B Cell Activating Factor (BAFF) and BAFF Receptor Expression in Autoimmune and Nonautoimmune Thyroid Diseases

Graves' Disease: Is It Time for Targeted Therapy? A Narrative Review

Current therapies for Graves' disease (GD) primarily aim to manage hyperthyroidism through synthetic antithyroid drugs, radioiodine, or surgery. However, these approaches are often limited by their incomplete efficacy and the risk of inducing hypothyroidism. The latest advances in understanding the autoimmune mechanisms driving GD have paved the way for novel therapies targeting the thyrotropin receptor (TSH-R) or immune pathways. Overall, key targets include cluster of differentiation 20 (CD20), cluster of differentiation 40 (CD40), protein tyrosine phosphatase non-receptor type 22 (PTPN22), cytotoxic T lymphocyte antigen-4 (CTLA-4), B cell-activating factor (BAFF), and the Fc receptor-like protein 3 (FcRL3). Recent preclinical studies and clinical trials testing targeted therapies have shown promising results in terms of efficacy and safety. Here, we present a narrative review of the literature on emerging therapeutic approaches for GD that are currently under investigation.

Supplementation with active vitamin D3 ameliorates experimental autoimmune thyroiditis in mice by modulating the differentiation and functionality of intrathyroidal T-cell subsets

Objective

People with Hashimoto's thyroiditis (HT) often have low vitamin D3 concentrations. Some research has suggested that vitamin D3 supplementation reduces thyroid inflammation, but this remains controversial.

Methods

EAT was induced in female NOD/ShiLtJ mice by giving them water containing 0.05% sodium iodide, and 1μg/kg of 1α,25-(OH)2D3 was injected intraperitoneally every other day. After 8 weeks, the morphological architecture of the mouse thyroid follicles was examined by histological sections, thyroid autoantibodies and thyroid hormone concentrations were determined by enzyme-linked immunosorbent assays (ELISAs), and the major functions and subsets of B- and T-lymphocytes in the mouse thyroid were determined by tissue multiple immunofluorescence technology and ELISA.

Results

EAT caused thyroiditis follicle destruction and interfollicular lymphocyte infiltration in mice, increased concentrations of circulating thyroid autoimmune antibodies TG-Ab and TPO-Ab, and abnormal thyroid hormone levels. EAT also increased the number and functionality of CD4+ Tfh, Th17,Th1 and Th2 cells in the thyroid, while decreasing the number and functionality of CD4+ Treg cells and CD19+B10 cells. Treatment with VD3 reversed these changes.

Conclusion

Vitamin D3 supplementation can effectively treat autoimmune thyroiditis in mice. VD3 reduces autoimmune thyroid damage and decreases serum thyroid antibody levels in mice by inhibiting the differentiation and functionality of pro-inflammatory Tfh, Th17, Th1 and Th2 cells and by facilitating the differentiation and functionality of anti-inflammatory B10 cells and Treg.

Novel perspectives on the pharmacological treatment of thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO), an autoimmune disease closely related to thyroid dysfunction, remains a challenging ophthalmic condition among adults. Its clinical manifestations are complex and diverse, and disease progression can lead to exophthalmos, diplopia, exposure keratitis, corneal ulceration, and compressive optic neuropathy, resulting in irreversible vision damage or even blindness. Traditional treatment methods for TAO, including glucocorticoids, immunosuppressants, and radiation therapy, often have limitations and side effects, making this disease problematic in ophthalmology. As a result, the development of novel targeted drugs has become a research hotspot for addressing the pathogenesis of TAO. A range of novel targeted drugs, such as teprotumumab and tocilizumab, have been successfully developed and demonstrated remarkable efficacy in relieving inflammation and managing this disease. In addition, some drug candidates and molecular targets identified in the TAO in vitro model have shown promising prospects. This article briefly reviews the potential new strategies for future clinical treatment and the progress of new drug therapies for TAO.

