Rituximab (Rituxan) therapy for severe thyroid-associated ophthalmopathy diminishes IGF-1R(+) T cells

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.

Graves disease: latest understanding of pathogenesis and treatment options

Graves disease is the most common cause of hyperthyroidism in iodine-sufficient areas. The main responsible mechanism is related to autoantibodies that bind and activate the thyrotropin receptor (TSHR). Although Graves hyperthyroidism is relatively common, no causal treatment options are available. Established treatment modalities are antithyroid drugs, which reduce thyroid hormone synthesis, radioactive iodine and surgery. However, emerging drugs that target the main autoantigen (monoclonal antibodies, small molecules, peptides) or block the immune pathway have been recently tested in clinical trials. Graves disease can involve the thyroid exclusively or it can be associated with extrathyroidal manifestations, among which Graves orbitopathy is the most common. The presence of Graves orbitopathy can change the management of the disease. An established treatment for moderate-to-severe Graves orbitopathy is intravenous glucocorticoids. However, recent advances in understanding the pathogenesis of Graves orbitopathy have allowed the development of new target-based therapies by blocking pro-inflammatory cytokine receptors, lymphocytic infiltration or the insulin-like growth factor 1 receptor (IGF1R), with several clinical trials providing promising results. This article reviews the new discoveries in the pathogenesis of Graves hyperthyroidism and Graves orbitopathy that offer several important tools in disease management.

Monoclonal Antibodies for the Treatment of Graves Orbitopathy: Precision Medicine?

PURPOSE

To summarize the development, nomenclature, and rationale of the reported use of monoclonal antibodies (Mabs) in Graves Orbitopathy (GO) and to undertake a systematic review of the management of GO with Mabs.

METHODS

The Pubmed and Embase databases and the Federal Brazilian searching site (Periódicos-CAPES) were screened. The authors searched all the keywords "monoclonal antibodies," "adalimumab," "belimumab," "infliximab," "rituximab," "teprotumumab," and "tocilizumab" combined with the terms "Graves Orbitopathy," "Graves eye disease" and "thyroid eye disease." All the articles published in English, French, and Spanish from 2000 to May 2022 were screened. Only publications with quantitative data on the activity of orbitopathy, proptosis, or both were included.

RESULTS

Seventy-six articles of the 954 screened records met the inclusion criteria. Seven Mabs were described for treating GO. The three most reported Mabs were Rituximab, Tocilizumab, and Teprotumumab. Only eight randomized clinical trials compared the effect of these three Mabs and Belimumab with the effect of steroids or placebos. Adalimumab, Infliximab, and K1-70 only appeared in a few case series and case reports. Frequent mild-to-moderate and few major side effects occurred with the three most used Mabs. Relapse rates ranged from 7.4% for Tocilizumab to at least 29.4% for Teprotumumab. No randomized clinical trials compared Mabs head-to-head.

CONCLUSION

Considering the lack of head-to-head comparisons between Mabs, the relapse rate, the possibility of severe collateral effects, and the cost of Mabs, it is not clear which Mab is the safest and most useful to treat GO.

Prostaglandin F2α Regulates Adipogenesis by Modulating Extracellular Signal-Regulated Kinase Signaling in Graves' Ophthalmopathy

Prostaglandin F2α (PGF2α), the first-line anti-glaucoma medication, can cause the deepening of the upper eyelid sulcus due to orbital lipoatrophy. However, the pathogenesis of Graves' ophthalmopathy (GO) involves the excessive adipogenesis of the orbital tissues. The present study aimed to determine the therapeutic effects and underlying mechanisms of PGF2α on adipocyte differentiation. In this study primary cultures of orbital fibroblasts (OFs) from six patients with GO were established. Immunohistochemistry, immunofluorescence, and Western blotting (WB) were used to evaluated the expression of the F-prostanoid receptor (FPR) in the orbital adipose tissues and the OFs of GO patients. The OFs were induced to differentiate into adipocytes and treated with different incubation times and concentrations of PGF2α. The results of Oil red O staining showed that the number and size of the lipid droplets decreased with increasing concentrations of PGF2α and the reverse transcription-polymerase chain reaction (RT-PCR) and WB of the peroxisome proliferator-activated receptor γ (PPARγ) and fatty-acid-binding protein 4 (FABP4), both adipogenic markers, were significantly downregulated via PGF2α treatment. Additionally, we found the adipogenesis induction of OFs promoted ERK phosphorylation, whereas PGF2α further induced ERK phosphorylation. We used Ebopiprant (FPR antagonist) to interfere with PGF2α binding to the FPR and U0126, an Extracellular Signal-Regulated Kinase (ERK) inhibitor, to inhibit ERK phosphorylation. The results of Oil red O staining and expression of adipogenic markers showed that blocking the receptor binding or decreasing the phosphorylation state of the ERK both alleviate the inhibitory effect of PGF2a on the OFs adipogenesis. Overall, PGF2α mediated the inhibitory effect of the OFs adipogenesis through the hyperactivation of ERK phosphorylation via coupling with the FPR. Our study provides a further theoretical reference for the potential application of PGF2α in patients with GO.

