Interactions of HLA-DRB4 and CTLA-4 genes influence thyroid function in Hashimoto's thyroiditis in Japanese population

Class II HLA-DRB4 is a predictive biomarker for survival following immunotherapy in metastatic non-small cell lung cancer

Immune checkpoint inhibitors (ICI) are important treatment options for metastatic non-small cell lung cancer (mNSCLC). However, not all patients benefit from ICIs and can experience immune-related adverse events (irAEs). Limited understanding exists for germline determinants of ICI efficacy and toxicity, but Human Leukocyte Antigen (HLA) genes have emerged as a potential predictive biomarker. We performed HLA typing on 85 patients with mNSCLC, on ICI therapy and analyzed the impact of HLA Class II genotype on progression free survival (PFS), overall survival (OS), and irAEs. Most patients received pembrolizumab (83.5%). HLA-DRB4 genotype was seen in 34/85 (40%) and its presence correlated with improved OS in both univariate (p = 0.022; 26.3 months vs 10.2 months) and multivariate analysis (p = 0.011, HR 0.49, 95% CI [0.29, 0.85]). PFS did not reach significance (univariate, p = 0.12, 8.2 months vs 5.1 months). Eleven patients developed endocrine irAEs. HLA-DRB4 was the predominant genotype among these patients (9/11, 81.8%). Cumulative incidence of endocrine irAEs was higher in patients with HLA-DRB4 (p = 0.0139). Our study is the first to suggest that patients with metastatic NSCLC patients on ICI therapy with HLA-DRB4 genotype experience improved survival outcomes. Patients with HLA-DRB4 had the longest median OS (26.3 months). Additionally, we found a correlation between HLA-DRB4 and the occurrence of endocrine irAEs.

Structural and functional differences in auto-antibody positive compared to auto-antibody negative hypothyroid patients with chronic thyroiditis

Most primary hypothyroidism in adults is caused by chronic thyroiditis. Autoantibodies such as anti-thyroglobulin antibody (TgAb) and anti-thyroid peroxidase antibody (TPOAb) are involved in the pathogenesis of chronic thyroiditis. On the other hand, the clinical features of antibody-negative hypothyroidism are not clear. In this study, we aimed to determine the prevalence of thyroid-related autoantibodies in patients with primary hypothyroidism and to evaluate the differences in thyroid structure between antibody-positive and antibody-negative hypothyroidism. Among 804 patients who attended Kawasaki Medical School Hospital for thyroid hormone abnormalities or thyroid gland enlargement between January 1, 2010 and December 31, 2021, 237 patients with primary hypothyroidism who underwent thyroid antibody measurement and thyroid ultrasound examination were included. Participants were divided into groups according to antibody positivity/negativity, and differences in antibody positivity and thyroid structure were evaluated. In this study, 34.6% of patients had antibody-negative hypothyroidism. The positive rate of each antibody was 62.0% for TgAb and 49.4% for TPOAb. The participants with antibody-positive hypothyroidism had significantly larger thyroid gland on thyroid ultrasound examination (p < 0.05). Thyroid-stimulating hormone was significantly higher in participants with antibody-positive compared to antibody-negative hypothyroidism. The present study reveals a positive rate of thyroid-related autoantibodies in patients with hypothyroidism and the differences in thyroid structure between patients with and without antibodies. This study clearly show that the prevalence of antibody-negative chronic thyroiditis is quite high among hypothyroid patients, although this point needs confirmation by further investigations. The data in this study would be useful for the treatment of antibody-negative hypothyroid patients.

Asian-type DEL (RHD*DEL1) with an allo-anti-D: A paradoxical observation in a healthy multiparous woman

BACKGROUND

The DEL phenotype is the D variant expressing the least amounts of D antigen per red cell. Asian-type DEL (RHD:c:1227G > A) is the most prevalent DEL in East Asia without any anti-D alloimmunization reported before. We investigated the first observation of an anti-D in any DEL phenotype, reported in the Japanese language at a 1987 conference, only 3 years after the discovery of DEL.