Ocular immune-related diseases: molecular mechanisms and therapy

Ocular immune-related diseases, represent a spectrum of conditions driven by immune system dysregulation, include but not limit to uveitis, diabetic retinopathy, age-related macular degeneration, Graves' ophthalmopathy, etc. The molecular and cellular mechanisms underlying these diseases are typically dysfunctioned immune responses targeting ocular tissues, resulting in inflammation and tissue damage. Recent advances have further elucidated the pivotal role of different immune responses in the development, progression, as well as management of various ocular immune diseases. However, there is currently a relative lack of connection between the cellular mechanisms and treatments of several immune-related ocular diseases. In this review, we discuss recent findings related to the immunopathogenesis of above-mentioned diseases. In particular, we summarize the different types of immune cells, inflammatory mediators, and associated signaling pathways that are involved in the pathophysiology of above-mentioned ophthalmopathies. Furthermore, we also discuss the future directions of utilizing anti-inflammatory regime in the management of these diseases. This will facilitate a better understanding of the pathogenesis of immune-related ocular diseases and provide new insights for future treatment approaches.

Polymorphisms of B-lymphocyte-associated genes CD20 and FCRL5 are associated with susceptibility to autoimmune thyroid diseases

BACKGROUND

Recent studies have confirmed that B cell-related genes CD20 and FCRL5 may be involved in the pathogenesis of autoimmune thyroid diseases (AITDs). However, there is a lack of comprehensive genetic susceptibility studies on this subject.

OBJECTIVE

The purpose of this study was to investigate the relationship of CD20 and FCRL5 gene polymorphisms with AITD susceptibility.

METHODS

A total of 1740 subjects were recruited from the Chinese Han population. They consisted of 1007 patients with AITD and 633 healthy controls. Multiplex polymerase chain reaction (PCR) combined with high-throughput sequencing was used to genotype four screened single nucleotide polymorphisms (SNPs). The four SNPs were rs7126354 of CD20 and rs6667109, rs6692977 and rs3811035 of FCRL5.

RESULTS

The minor allele frequency of rs7126354 was significantly lower in patients with AITD and Hashimoto's thyroiditis (HT) than in healthy controls (P = 0.031; P = 0.017). The minor allele frequency of rs6667109 was significantly higher in the Graves' disease (GD) subgroup than in the healthy control group (P = 0.029). In the Log-additive model, rs6667109 in the GD group also showed an increased risk of onset disease.

CONCLUSIONS

This study presents robust evidence of a genetic association of CD20 and FCRL5 with AITDs. The C allele of CD20 rs7126354 is a protective factor for HT susceptibility. The A allele of FCRL5 rs6667109 is a risk factor for the susceptibility to GD.

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.

B-cell-activating factor (BAFF) and platelet-activating factor (PAF) in pregnancies complicated by maternal obesity and diabetes: a preliminary study

OBJECTIVE

In pregnancies complicated by maternal obesity and diabetes, a disruption in inflammatory mediators occurs, resulting in endothelial microvascular dysfunction, oxidative stress, tissue damage, and maternal and feto-neonatal complications. To outline this proinflammatory status, an innovative approach is represented by the measurement of proinflammatory cytokines. Among these biomarkers, B-cell-activating factor (BAFF) and platelet-activating factor (PAF) play a key role in metabolic regulation, immune response to infections, tissue homeostasis, and "food-related inflammation." The aim of the present study is to investigate the blood expression of BAFF and PAF in a cohort of pregnant women affected by obesity and diabetes compared with a control group of healthy pregnant women.

METHODS

A prospective longitudinal cohort study has been conducted on pregnant women referred to Fondazione Policlinico Universitario Gemelli IRCCS in Rome. For each pregnant woman, a capillary sample was collected with a swab in three different consecutive evaluations carried out in the three trimesters of pregnancy.

RESULTS

A total of 77 pregnant women have been enrolled. No significant differences in BAFF and PAF levels were longitudinally observed between groups. Focusing on the exposed group, in the third trimester of pregnancy, both PAF and BAFF levels were lower than the basal time. Among the selected group of patients who developed Gestational Diabetes, only PAF values were longitudinally lower when compared to other groups. The multivariate analysis showed that BAFF levels were positively correlated with thyroid-stimulating hormone levels. No macrosomia, no shoulder dystocia, no major perineal lacerations at birth, and no intrauterine growth restriction were observed in the whole population.

CONCLUSIONS

This study supports the involvement of metabolic and proinflammatory biomarkers in the mechanisms related to pregnancy complications. Improving a good metabolic environment for obese and diabetic pregnant women could break the vicious cycle connecting inflammation, oxidative stress, and metabolic disorders.

