Genetic susceptibility to Graves' ophthalmopathy: The role of polymorphisms in anti-inflammatory cytokine genes

Cytokines in Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO), also known as thyroid eye disease (TED) or Graves' orbitopathy (GO), is a complex autoimmune condition causing visual impairment, disfigurement, and harm to patients' physical and mental health. The pathogenesis of TAO has not been fully elucidated, and the mainstream view is that coantigens shared by the thyroid and orbit trigger remodeling of extraocular muscles and orbital connective tissues through an inflammatory response. In recent years, cytokines and the immune responses they mediate have been crucial in disease progression, and currently, common evidence has shown that drugs targeting cytokines, such as tocilizumab, infliximab, and adalimumab, may be novel targets for therapy. In this review, we summarize the research development of different cytokines in TAO pathogenesis in the hope of discovering new therapeutic targets.

The role of transforming growth factor beta in thyroid autoimmunity: current knowledge and future perspectives

The complex mechanisms, which are related to the pathophysiology and the development of autoimmune thyroid diseases, involve transforming growth factor beta (TGF-β) and its interplay with the immune system. The aim of this review is to examine the role of TGF-β regarding thyroid autoimmunity and explore the potent role of this molecule either as a diagnostic or prognostic marker or a therapeutic target regarding autoimmune thyroid diseases. TGF-β is clearly a master regulator of the immune response, exerting either inhibitory or facilitatory effects on cells of the immune system. Thus, this molecule is involved in the pathogenesis and development of autoimmune thyroid diseases. Recent research has revealed the involvement of TGF-β in the pathophysiology of autoimmune thyroid diseases. The role of TGF-β in the development of autoimmune thyroid diseases varies, depending on its concentrations, the type of the activated TGF-β signalling pathway, the genetic predisposition of the patient and the pathophysiologic stage of the disease. TGF-β could emerge as a useful diagnostic or prognostic marker for the evolution of thyroid autoimmunity. Promising perspectives for the effective therapeutic use of TGF-β regarding thyroid autoimmunity exist. The main treatment approaches incorporate either enhancement of the immunosuppressive role of TGF-β or inhibition of its facilitatory role in the autoimmune thyroid diseases. Further research towards deeper understanding of TGF-β physiology and clinical application of its possible therapeutic role regarding thyroid autoimmunity is needed.

TGF-β Physiology as a Novel Therapeutic Target Regarding Autoimmune Thyroid Diseases: Where Do We Stand and What to Expect

Transforming growth factor beta (TGF-β), as a master regulator of immune response, is deeply implicated in the complex pathophysiology and development of autoimmune thyroid diseases. Based on the close interplay between thyroid autoimmunity and TGF-β, scientific interest was shifted to the understanding of the possible role of this molecule regarding the diagnosis, prognosis, and therapy of these diseases. The main aim of this review is to present research data about possible treatment options based on the role of TGF-β in thyroid autoimmunity. Suggested TGF-β-mediated therapeutic strategies regarding autoimmune thyroid diseases include either the enhancement of its immunosuppressive role or inhibition of its facilitatory role in thyroid autoimmunity. For example, the application of hr-TGF-β can be used to bolster the inhibitory role of TGF-β regarding the development of thyroid diseases, whereas anti-TGF-β antibodies and similar molecules could impede its immune-promoting effects by blocking different levels of TGF-β biosynthesis and activation pathways. In conclusion, TGF-β could evolve to a promising, novel therapeutic tool for thyroid autoimmunity.

Association between polymorphic markers in candidate genes and the risk of manifestationof endocrine ophthalmopathy in patients with Graves’ disease