METHODS

We contacted the proband 35 years after the initial report. Standard hemagglutination, adsorption/elution, and flow cytometry tests were performed, as was nucleotide sequencing for the RHD, RHCE, and HLA class I and class II genes.

RESULTS

The healthy multiparous Japanese woman, a regular blood donor, still had the anti-D of titer 8 representing an alloantibody by standard serologic methods. Unexpectedly, she carried an Asian-type DEL without any additional RHD gene variation. All 12 HLA alleles identified were known in the Japanese population. Interestingly, one of her HLA-DRB1 and a variant of her HLA-DQB1 alleles had previously been associated with anti-D immunization.

CONCLUSION

We described an allo-anti-D, maintained for more than three decades, in an Asian-type DEL. The combination of two implicated HLA alleles were rare and could have contributed to the anti-D immunization. Continued monitoring of anti-D immunization events in patients with DEL is warranted, and we discuss possible mechanisms for further study. As only this single observation has been recognized in the last 35 years, the current recommendation is affirmed: Individuals with Asian-type DEL should be treated as Rh D-positive for transfusion and Rh immune prophylaxis purposes.

The C55A Single Nucleotide Polymorphism in CTLA-4 Gene, a New Possible Biomarker in Thyroid Autoimmune Pathology Such as Hashimoto's Thyroiditis

Hashimoto's thyroiditis (HT) is a chronic autoimmune disorder characterized by the production of autoantibodies against the thyroid gland. Different studies have shown that several genes may be associated with HT, which explains why patients often have family members with thyroiditis or other autoimmune diseases. The aim of this case-control study was to evaluate the correlation between polymorphisms at the level of exon 1 from the CTLA-4 gene and the susceptibility to developing HT. In this study, we found that there is no statistically significant association between the polymorphism rs231775 (A22G in exon 1) of the CTLA-4 gene and a genetic predisposition to HT. In contrast, a strong association was discovered for the first time between C55A in exon 1 of the CTLA-4 gene and HT. Our findings suggest that there is a genetic relationship between the CTLA-4 (+55A/C) genotype and the seropositivity against thyroid autoantigens, such as anti-thyroid peroxidase (ATPO) and anti-thyroglobulin antibodies (ATG).

A significant association of the CTLA4 gene variants with the risk of autoimmune Graves' disease in ethnic Kashmiri population

Graves' disease (GD) is the commonest cause of hyperthyroidism in populations with adequate iodine intake. It results from an abnormality in the immune system, which produces unique antibodies causing over production of thyroid hormones and glandular hyperplasia in individuals with genetic susceptibility. The Cytotoxic Lymphocyte Associated Antigen-4 (CTLA4) gene product serves the important function of immunomodulation, thereby helping in maintenance of peripheral self-tolerance. Studies on the association of the CTLA4 SNPs with GD have shown variations in the results from different populations. Since no such study has been carried out in ethnic Kashmiri population, we aimed to study a possible association of the CTLA4 SNPs (+49 A/G, -318C/T, CT 60 A/G and -1661 A/G) with GD. A total of 285 individuals (135 patients with GD and 150 healthy individuals) were genotyped using PCR-RFLP method and the results showed statistically significant differences in genotypic and allelic frequencies of cases and controls for + 49 A/G SNP (p=<0.001; OR = 5.14; CI = 2.17-12.19) and CT 60 A/G SNP (p = < 0.001; OR = 6.9; CI = 2.8-16.6), while -318C/T and -1661 A/G SNPs showed no significant association. We also studied the mRNA expression of the CTLA4 in patients with GD and healthy individuals by Real-Time PCR and found a decreased expression of the CTLA4 mRNA in PBMCs of patients with GD as compared to healthy controls with a -3.71-fold change. We conclude that the CTLA4 + 49 A/G and CT 60 A/G SNPs have a significant association with the risk of GD development in Kashmiri population and CTLA4 mRNA expression is significantly decreased in GD.

