Interleukin-1-beta gene, but not the interleukin-1 receptor antagonist gene, is associated with Graves' disease

Association of IL-1β, NLRP3, and COX-2 Gene Polymorphisms with Autoimmune Thyroid Disease Risk and Clinical Features in the Iranian Population

Background

Grave's disease (GD) and Hashimoto's thyroiditis (HT) are autoimmune diseases of the thyroid gland in which genetic predisposition plays a major role in their development. Currently, the role of NLRP3 inflammasome and COX-2 has been documented in many autoimmune diseases. The purpose of the study is to delineate the impact of IL-1β (rs1143634), NLRP3 (rs3806265), and COX-2 (rs2745557) gene polymorphisms in the development of GD and HT.

Methods

A total of 256 newly diagnosed patients with autoimmune thyroid disease (135 patients with HT and 121 GD patients) as case groups and 145 controls were included in the study.

Results

Recessive and overdominant models showed a significant association between IL-1β rs1143634 SNP and HT development risk. The frequency of TT genotype and T allele of IL-1β rs1143634 SNP in the control group was significantly higher than the GD group. There was no significant association between NLRP3 rs3806265 polymorphism and HT and GD development. The frequency of GA genotype of COX-2 (rs2745557) in the control group was significantly higher than that in the HT group. There was no significant association between COX-2 rs2745557 genotypic and allelic distribution and GD development risk. The results revealed a significant relationship between some clinical features of HT and GD groups and SNPs studied.

Conclusion

The results manifest the significant impact of IL-1β rs1143634 and COX-2 (rs2745557) SNPs and HT development and IL-1β rs1143634 SNP on GD occurrence risk. Furthermore, a significant relationship was observed between some clinical features of HT and GD groups and studied SNPs.

Association of polymorphic variants of IL-1β and IL-1RN genes in the development of Graves' disease in Kashmiri population (North India)

PURPOSE

Graves' disease (GD) is a multigenic, organ specific autoimmune disorder with a strong genetic predisposition and IL-1β has been shown to be involved in its pathogenesis. The present study was aimed to determine the genetic associations between polymorphisms of IL-1β gene promoter region (-511 T>C) (rs16944), exon 5 (+3954 C>T) (rs1143634) and IL-1RN gene VNTR (rs2234663) polymorphism in patients with GD in ethnic Kashmiri population.

METHODS

A total of 135 Graves' disease patients and 150 healthy individuals were included in the study. PCR and PCR-based restriction analysis methods were done for IL-1RN^VNTR and IL-1β gene polymorphisms respectively.

RESULTS

We found statistically significant increased frequencies of the C/C + CT genotype (P = 0.001; odds ratio (OR) = 5.04, 95% confidence interval (CI) = 3.02-8.42) and the C allele (P = 0.001; OR = 3.10, 95% CI = 2.14-4.50) in IL-1β gene promoter polymorphism (rs16944) with GD patients compared to normal controls. Also in the exon 5 (rs1143634), a significant increase in frequency of the C/C homozygous genotype (P = 0.001; OR = 0.18, 95% CI = 0.11-0.30) and C allele (P = 0.001; OR = 0.31, 95% CI = 0.20-0.48) was observed in GD cases as against controls. For IL-1RN^VNTR (rs2234663), we didn't observe any significant difference in the allelic and genotypic frequencies between cases and controls.

CONCLUSION

Our findings suggest that both promoter and exon polymorphisms of IL-1β gene have a significant role in the risk of developing GD, whereas IL-1RN^VNTR has no association with GD.

The tear cytokine profile in patients with active Graves' orbitopathy

PURPOSE

The primary aim of this study is to isolate cytokines specific for active Graves' orbitopathy (GO) in the tears of affected patients. The secondary aim is to identify other cytokines of interest and to look at the profile of their levels over time.

METHODS

This is a prospective pilot study conducted at the Singapore National Eye Centre. A total of 10 patients with active GO and 10 patients from each of 3 control groups were recruited. The 3 control groups were the following: age-matched normal female patients, patients with GO who were clinically inactive and patients with bilateral viral conjunctivitis. Tears from patients from the control groups were collected on a single visit. For patients with active GO, tears were collected on presentation, at 6 months, 12 months and 18 months.

RESULTS

Of all the cytokines examined, only IL-7 yielded a difference when the concentration in patients with active GO was compared with concentrations in all the control groups. This difference was most significant at the 18-month follow-up visit.