Aim. To analyze the association between the polymorphic markers in CTLA4, TNF, IL10 and IL16 genes and the risk of manifestation of endocrine ophthalmopathy (EO) in patients with Graves’ disease (GD). Materials and methods. Case-control study included 248 patients with GD. Using polymerase chain reaction we studied the distribution of alleles and genotypes of polymorphic markers such as A60G (rs3087243) in CTLA4 gene, G(-308)A (rs1800629) in TNF gene, G(-1082)A (rs1800896) in IL10 gene, T3249C (rs4778641) in IL16 gene among 141 patients with Graves’ disease and EO and 107 patients with GD without EO. Results and discussion. The frequencies of A alleles and the AA genotypes were significantly increased and the frequencies of G alleles and the GG genotype polymorphic markers rs3087243 of CTLA4 gene and rs1800896 of IL10 gene, as well as the GG genotype polymorphic marker rs1800629 of TNF gene were reduced in patients with GD and EO. The polymorphism in CTLA4 gene was also associated with the activity and the severity of EO. The comparative analysis of the allele and genotype frequency distribution of polymorphic markers of IL16 gene did not show the significant difference. Conclusion. The risk of manifestation and the development of EO in patients with Graves’ disease can be caused by not only environmental, but also genetic risk factors.

Differential profiling of lacrimal cytokines in patients suffering from thyroid-associated orbitopathy

The aim was to investigate the levels of cytokines and soluble IL-6R in the tears of patients with thyroid-associated orbitopathy (TAO) disease. Schirmer’s test was adopted to collect tears from TAO patients (N = 20, 17 women, mean age (±SD): 46.0 years (±13.4)) and healthy subjects (N = 18, 10 women, 45.4 years (±18.7)). Lacrimal cytokines and soluble IL-6R (sIL-6R) were measured using a 10-plex panel (Meso Scale Discovery Company) and Invitrogen Human sIL-6R Elisa kit, respectively. Tear levels of IL-10, IL-12p70, IL-13, IL-6 and TNF-α appeared significantly higher in TAO patients than in healthy subjects. Interestingly, IL-10, IL-12p70 and IL-8 levels increased in tears whatever the form of TAO whereas IL-13, IL-6 and TNF-α levels were significantly elevated in inflammatory TAO patients, meaning with a clinical score activity (CAS) ≥ 3, compared to controls. Furthermore, only 3 cytokines were strongly positively correlated with CAS (IL-13 Spearman coeff. r: 0.703, p = 0.0005; IL-6 r: 0.553, p = 0.011; IL-8 r: 0.618, p = 0.004, respectively). Finally, tobacco use disturbed the levels of several cytokines, especially in patient suffering of TAO. The differential profile of lacrimal cytokines could be useful for the diagnosis of TAO patients. Nevertheless, the tobacco use of these patients should be taken into account in the interpretation of the cytokine levels.

Association of Interleukin 10 Gene Polymorphisms with Autoimmune Thyroid Disease: Meta-Analysis

The aim of this study was to perform a meta-analysis of eligible studies and to derive a precise estimate of the association between interleukin 10 (IL10) polymorphisms and susceptibility to autoimmune thyroid disease (AITD). Meta-analyses were conducted on the associations between AITD and the -1082 G/A (rs1800896), -819 C/T (rs1800871) and -592 C/A (rs1800872) polymorphisms in IL10, and the haplotype of these polymorphisms and AITD. A total of 2903 AITD patients and 3060 controls in 10 eligible studies were included in the meta-analysis. This meta-analysis showed significant associations between IL10 at the -1082 G allele and overall AITD (OR: 1.44, 95% CI 1.13-1.82, P = 0.003), but no association between the IL10 -592 C allele and the -819 C allele and AITD. Subgroup studies demonstrated significant associations between the -1082 G allele and susceptibility to Graves' disease. Ethnicity-specific meta-analysis revealed significant associations between the -1082 G allele and AITD susceptibility in Asian populations; however, in Middle Eastern populations, no association was evident. Meta-analysis of the IL10 haplotype revealed an association between the ATA haplotype and AITD (OR: 1.17, 95% CI 1.00-1.36, P = 0.04). Meta-analysis demonstrates that the IL10 polymorphisms are associated with susceptibility to AITD.

Association of IL4 and IL4R polymorphisms with multiple sclerosis susceptibility in Caucasian population: A meta-analysis

BACKGROUND

Previous studies have suggested a role for interleukin-4 (IL4) and its receptor (IL4R) gene in susceptibility to multiple sclerosis (MS), but the results remain controversial and under-powered.

OBJECTIVES

To investigate the contradictory results, we performed a meta-analysis to assess the possible association between polymorphisms of the IL4 rs2243250 (C/T), variable number of tandem repeat (VNTR) polymorphism in intron-3 (I3(709)VNTR), IL4R rs1801275 (T/C) and MS in Caucasian populations.