Current and promising therapies based on the pathogenesis of Graves' ophthalmopathy

Graves' ophthalmopathy (GO) is a hyperthyroidism-related and immune-mediated disease that poses a significant threat to human health. The pathogenesis of GO primarily involves T cells, B cells, and fibroblasts, suggesting a pivotal role for the thyrotropin-antibody-immunocyte-fibroblast axis. Traditional treatment approaches for Graves' disease (GD) or GO encompass antithyroid drugs (ATDs), radioactive iodine, and beta-blockers. However, despite decades of treatment, there has been limited improvement in the global incidence of GO. In recent years, promising therapies, including immunotherapy, have emerged as leading contenders, demonstrating substantial benefits in clinical trials by inhibiting the activation of immune cells like Th1 and B cells. Furthermore, the impact of diet, gut microbiota, and metabolites on GO regulation has been recognized, suggesting the potential of non-pharmaceutical interventions. Moreover, as traditional Chinese medicine (TCM) components have been extensively explored and have shown effective results in treating autoimmune diseases, remarkable progress has been achieved in managing GO with TCM. In this review, we elucidate the pathogenesis of GO, summarize current and prospective therapies for GO, and delve into the mechanisms and prospects of TCM in its treatment.

Physiological Changes in the Levels of Anti-Cytokine Autoantibodies in Early Pregnancy Are Missing in Pregnant Women with Hashimoto's Thyroiditis

T helper type 1 (Th1) and inflammatory cytokines play essential roles in early pregnancy and also in the pathogenesis of Hashimoto's thyroiditis (HT). Changes in the serum level of autoantibodies to cytokines, which may be able to modulate their availability and actions have been described in several autoimmune disorders. Yet, no data are available on anti-cytokine autoantibodies either during early pregnancy or in patients with HT. The aim of the study was to measure autoantibodies to inflammatory-, Th1- and Th22-cytokines in serum samples in healthy pregnancy (HP) and in pregnant women with HT (HTP). As pathological autoantibodies are hallmarks of HT, in addition we also measured anti-B-cell activator factor (BAFF) autoantibodies. The measurement was carried out with a Luminex multiplex assay and the Luminex MAGPIX Instrument, age-matched healthy women (HC) and women with HT (HT) were used as controls. In the first trimester of HP, anti-TNFα, anti-IL-8, and anti-IFNγ autoantibodies were significantly decreased, while autoantibodies to BAFF were significantly elevated compared to the HC. However, these alterations were not present in the HTP. Moreover, the levels of autoantibodies to IL-22 and TNFα were significantly increased in HTP compared to the HP. All differences in the levels of the investigated autoantibodies could be detected in the first trimester of pregnancies except for anti-IL-22 autoantibodies. According to our results we can conclude that alterations in the levels of autoantibodies to inflammatory and Th1 cytokines are physiological in the first trimester of pregnancy and their disturbance can be associated with autoimmune conditions such as HT.

Induced Overexpression of B Cell-Activating Factor by Triiodothyronine Results in Abnormal B Cell Differentiation in Mice

Breakdown of tolerance and abnormal activation in B cells is an important mechanism in the pathogenesis of Graves' disease (GD) and high levels of thyroid hormones (THs) can drive the progression of GD. However, the interactions between THs and abnormal activation of B cells in the context of GD are not well understood. The aim of this study was to investigate B cell-activating factor (BAFF) mediating the cross talk between THs and B cells and the possible underlying mechanisms. A high-level triiodothyronine (T3) mouse model was used to verify T3-mediated induction of overexpression of BAFF and B cell abnormal differentiation. The possible promotion of BAFF overexpression in the mice spleen macrophages during polarization to M1 by T3 was also studied. We showed that high levels of T3 can induce BAFF overexpression and lead to abnormal differentiation of B cells in the mice. While the overexpression of BAFF was observed across many tissue types in the mice, high levels of T3 could induce M1 macrophages polarization by IFN (interferon-gamma)-γ in the spleen of the mice, which in turn generated BAFF overexpression. Our findings provide a novel insight into the interactions between the endocrine and immune systems, as well as provide insight into the role of TH in the pathogenesis of GD.