CONCLUSIONS

Low concentrations of IL-7 in tears exhibit specificity for active GO in patients nearly 2 years from the clinical onset of activity. Although using IL-7 in tears as a biomarker for disease activity may be limited due to its late manifestation, targeting immune restitution using IL-7 may have disease modifying effects.

The teleost head kidney: Integrating thyroid and immune signalling

The head kidney, analogous to the mammalian adrenal gland, is an organ unique for teleost fish. It comprises cytokine-producing lymphoid cells from the immune system and endocrine cells secreting cortisol, catecholamines, and thyroid hormones. The intimate organization of the immune system and endocrine system in one single organ makes bidirectional signalling between these possible. In this review we explore putative interactions between the thyroid and immune system in the head kidney. We give a short overview of the thyroid system, and consider the evidence for the presence of thyroid follicles in the head kidney as a normal, healthy trait in fishes. From mammalian studies we gather data on the effects of three important pro-inflammatory cytokines (TNFα, IL-1β, IL-6) on the thyroid system. A general picture that emerges is that pro-inflammatory cytokines inhibit the activity of the thyroid system at different targets. Extrapolating from these studies, we suggest that the interaction of the thyroid system by paracrine actions of cytokines in the head kidney is involved in fine-tuning the availability and redistribution of energy substrates during acclimation processes such as an immune response or stress response.

Association of Interleukin-1B and Interleukin-4 Gene Variants with Autoimmune Thyroid Diseases in Tunisian Population

Autoimmune thyroid diseases (AITD) including Graves' disease (GD) and Hashimoto's thyroiditis (HT) are complex genetic diseases. Cytokines IL-1B and IL-4 play a role in the pathogenesis of AITD. This study was conducted on Tunisian patients with GD or HT to investigate the association of IL-1B and IL-4 gene polymorphisms with the risk and the prognosis of AITD. A total of 358 healthy controls and 341 patients with AITDs (249 HT and 92 GD) were genotyped for IL-1B+3953C/T and IL-4 intron 3 VNTR polymorphisms. A significant association was found between IL-1B+3953C/T polymorphism and GD or HT, both in the dominant and additive models. The IL-1B+3953T allele was associated with GD (p = 0.0003, OR = 1.93, CI = 1.34-2.78) and HT (p = 0.009, OR = 1.43, CI = 1.09-1.88). The IL-4 VNTR polymorphism was associated only with HT risk both in additive (p = 0.03, OR = 0.31, CI = 0.11-0.86) and recessive (p = 0.03, OR = 3.04, CI = 1.13-8.17) models. No significant association was found between IL-1B+3953C/T polymorphism and change in the serum concentrations of TSH and FT4 in GD and HT patients. In HT patients, the IL-1B+3953T allele (p = 0.009, OR = 0.42, CI = 0.22-0.83) and the IL-1B+3953T/T genotype (p = 0.03, OR = 0.21, CI = 0.04-1.07) were more frequent in the absence than in the presence of an anti-TPO antibody. The proportion of HT patients with the P1P2 genotype of the IL-4 gene was significantly higher in the absence than in the presence of the anti-TPO antibody (p = 0.04, OR = 0.39, CI = 0.17-0.89). These preliminary results suggest that IL-1B and IL-4 gene polymorphisms may be associated with GD and HT susceptibility and may represent prognostic factors for predicting the severity of HT.

Polymorphisms in the TNFA and IL6 genes represent risk factors for autoimmune thyroid disease

BACKGROUND

Autoimmune thyroid disease (AITD) comprises diseases including Hashimoto's thyroiditis and Graves' disease, both characterized by reactivity to autoantigens causing, respectively, inflammatory destruction and autoimmune stimulation of the thyroid-stimulating hormone receptor. AITD is the most common thyroid disease and the leading form of autoimmune disease in women. Cytokines are key regulators of the immune and inflammatory responses; therefore, genetic variants at cytokine-encoding genes are potential risk factors for AITD.

METHODS

Polymorphisms in the IL6-174 G/C (rs1800795), TNFA-308 G/A (rs1800629), IL1B-511 C/T (rs16944), and IFNGR1-56 T/C (rs2234711) genes were assessed in a case-control study comprising 420 Hashimoto's thyroiditis patients, 111 Graves' disease patients and 735 unrelated controls from Portugal. Genetic variants were discriminated by real-time PCR using TaqMan SNP genotyping assays.

