T-cell-mediated immunity in thyroid-associated ophthalmopathy

Machine learning-based prediction of diagnostic markers for Graves' orbitopathy

PURPOSE

The pathogenesis of Graves' orbitopathy/thyroid-associated orbitopathy (TAO) is still unclear, and abnormal DNA methylation in TAO has been reported. Thus, selecting and exploring TAO biomarkers associated with DNA methylation may provide a reference for new therapeutic targets.

METHODS

The TAO-associated expression data and methylation data were downloaded from The Gene Expression Omnibus database. Firstly, weighted gene co-expression network analysis was used to obtain the TAO-related genes, which were intersected with differentially methylated genes (DMGs), and differentially expressed genes between TAO samples and normal samples to obtain TAO-associated DMGs (TA-DMGs). Thereafter, the functions of the TA-DMGs were analyzed, and diagnostic markers were screened by least absolute shrinkage and selection operator (Lasso) regression analysis and support vector machine (SVM) analysis. The expression levels and diagnostic values of the diagnostic markers were also analyzed. Furthermore, single gene pathway enrichment analysis was performed for each diagnostic marker separately using gene set enrichment analysis (GSEA) software. Next, we also performed immune infiltration analysis for each sample in the GSE58331 dataset using the single-sample GSEA algorithm, and the correlation between diagnostic markers and differential immune cells was explored. Lastly, the expressions of diagnostic markers were explored by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

A total of 125 TA-DMGs were obtained. The enrichment analysis results indicated that these TA-DMGs were mainly involved in immune-related pathways, such as Th1 and Th2 cell differentiation and the regulation of innate immune response. Moreover, two diagnostic markers, including S100A11 and NKD2, were obtained by Lasso regression analysis and SVM analysis. Single gene pathway enrichment analysis showed that S100A11 was involved in protein polyufmylation, pancreatic-mediated proteolysis, and NKD2 was involved in innate immune response in mucosa, Wnt signaling pathway, etc. Meanwhile, immune cell infiltration analysis screened 12 immune cells, including CD56 dim natural killer cells and Neutrophil cells that significantly differed between TAO and normal samples, with the strongest positive correlation between NKD2 and CD56 dim natural killer cells. Finally, the qRT-PCR illustrated the expressions of NKD2 and S100A11 between normal and TAO.

CONCLUSION

NKD2 and S100A11 were screened as biomarkers of TAO and might be regulated by DNA methylation in TAO, providing a new reference for the diagnosis and treatment of TAO patients.

Single-cell RNA sequencing depicts the local cell landscape in thyroid-associated ophthalmopathy

There is a specific reactivity and characteristic remodeling of the periocular tissue in thyroid-associated ophthalmopathy (TAO). However, local cell changes responsible for these pathological processes have not been sufficiently identified. Here, single-cell RNA sequencing is performed to characterize the transcriptional changes of cellular components in the orbital connective tissue in individuals with TAO. Our study shows that lipofibroblasts with RASD1 expression are highly involved in inflammation and adipogenesis during TAO. ACKR1⁺ endothelial cells and adipose tissue macrophages may engage in TAO pathogenesis. We find CD8⁺CD57⁺ cytotoxic T lymphocytes with the terminal differentiation phenotype to be another source of interferon-γ, a molecule actively engaging in TAO pathogenesis. Cell-cell communication analysis reveals increased activity of CXCL8/ACKR1 and TNFSF4/TNFRSF4 interactions in TAO. This study provides a comprehensive local cell landscape of TAO and may be valuable for future therapy investigation.

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A local transcriptional landscape of orbital connective tissue in TAO is developed

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RASD1-expressing lipofibroblasts are highly involved in adipogenesis and inflammation

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ACKR1⁺ endothelial cells contribute to inflammatory cell infiltration in TAO

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Adipose tissue macrophages engage in lipid metabolism and inflammatory response in TAO

Efficacy and safety of mycophenolate mofetil in patients with active moderate-to-severe Graves' orbitopathy

CONTEXT

Graves' orbitopathy (GO) is a potentially sight-threatening disease for which currently available medical therapy is not reliably successful. Mycophenolate mofetil (MMF) is a selective immunosuppressant used widely in many autoimmune diseases. Preliminary studies have shown that MMF is effective in the treatment of active GO.