Relationship of paratracheal lymph nodes with the progression of chronic autoimmune thyroiditis: 5-year follow-up results

Background/aim: To examine changes in paratracheal lymph nodes (PLNs) and the relationship with the course of the disease in patients with chronic autoimmune thyroiditis (CAT) 5 years after diagnosis. Materials and methods: A total of 169 patients with newly diagnosed CAT and 53 healthy subjects were included in the study. All patients underwent ultrasonographic (US) examinations of the thyroid, paratracheal regions, and examined thyroid function tests. Eighty-four patients who were euthyroid at baseline and who were contacted 5 years after the diagnosis were reevaluated by US and thyroid function tests. Results: The PLNs frequency was significantly higher in the CAT group than the controls (75.1 % vs. 30.1 %, P < 0.001). Among the 84 patients who were euthyroid at the time of diagnosis and were contacted again after 5 years, 15 developed hypothyroidism. Initially, PLNs were present in all patients who developed hypothyroidism and were significantly higher than in those who remained euthyroid (respectively 100% vs. 68.7%, P = 0.009). PLN presence and PLN volume in patients who were euthyroid at baseline predicted hypothyroidism at the end of 5 years. Conclusion: PLNs may be used as an indicator of disease progression. In addition, patient age and baseline TSH levels are other factors that predict the development of hypothyroidism in time.

Construction of synergy networks from gene expression data related to disease

A few methods have been developed to determine whether genes collaborate with each other in relation to a particular disease using an information theoretic measure of synergy. Here, we propose an alternative definition of synergy and justify that our definition improves upon the existing measures of synergy in the context of gene interactions. We use this definition on a prostate cancer data set consisting of gene expression levels in both cancerous and non-cancerous samples and identify pairs of genes which are unable to discriminate between cancerous and non-cancerous samples individually but can do so jointly when we take their synergistic property into account. We also propose a very simple yet effective technique for computation of conditional entropy at a very low cost. The worst case complexity of our method is O(n) while the best case complexity of a state-of-the-art method is O(n(2)). Furthermore, our method can also be extended to find synergistic relation among triplets or even among a larger number of genes. Finally, we validate our results by demonstrating that these findings cannot be due to pure chance and provide the relevance of the synergistic pairs in cancer biology.

Association of Cytotoxic T-Lymphocyte-Associated Protein 4 (CTLA4) Gene Polymorphisms with Autoimmune Thyroid Disease in Children and Adults: Case-Control Study

Autoimmune thyroid disease (AITD), including Graves disease (GD) and Hashimoto disease (HD), is an organ-specific autoimmune disease with a strong genetic component. Although the cytotoxic T-lymphocyte-associated protein 4 (CTLA4) polymorphism has been reported to be associated with AITD in adults, few studies have focused on children. The aim of our study was to investigate whether the CTLA4 polymorphisms, including -318C/T (rs5742909), +49A/G (rs231775), and CT60 (rs3087243), were associated with GD and HD in Han Chinese adults and children. We studied 289 adult GD, 265 pediatric GD, 229 pediatric HD patients, and 1058 healthy controls and then compared genotype, allele, carrier, and haplotype frequencies between patients and controls. We found that CTLA4 SNPs +49A/G and CT60 were associated with GD in adults and children. Allele G of +49A/G was significantly associated with GD in adults (odds ratio [OR], 1.50; 95% confidence interval [CI], 1.21–1.84; corrected P value [Pc] < 0.001) and children (OR, 1.42; 95% CI, 1.15–1.77; Pc = 0.002). Allele G of CT60 also significantly increased risk of GD in adults (OR, 1.63; 95% CI, 1.27–2.09; Pc < 0.001) and GD in children (OR, 1.58; 95% CI, 1.22–2.04; Pc < 0.001). Significant linkage disequilibrium was found between +49A/G and CT60 in GD and control subjects (D’ = 0.92). Our results showed that CTLA4 was associated with both GD and HD and played an equivalent role in both adult and pediatric GD in Han Chinese population.