Heterogeneity of antibody-secreting cells infiltrating autoimmune tissues

The humoral response is frequently dysfunctioning in autoimmunity with a frequent rise in total serum immunoglobulins, among which are found autoantibodies that may be pathogenic by themselves and/or propagate the inflammatory reaction. The infiltration of autoimmune tissues by antibody-secreting cells (ASCs) constitutes another dysfunction. The known high dependency of ASCs on the microenvironment to survive combined to the high diversity of infiltrated tissues implies that ASCs must adapt. Some tissues even within a single clinical autoimmune entity are devoid of infiltration. The latter means that either the tissue is not permissive or ASCs fail to adapt. The origin of infiltrated ASCs is also variable. Indeed, ASCs may be commonly generated in the secondary lymphoid organ draining the autoimmune tissue, and home at the inflammation site under the guidance of specific chemokines. Alternatively, ASCs may be generated locally, when ectopic germinal centers are formed in the autoimmune tissue. Alloimmune tissues with the example of kidney transplantation will also be discussed own to their high similarity with autoimmune tissues. It should also be noted that antibody production is not the only function of ASCs, since cells with regulatory functions have also been described. This article will review all the phenotypic variations indicative of tissue adaptation described so for at the level of ASC-infiltrating auto/alloimmune tissues. The aim is to potentially define tissue-specific molecular targets in ASCs to improve the specificity of future autoimmune treatments.

High levels of thyroid hormones promote recurrence of Graves' disease via overexpression of B-cell-activating factor

Background

Elevated thyroid hormone (TH) levels have been suggested to be associated with the pathological progression of Graves' disease (GD). However, direct evidence from clinical studies remains unclear.

Methods

Peripheral blood samples were collected from patients with or without the recurrence of Graves' hyperthyroidism (GH) and healthy donors. Thyroid tissue samples were obtained from patients with benign thyroid nodules. To assess the differentiation of autoreactive B cells, the expression of B‐cell‐activating factor (BAFF) and the proportion of CD11c+/–IgG+/− subsets of B cells stimulated by high levels of triiodothyronine (T3) in vivo and in vitro were examined by ELISA, flow cytometry, western blotting, and qRT‐PCR.

Results

Serum BAFF levels in patients with GD were significantly and positively correlated with FT3, FT4, and TRAb levels. Furthermore, the ratio of abnormally differentiated CD11c+ autoreactive B cells positively correlated with BAFF and TRAb. High levels of triiodothyronine (T3) induced BAFF overexpression in thyroid follicular cells and mononuclear cells of the normal thyroid in vitro, thereby promoting the differentiation of CD11c+IgG+ autoreactive secretory B cells (ASCs). However, the precise knockdown of BAFF expression significantly inhibited the abnormal differentiation of ASCs.

Conclusion

The pathological progression of GD was prolonged and exacerbated by autoimmune positive feedback modulation caused by high TH levels. BAFF could be considered a potential target for localized thyroid immunosuppressive treatment of Graves' hyperthyroidism recurrence.

High triiodothyronine levels induce myocardial hypertrophy via BAFF overexpression

Activated B cells contribute to heart diseases, and inhibition of B‐cell activating factor (BAFF) expression is an effective therapeutic target for heart diseases. Whether activated B cells participate in the development and progression of hyperthyroid heart disease, and what induces B cells activation in hyperthyroidism are unknown. The present study aimed to determine the roles of BAFF overexpression induced by high concentrations of triiodothyronine (T3) in the pathogenesis of hyperthyroid heart disease. Female C57BL/6J mice were subcutaneously injected with T3 for 6 weeks, and BAFF expression was inhibited using shRNA. Protein and mRNA expression of BAFF in mouse heart tissues evaluated via immunohistochemistry, western blotting and polymerase chain reaction (PCR). Proportions of B cells in mouse cardiac tissue lymphocytes were quantified via flow cytometry. Morphology and left ventricle function were assessed using pathological sections and echocardiography, respectively. Here, we demonstrate that compared with the control group, the proportion of myocardial B cells was larger in the T3 group; immunohistochemistry, western blotting and PCR analyses revealed increased protein and mRNA expression levels of TNF‐α and BAFF in heart tissues of the T3 group. Compared with the normal controls group, in the T3 group, the diameter of myocardial cells and some echocardiographic values significantly increased and hypertrophy and structural disorder were noticeable. Our results revealed that elevated levels of circulating T3 can promote the expression of BAFF in myocardial cells and can lead to B‐cell activation, an elevated inflammatory response and ventricular remodelling.

