severe, active eye disease who were hypercholesterolaemic. Future phase 3 studies, which could potentially recruit patients regardless of low-density lipoprotein cholesterol concentration, are required to confirm this association. FUNDING: Associazione Allievi Endocrinologia Pisana.

Cepharanthine Blocks Presentation of Thyroid and Islet Peptides in a Novel Humanized Autoimmune Diabetes and Thyroiditis Mouse Model.

Autoimmune polyglandular syndrome type 3 variant (APS3v) refers to an autoimmune condition in which both type 1 diabetes (T1D) and autoimmune thyroiditis (AITD) develop in the same individual. HLA-DR3 confers the strongest susceptibility to APS3v. Previously we reported a unique amino acid signature pocket that predisposes to APS3v. We found that this pocket is flexible and can trigger APS3v by presenting both thyroid (Tg.1571, TPO.758) and islet (GAD.492) peptides to induce autoimmune response. We hypothesized that blocking the specific APS3v-HLA-DR3 pocket from presenting thyroid/islet antigens can block the autoimmune response in APS3v. To test this hypothesis we performed a virtual screen of small molecules blocking APS3v-HLA-DR3, and identified 11 small molecules hits that were predicted to block APS3v-HLA-DR3. Using the baculovirus-produced recombinant APS3v-HLA-DR3 protein we tested the 11 small molecules in an in vitro binding assay. We validated 4 small molecule hits, S9, S5, S53 and S15, that could block the APS3v-HLA-DR3 pocket in vitro. We then developed a novel humanized APS3v mouse model induced by co-immunizing a peptide mix of Tg.1571, TPO.758 and GAD.492. The immunized mice developed strong T-cell and antibody responses to the thyroid/islet peptides, as well as mouse thyroglobulin. In addition, the mice showed significantly lower free T4 levels compared to controls. Using the APS3v mouse model, we showed that one of the 4 small molecules, Cepharanthine (S53), blocked T-cell activation by thyroid/islet peptides ex vivo and in vivo. These findings suggested Cepharanthine may have a therapeutic potential in APS3v patients carrying the specific APS3v-HLA-DR3 pocket.

Employing a recombinant HLA-DR3 expression system to dissect major histocompatibility complex II-thyroglobulin peptide dynamism: a genetic, biochemical, and reverse immunological perspective.

Previously, we have shown that statistical synergism between amino acid variants in thyroglobulin (Tg) and specific HLA-DR3 pocket sequence signatures conferred a high risk for autoimmune thyroid disease (AITD). Therefore, we hypothesized that this statistical synergism mirrors a biochemical interaction between Tg peptides and HLA-DR3, which is key to the pathoetiology of AITD. To test this hypothesis, we designed a recombinant HLA-DR3 expression system that was used to express HLA-DR molecules harboring either AITD susceptibility or resistance DR pocket sequences. Next, we biochemically generated the potential Tg peptidic repertoire available to HLA-DR3 by separately treating 20 purified human thyroglobulin samples with cathepsins B, D, or L, lysosomal proteases that are involved in antigen processing and thyroid biology. Sequences of the cathepsin-generated peptides were then determined by matrix-assisted laser desorption ionization time-of-flight-mass spectroscopy, and algorithmic means were employed to identify putative AITD-susceptible HLA-DR3 binders. From four predicted peptides, we identified two novel peptides that bound strongly and specifically to both recombinant AITD-susceptible HLA-DR3 protein and HLA-DR3 molecules expressed on stably transfected cells. Intriguingly, the HLA-DR3-binding peptides we identified had a marked preference for the AITD-susceptibility DR signatures and not to those signatures that were AITD-protective. Structural analyses demonstrated the profound influence that the pocket signatures have on the interaction of HLA-DR molecules with Tg peptides. Our study suggests that interactions between Tg and discrete HLA-DR pocket signatures contribute to the initiation of AITD.

Tg.2098 is a major human thyroglobulin T-cell epitope.