RESULTS

A significant association was found between the allele A in TNFA-308 G/A and Hashimoto's thyroiditis, both in the dominant (OR = 1.82, CI = 1.37-2.43, p-value = 4.4×10(-5)) and log-additive (OR = 1.64, CI = 1.28-2.10, p-value = 8.2×10(-5)) models. The allele C in IL6-174 G/C is also associated with Hashimoto's thyroiditis, however, only retained significance after multiple testing correction in the log-additive model (OR = 1.28, CI = 1.06-1.54, p-value = 8.9×10(-3)). The group with Graves' disease also registered a higher frequency of the allele A in TNFA-308 G/A compared with controls both in the dominant (OR = 1.85, CI = 1.19-2.87, p-value = 7.0×10(-3)) and log-additive (OR = 1.69, CI = 1.17-2.44, p-value = 6.6×10(-3)) models. The risk for Hashimoto's thyroiditis and Graves' disease increases with the number of risk alleles (OR for two risk alleles is, respectively, 2.27 and 2.59).

CONCLUSIONS

This study reports significant associations of genetic variants in TNFA and IL6 with the risk for AITD, highlighting the relevance of polymorphisms in inflammation-related genes in the etiopathogenesis of AITD.

Association between the IL1B (-511), IL1B (+3954), IL1RN (VNTR) polymorphisms and Graves' disease risk: a meta-analysis of 11 case-control studies

BACKGROUND

Data on the association between the interleukin-1 (IL-1) gene polymorphisms and Graves' disease (GD) risk were conflicting. A meta-analysis was undertaken to assess this association.

METHODS

We searched for case-control studies investigating the association between the IL1B (-511), IL1B (+3954), IL1RN (VNTR) polymorphisms and GD risk. We extracted data using standardized forms and calculated odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

A total of 11 case-control studies were included in this meta-analysis. Available data indicated that the IL1B (-511) polymorphism was associated with GD risk in the overall populations (Caucasians and Asians) in homozygote model (TT vs. CC, OR = 0.86, 95% CI: 0.76-0.97, Pz  = 0.015), but not in dominant and recessive models (TT+TC vs. CC: OR = 0.95, 95% CI: 0.81-1.12, Pz  =  0.553 and TT vs. TC+CC: OR = 0.82, 95% CI: 0.60-1.12, Pz  =  0.205, respectively). No association between the IL1B (+3954), IL1RN (VNTR) polymorphisms and GD risk was found in the overall populations in any of the genetic models. In subgroup analyses according to ethnicity, the IL1B (-511) polymorphism was associated with GD risk in Asians in recessive and homozygote models (TT vs. TC+CC: OR =  0.68, 95% CI: 0.55-0.84, Pz < 0.001 and TT vs. CC: OR = 0.81, 95% CI: 0.70-0.93, Pz  =  0.003, respectively), but not in dominant model (TT+TC vs. CC: OR =  0.92, 95% CI: 0.77-1.11, Pz  =  0.389). No association between the IL1B (+3954), IL1RN (VNTR) polymorphisms and GD risk was indicated in Asians, and we found no association between the IL1B (-511), IL1B (+3954), IL1RN (VNTR) polymorphisms and GD risk in Caucasians in any of the genetic models.

CONCLUSION

The IL1B (-511) polymorphism, but not the IL1B (+3954) and IL1RN (VNTR) polymorphisms was associated with GD risk in Asians. There was no association between these polymorphisms and GD risk in Caucasians.

The new perspectives on genetic studies of type 2 diabetes and thyroid diseases

Recently, genome-wide association studies (GWAS) have led to the discovery of hundreds of susceptibility loci that are associated with complex metabolic diseases, such as type 2 diabetes and hyperthyroidism. The majority of the susceptibility loci are common across different races or populations; while some of them show ethnicity-specific distribution. Though the abundant novel susceptibility loci identified by GWAS have provided insight into biology through the discovery of new genes or pathways that were previously not known, most of them are in introns and the associated variants cumulatively explain only a small fraction of total heritability. Here we reviewed the genetic studies on the metabolic disorders, mainly type 2 diabetes and hyperthyroidism, including candidate genes-based findings and more recently the GWAS discovery; we also included the clinical relevance of these novel loci and the gene-environmental interactions. Finally, we discussed the future direction about the genetic study on the exploring of the pathogenesis of the metabolic diseases.