METHODS

A comprehensive search was conducted to identify all case-control or cohort design studies. The fixed or random effect pooled measure was selected based on the homogeneity test among studies that was evaluated with I(2). Publication bias was estimated using the Begg's and Egger's test.

RESULTS

A total of ten studies were included in the meta-analysis. The crude odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated to evaluate the association. Overall, after excluding articles deviating from Hardy-Weinberg equilibrium in controls and sensitive analysis, the meta-analysis showed a significant association between polymorphism of IL4 rs2243250 and MS susceptibility in allele model (OR=1.209, 95% CI=1.022-1.429, P=0.026) and dominant model (OR =1.225, 95% CI=1.013-1.480, P=0.036). However, no significant association was found between polymorphisms of IL4 I3(709)*VNTR, IL4R rs1801275 and MS susceptibility, respectively.

CONCLUSIONS

The meta-analysis indicates that the T allele, CT and TT genotype of polymorphism of IL4 rs2243250 (C/T) may reduce the risk of MS in Caucasian populations, while polymorphisms of IL4 I3(709)*VNTR and IL4R rs1801275 may not associated with risk of MS in Caucasian populations.

Genetic Associations of Interleukin-related Genes with Graves' Ophthalmopathy: a Systematic Review and Meta-analysis

Graves’ ophthalmopathy (GO) is the commonest extra-thyroidal manifestation of Graves’ disease (GD). Associations between interleukin-related (IL) gene polymorphisms and GO have been reported in different populations. We aim to confirm such associations by conducting a meta-analysis. Totally 382 publications were retrieved in MEDLINE and EMBASE up to 25/2/2015. After removing the duplicates and assessing the studies, we retrieved 16 studies that met the selection criteria for meta-analysis, involving 12 polymorphisms in 8 IL-related genes, and 1650 GO cases and 2909 GD controls. The summary odds ratio (OR) and 95% confidence intervals (CI) were estimated. We found one polymorphism in IL1A (rs1800587, c.-889C>T) showing a suggestive association with GO in the meta-analysis (allelic model [T vs. C]: OR = 1.62, 95% CI: 1.00–2.62, P = 0.050, I² = 53.7%; recessive model [TT vs. TC + CC]: OR = 2.39, 95% CI: 1.07–5.37, P = 0.039, I² = 23.6%; heterozygous model [TC vs. CC]: OR = 1.52, 95% CI: 1.04–2.22, P = 0.034, I² = 37.0%). No association with GO was detected for the other 7 genes (IL1B, IL1RA, IL4, IL6, IL12B, IL13 and IL23R). Our results thus indicate that IL1A is likely to be a genetic biomarker for GO. Further studies with larger sample sizes are warranted to confirm the associations of IL1A and other IL-related genes with GO.

TSHR intronic polymorphisms (rs179247 and rs12885526) and their role in the susceptibility of the Brazilian population to Graves' disease and Graves' ophthalmopathy

PURPOSE

Intronic thyroid-stimulating hormone receptor polymorphisms have been associated with the risk for both Graves' disease and Graves' ophthalmopathy, but results have been inconsistent among different populations. We aimed to investigate the influence of thyroid-stimulating hormone receptor intronic polymorphisms in a large well-characterized population of GD patients.

METHODS

We studied 279 Graves' disease patients (231 females and 48 males, 39.80 ± 11.69 years old), including 144 with Graves' ophthalmopathy, matched to 296 healthy control individuals. Thyroid-stimulating hormone receptor genotypes of rs179247 and rs12885526 were determined by Real Time PCR TaqMan(®) SNP Genotyping.

RESULTS

A multivariate analysis showed that the inheritance of the thyroid-stimulating hormone receptor AA genotype for rs179247 increased the risk for Graves' disease (OR = 2.821; 95 % CI 1.595-4.990; p = 0.0004), whereas the thyroid-stimulating hormone receptor GG genotype for rs12885526 increased the risk for Graves' ophthalmopathy (OR = 2.940; 95 % CI 1.320-6.548; p = 0.0083). Individuals with Graves' ophthalmopathy also presented lower mean thyrotropin receptor antibodies levels (96.3 ± 143.9 U/L) than individuals without Graves' ophthalmopathy (98.3 ± 201.9 U/L). We did not find any association between the investigated polymorphisms and patients clinical features or outcome.