Current concepts regarding Graves' orbitopathy

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

Mechanisms That Underly T Cell Immunity in Graves' Orbitopathy

Graves' orbitopathy (GO), also known as thyroid-associated ophthalmopathy, is the most common ocular abnormality of Graves' disease. It is a disfiguring, invalidating, and potentially blinding orbital disease mediated by an interlocking and complicated immune network. Self-reactive T cells directly against thyroid-stimulating hormone receptor-bearing orbital fibroblasts contribute to autoimmune inflammation and tissue remodeling in GO orbital connective tissues. To date, T helper (Th) 1 (cytotoxic leaning) and Th2 (antibody leaning) cell subsets and an emerging role of Th17 (fibrotic leaning) cells have been implicated in GO pathogenesis. The potential feedback loops between orbital native residential CD34^- fibroblasts, CD34⁺ infiltrating fibrocytes, and effector T cells may affect the T cell subset bias and the skewed pattern of cytokine production in the orbit, thereby determining the outcomes of GO autoimmune reactions. Characterization of the T cell subsets that drive GO and the cytokines they express may significantly advance our understanding of orbital autoimmunity and the development of promising therapeutic strategies against pathological T cells.

Thyroid eye disease: current and potential medical management

INTRODUCTION

Thyroid eye disease (TED) is the most frequent extra-thyroid manifestation of Graves' disease and it is more frequent in middle age and in female gender. Nowadays, the causal mechanisms of this disease are not completely understood, but the current available studies suggest that the main causative factor is the thyroid stimulating hormone receptor.

MATERIALS AND METHODS

To collect reports on TED medical management, a thorough literature search was performed in PubMed database. An additional search was made in Google Scholar to complete the collected items.

RESULTS

Among the indentified risk factors, tobacco habit is the most relevant. The main criteria to choose a suitable treatment are the activity and severity of the disease. Support measures can be used to improve the patient's symptoms in any phase of the disease. There is a large number of drugs proposed to manage TED, although with different reported rates of success.

CONCLUSIONS

Currently, the drugs of choice are corticosteroids in moderate-to-severe and in sight-threatening forms. The main problem of corticosteroids is their spectrum of side effects. Therefore, other alternatives are being suggested for medical management of this disease. The efficacy of these alternatives remains unclear.

Fingolimod Improves the Outcome of Experimental Graves' Disease and Associated Orbitopathy by Modulating the Autoimmune Response to the Thyroid-Stimulating Hormone Receptor

Graves' disease (GD) and Graves' orbitopathy are associated with stimulating thyrotropin receptor (TSHR) autoantibodies and autoreactive T cells. Recent in vitro studies suggested that sphingosine-1-phosphate (S1P) signaling is involved in the pathogenesis of orbitopathy. In this study, we explored the immune modulatory potential of S1P receptor antagonist fingolimod in a murine model for GD. Fingolimod was orally administered preventively during disease onset or therapeutically after disease onset. Administration of fingolimod during disease onset completely prevented the formation of TSHR-stimulating autoantibodies. Intervention after disease onset rarely reduced TSHR-stimulating autoantibodies and blocking autoantibodies were induced in some animals. Consequently, autoimmune hyperthyroidism characterized by elevated serum thyroxin levels, hyperplastic thyroid morphology accompanied by T cell infiltration, weight gain, enhanced body temperature, and tachycardia did not manifest preventively and showed milder manifestation in therapeutically treated animals. Importantly, examination of orbital tissue showed significant amelioration of orbitopathy manifestations through reduction of T cell infiltration, adipogenesis, and hyaluronan deposition. Autoimmune hyperthyroidism and orbitopathy were accompanied by changes in peripheral and splenic T cell proportions with high CD3⁺, CD4⁺, and CD8⁺ T cells. Activated T cells CD4⁺CD25⁺ were elevated whereas regulatory T cells CD4⁺Foxp3⁺ cells remained unchanged in spleens. Fingolimod decreased elevated T cell levels and increased CD4⁺CD25⁺Foxp3⁺ regulatory T cell populations. Analysis of total disease outcome revealed that treatment during disease onset protected animals against autoimmune hyperthyroidism and orbitopathy. Of note, therapeutic intervention after disease onset suppressed disease in half of the animals and in the other half disease remained at mild stages. The results of this study support a clinical trial to investigate the immunologic and clinical benefits of early treatment with S1P-based drugs in GD.