New Therapeutic Horizon of Graves' Hyperthyroidism: Treatment Regimens Based on Immunology and Ingredients From Traditional Chinese Medicine

Graves’ disease is an autoimmune disease characterized by goiter and hyperthyroidism, and 25% patients develop GO. Traditional treatment options, such as antithyroid drugs, radioiodine or thyroidectomy, have remained largely unchanged over the past 70 years. For many patients, there is a high rate of recurrence after antithyroid drugs and lifelong hypothyroidism after ablation and thyroidectomy. The symptoms and quality of life of some patients have not been effectively improved. The clinical demand for new therapeutic regimens, coupled with a deeper understanding of the pathophysiology and immunobiology of Graves’ disease, has led to the emergence of several new therapeutic ideas, including biologics, small molecule peptides, immunomodulators and teprotumumab, a specific antibody targeting IGF-1R. Besides, the elements of TCM have attracted more and more interests in modern medicine, because some effective components have been successfully used in the treatment of autoimmune diseases. Based on the pathophysiology and efficacy of clinical management and treatment in Graves’ hyperthyroidism, here we review the new strategies under investigation and summarize the effective components of traditional Chinese medicine used for Graves’ hyperthyroidism, and explore their mechanisms. These therapies have opened a new window for the treatment of Graves’ disease, but the exact mechanism and the research direction still need to be further explored.

Cytokines in the Immune Microenvironment Change the Glycosylation of IgG by Regulating Intracellular Glycosyltransferases

Background

Changes in IgG glycosylation, as a novel pathological feature, are observed in various autoimmune diseases (AIDs). The glycosylation patterns of IgG play a critical role in regulating the biological function and stability of IgG involved in the pathophysiology of many AIDs. However, the intracellular regulatory mechanisms underlying the effects of disturbances in various cytokines on IgG glycosylation are poorly understood. Thus, we investigated the regulatory effects of elevated cytokines in AIDs on intracellular IgG glycosylation within B cells.

Methods

First, we established a controlled primary culture system in vitro to differentiate human CD19+ B cells into antibody-secreting cells (ASCs). Then, the IgG concentrations in the supernatants were measured by enzyme-linked immunoassay (ELISA) under IFN-γ, TNF-α, IL-21, IL-17A, BAFF, or APRIL stimulation. Next, the glycosylation levels of IgG under different stimuli were compared via a lectin microarray. The fine carbohydrate structures of IgG were confirmed by matrix-assisted laser desorption/ionization-quadrupole ion trap-time of flight-mass spectrometry (MALDI-TOF-MS). Finally, the expression of glycosyltransferases and glycosidases in B cells under stimulation with several cytokines was detected by real-time PCR and western blotting.

Results

We found that cytokines significantly promoted IgG production in vitro and led to considerably different IgG glycan patterns. Specifically, the results of lectin microarray showed the galactose level of IgG was increased by IFN-γ stimulation (p<0.05), and the sialylation of IgG was increased by IL-21 and IL-17A (p<0.05). The MALDI-TOF-MS data showed that the frequency of agalactosylation was decreased by IFN-γ with the increased frequency of mono-galactosylation and decreased frequency of digalactosylation, accompanied by upregulation of β-1,4-galactosyltransferase 1. Both frequencies of mono-sialylated and disialylated N-glycans were increased by IL-21 and IL-17A with decreased frequency of asialylation, and the expression of β-galactoside α-2,6-sialyltransferase 1 was upregulated by IL-21 and IL-17A.

Conclusion

Abnormally elevated cytokines in the microenvironment regulates IgG glycan patterns by regulating intracellular glycosyltransferases in human B cells.