An HLA-DR variant containing Arginine at position 74 of the DRbeta1 chain confers a strong genetic susceptibility to autoimmune thyroid diseases (AITD), Graves' disease (GD) and Hashimoto's thyroiditis (HT), while Glutamine at position DRbeta1-74 is protective. We hypothesized that the DRbeta1-Arg74 variant is able to present pathogenic thyroglobulin (Tg) peptides to T-cells more efficiently, thereby triggering thyroid autoimmunity. Indeed, we have previously identified 4 human Tg (hTg) peptides that bind specifically to DRbeta1-Arg74 with much weaker binding to the protective variant DRbeta1-Gln74. The aim of our study was to examine in vivo whether an hTg peptide that binds strongly and specifically to DRbeta1-Arg74 is capable of stimulating T-cells during the induction of thyroiditis in a "humanized" mouse expressing human DR3, and in patients positive for Tg antibodies. Sequencing of exon 2 of the DR transgene in the DR3 mice, null for endogenous MHC II molecules, confirmed that they expressed the disease-associated DRbeta1-Arg74 variant, thus making them an ideal in vivo model to test the presentation of hTg peptides by DRbeta1-Arg74 HLA-DR. Induction of EAT in the DR3 mice lead to T-cell stimulation and proliferation to Tg.2098, a strong and specific DRbeta1-Arg74 binder, while a non-binding control peptide, Tg.2766 did not induce this response. Moreover, Tg.2098 stimulated T-cells from 4 individuals who were positive for thyroglobulin antibodies, demonstrating that Tg.2098 is an immunogenic peptide capable of being presented in vivo and activating T-cells in EAT and AITD. Energetic analysis of the complex formed by Tg.2098 and DRbeta-Arg74 has shown that the origin of the affinity was determined by residues 1, 7 and 9 in the peptide, while the selectivity of the peptide for the MHC was determined by the Asp in position 4. The disease-protective substitution R74Q, leads to reduction in affinity due to changes in local interaction with D4 as well as non-local interaction with other residues. The electrostatic potential on the surface of the DRbeta-Arg74-Tg.2098 complex has a unique signature which may be recognized by T-cell receptors leading to autoimmune thyroiditis. Taken together these findings suggest that Tg.2098, a strong and specific binder to the disease-associated HLA-DRbeta-Arg74, is a major human T-cell epitope and participant in the pathoetiology of AITD.

A Case of Unilateral Dermopathy Possibly Related to Graves' Disease.

BACKGROUND: The pathogenesis of the extrathyroidal manifestations of Graves' disease (GD) is not fully clarified. According to the most common hypothesis, they would reflect an autoimmune reaction against antigens constitutively expressed by the thyroid and by the extrathyroidal affected tissues. According to another hypothesis, the so-called Kriss' hypothesis, soluble autoantigens released from the thyroid would reach the affected tissues, where they would become the target of the immune system. In this regard, a shift in gravity during sleep may favour antigen deposition. CASE REPORT: A 59-year old man with GD came to our observation because of a dermopathy. He had been treated with radioactive iodine for Graves' hyperthyroidism and with glucocorticoids and orbital decompression for a bilateral Graves' orbitopathy (GO). The patient complained of a monolateral, untreated dermopathy, affecting the left leg and hand. At physical examination the skin of the left pretibial area and of the dorsal surface of the left hand appeared red and thickened, with an orange peel aspect. Interestingly, the patient reported that he usually slept laying on the left side of his body. DISCUSSION: The observation of a patient with a monolateral dermopathy somehow reports to the Kriss' hypothesis, especially in view of the patient's habit of sleeping on the same side as dermopathy was present. Of course, this does not represent a proof that the Kriss' hypothesis is correct, but it carries an element in favour of it. The fact that GO was bilateral is somehow against it, but does not exclude this possibility.

High Serum Cholesterol Is a Novel Risk Factor for Graves' Orbitopathy: Results of a Cross-Sectional Study.