B cells in Graves' Orbitopathy: more than just a source of antibodies?

B cells have multiple actions on different phases of an immune reaction, mainly resulting in B and T cell-interaction (help), production of cytokines, regulation of dendritic cells and downregulation of regulatory B cells. The effectiveness of B cell depletion therapy is probably due to blockade of the antigen-presenting function of B cells, occurring very early in the setting of autoimmune reactions. B cells undergo a maturation process from stem cells during which the CD 20 antigen, which is the target of rituximab (RTX), is expressed from the stage of pre-B cells to mature and memory B cells, but not on plasma cells. During the maturation process, the cytokine B cell stimulating factor (BAFF) induces maturation of B cells and expansion of clones to produce plasma cells and eventually antibodies. The effect of RTX in GO is rather rapid, with significant improvement of the disease already 4-6 weeks after the first RTX infusion. Based on the evidence of significant lymphocytic infiltration in the orbits of patients with active GO, it is reasonable to postulate that RTX may cause depletion of B cells and block their antigen-presenting cell mechanism. Since it has been reported that serum BAFF concentrations are elevated in hyperthyroid GD patients and that BAFF is expressed on the thyrocytes of patients with either autoimmune disease or nodular goiter, the hypothesis that belimumab, an anti-BAFF monoclonal antibody, may be effective in patients with active GO his currently being tested in a randomized controlled trial.

Thyroid-Associated Orbitopathy and Biomarkers: Where We Are and What We Can Hope for the Future

Background

Thyroid-associated orbitopathy (TAO) is the most common autoimmune disease of the orbit. It occurs more often in patients presenting with hyperthyroidism, characteristic of Graves' disease, but may be associated with hypothyroidism or euthyroidism. The diagnosis of TAO is based on clinical orbital features, radiological criteria, and the potential association with thyroid disease. To date, there is no specific marker of the orbital disease, making the early diagnosis difficult, especially if the orbital involvement precedes the thyroid dysfunction.

Summary

The goal of this review is to present the disease and combine the available data in the literature concerning investigation of TAO biomarkers.

Conclusions

Despite the progress done in the understanding of TAO disease, some important pieces are still missing. Typically, for the future, major efforts have to be done in the discovery of new biomarkers, validation of the suspected candidates on multicenter cohorts with standardized methodologies, and establishment of their clinical performances on the specific clinical application fields in order to improve not only the management of the TAO patients but also the therapeutic options and follow-up.

Does rituximab improve clinical outcomes of patients with thyroid-associated ophthalmopathy? A systematic review and meta-analysis

BACKGROUND

The current therapies of thyroid-associated ophthalmopathy (TAO) were still a challenging matter. In this study, we aimed to contrast the impact of before- after rituximab (RTX) therapy in the patients with TAO.

METHODS

We searched the PubMed, EMBASE, and SCOPUS databases for articles published up to July 3, 2017. Fixed- or random-effects meta-analysis was used to provide pooled estimates of standard mean difference (SMD) both the primary outcome from clinical activity score (CAS), and secondary outcomes from thyrotropin receptor antibody (TRAb), proptosis, thyroid stimulating hormone (TSH), and interleukin-6 (IL-6) levels. In addition, the quality and each study was assessed using either the Newcastle Ottawa Scale (NOS) or the Cochrane Risk of Bias tool, and reliability of the meta-analytic result using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Of the 839 articles initially searched, 11 studies were finally eligible for inclusion. Subgroup analysis results showed that comparing with initial value, there was a decline in CAS at 1,3,6,12 month after RTX treatment, decreased TRAbs level at 6,12 month, proptosis improvement at least 1 month, unchanged IL-6 level at 6 month, decreased TSH level at 3 month but unchanged at 12 month. All included studies were classified as good quality.

CONCLUSIONS

The pooled data suggested that the preliminary effects of RTX treatment on TAO might be promising. However, more large-sample and high-quality studies targeting RTX use during this disease and long-term surveillance of prognosis are urgently needed.