Possible interplay between estrogen and the BAFF may modify thyroid activity in Graves' disease

A link between sex hormones and B-cell activating factor (BAFF), a crucial immunoregulator of autoimmune thyroid disease (AITD), may exist. The study aimed to elucidate the role of estrogen (E2) in regulating BAFF in Graves' disease (GD). In clinical samples, serum BAFF levels were higher in women than in men in both the GD and control groups. serum BAFF levels were associated with thyroid-stimulating hormone receptor antibody levels and thyroid function only in women and not in men. BAFF transcripts in peripheral blood mononuclear cells were higher in women with GD than those in the control group. Among GD patients with the AA genotype of rs2893321, women had higher BAFF transcripts and protein levels than men. In the progression of a spontaneous autoimmune thyroiditis (SAT) murine model, NOD.H-2h4, serum free thyroxine and BAFF levels were higher in female than in male mice. Moreover, exogenous E2 treatment increased serum BAFF levels in male SAT mice. Meanwhile, female SAT mice exhibited higher thyroid BAFF transcripts levels than either the E2-treated or untreated male SAT mouse groups. Our results showed that E2 might be implicated in modulating BAFF expression, and support a possible mechanism for the higher incidence of AITD in women.

Expansion of inflammatory monocytes in periphery and infiltrated into thyroid tissue in Graves' disease

Monocytes are important mediators of immune system and are reported to be altered in autoimmune disorders. Little is known about the pathological role of monocytes in Graves' disease (GD). Thus, we investigated monocytes in periphery and thyroid tissue in GD. Untreated GD patients were enrolled and followed up until remission. Monocytes were significantly increased and positively correlated with anti-thyrotropin receptor antibody (TRAb) in untreated GD (r_counts = 0.269, P < 0.001; r_percentage = 0.338, P < 0.001). Flow cytometry showed CD14++ CD16+ monocytes were increased and CD14++ CD16- monocytes were decreased in untreated GD (both P < 0.001). Skewed monocyte subsets were recovered in GD with remission. Serum B cell-activating factor (BAFF) was positively correlated with TRAb (r = 0.384 and P = 0.001). CD14++ CD16+ monocytes expressed higher level of BAFF in untreated GD (P < 0.05). The frequency of CD14+ monocytes and CD14+ CD16+ monocytes were significantly higher in GD thyroid tissue than in normal thyroid tissue (both P < 0.001). Our study suggested CD14++ CD16+ monocytes were significantly expanded and involved in the production of TRAb via secreting a higher level of BAFF in periphery. Besides, monocytes infiltrated into thyroid tissue and thus could serve as an important participant in GD pathogenesis.

Altered expression profile of BAFF receptors on peripheral blood B lymphocytes in Graves' disease

BACKGROUND

B lymphocyte activating factor (BAFF) is a growth factor regulating B lymphocytes survival and maturation. Serum BAFF levels were elevated in patients affected with autoimmune thyroid diseases (AITD), including Graves' disease (GD) and Hashimoto's thyroiditis (HT). The aim of this study is to explore the association of expression levels of BAFF and its receptors with AITD.

METHODS

Fifty-two GD patients, 39 Hashimoto's thyroiditis (HT) patients and 23 healthy controls (HC) were recruited in this study. Serum BAFF levels were measured by ELISA. Expression of BAFF receptors, including BAFF receptor 3 (BR3) and transmembrane activator and calcium-modulating and cyclophilin ligand interactor (TACI), on B lymphocytes were analyzed by flowcytometry. Effects of steroids on serum BAFF levels and expression of BR3 and TACI were also observed in 10 patients with Graves' orbitopathy (GO) receiving steroids therapy.

RESULTS

Serum BAFF levels were significantly elevated from 0.93 ± 0.24 ng/ml in HC to 1.18 ± 0.33 ng/ml in GD (P = 0.0027) and 1.02 ± 0.24 ng/ml in HT (P = 0.0331). BR3 expression on peripheral B lymphocytes were elevated in GD (mean MFI: 4.52 ± 2.06 in GD vs. 3.00 ± 0.87 in HC, P = 0.0015), while TACI expression on peripheral B lymphocytes were decreased in GD without significance (mean MFI: 7.96 ± 4.06 in GD vs. 9.10 ± 3.37 in HC, P = 0.1285). Expression of BR3 and TACI was not changed significantly in HT patients. Steroids significantly suppressed serum BAFF concentrations (from 1.18 ± 0.27 ng/ml to 0.97 ± 0.10 ng/ml, P = 0.0364) and BR3 expression in GO patients (mean MFI from 6.26 ± 4.91 to 4.05 ± 1.58, P = 0.0083).

CONCLUSIONS

Altered expression of BAFF and its receptor may mediate the autoimmunity in GD. Restoring the normal expression profile of receptors for BAFF could be a new strategy to treat GD.