OBJECTIVE

To evaluate the efficacy and safety of MMF in patients with active moderate-to-severe GO.

PATIENTS

One hundred and 74 patients with active moderate-to-severe GO were randomized to receive either MMF or glucocorticoids (GC).

MAIN OUTCOME MEASURES

The primary outcome was overall response at the 12th and 24th weeks; the outcome assessments included clinical activity score (CAS), soft tissue involvement, pain, visual acuity, proptosis, diplopia and reduction in eye movements. The secondary outcome was changes in those individual parameters. Adverse effects were recorded at each visit.

RESULTS

A greater overall response rate was found in the MMF group compared with the GC group at the 24th week (91·3% vs 67·9%, P = 0·000). MMF therapy showed a better CAS response than GC (92·5% vs 70·5% improved, P < 0·05). Patients treated with MMF showed a significantly improved rate of diplopia and proptosis than patients treated with GC at the 24th week (90·4% and 68·8% improved, respectively). Disease reactivation was not observed in the patients treated with MMF but was observed in five patients after GC therapy. Adverse events occurred in 4 of 80 patients treated with MMF (5%), all of which were mild to moderate. A severe adverse event was only observed in one patient treated with GC but not at all in patients treated with MMF.

CONCLUSION

Compared with GC treatment, MMF therapy is more effective and safer for patients with active moderate-to-severe GO.

Comparative Assessment of Female Mouse Model of Graves' Orbitopathy Under Different Environments, Accompanied by Proinflammatory Cytokine and T-Cell Responses to Thyrotropin Hormone Receptor Antigen

We recently described a preclinical model of Graves' orbitopathy (GO), induced by genetic immunization of eukaryotic expression plasmid encoding human TSH receptor (TSHR) A-subunit by muscle electroporation in female BALB/c mice. The onset of orbital pathology is characterized by muscle inflammation, adipogenesis, and fibrosis. Animal models of autoimmunity are influenced by their environmental exposures. This follow-up study was undertaken to investigate the development of experimental GO in 2 different locations, run in parallel under comparable housing conditions. Functional antibodies to TSHR were induced in TSHR A-subunit plasmid-immunized animals, and antibodies to IGF-1 receptor α-subunit were also present, whereas control animals were negative in both locations. Splenic T cells from TSHR A-subunit primed animals undergoing GO in both locations showed proliferative responses to purified TSHR antigen and secreted interferon-γ, IL-10, IL-6, and TNF-α cytokines. Histopathological evaluation showed orbital tissue damage in mice undergoing GO, manifest by adipogenesis, fibrosis, and muscle damage with classic signs of myopathy. Although no inflammatory infiltrate was observed in orbital tissue in either location, the appearances were consistent with a "hit-and-run" immune-mediated inflammatory event. A statistically significant increase of cumulative incidence of orbital pathology when compared with control animals was shown for both locations, confirming onset of orbital dysimmune myopathy. Our findings confirm expansion of the model in different environments, accompanied with increased prevalence of T cell-derived proinflammatory cytokines, with relevance for pathogenesis. Wider availability of the model makes it suitable for mechanistic studies into pathogenesis and undertaking of novel therapeutic approaches.