Correlation of fine needle aspiration cytology findings with thyroid function test in cases of lymphocytic thyroiditis

Background. Chronic lymphocytic thyroiditis is the second most common thyroid lesion diagnosed on FNAC after goiter. FNAC is reliable tool in the diagnosis of thyroid lesion. Objective. To correlate FNAC cytologic findings with TFT in the lymphocytic thyroiditis. Methods. 175 patients with thyroid swellings were referred for FNAC as well as TFT during 2011-2013. Fine needle aspiration cytology was performed using non-aspiration or aspiration techniques and TFT performed on Beckman culter access 2. Results. Lymphoid infiltrate was seen in 55 cases. The commonest age group of lymphocytic thyroiditis was 21-30 years with male : female ratio being 1 : 10. Anti-TPO and TSH were elevated in 96.16% (25/26) of cases with grade 3 lymphoid infiltrate, 94.12% (16/17) of cases with grade 2, and 91.67% (11/12) of cases with 1 grade. Increased anti-TPO with raised TSH without any lymphoid infiltrate was seen in 5 cases and 5 cases showed only raised TSH without raised anti-TPO and without any lymphoid infiltrate. We observed that grade 3 lymphocytic infiltration has correlation with anti-TPO and TSH together or TSH alone but not with anti-TPO alone. We also observed that anti-TPO and TSH together are significant even if no lymphocytic infiltration is present. Conclusion. Grade 3 lymphocytic infiltration has statistical correlation with anti-TPO and TSH together or TSH alone but not with anti-TPO alone. Anti TPO was adjunct to TSH in grade 3. The presence of Hurthle cell change, giant cells, and granulomas has no statistical correlation with lymphocytic thyroiditis.

Cytotoxic T-lymphocyte associated antigen 4 polymorphism and Hashimoto's thyroiditis susceptibility: a meta-analysis

The association between cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) exon-1 +49 A/G polymorphism and Hashimoto's thyroiditis (HT) has been widely studied. The results, however, are mixed. This study provides a comprehensive evaluation of the relationship between the genetic risks of CTLA-4 +49 A/G polymorphism and HT. A meta-analysis was conducted in over 4,600 subjects included in 18 case-control studies that were published up to November 15th, 2012. Our meta-analysis indicated that the CTLA-4 genotype was associated with the risk of HT in the allele comparison, homozygote comparison, heterozygote comparison, the dominant genetic model and the recessive genetic model. In the dominant genetic model, variant G allele carriers (GG + GA) of CTLA-4 +49 A/G polymorphism increased the risk of HT comparing to the homozygote AA [odds ratio (OR) = 1.70, 95% confidence interval (CI) 1.37-2.12 for GG + AG vs. AA]. The analysis by ethnicity groups suggested that Asian population (OR = 2.13, 95% CI 1.48-3.07 for GG + AG vs. AA) and Caucasian population (OR = 1.47, 95% CI 1.13-1.91 for GG + AG vs. AA) had significant increased HT risks. The association remained significant after adjusting for publication bias using the trim and fill method. Sensitivity analysis showed that the results were less stable, suggesting that these results should be explained with caution. In summary, this meta-analysis suggested that CTLA-4 +49 A/G polymorphism may be a risk factor for HT.

The CTLA4 +49A/G polymorphism is associated with an increased risk of Hashimoto's thyroiditis in Asian but not Caucasian populations: an updated meta-analysis

The polymorphism +49A/G in the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) gene has been implicated in susceptibility to Hashimoto's thyroiditis (HT), but the findings are not clear-cut. This study aimed to investigate the association between CTLA-4 polymorphisms and HT risk using an updated meta-analysis. A meta-analysis was carried out of 14 previous studies that investigated the CTLA-4 +49A/G polymorphism and HT risk. +49A/G was associated with a significantly increased HT risk in both allele analysis and all genetic models (allele analysis: G vs. A: P < 0.001, OR = 1.379, 95 % CI = 1.244-1.529). Subgroup analysis by ethnicity showed a significantly increased HT risk with the G allele and all other genetic models in the Asian subgroup (P < 0.001). In the Caucasian subgroup, no significant association was detected between the CTLA-4 +49 G allele and HT, or in the genetic model analysis (P = 0.05). This gene-based analysis indicates that the cumulative effect of the +49A/G polymorphism in CTLA-4 is associated with HT in Asians, but appears to have no effect on HT in Caucasians.