New Therapeutic Horizons for Graves' Hyperthyroidism

Graves' hyperthyroidism is characterized by the presence of autoantibodies that stimulate the thyroid-stimulating hormone receptor (TSHR), resulting in uncontrolled secretion of excessive thyroid hormone. Conventional treatments, including antithyroid medication, radioiodine, or surgery have remained largely unchanged for the past 70 years and either lack efficacy for many patients, or result in lifelong thyroid hormone replacement therapy, in the case of the latter 2 options. The demand for new therapeutic options, combined with greater insight into basic immunobiology, has led to the emergence of novel approaches to treat Graves' hyperthyroidism. The current therapies under investigation include biologics, small molecules, and peptide immunomodulation. There is a growing focus on TSHR-specific treatment modalities, which carry the advantage of eliciting a specific, targeted approach, with the aim of avoiding disruption of the functioning immune system. These therapies present a new opportunity to supersede the inadequate treatments currently available for some Graves' patients, offering hope of successful restoration of euthyroidism without the need for ongoing therapy. Several of these therapeutic options have the potential to translate into clinical practice in the near future. This review provides a comprehensive summary of the recent advances and various stages of development of the novel therapeutic approaches to treat Graves' hyperthyroidism.

Analysis of BAFF gene polymorphisms in UK Graves' disease patients

OBJECTIVE

B lymphocyte activating factor (BAFF), a member of the tumour necrosis factor superfamily, is essential for B cell activation, differentiation and survival. Elevated circulating BAFF levels have been found in patients with several autoimmune conditions, including Graves' disease. In addition, BAFF gene variants have been associated with Graves' disease in a Taiwanese cohort, and with several other autoimmune conditions in non-Taiwanese populations.

DESIGN AND METHODS

We performed a case-control association study to investigate two BAFF polymorphisms (rs9514828 and rs4000607) in a UK cohort of 444 patients with Graves' disease. Genotype frequencies were compared to those from 447 local controls and more than 5000 healthy controls from the Wellcome Trust case-control consortium (WTCCC2).

RESULTS

There was a significant difference in the frequency of the AA genotype at rs4000607 between the Graves' disease cohort and both the local controls (P = 0.045) and the WTCCC2 controls (P = 4.56 × 10^-6 ). Furthermore, the frequency of the A allele was found to be increased in the Graves' disease group compared to WTCCC2 controls (P = 0.02, OR 1.20 (95% CI 1.03-1.41). No association was observed at the rs9514828 locus.

CONCLUSION

Dysfunction of the humoral immune system is an obligatory pathophysiological component of Graves' disease, hence BAFF is an excellent functional candidate gene. We have demonstrated, for the first time, a significant association of the BAFF polymorphism rs4000607 with Graves' disease in a UK cohort. Further work to elucidate the role of BAFF in the pathogenesis of Graves' disease is now warranted.

Expression Density of Receptors as a Potent Regulator of Cell Function and Property in Health and Pathology

The expression of cytokine receptors has a crucial role in many cellular processes. Recent studies reported that changes of receptor expression could control the action of mediators on target cells. The initiation of different signaling pathways and, therefore, specific effects on cells, depends on certain components forming the cytokine-receptor complex. These mechanisms control the immune response and affect both the course of diseases (oncological, autoimmune, inflammatory) and the effectiveness of therapy. This review describes the potential of immune mediator receptors to regulate the efficiency of cytokine activity during pathologic processes and ensure the variability of their biological effects. Our aim was to investigate the spectrum of potential roles of changes in mediator receptor expression for main classes of pathologies. For all major types of immune mediators (cytokines, interleukins, chemokines, growth factors, and tumor necrosis factors), it has been shown that changes in their receptor expression are associated with impaired functioning of the organism in chronic diseases.

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.

The thyroid, the eyes and the gut: a possible connection

INTRODUCTION

Graves' disease (GD) is an autoimmune disorder responsible for 60-90% of thyrotoxicosis, with an incidence of 1 to 2 cases per 1000 population per year in England. Graves' orbitopathy (GO) is the most frequent extrathyroidal manifestation, not provoked directly by abnormal thyroid hormone levels, but by the consequence of the underlying autoimmune process. The aetiology of autoimmune disorders is due to an interplay between susceptibility genes and environmental factors, such as infections and stress. What triggers the autoimmune reaction to a specific site of the body is not yet clearly understood. The lack of knowledge in GD and GO pathogenesis implicates therapies that only limit damage but do not prevent disease onset.