CONCLUSION

We demonstrate that thyroid-stimulating hormone receptor intronic polymorphisms are associated with the susceptibility to Graves' disease and Graves' ophthalmopathy in the Brazilian population, but do not appear to influence the disease course.

[Association of CTLA4 and TNF gene polymorphisms with endocrine ophthalmopathy in ethnic Russian patients with Graves' disease]

AIM

To analyze the associations of the rs3087243 CTLA4 polymorphism and the rs1800629 TNF polymorphism with endocrine ophthalmopathy (EOP) in ethnic Russian patients with Graves' disease (GD).

MATERIAL AND METHODS

The case-control study enrolled 205 patients with GD. The distribution of alleles and genotypes of the rs3087243 CTLA4 and rs1800629 TNF polymorphisms was studied in 141 patients with GD and EOP (a GD+EOP group) and 64 patients with GD without EOP (a GD-EOP group). The polymorphic alleles were identified by polymerase chain reaction-restriction fragment length analysis.

RESULTS

The patients with GD in their history and EOP had significantly higher frequencies of A allele and AA genotype and a lower proportion of G allele and GG genotype of the rs3087243 CTLA4 polymorphism. Comparative analysis revealed no significant differences in the frequency of the alleles and genotypes of the rs1800629 TNF polymorphism.

CONCLUSION

The rs3087243 CTLA4 polymorphism is associated with the risk of EOP in ethnic Russian patients with GD.

Association between polymorphisms in the TSHR gene and Graves' orbitopathy

BACKGROUND

Graves' orbitopathy (GO) as well as Graves' disease (GD) hyperthyroidism originate from an autoimmune reaction against the common auto-antigen, thyroid-stimulating hormone receptor (TSHR). GO phenotype is associated with environmental risk factors, mainly nicotinism, as well as genetic risk factors which initiate an immunologic reaction. In some patients GO is observed before diagnosis of GD hyperthyroidism, while it can also be observed far after diagnosis. The intensity of GO symptoms varies greatly in these patients. Thus, the pathogenesis of GD and GO may correlate with different genetic backgrounds, which has been confirmed by studies of correlations between GO and polymorphisms in cytokines involved in orbit inflammation. The aim of our analysis was to assess genetic predisposition to GO in young patients (age of diagnosis ≤30 years of age), for whom environmental effects had less time to influence outcomes than in adults.

METHODS

768 GD patients were included in the study. 359 of them had clinically evident orbitopathy (NOSPECS ≥2). Patients were stratified by age at diagnosis. Association analyses were performed for genes with a known influence on development of GD - TSHR, HLA-DRB1, cytotoxic T-lymphocyte antigen 4 (CTLA4) and lymphoid protein tyrosine phosphatase (PTPN22).

RESULTS

The rs179247 TSHR polymorphism was associated with GO in young patients only. In young GO-free patients, allele A was statistically more frequent and homozygous carriers had a considerable lower risk of disease incidence than patients with AG or GG genotypes. Those differences were not found in either elderly patients or the group analyzed as a whole.

CONCLUSIONS

Allele A of the rs179247 polymorphism in the TSHR gene is associated with lower risk of GO in young GD patients.

Cytokine profiles in clinical subtypes of ophthalmic Graves' disease

PURPOSE

To examine the association of cytokines in the two clinical subtypes of ophthalmic Graves' disease by comparing cytokine expression in the fat and ethmoid tissue of type I and type II patients.

METHODS

Patients needing orbital decompression or eyelid surgery were identified and enrolled into a prospective study. Patients were assigned to the type I or type II subclassification, based on the presence of diplopia. Orbital fat, sinus tissue or muscle removed during surgery was evaluated. The mRNA expression profiles of Th1 cytokines (TNF-alpha/beta, IFN-gamma, IL-2) and Th2 cytokines (IL-4, IL-5, IL-6, IL-10) were analyzed using real time PCR.