Interleukin-7 expression in tears and orbital tissues of patients with Graves' ophthalmopathy

The aim of this study was to explore whether IL-7 participates in the pathogenesis of Graves' ophthalmopathy (GO). This was a prospective study. 20 GO patients (40 eyes) and 20 healthy volunteers (40 eyes) were recruited. The tear concentration of IL-7 was measured using ELISA assay. IL-7 expression in orbital tissues was evaluated by immunohistochemistry. Patients with inactive GO had the highest IL-7 concentrations in the tears, followed by healthy controls and patients with active GO per ELISA. Immunohistochemistry analysis showed that IL-7 expression in orbital tissues of the inactive GO samples was higher than that of the volunteers. Changes of IL-7 expression in different phases of GO suggested that IL-7 may play an important role in the pathogenesis of GO.

Endothelial dysfunction in Graves' disease

PURPOSE

Graves' disease (GD) is an organ-specific autoimmune thyroid disease, characterized by hyperthyroidism due to excessive production of thyroid hormone induced by thyrotropin receptor-specific stimulatory autoantibodies. In this study, we determined serum levels of the soluble forms of ICAM-1, VCAM-1, vWF, IL-6, IL-12, IL-18, fibrinogen and CRP in patients with subclinical (SH) and overt hyperthyroidism (OH) caused by GD to elucidate a possible role of those parameters as markers of endothelium dysfunction (ED).

MATERIAL/METHODS

The study included 96 patients: 52 with GD and 44 euthyroid controls, divided into 3 groups according to their thyroid function tests: SH, OH and controls (CG).

RESULTS

The values of IL-6, IL-12 and IL-18 were significantly higher in GD than in CG patients (p < 0.0001, p < 0.0001; p < 0.00001, respectively). Significant difference of sVCAM-1 values were found in the patients with GD compared to CG (p < 0.0001). Patients with GD had significantly higher levels of PAI-1 (p < 0.00001), vWF (p < 0.0001), fibrinogen (p < 0.0001) in comparison to CG. In patients with OH, we observed statistically higher values of fibrinogen compared to SH group (p < 0.05). There were no significant differences in serum concentration of other study parameters in patients with SH compared to the OH.

CONCLUSIONS

ED occurs during subclinical and overt hyperthyroidism causing decreased fibrinolytic activity, hypercoagulability and increased levels of IL-6, Il-12 and IL-18. These results support the notion that serum cytokines could be used as a marker of GD activity. Results of this study support the opinion that GD might require treatment as early as in the phase of SH.

The interleukin-1 family gene polymorphisms and Graves' disease

Genetic factors, including cytokine gene polymorphisms, are potential contributors to the pathogenesis of the Graves' disease (GD). We attempted in this study to determine the association between GD and the following polymorphisms in the interleukin-1 (IL-1) family genes: IL-1alpha (-889C/T), IL-1ss (-511C/T), IL-1ss (+3962C/T), IL-1R (Pst-1 1970C/T) and IL-1RA (Mspa-I 11100C/T). We studied 107 patients with an established diagnosis of GD and 140 healthy controls. Cytokine typing was performed by the polymerase chain reaction with sequence-specific primers assay. Genotype distributions among patients were in Hardy-Weinberg equilibrium for all polymorphisms. The frequency of the IL-1alpha -889T allele was significantly higher in patients than in controls (51.9% vs. 31.6%, OR=2.33, 95% CI=1.61-3.38; p<0.0001). The IL-1RA Msp-I 11100C allele was significantly more frequent in patients than in controls (50.0% vs. 22.9%, OR=3.38, 95% CI=2.29-4.97, p<0.0001). No significant associations were found for other polymorphisms. Although the IL-1 family has well-known roles in GD pathogenesis, the contributions of their genetic variations to the disease are unclear. In this study, we documented a highly significant association between GD and polymorphism in IL-1alpha and IL-1RA genes. Further studies in other populations are necessary to confirm our results.