MATERIAL AND METHODS

We performed on PubMed and the Cochrane Library a literature search for the articles published until July 2016 by using the search terms 'graves disease' and 'microbiome', 'orbitopathy' and 'autoimmune pathogenesis'. Reference lists of relevant studies were hand-searched for additional studies.

CONCLUSION

In this scenario, a Marie Sklodowska-Curie funded project INDIGO ( http://www.indigo-iapp.eu/ ) is investigating the role of the gut bacteria in GD and GO pathogenesis. The gut is the first and the widest area of bacteria access, with the highest concentration of T cells in the human body and trained to react to microorganisms. Interestingly, all the environmental factors involved in GD and GO pathogenesis can alter the balance within the microorganisms located in the gut, and influence the immune system, in particular the proportions of regulatory Treg and inflammatory TH17 cells. It is hoped that investigating GD and GO pathogenesis from this novel aspect will identify new targets for prevention and treatment.

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.

CD40 Signaling in Graves Disease Is Mediated Through Canonical and Noncanonical Thyroidal Nuclear Factor κB Activation

CD40, a tumor necrosis factor receptor, is a major immune-modulating susceptibility gene for Graves disease (GD) as well as for a variety of other autoimmune diseases. Its broad association with autoimmunity underscores its paramount role in the development of a normal adaptive immune response, primarily in coordinating effective antigen presentation. The molecular pathways by which CD40 activation in the thyroid induces GD are unknown. In this study, we investigated whether NF-κB, a ubiquitious family of transcription factors, mediates the downstream effects of thyroid-specific CD40 activation. Cultured primary human thyrocytes, from patients with and without GD, underwent CD40 stimulation. Once stimulated, cytokines and transcription factors specific for either the canonical nuclear factor κB (NF-κB)1 pathway [interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α], which primarily recruits cells for innate immunity, or the noncanonical NF-κB2 pathway [B cell-activating factor of the TNF family, CC chemokine ligand (CCL)21], which directs B cell viability, were analyzed. Significant upregulation in the messenger RNA and protein levels of both canonical and noncanonical pathway cytokines was observed. Western blot analyses of the specific transcription factors for the NF-κB1 and NF-κB2 pathways (p65 and p100/p52, respectively) demonstrated that p65 is constitutively expressed. In contrast, CD40 stimulation robustly increased the expression of the NF-κB2 p52 transcription factor, and the upregulation was significantly more profound in the GD tissue than in the normal thyroid tissue. Our data show that CD40 activity in thyrocytes is prominently mediated via NF-κB and furthermore suggest that the NF-κB1 and NF-κB2 pathways both contribute to the triggering and the progression of GD.

Serum BAFF and thyroid autoantibodies in autoimmune thyroid disease

BACKGROUND

This study investigated the association of serum B-lymphocyte activating factor (BAFF) levels with autoimmune thyroid disease (AITD) in a Chinese population.

MATERIALS AND METHODS

We enrolled 221 patients with AITD [170 patients with Graves' disease (GD), 51 patients with Hashimoto's thyroiditis (HT)], and 124 healthy controls. Serum BAFF levels, thyroid function and thyroid autoantibody (TAb) levels, including of thyroid-stimulating hormone receptor antibody (TSHRAb), anti-thyroid peroxidase antibody (Anti-TPO Ab), and antithyroglobulin antibody (ATA), were measured at baseline.

RESULTS

Serum BAFF levels were higher in the GD, HT, and AITD groups than in the control group. Significant correlations were observed between BAFF and TSHRAb levels (r=0.238, p=0.018), between BAFF and Anti-TPO Ab levels (p=0.038), and between BAFF and ATA titers (p=0.025) in women but not in men. In addition, serum BAFF levels were significantly associated with free thyroxine (r=0.430, p=0.004) and TSHRAb (r=0.495, p=0.001) levels in women with active GD but not in those with inactive GD.

CONCLUSIONS

Serum BAFF levels are increased in GD, HT, and AITD. The correlation between serum BAFF and TAb levels exhibits a dimorphic pattern, particularly in active GD.