Updated analysis of studies on the cytotoxic T-lymphocyte-associated antigen-4 gene A49G polymorphism and Hashimoto's thyroiditis risk

Published data on the association between the cytotoxic T-lymphocyte-associated antigen-4 gene A49G polymorphism and the risk for Hashimoto's thyroiditis (HT) are inconclusive. A meta-analysis was performed to derive a more precise estimation. Published case-control studies in English or Chinese were identified. In total, 24 studies with 2295 cases and 4521 controls were investigated. A random-effect model was performed irrespective of between-study heterogeneity. Study quality was assessed in duplicate, and subgroup analyses were conducted by ethnicity or age. Overall, the 49G allele was associated with an increase in HT risk [odds ratio (OR) = 1.31; 95% confidence interval (95%CI) = 1.17-1.47; P < 0.00001]. In a subgroup analysis by ethnicity, comparison of allele 49G with 49A generated a 27% increased risk among East Asians (OR = 1.48; 95%CI = 1.24-1.76; P < 0.00001) and whites (OR = 1.27; 95%CI = 1.12-1.44; P = 0.0002). We also found an increased risk among adults (OR = 1.31; 95%CI = 1.17-1.47; P < 0.00001) but not among children (OR = 1.44; 95%CI = 0.75-2.79; P = 0.27), possibly owing to the small sample sizes in children. No publication biases were observed. This meta-analysis suggested that the cytotoxic T-lymphocyte-associated antigen-4 gene 49G allele was associated with an increased HT risk, especially in adults.

Thyroid heterogeneity, as indicated by the CV of ultrasonographic intensities, correlates with anti-thyroid peroxidase antibodies in euthyroid Hashimoto's thyroiditis

Objective

To prospectively evaluate the heterogeneous appearance of the thyroid gland, reflecting inflammation and destruction in euthyroid Hashimoto’s thyroiditis (HT), we investigated the clinical utilities of the heterogeneity index (HI) [the coefficient of variance (CV) of the ultrasonographic (US) intensities], focusing on anti-thyroid peroxidase antibodies (TPO-Ab), which represent not only disease activity but also subsequent thyroid destruction of HT.

Methods

Forty-four consecutive patients with euthyroid HT [60.5 ± 2.7 years old (mean ± SE)] and 30 age-matched normal controls were studied. HI was calculated as the CV (SD/mean) of US intensities of either four points per lobe of the thyroid gland along a horizontal line at the depth of the right common carotid artery. Evaluation included serum levels of free thyroxine (FT4), free triiodothyronine (FT3), thyroid stimulating hormone (TSH), anti-thyroid peroxidase antibodies (TPO-Ab), anti-thyroglobulin antibodies (Tg-Ab), thyroglobulin and thyroid volume.

Results

While no differences were observed for TSH, FT₄ and FT_3, thyroglobulin and thyroid volume between the two groups, HI exhibited a tendency towards a significant difference (3.59 ± 0.20% in HT patients vs 3.23 ± 0.19% in normal group, p = 0.089). In HT patients, there was a significant and positive correlation of HI with TPO-Ab (r = 0.396, p = 0.034), whereas such a correlation was absent in normal controls. In both groups, there were no significant correlations of HI with Tg-Ab, FT₃, FT₄ or TSH.

Conclusions

This is the first report of the close relation between heterogeneity of US of the thyroid gland and TPO-Ab in euthyroid HT patients before the heterogeneity becomes distinguishable from normal thyroid glands. Furthermore, at this stage, subsequent thyroid destruction in HT might be already be predicted through the heterogeniety of the thyroid tissue.

CTLA-4 gene polymorphisms and their influence on predisposition to autoimmune thyroid diseases (Graves' disease and Hashimoto's thyroiditis)

INTRODUCTION

Autoimmune thyroid disease (AITD) is associated with both genetic and environmental factors which lead to the overactivity of immune system. Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) gene polymorphisms belong to the main genetic factors determining the susceptibility to AITD (Hashimoto's thyroiditis, HT and Graves' disease, GD) development. The aim of the study was to evaluate the relationship between CTLA-4 polymorphisms (A49G, 1822 C/T and CT60 A/G) and HT and/or GD in Polish patients.