Th1, Th2, and Th17 Cytokine Involvement in Thyroid Associated Ophthalmopathy

To determine serum cytokine profiles in Graves' disease (GD) patients with or without active and inactive thyroid associated ophthalmopathy (TAO), we recruited 65 subjects: 10 GD only (without TAO), 25 GD + active TAO, 20 GD + TAO, and 10 healthy controls. Liquid chip assay was used to measure serum Th1/Th2/Th17 cytokines including IFN-γ (interferon-gamma), TNF-α (tumor necrosis factor-alpha), IL-1α (interleukin-1 alpha), IL-1Ra (IL-1 receptor antagonist), IL-2, IL-4, IL-6, and IL-17 and two chemokines: RANTES (regulated upon activation, normal T cell expressed and secreted) and IP-10 (IFN-γ-induced protein 10). Serum levels of TSH (thyroid stimulating hormone) receptor autoantibodies (TRAb) were measured using an enzyme linked immunosorbent assay. Compared with healthy controls, TAO patients showed significantly elevated serum levels of IFN-γ, TNF-α, IL-1α, IL-4, IL-6, IL-17, and IP-10. Comparing active and inactive TAO, serum Th1 cytokines IFN-γ and TNF-α were elevated in active TAO, while serum Th2 cytokine IL-4 was elevated in inactive TAO. Serum Th17 cytokine IL-17 was elevated in GD but reduced in both active and inactive TAO. A positive correlation was found between TRAb and IFN-γ, TNF-α, IL-1α, IL-2, IL-4, and IL-6. Taken together, serum Th1/Th2/Th17 cytokines and chemokines reflect TAO disease activity and may be implicated in TAO pathogenesis.

The association between polymorphisms of B7 molecules (CD80 and CD86) and Graves' ophthalmopathy in a Taiwanese population

OBJECTIVE

This study evaluates whether B7 molecules (CD80 and CD86) could be used as genetic markers for the development of Graves' ophthalmopathy (GO).

DESIGN

Cross-sectional study.

PARTICIPANTS

We included 471 patients with Graves' disease (GD; 200 patients with GO and 271 patients without GO) in a Chinese population in Taiwan.

METHODS

An endocrinologist with substantial experience in thyroid diseases identified GO. Blood samples were taken for DNA extraction from GD subjects. The gene polymorphism of CD80 and CD86 was genotyped by polymerase chain reaction in each patient.

MAIN OUTCOME MEASURES

Genotypes of CD80 and CD86 polymorphism.

RESULTS

We found that the frequency of C allele at position rs_9831894 of the CD86 gene is different in patients with GD (with and without GO; chi-square test, P = 0.0017). In addition, the multifactor dimensionality reduction method was used to identify the best gene-gene interaction to predict the risk of GO. We identified an interaction between CD80_rs9289131 and CD86_rs9872483 (sign test, P = 0.0010). Moreover, the G-A haplotype was shown to have a protective effect in the development of ophthalmopathy among patients with GD (odds ratio, 0.63; 95% confidence interval, 0.44-0.90). Moreover, among patients with GO, the patients carrying the G-A haplotype had a lower level of free thyroxine T(4) than those not carrying the G-A haplotype (P = 0.0001).

CONCLUSIONS

These results suggest that the polymorphisms of the CD86 gene may be used as genetic markers for making the diagnosis and prognosis of GO. Therefore, GO could be a disease with complex genetic factors, resulting from the existing gene-gene interaction found in the present study.

Pathogenesis of thyroid-associated ophthalmopathy: does autoimmunity against calsequestrin and collagen XIII play a role?

Thyroid-associated ophthalmopathy (TAO), or thyroid eye disease, is a complex inflammatory disorder of the eye that, as its name implies, is associated with thyroid disease. TAO can be divided into three subtypes: ocular myopathy, congestive myopathy and mixed congestive and myopathic ophthalmopathy. Although the precise pathophysiology of TAO remains unclear it is likely to reflect an autoimmune reaction involving sensitized T-cells and autoantibodies directed against a thyroid and orbital tissue shared antigen. One well studied candidate in this immune reaction is the thyroid-stimulating hormone receptor (TSH-r), expressed in the orbital fibroblast and pre adipocyte. In our studies of TAO, we have investigated the nature and significance of antibodies targeting other eye muscle and orbital connective tissue (OCT) antigens. Our findings suggest that autoimmunity against the eye muscle antigen calsequestrin and the OCT antigen collagen XIII plays a role in the pathogenesis of TAO. We propose that ocular myopathy and chronic eyelid retraction are due to autoimmunity against skeletal muscle calsequestrin in the extraocular and eyelid muscles, respectively. This may be initiated in the thyroid where calsequestrin expression is upregulated, possibly due to a stimulatory effect of TSH-r antibodies. We also propose that congestive ophthalmopathy results from a reaction against the TSH-r or collagen XIII in orbital fibroblast cell membranes. Further insight into the role of eye muscle and OCT antigens in the pathogenesis of TAO may allow for the development of new therapies to treat the eye disorder and reduce patient morbidity.