The association of interleukin-1alpha and interleukin-1beta polymorphisms with the risk of Graves' disease in a case-control study and meta-analysis

The proinflammatory cytokine interleukin (IL)-1 family has a central role in mediating inflammation and joint destruction in Graves' disease (GD). A number of studies, investigating rs1800587 (IL-1alpha, T-889 C) and rs16944 (IL-1beta, A-511 G) polymorphisms to test their possible association with GD and Graves' ophthalmopathy (GO), had inconsistent results. Our study aims to further evaluate the possible association of these two polymorphisms with GD and GO within the Han Chinese population using a case-control association study as well as a meta-analysis covering three previous studies from Taiwan, Iran, and Poland. Based on 760 Chinese GD patients, including 190 of GO cases among them, and 735 healthy control subjects, our data showed that the genotype or allele distributions of rs1800587 and rs16944 polymorphisms were significantly associated with GD (p = 0.003-0.049) and more so with GO (p = 0.001-0.021). The meta-analysis showed the risk-increasing effects for the TC and TT genotypes of rs1800587 in GD (odds ratio [OR] = 2.07, p = 0.03) and GO (OR = 3.22, p = 0.04), and a protective effect for the AA genotype of rs16944 in GD (OR = 0.70, p = 0.002) and GO (OR = 0.65, p = 0.02). The results confirmed that the rs1800587 (IL-alpha, T-889 C) and rs16944 (IL-1beta, A-511 G) polymorphisms may confer susceptibility to GD and GO in Asian population.

Graves' ophthalmopathy and gene polymorphisms in interleukin-1alpha, interleukin-1beta, interleukin-1 receptor and interleukin-1 receptor antagonist

PURPOSE

Interleukin-1 (IL-1) is known to have an important role in pathogenesis of Graves' ophthalmopathy (GO). Polymorphisms in IL-1 gene have been associated with autoimmune reactions. This study aimed to investigate the association of GO with single-nucleotide polymorphisms (SNPs) in the IL-1 family (IL-1alpha, IL-1beta, IL-1 receptor [IL-1R] and IL-1 receptor antagonist [IL-1RA]).

METHODS

A total of 57 patients of Graves' disease without GO, 50 patients with GO and 140 healthy controls were enrolled. Patients were recruited consecutively from the outpatient endocrine clinic of a large university general hospital. Cytokine typing was performed by the polymerase chain reaction with sequence-specific primers assay. The allele and genotype frequencies of the following polymorphisms were determined: IL-1alpha (-889C/T), IL-1beta (-511C/T), IL-1beta (+3962C/T), IL-1R (Pst-1 1970C/T) and IL-1RA (Mspa-1 11100C/T). Genotype distributions among patients were in Hardy-Weinberg equilibrium for all polymorphisms.

RESULTS

Among the five SNPs studied, the frequencies of the T allele and the TT genotype of IL-1alpha (-889C/T) were significantly higher among patients with GO than those without GO (odds ratio [OR] = 2.16, 95% confidence interval [CI] = 1.25-3.74; P = 0.006 and 5.67, 95% CI = 1.66-49.34; P = 0.005, respectively). For IL-1RA (Mspa-1 11100C/T), the frequencies of the C allele and the CC genotype were significantly higher among patients with GO (OR = 2.31, 95% CI = 1.34-4.00; P = 0.004 and 6.73 95% CI = 1.94-23.36; P = 0.004, respectively; P < 0.01). No significant association was found for other SNPs.

CONCLUSION

This is the first study to show a positive correlation between polymorphisms in the IL-1alpha and IL-1RA genes and susceptibility to GO. These findings promote further research into genetic correlates of GO.

Interleukin-1beta gene (IL-1beta) polymorphisms (SNP -511 and SNP +3953) in thyroid-associated ophthalmopathy (TAO) among the Polish population

OBJECTIVE

The aim of this study was to evaluate whether the IL-1beta gene could be a genetic marker of the thyroid-associated ophthalmopathy (TAO) development.

MATERIALS AND METHODS

The IL-1beta gene polymorphisms at -511 and +3953 regions in 117 TAO patients of Polish origin (ATA/NOSPECS class III or greater) and in 106 controls were studied.

RESULTS

We found no significant differences in the frequencies of genotypes and allelic variants for SNP -511 and SNP +3953 between the controls and the studied groups.

CONCLUSIONS

No association between the IL-1beta polymorphisms and the TAO existed, so those polymorphisms are not suitable genetic markers for TAO.

Cytokines, Graves' disease, and thyroid-associated ophthalmopathy

Graves' disease, an autoimmune process associated with thyroid dysfunction, can also manifest as remodeling of orbital connective tissue. Affected tissues exhibit immune responses that appear to be orchestrated by resident cells and those recruited from the bone marrow through their expression and release of cytokines and surface display of cytokine receptors. Cytokines are small molecules produced by many types of cells, including those of the "professional" immune system. Aberrant cytokine expression appears to play an important role in the pathogenesis of many human diseases, including thyroid autoimmunity. The skewed pattern of cytokine expression in the thyroid, including the T helper cell bias, may condition the response to apoptotic signals and determine the characteristics of an autoimmune reaction. Furthermore, chemoattractant cytokines, including IL16, RANTES, and CXCL10, elaborated by resident cells in the thyroid and orbit may provoke mononuclear cell infiltration. Other cytokines may drive cell activation and tissue remodeling. Thus cytokines and the signaling pathways they activate represent attractive therapeutic targets. Interruption of these might alter the natural course of Graves' disease and its orbital manifestations.