MATERIAL AND METHODS

Molecular analysis involved AITD group, consisting of HT (n=28) and GD (n=14) patients, and a control group of healthy persons (n=20). Genomic DNA was isolated from peripheral blood and CTLA-4 polymorphisms were assessed by polymerase chain reaction-restriction fragment length polymorphism method, using three restriction enzymes: Fnu4HI (A49G), BsmAI (1822 C/T) and BsaAI (CT60 A/G).

RESULTS

Statistical analysis (χ(2) test) confirmed significant differences between the studied groups concerning CTLA-4 A49G genotypes. CTLA-4 A/G genotype was significantly more frequent in AITD group and OR analysis suggested that it might increase the susceptibility to HT. In GD patients, OR analysis revealed statistically significant relationship with the presence of G allele. In controls, CTLA-4 A/A genotype frequency was significantly increased suggesting a protective effect. There were no statistically significant differences regarding frequencies of other genotypes and polymorphic alleles of the CTLA-4 gene (1822 C/T and CT60 A/G) between the studied groups.

CONCLUSIONS

CTLA-4 A49G polymorphism seems to be an important genetic determinant of the risk of HT and GD in Polish patients.

Hashimoto's Thyroiditis: From Genes to the Disease

Hashimoto's thyroiditis (HT) is the most prevalent autoimmune thyroid disorder. Intrathyroidal lymphocytic infiltration is followed by a gradual destruction of the thyroid gland which may lead to subclinical or overt hypothyroidism. Biochemical markers of the disease are thyroid peroxidase and/or thyroglobulin autoantibodies in the serum which are present with a higher prevalence in females than in males and increase with age. Although exact mechanisms of aetiology and pathogenesis of the disorder are not completely understood, a strong genetic susceptibility to the disease has been confirmed predominantly by family and twin studies. Several genes were shown to be associated with the disease occurrence, progression, and severity. Genes for human leukocyte antigen, cytotoxic T lymphocyte antigen-4, protein tyrosine phosphatase nonreceptor-type 22, thyroglobulin, vitamin D receptor, and cytokines are considered to be of utmost importance. Amongst endogenous factors for the disease development, the attention is focused predominantly on female sex, pregnancy with postpartum period and fetal microchimerism. Environmental factors influencing HT development are iodine intake, drugs, infections and different chemicals. Disturbed self-tolerance accompanied by the increased antigen presentation is a prerequisite for the HT occurrence, whereas proper interaction of thyroid cells, antigen presenting cells, and T cells are necessary for the initiation of thyroid autoimmunity. Secreted cytokines lead predominantly to T-helper type 1 (Th1) response as well as to Th 17 response which has only recently been implicated. Final outcome of HT is thyroid destruction which is mostly a consequence of the apoptotic processes combined with T-cell mediated cytotoxicity.

Hashimoto's thyroiditis: TGAb, TPOAb, TRAb and recovery from hypothyroidism

Hashimoto described four patients with goiter. The histology of the goiter was characterized by diffuse lymphocytic infiltration, fibrosis and epithelial cell destruction. Thyroglobulin antibody (TGAb) and thyroid peroxidase antibody (TPOAb) have been used to diagnose Hashimoto's thyroiditis. Patients with positive TGAb and/or TPOAb have been assumed to have Hashimoto's thyroiditis. Approximately 10% of those with positive TGAb and/or TPOAb have hypothyroidism. There are two types of autoimmune thyroiditis: goitrous Hashimoto's thyroiditis and atrophic thyroiditis. The latter patients have blocking antibody (thyroid-stimulating hormone [TSH]-stimulation blocking antibody [TSBAb]). TSBAb is a TSH-receptor antibody (TRAb). TSBAb causes thyroid atrophy and hypothyroidism. TGAb and/or TPOAb do not necessarily cause hypothyroidism. Hypothyroid patients with Hashimoto's thyroiditis usually receive life-long l-thyroxine therapy. However, spontaneous recovery from hypothyroidism has been reported. Patients who had Hashimoto's hypothyroidism and then Graves' hyperthyroidism (and vice versa), have also been reported. Hashimoto's hypothyroidism and Graves' hyperthyroidism could be the opposite spectrums of one disease.

