Graves' disease (GD) is an autoimmune oligogenic disorder with a strong hereditary component. Several GD susceptibility genes have been identified and confirmed during the last two decades. However, ...there are very few studies that evaluated susceptibility genes for GD in specific geographic subsets. Previously, we mapped a new locus on chromosome 3q that was unique to GD families of Italian origin. In the present study, we used association analysis of single-nucleotide polymorphism (SNPs) at the 3q locus in a cohort of GD patients of Italian origin in order to prioritize the best candidates among the known genes in this locus to choose the one(s) best supported by the association. DNA samples were genotyped using the Illumina GoldenGate genotyping assay analyzing 690 SNP in the linked 3q locus covering all 124 linkage disequilibrium blocks in this locus. Candidate non-HLA (human-leukocyte-antigen) genes previously reported to be associated with GD and/or other autoimmune disorders were analyzed separately. Three SNPs in the 3q locus showed a nominal association (p < 0.05): rs13097181, rs763313, and rs6792646. Albeit these could not be further validated by multiple comparison correction, we were prioritizing candidate genes at a locus already known to harbor a GD-related gene, not hypothesis testing. Moreover, we found significant associations with the thyroid-stimulating hormone receptor (TSHR) gene, the cytotoxic T-lymphocyte antigen-4 (CTLA-4) gene, and the thyroglobulin (TG) gene. In conclusion, we identified three SNPs on chromosome 3q that may map a new GD susceptibility gene in this region which is unique to the Italian population. Furthermore, we confirmed that the TSHR, the CTLA-4, and the TG genes are associated with GD in Italians. Our findings highlight the influence of ethnicity and geographic variations on the genetic susceptibility to GD.
Background: Graves’ orbitopathy (GO) is believed to be the consequence of autoimmunity against antigens that are present both in the thyroid and orbital tissues. Massive release of thyroid antigens ...causes the appearance or deterioration of GO in patients with Graves’ hyperthyroidism (GH), as it occurs following radioiodine treatment. In theory, a similar release of autoantigens may occur at the eye level, for example due to an orbital trauma or surgical manipulation. To our knowledge, this is the first report of a case of de novo appearance of GO and then GH after an eye trauma, possibly reflecting spreading of autoantigens and activation of the immune system against shared orbital and thyroid antigens. Case Report: An otherwise healthy, 57-year-old man presented 6 months after the appearance of a monolateral right orbitopathy, which occurred 40 days after a trauma in the ipsilateral eye. His thyroid function was normal, with positive serum anti-TSH receptor autoantibodies. The thyroid was normal on ultrasound. A month later he developed hyperthyroidism and orbitopathy in the left eye. Discussion: The development of GO after an eye trauma may reflect tissue damage with release of autoantigens and consequent autoimmunity in a predisposed individual (our patient had a familial history of autoimmune thyroid disease). The subsequent development of hyperthyroidism is in keeping with the hypothesis that GH and GO are due to autoimmunity against antigens present both in the thyroid and in orbital tissues.
Oncocytes of the thyroid gland (Hürthle cells) are found in tumors and autoimmune diseases. They have a unique appearance characterized by abundant granular eosinophilic cytoplasm and hyperchromatic ...nucleus. Their pathogenesis has remained, thus far, unknown.
Using transgenic mice chronically expressing IFNgamma in thyroid gland, we showed changes in the thyroid follicular epithelium reminiscent of the human oncocyte. Transcriptome analysis comparing transgenic to wild type thyrocytes revealed increased levels of immunoproteasome subunits like LMP2 in transgenics, suggesting an important role of the immunoproteasome in oncocyte pathogenesis. Pharmacologic blockade of the proteasome, in fact, ameliorated the oncocytic phenotype. Genetic deletion of LMP2 subunit prevented the development of the oncocytic phenotype and primary hypothyroidism. LMP2 was also found expressed in oncocytes from patients with Hashimoto thyroiditis and Hürthle cell tumors.