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.

Proinflammatory cytokine gene polymorphisms among Hashimoto's thyroiditis patients

Proinflammatory cytokines are involved in the pathogenesis of Hashimoto's thyroiditis (HT). To test whether certain specific proinflammatory cytokine gene polymorphisms could be genetic markers for an individual's susceptibility to HT, we investigated single-site polymorphisms of certain proinflammatory cytokine genes of interest for 107 HT sufferers and 163 controls, subsequent to preparing the necessary experimental genomic DNA from peripheral blood, using a polymerase chain reaction (PCR)-based restriction analysis. The polymorphisms we detected were as follows: 1) C/T and E1/E2 polymorphisms for the interleukin (IL)-1beta gene at promoter (-511) and exon 5, respectively; 2) a variable number of tandem repeats (VNTRs) for the IL-1 receptor antagonist (IL-1Ra) gene at intron 2; 3) a C/G polymorphism for the IL-6 gene at promoter (-572); and 4) an A/G polymorphism for the tumor necrosis factor (TNF)-alpha gene at promoter (-308). The data demonstrated an increased ratio of CG genotype and decreased ratios of CC and GG genotypes (chi-squared test; P = 0.025) for the IL-6 gene promoter for HT patients when compared with normal controls. The odds ratio (OR) for the CG genotype, as compared to the GG genotype, for HT patients was shown to be 4.065 (95% confidence interval (CI): 1.268-13.032). Comparison of the genotype analysis for the remaining gene polymorphisms and the allelic analysis for all of the screened gene polymorphisms, however, all revealed no statistically significant difference between the two study groups as regards frequency of genotype. In conclusion, we suggest that an IL-6 gene promoter (-572) C/G polymorphism could represent a potential "candidate" genetic marker to predict an individual's susceptibility to HT.

New insights into antibody-mediated hyperthyroidism

The most common cause of hyperthyroidism is Graves' disease, which represents a typical example of an organ-specific autoimmune condition. The exact triggers for the disease remain unknown, but are likely to involve a complex interaction between multiple environmental factors in a genetically predisposed individual. The main feature of the condition is the presence of thyroid-stimulating antibodies, which activate the thyroid- stimulating hormone receptor, resulting in hyperthyroidism. These antibodies may also be involved in the extrathyroidal complications of the disease. The recent generation of thyroid-stimulating antibodies in animal models and the isolation of monoclonal thyroid-stimulating antibodies from a patient with Graves' disease should allow the detailed study of thyroid-stimulating antibodies-thyroid-stimulating hormone receptor interactions. This will help to shed more light on disease pathogenesis and may offer new treatment strategies in difficult cases, particularly in patients with extrathyroidal complications.

Lack of association between pro-inflammatory cytokine (IL-6, IL-8 and TNF-alpha) gene polymorphisms and Graves' disease

Graves' disease (GD) is a common, autoimmune disease involving the thyroid gland, and it has been previously suggested that pro-inflammatory cytokines are involved in the disease's pathogenesis. The aim of this study was to test whether the interleukin (IL)-6 gene promoter region, or tumour necrosis factor (TNF)-alpha or IL-8 gene 3'-untranslated region (3'-UTR) polymorphisms could provide useful genetic markers for an individual's susceptibility to GD. A normal control group of 60 healthy people and 95 patients featuring GD were examined. Polymerase chain reaction (PCR)-based restriction analysis was performed for the three gene polymorphisms using endonucleases BsrBI, NcoI and ApaLI, respectively. We found no significant difference between the frequencies of genotype and allelic variants for the IL-6 gene promoter (-572 G/C), the TNF-alpha gene promoter (-308 A/G) and the IL-8 gene 3'-UTR (2767 A/G) for GD patients and for normal controls. Cytokines are a large group of proteins that may elicit multiple effects upon immunological reactions. It still appears to be very worthwhile to continue to aggressively search for cytokine gene polymorphisms in order to predict the development of such disease.