Immunogenetics of drug-induced skin blistering disorders. Part II: Synthesis

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon examining the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events including Stevens–Johnson syndrome and Toxic epidermal necrolysis). New results from an exemplar study on shared precipitating and perpetuating inner causes with other related disease phenotypes including aphtous stomatitis, Behçets, erythema multiforme, Hashimoto’s thyroiditis, pemphigus, periodic fevers, Sweet’s syndrome and drug-induced multisystem hypersensitivity are presented. A call for a collaborative, wider demographic profiling and deeper immunotyping in suggested future work is made.

Serological evidence of thyroid autoimmunity among schoolchildren in two different socioeconomic environments

CONTEXT

The mechanisms leading to thyroid autoimmunity are largely unknown.

OBJECTIVE

Our objective was to assess the role of environment in the development of thyroid autoimmunity.

DESIGN

Prevalence of thyroid autoantibodies in two neighboring populations living in completely different socioeconomic circumstances (Russian Karelia and Finland) was studied.

SETTING

We studied two population-based cohorts partly sharing the same ancestry.

PATIENTS OR OTHER PARTICIPANTS

A total of 532 schoolchildren from Russian Karelia and 532 schoolchildren in Finland matched for age, gender, and season of the blood sampling were included.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURES

The prevalence of thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TGAb) and HLA-DQ alleles was measured.

RESULTS

The prevalence of TPOAb was significantly lower in Russian Karelian than in Finnish children (0.4 vs. 2.6%, P=0.006). A similar difference was observed for TGAb (0.6 vs. 3.4%, P=0.002). Finnish girls tested positive for both TPOAb (4.3 vs. 0.4%, P=0.01) and TGAb (5.3 vs. 0.9%, P=0.01) more frequently than Finnish boys. Seven of the 23 tested subjects with signs of thyroid autoimmunity (30%) had increased serum TSH concentrations as a sign of subclinical hypothyroidism. The frequency of HLA genotypes did not differ between the two countries or between autoantibody-positive and -negative subjects.

CONCLUSIONS

The prevalence of thyroid autoimmunity is lower in Russian Karelia than in Finland. This difference was not related to ethnic background or HLA-DQ alleles. The results support the idea that the Russian Karelian environment, which is characterized by inferior prosperity and standard of hygiene, may provide protection against thyroid autoimmunity.

Cytotoxic T-lymphocyte associated antigen 4 gene polymorphisms and autoimmune thyroid disease: a meta-analysis

CONTEXT

Cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) polymorphisms have been widely examined for their associations with autoimmune thyroid diseases [Graves' disease (GD) and Hashimoto thyroiditis (HT)], but their relative population effect remains unclear.

OBJECTIVE

The aim was to generate large-scale evidence on whether the CTLA-4 polymorphisms (A49G and CT60) and haplotypes thereof increase the susceptibility to GD and/or HT.

DESIGN, SETTING, AND PARTICIPANTS

Meta-analyses of group-level data were reviewed from 32 (11,019 subjects) and 12 (4,479) published and unpublished studies for the association of the A49G polymorphism with GD and HT, respectively (PubMed and HuGeNet search until July 2006). There were 15 (n = 7246) and six (n = 3086) studies available for the CT60 polymorphism, respectively. Meta-analyses of individual-level data from 10 (4906 subjects) and five (2386) collaborating teams for GD and HT, respectively, were also reviewed.

MAIN OUTCOME MEASURES

Association of gene variants and haplotypes with GD and HT was measured.