IGF-1R signalling contributes to IL-6 production and T cell dependent inflammation in rheumatoid arthritis

BACKGROUND

Signalling through insulin-like growth factor 1 receptor (IGF-1R) is essential for cell survival, but may turn pathogenic in uncontrolled tissue growth in tumours. In rheumatoid arthritis (RA), the IGF-1R signalling is activated and supports expansion of the inflamed synovia.

AIM

In the present study, we assess if disruption of IGF-1R signalling resolves arthritis.

MATERIAL AND METHODS

Clinical associations of IGF-1R expression in leukocytes of the peripheral blood were studied in 84 RA patients. Consequences of the IGF-1R signalling inhibition for arthritis were studied in mBSA immunised Balb/c mice treated with NT157 compound promoting degradation of insulin receptor substrates.

RESULTS

In RA patients, high expression of IGF-1R in leukocytes was associated with systemic inflammation as verified by higher expression of NF-kB, serum levels of IL6 and erythrocyte sedimentation rate, and higher pain perception. Additionally, phosphorylated IGF-1R and STAT3 enriched T cells infiltrate in RA synovia. Treatment with NT157 inhibited the phosphorylation of IGF-1R and STAT3 in synovia, and alleviated arthritis and joint damage in mice. It also reduced expression of IGF-1R and despaired ERK and Akt signalling in spleen T cells. This limited IL-6 production, changed RoRgt/FoxP3 balance and IL17 levels.

CONCLUSION

IGF-1R signalling contributes to T cell dependent inflammation in arthritis. Inhibition of IGF-1R on the level of insulin receptor substrates alleviates arthritis by restricting IL6-dependent formation of Th17 cells and may open for new treatment strategies in RA.

Orbital fibroblasts of Graves' orbitopathy stimulated with proinflammatory cytokines promote B cell survival by secreting BAFF

The success of rituximab for the treatment of active Graves' orbitopathy (GO) suggests that B cells play a critical role in intraorbital inflammation. B cell activating factor (BAFF) and its homolog a proliferation-inducing ligand (APRIL) are critical for B cell survival. However, the contribution of BAFF/APRIL to GO remains unclear. We sought to determine the role of BAFF/APRIL in the orbits of GO, and found that BAFF was markedly upregulated, while APRIL was not. Additionally, cultured GO orbital fibroblasts (GO-OFs)² expressing BAFF were induced to produce a large amount of BAFF. In contrast, a weak APRIL expression was detected in the OFs, and they exhibited a slight response to stimulation. Notably, pretreated GO-OFs promoted B cell survival, and this effect was significantly inhibited by a BAFF-R neutralizing antibody. This study indicates that OFs from GO can express BAFF and mediate the intraorbital survival of B cells via BAFF mechanism.

Update on thyroid-associated Ophthalmopathy with a special emphasis on the ocular surface

Thyroid-associated ophthalmopathy (TAO) is a condition associated with a wide spectrum of ocular changes, usually in the context of the autoimmune syndrome, Graves’ disease. In this topical review, we attempted to provide a roadmap of the recent advances in current understanding the pathogenesis of TAO, important aspects of its clinical presentation, its impact on the ocular surface, describe the tissue abnormalities frequently encountered, and describe how TAO is managed today. We also briefly review how increased understanding of the disease should culminate in improved therapies for patients with this vexing condition.

Immunotherapy for Graves' ophthalmopathy

PURPOSE OF REVIEW

In recent years, immunosuppressive therapy, as an alternative to corticosteroids, has been proposed as novel agents which target the various antigens involved in the pathogenesis of Graves' ophthalmopathy. Although the lack of randomized and controlled studies suggests caution in generalizing results, some data show interesting results.

RECENT FINDINGS

Potential targets for immune therapy in Graves' ophthalmopathy are the antigens expressed on the target organ of inflammation, namely the receptor and the insulin growth factor -1 receptor on fibroblasts, inflammatory cytokines, and B and T cells. The most promising results are observed with small thyroid stimulating hormone receptor molecules interacting with the receptor on thyrocytes and fibroblasts and with the anti-IGF-1 receptor antibody teprotumumab. A recent open study with tocilizumab, an anti-soluble interleukin-6 receptor, has shown inactivation of Graves' ophthalmopathy. Consistent reports on the efficacy of rituximab will have to be confirmed by randomized controlled trials, which are now in progress.

SUMMARY

Current clinical practice for Graves' ophthalmopathy will greatly benefit from the availability of immunosuppressors that act as disease-modifying drugs, as compared to steroids, the current standard treatment for Graves' ophthalmopathy. Rituximab seems to be a good candidate, as preliminary results from ongoing randomized trials suggest good efficacy with a relative well tolerated profile.