Immunohistochemical Analysis of Orbital Connective Tissue Specimens of Patients With Active Graves Ophthalmopathy

PURPOSE

To explore the immune mechanism of Graves ophthalmopathy (GO) by analyzing infiltrating cells in orbital connective tissue (OCT) specimens of patients with active GO using immunohistochemical methods.

METHODS

Five OCT specimens obtained from patients with active GO and five control specimens obtained from forensic cadavers who died from nonmedical reasons were stained with anti-CD3, CD4, CD8, CD45RO, HLA-Dr, CD25, and TNF-alpha monoclonal antibodies. Positively stained cells were counted and results were interpreted as cell counts/mm2. Four of five GO patients had never been treated with any immunomodulating therapy. Only one had received oral prednisolone prior to tissue sampling, but this treatment had ceased 5 months before surgery.

RESULTS

The retro-orbital tissue specimens obtained from forensic cadavers did not show any significant positive staining for any monoclonal antibody tested. However, the specimens from GO patients showed positively stained means of 36.66 +/- 4.61 HLA-Dr+, 12.8 +/- 3.42 CD8+, 11.8 +/- 1.78 CD4+, 16.6 +/- 1.81 CD3+, 21.2 +/- 3.12 CD45RO+, 10.4 +/- 2.07 TNF-alpha+, 7.2 +/- 1.48 CD25+, 3.2 +/- 1.09 CD4+CD8+, 4.6 +/- 1.67 CD4+CD45RO+, 2.8 +/- 0.83 CD8+CD45RO+, 1.6 +/- 0.89 CD4+CD25+, and 1.8 +/- 1 0.83 CD8+CD25+ cells/mm2.

CONCLUSIONS

Our study supports that most of the infiltrating lymphocytic cells in the active stage of GO are T cells, and a significant proportion of them are CD45RO+ cells. Infiltration of OCT by HLA-Dr+, CD25+, and TNF-alpha cells suggests that Th1-type immune reaction with the interference of proinflammatory cytokine(s) (TNF-alpha) may be important in the pathogenesis of disease. Further studies are needed to understand the disease pathogenesis and may provide a scientific basis for future treatment alternatives for the disease (e.g., anti-cytokine treatment).

Susceptibility genes in Graves' ophthalmopathy: searching for a needle in a haystack?

The variety of clinical presentations of eye changes in patients with Graves' disease suggests that complex interactions between genetic, environmental, endogenous and local factors influence the development/severity of Graves' ophthalmopathy (GO). At present, the role of genetic factors in the development of GO remains unknown. Based on small case-control association studies with candidate genes, several susceptibility loci in GO have been proposed. These are human leucocyte antigen (HLA, 6p21.3), cytotoxic T-lymphocyte antigen-4 (CTLA-4, 2q33), tumour necrosis factor (TNF, 6p21.3), interferon-gamma (IFN-gamma, 12q14), intercellular adhesion molecule-1 (ICAM-1, 19p13), and thyroid stimulating hormone receptor gene (TSH-R, 14q31). Unfortunately, these results were either not confirmed or require replication in larger studies. There are many reasons for the lack of reproducibility of association studies in GO, including poor characterization of the studied groups and small sample sizes, which may result in both false positive and negative results. Thus, the genetic background of GO remains to be elucidated in future research. However, the possibility that GO may be a genetically heterogeneous disorder, or that the development of GO may be predominantly influenced by environmental factors such as cigarette smoking, can not be disregarded.