RESULTS

Group-level data suggested significant associations with GD and HT for both A49G [odds ratios 1.49 (P = 6 x 10(-14)) and 1.29 (P = 0.001) per G allele, respectively] and CT60 [1.45 (P = 2 x 10(-9)) and 1.64 (P = 0.003) per G allele, respectively]. Results were consistent between Asian and Caucasian descent subjects. Individual-level data showed that compared with the AA haplotype, the risk conferred by the GG haplotype was 1.49 (95% confidence interval 1.31,1.70) and 1.36 (95% confidence interval 1.16,1.59) for GD and HT, respectively. Data were consistent with a dose-response effect for the G allele of CT60.

CONCLUSION

The CT60 polymorphism of CTLA-4 maps an important genetic determinant for the risk of both GD and HT across diverse populations.

Thyroid autoantibody production is influenced by exon 1 and promoter CTLA-4 polymorphisms in patients with Hashimoto's thyroiditis

Strong genetic susceptibility to thyroid autoantibody (TAb) diathesis has been shown and one of the major genes involved is probably CTLA-4 gene. Our recent study of patients with Graves' disease has demonstrated that exon 1 CTLA-4 gene polymorphism influences higher TAb production. Here, we evaluated the influence of exon 1 and promoter CTLA-4 polymorphisms on TAb production in 109 newly diagnosed patients with Hashimoto's thyroiditis (HT). Serum TSH, thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibodies (TgAb) were measured. 49 A/G and -318 C/T polymorphisms were detected using polymerase chain reaction amplification of genomic DNA and restriction fragment length polymorphism analysis. Patients with AG and GG genotype had significantly higher TPOAb median values compared to patients with AA genotype (P < 0.003). Similarly, TgAb median value was significantly higher in AG patients and in the entire G-allele carrying group (P < 0.02). Compared to both T-allele carrying genotypes, CC genotype presented with significantly higher TPOAb median value (P < 0.02), whereas TgAb median values did not differ significantly between various genotypes. In conclusion, our results indicate that G allele influences higher TPOAb and TgAb production, whereas C allele affects especially TPOAb production in patients with HT. Therefore, our findings provide further evidence that CTLA-4 is a major TAb susceptibility gene.

Immunogenetic association and thyroid autoantibodies in juvenile autoimmune thyroiditis in North India

OBJECTIVES

Autoimmune thyroid diseases (AITD) encompass a number of conditions that have in common cellular and humoral responses targeting the thyroid gland. Interactions between susceptibility genes and environmental triggers are thought to initiate an autoimmune response to thyroid antigens leading to disease manifestation. Commencement of the disease in childhood leads to the presumption that genetics may have an important role in the causation of the disease.

DESIGN

The present study was aimed at evaluating the human leucocyte antigen (HLA) encoded susceptibility to develop juvenile autoimmune thyroiditis (JAT) in patients from North India.

PATIENTS

We studied 48 consecutive patients of JAT along with 176 first-degree relatives for their thyroid function (FT4, TSH) and anti-thyroid peroxidase antibody status (AbTPO).

MEASUREMENTS

HLA studies were carried out using serology for HLA-class I antigens and DNA analysis of HLA-class II alleles. The data were compared with a cohort of 308 ethnically matched healthy individuals.

RESULTS

We observed overt hypothyroidism in 50% and AbTPO positivity in 70.8% of the index cases. Among the first-degree relatives, goitre was observed in 51.7%, thyroid dysfunction in 28.4% and AbTPO in 29.5% of individuals. Of the 37 relatives who underwent fine-needle aspiration cytology (FNAC), 60% had evidence of chronic lymphocytic thyroiditis (CLT). A strong positive association of HLA-DRB1*1404 was observed with the JAT (35.4%vs. 10.4%, chi2 = 19.8, Pc = 0.0001). We also observed a higher (72%, P = 0.03) paternal transmission of HLA-DRB1*1404 to affected offspring in comparison to unaffected offspring. HLA-DRB1*03 was also increased among JAT patients but did not reach statistical significance.

CONCLUSION

These studies point towards an important role of immune modifying genes, such as HLA, in influencing susceptibility to juvenile-onset AITD.