BACKGROUND: Limited data suggest that treatment with statins is associated with a reduced risk of Graves' orbitopathy (GO) in patients with Graves' disease (GD), attributed to the anti-inflammatory rather than to the hypolipemic effects of these medications. The aim of the present study was to investigate whether there is an association between high cholesterol and GO. The primary outcome was the relation between GO and low-density lipoprotein (LDL)-cholesterol. The secondary outcomes were the relation between severity or activity (the clinical activity score [CAS]) of GO and LDL-cholesterol. METHODS: A cross-sectional investigation was conducted in consecutive patients with GD who came under the authors' observation to undergo radioiodine treatment, a stratification aimed at forming two distinct groups of patients under the same conditions. A total of 250 patients were enrolled, 133 with and 117 without GO. Ophthalmological assessments and serum lipids measurements were performed. RESULTS: In multivariate analyses with correction for the duration of hyperthyroidism, a variable that differed between patients with respect to the presence or absence of GO, a correlation between the presence of GO and both total (p = 0.01) and LDL-cholesterol (p = 0.02) was observed. In patients with hyperthyroidism lasting <44 months, total and LDL-cholesterol were higher (p = 0.01 and p = 0.008, respectively) among GO patients. In this subgroup, based on the presence/absence of GO, cutoff values were established for total (191 mg/dL) and LDL-cholesterol (118.4 mg/dL), above which an increased risk of GO was observed (total cholesterol relative risk: 1.47; p = 0.03; LDL-cholesterol relative risk: 1.28; p = 0.03). GO severity and CAS did not correlate with serum lipids. However, CAS was found to be higher (p = 0.02) in patients with high total cholesterol. When the analysis was restricted to untreated GO patients, a correlation was found between CAS and both total (p = 0.04) and LDL-cholesterol (p = 0.03), after adjustment for GO duration. CONCLUSIONS: In patients with a short duration of hyperthyroidism, total and LDL-cholesterol correlate with the presence of GO, suggesting a role of cholesterol in the development of GO. Depending on GO duration, total and LDL-cholesterol correlate with GO activity, suggesting a role of cholesterol in the clinical expression of GO.

Association of T and B Cells Infiltrating Orbital Tissues With Clinical Features of Graves Orbitopathy.

Importance: Graves orbitopathy (GO) responds to immunosuppressive treatments when clinically active but poorly when inactive. In other autoimmune diseases, response has been ascribed to a reduction in lymphocytes infiltrating the target organ. It is not known whether active vs inactive GO differs in this regard, which would help in understanding the link between GO immunologic features and clinical behavior. Objective: To investigate the association between orbital lymphocytic infiltrate and GO clinical features. Design, Setting, and Participants: A cohort study aimed at assessing the extent and immunohistochemical phenotype of orbital lymphocytes and associating it with the ophthalmologic features of GO, especially its clinical activity score (CAS), was conducted at a tertiary referral center. Twenty consecutive patients with GO who underwent orbital decompression were included. The study was conducted from January 1 to May 31, 2017. Exposures: Orbital tissue histology and immunohistochemistry testing as well as ophthalmologic evaluation. Main Outcomes and Measures: Association between CAS and orbital lymphocytes, analyzed as total number of lymphocytes and main lymphoid subsets. Results: The patient population included 8 men and 12 women, all of white race, with a mean (SD) age of 46 (13) years. With an established cutoff value of 300 lymphoid cells per tissue sample, lymphocytes above this value were found in orbital tissues of 9 of 20 patients (45%), often organized into distinct foci. The lymphocytes comprised a mixture of T (CD3-positive) and B (CD20-positive) cells, suggesting a mature, polyclonal autoimmune response. In a simple linear regression model, the total number of lymphocytes, as well as the number of CD3- and CD20-positive subsets, correlated with CAS (R = 0.63; 95% CI, 0.27-0.84; P = .003; R = 0.59; 95% CI, 0.20-0.82; P = .006; and R = 0.65; 95% CI, 0.30-0.85; P = .002, respectively). In a multiple linear regression model, lymphocytes maintained their effect on CAS when adjusted for 2 additional variables that were correlated with CAS-smoking and GO duration-highlighting even more the important role of orbital lymphocytes in affecting CAS (total number: R = 0.58; 95% CI, 0.18-0.82; P = .01; CD3-positive: R = 0.58; 95% CI, 0.17-0.82; P = .01; and CD20-positive: R = 0.59; 95% CI, 0.19-0.83; P = .01). Conclusions and Relevance: This study shows a correlation between T and B lymphocytes infiltrating orbital tissues and the activity of GO, possibly enhancing our understanding of the association between GO immunologic features and clinical expression.