The common −318C/T polymorphism in the promoter region of CTLA4 gene is associated with reduced risk of ophthalmopathy in Chinese Graves' patients

Studies in the past have clearly established that CTLA4 is a susceptible gene for Graves' disease (GD). However, association studies between CTLA4 and the risk of developing Graves' ophthalmopathy (GO) in GD patients have shown conflicting results. In this study, associations of five CTLA4 single nucleotide polymorphisms (-1722A/G, -1661A/G, -318C/T, +49G/A, CT60) with GD risk and GO susceptibility in GD patients were investigated in a Chinese population. Our results showed that either +49A/G or CT60 polymorphism was associated with GD susceptibility in the Chinese population. Significant differences in the distribution of the genotypes or alleles evaluated between GD patients with and without clinically evident GO were only found for -318C/T polymorphism (P = 0.03). Multiple logistic regressions revealed that the -318T allele was negatively associated with GO under both additive and dominant genetic models (adjusted OR = 0.56, 95%CI 0.35-0.89, P = 0.014; adjusted OR = 0.51, 95%CI 0.30-0.84, P = 0.009, respectively). Stratification analysis according to gender demonstrated different scenarios concerning the role of the -318T allele in GO risk: a significant protective role for GO was only confirmed in male but not in female GD patients. Haplotype analyses showed that only the haplotypes containing the -318T allele played a protective role in GO. In conclusion, results from this study suggested that the -318T allele might play a protective role in GO susceptibility for GD patients at least in the Chinese population. However, extended analyses with larger sample size should be carried out in patients from different ethnic origins to further verify this association.

CTLA4 polymorphisms and ophthalmopathy in Graves' disease patients: association study and meta-analysis

Studies in the past have clearly established that cytotoxic T-lymphocyte antigen-4 (CTLA4) is a susceptible gene for Graves' disease (GD). However, association studies between the CTLA4 exon-1 +49A/G polymorphism and the risk of developing Graves' ophthalmopathy (GO) in GD patients have revealed conflicting results. In this study, associations of two CTLA4 polymorphisms (+49A/G and CT60) with GD risk and GO susceptibility in GD patients were investigated in a Chinese population. In addition, a meta-analysis was performed to better assess the purported association between the +49A/G polymorphism and GO susceptibility in GD patients. Our results demonstrated that both the +49A/G and CT60 polymorphisms were associated with GD susceptibility in the Chinese population. No significant association with GO susceptibility in GD patients was confirmed regardless of which polymorphism was tested individually. Similarly, the meta-analysis results provided minimal evidence about the role of the +49A/G polymorphism and GO risk in GD patients. Interestingly, haplotypic analysis demonstrated different scenarios concerning the role of CTLA4 in GO susceptibility in the Chinese GD patients. We found that the +49A-CT60G haplotype was marginally statistically associated with the increased risk of GO in GD patients (OR = 1.63, 95%CI 1.00-2.64, p = 0.05). In conclusion, our results suggested that CTLA4 might be involved in the susceptibility to GD in the Chinese population. Although neither +49A/G nor CT60 polymorphism was associated with the risk of GO in GD patients, the haplotypic analysis provided some evidence about its role in GO susceptibility in the Chinese GD patients. We suggest that more association studies recruiting haplotypic analysis should be performed to investigate the role of CTLA4 gene in GO susceptibility in patients from different nations.