RESULTS

30 patients were enrolled in the study: 5 type I (80% female), 14 type II (71% female) and 11 controls (73% female). There were 14 decompressions (3 type I and 11 type II), 17 lid procedures (2 type I, 4 type II and 11 controls) and 10 ethmoidectomies (3 type I and 7 type II). The average ages were 45, 56 and 66 in the type I, type II and control groups, respectively. There was more TNF-alpha (p value 0.009) and IL-6 (p value 0.04) in ethmoid sinus cells of type II patients compared to ethmoid sinus cells of type I patients and a trend of higher expression of all cytokines in type II patients.

CONCLUSIONS

There is a trend towards greater mRNA expression of both Th1 and Th2 cytokines in both orbital fat and ethmoidal sinus tissue of type II patients compared to type I patients.

Graves' ophthalmopathy: a review of immunogenetics

Graves’ disease (GD) is the most common cause of thyrotoxicosis and often involves the orbits. Graves’ ophthalmopathy (GO), also known as Thyroid Eye Disease (TED), can be clinically significant and advance to sight-threatening stages. Our knowledge of the immunogenetic pathophysiology of GO is rapidly expanding. The present review is an attempt to summarize the current state of knowledge on the immunogenetics of GO. First we briefly review the epidemiology and clinical importance of GO, and then we describe in detail the macromolecular pathogenesis and finally immunogenetics of GO. Discrepancies between the results from various reports and the limitations of the available data are discussed. In particular, there is a scarcity of data from non-Asian populations. While several studies have demonstrated significant associations between polymorphisms in certain genes (especially CTLA-4, HLA-DRB-1, and TNF-α), there is a need for studies that investigate the relationship between polymorphisms and both serum and local concentrations of the resulting proteins. A complete understanding of GO susceptibility and pathogenesis has not been yet possible due to a number of important knowledge gaps that need to be filled by future research.

Long-term follow-up of seven patients with ophthalmopathy not associated with thyroid autoimmunity: heterogeneity of autoimmune ophthalmopathy

BACKGROUND

Ophthalmopathy is the most common extrathyroidal manifestation of Graves' disease. However, in approximately 5% of cases this autoimmune eye disorder occurs in the apparent absence of Graves' hyperthyroidism: the so-called euthyroid Graves' disease (EGD).

METHODS

Seven patients with EGD were followed for evidence of thyroid and orbital autoimmunity, for up to 10 years. Calsequestrin and collagen XIII antibodies were measured by enzyme linked immunosorbent assay (ELISA), and TSH-receptor (TSH-r) antibodies were measured as TSH-r-binding antibody (TRAb) and thyroid-stimulating immunoglobulin (TSI). Eye signs were characterized and quantified as clinical activity score (CAS), NOSPECS classes, Nunery types 1 and 2, and margin-reflex distance (MRD).

RESULTS

Calsequestrin antibodies were detected on at least one occasion in three of the seven patients and collagen XIII antibodies were detected one or more times in five patients. In one patient with isolated congestive ophthalmopathy who was studied intensely, collagen XIII antibodies were initially positive and then became negative as the eye disease stabilized, while antibodies targeting calsequestrin were always negative. TRAb was not detected in any patient, but TSI was detected in three patients on one occasion each. Ultrasound abnormalities were found in four of the six patients for whom this was carried out, but there was no clear evidence for thyroiditis in any of these patients. For comparison, 13 patients were studied with typical Graves' ophthalmopathy. There were no significant differences compared to EGD in respect to the prevalence of positive calsequestrin or collagen XIII antibodies, but these patients included more smokers (eight out of 13 versus none out of seven).

CONCLUSIONS

Earlier studies suggesting that patients with EGD eventually develop thyroid dysfunction have not been confirmed here, although follow-up continues, and the possibility that such patients have had thyroid autoimmunity in the past, or that they will develop it in the future cannot be excluded. Overall, it is likely that the ophthalmopathy associated with Graves' hyperthyroidism is the same disease as that observed in patients - such as those reported here - in whom thyroid dysfunction and thyroid autoimmunity are not present during the period of follow- up. The role of autoimmunity against the TSH-r in euthyroid patients with ophthalmopathy has not been proven and the significance of the orbital antibodies is unclear.