Analysis of peripheral blood T-cell subsets in active thyroid-associated ophthalmopathy: absence of effect of octreotide-LAR on T-cell subsets in patients with thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is thought to be a T-cell-mediated autoimmune disorder. We sought to characterize abnormalities in the peripheral blood T-cell subsets in patients with TAO, and examine whether the long-acting somatostatin analogue, octreotide-LAR, treatment affects these cells. We analyzed peripheral blood T-cell subsets by flow cytometry in 26 euthyroid patients with moderately severe active TAO and 24 controls. Twenty-five of the patients with TAO were enrolled in a randomized trial to receive either 30 mg of octreotide-LAR (n = 11) or placebo (n = 14) every 4 weeks for 16 weeks; all 25 patients subsequently received octreotide-LAR 30 mg every 4 weeks from week 16 to 32. T-cell subsets were analysed at baseline, week 16, and week 32. At baseline, the relative percentage of CD4+ helper T-cells (p = 0.0003) and the CD4+/CD8+ ratio (p = 0.008) were significantly higher in patients with TAO compared to controls. Patients with TAO had higher naïve active T cells (CD45RA+, CD45RA+ CD4+) and lower memory T cells (CD45RO+, CD45RO+ CD4+) than controls. At weeks 16 and 32, there were no significant differences in any T-cell subsets between the octreotide-LAR-treated and placebo groups. These results support a role of T cell in the pathogenesis of TAO, and show that octreotide-LAR has no effect on T-cell subsets during 32-weeks of treatment.

Relationship between longitudinal behaviour of some markers of eye autoimmunity and changes in ocular findings in patients with Graves' ophthalmopathy receiving corticosteroid therapy

OBJECTIVE

To investigate whether variations over time of TSH-receptor antibodies (TRAb) and antibodies against G2s (G2sAb) and extraocular muscles (EMAb) can predict worsening of ophthalmopathy in Graves' patients treated with intravenous glucocorticoid (IVGC) therapy.

PATIENTS

Of 65 consecutive patients with treated Graves' disease and severe and active ophthalmopathy (GO) chosen to undergo IVGC treatment, only 57 patients, persistently euthyroid under methimazole therapy, were studied longitudinally for ocular parameters, TRAb, G2sAb and EMAb before therapy, at the end of therapy and, subsequently, every month for 21 months.

MEASUREMENTS

TRAb was detected by radioimmunoassay (RIA), G2sAb by enzyme-linked immunosorbent assay (ELISA) and EMAb by indirect immunofluorescence.

RESULTS

Forty-three out of 57 patients (75.4%, group 1) responded positively to therapy [improvement in diplopia and decrease in proptosis and clinical activity score (CAS)] but 14 (24.6%) did not (group 2). During follow-up after IVGC therapy, 12 out of 43 patients in group 1 (28%) showed a worsening in GO (group 1a), while 31 (72%) had stable ocular conditions or further improvement (group 1b). At the start of the study, TRAb, G2sAb and EMAb were not significantly different among the three groups. At the end of IVGC therapy TRAb levels decreased significantly with respect to starting values in all three groups of patients, whereas G2sAb and EMAb decreased significantly in groups 1a and 1b but not in group 2. During the subsequent follow-up, 10 patients in group 1a one/two months before and all 12 patients at the time of GO worsening showed an increase in G2sAb and EMAb but not in TRAb, which were consistently absent or present at low titre in all patients in this group. In group 1b TRAb, G2sAb and EMAb further decreased or became negative during the follow-up period. In all patients, TRAb were positively correlated with both CAS and proptosis only at the start of the study; by contrast, a significant correlation between both G2sAb and EMAb and diplopia was observed in groups 1a and 1b at all the times during the study, except one/two months before the worsening of GO in group 1a.

CONCLUSIONS

Our results indicate that TRAb, G2sAb and EMAb can be considered sensitive markers of Graves' ophthalmopathy during the initial stages of ophthalmopathy, but that only G2sAb and EMAb seem to be good predictive markers of the outcome in patients after corticosteroid therapy. Thus, taking into account the cost/benefit ratio, a longitudinal evaluation of either EMAb or G2sAb could be useful in monitoring the intravenous glucocorticoid therapy in patients with severe and active ophthalmopathy to predict a possible worsening of Graves' ophthalmopathy.