In summary, we report that oncocytes are the result of an increased immunoproteasome expression secondary to a chronic inflammatory milieu, and suggest LMP2 as a novel therapeutic target for the treatment of oncocytic lesions and autoimmune hypothyroidism.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Bacterial infections and other pathologic conditions induce complex dysfunctions of the hypothalamic-pituitary-thyroid axis, collectively known as nonthyroidal illness (NTI). To explore the ...pathogenesis of bacterial NTI, we injected Mycobacterium tuberculosis extracts or Escherichia coli LPS in mice lacking key components of the Toll-like receptor or crystallizable fragment (Fc) receptor pathways. In wild-type mice, the bacterial components induced a hypothyroidism characterized by elements of both hypothalamic and thyroidal dysfunction. This NTI hypothyroidism did not develop in mice lacking the MyD88 adaptor or in those with a reduced number of mast cells. The hypothyroid responsiveness to LPS, however, was restored upon reconstitution with mast cells derived from the bone marrow of wild-type donors. In addition to bacterial components, whole immunoglobulins induced NTI hypothyroidism in wild-type mice, but not in those lacking activating Fc receptors or mast cells. The study demonstrates a link between Toll-like and Fc receptor signaling and thyroid gland function, uncovering a role of mast cells in murine NTI.
Interferon (IFN)-γ has been involved in the pathogenesis of Hashimoto thyroiditis. It is a cytokine released by infiltrating mononuclear cells that mediates its actions mainly through signal ...transducer and activator of transcription-1 (STAT1) but also through other transcription factors. To dissect the effect of IFNγ on thyroid morphology and function, we crossed transgenic mice that express IFNγ specifically in the thyroid gland to mice deficient in STAT1. Lack of STAT1 ameliorated the abnormal thyroid morphology and the primary hypothyroidism typical of IFNγ transgenic mice but not the suppressed iodine accumulation. Interestingly, lack of STAT1 alone decreased iodine accumulation, seemingly through expression of TGFβ. These results indicate that STAT1 is required to mediate some but not all of the phenotypic changes induced by IFNγ and that it also regulates iodine accumulation via TGFβ signaling.
STAT1 mediates in the thyroid some, but not all, of the effects induced by IFNγ, and regulates iodine accumulation via TGFβ signaling.
Limited data suggest that treatment with statins is associated with a reduced risk of Graves' orbitopathy (GO) in patients with Graves' disease (GD), attributed to the anti-inflammatory rather than ...to the hypolipemic effects of these medications. The aim of the present study was to investigate whether there is an association between high cholesterol and GO. The primary outcome was the relation between GO and low-density lipoprotein (LDL)-cholesterol. The secondary outcomes were the relation between severity or activity (the clinical activity score CAS) of GO and LDL-cholesterol.
A cross-sectional investigation was conducted in consecutive patients with GD who came under the authors' observation to undergo radioiodine treatment, a stratification aimed at forming two distinct groups of patients under the same conditions. A total of 250 patients were enrolled, 133 with and 117 without GO. Ophthalmological assessments and serum lipids measurements were performed.
In multivariate analyses with correction for the duration of hyperthyroidism, a variable that differed between patients with respect to the presence or absence of GO, a correlation between the presence of GO and both total (p = 0.01) and LDL-cholesterol (p = 0.02) was observed. In patients with hyperthyroidism lasting <44 months, total and LDL-cholesterol were higher (p = 0.01 and p = 0.008, respectively) among GO patients. In this subgroup, based on the presence/absence of GO, cutoff values were established for total (191 mg/dL) and LDL-cholesterol (118.4 mg/dL), above which an increased risk of GO was observed (total cholesterol relative risk: 1.47; p = 0.03; LDL-cholesterol relative risk: 1.28; p = 0.03). GO severity and CAS did not correlate with serum lipids. However, CAS was found to be higher (p = 0.02) in patients with high total cholesterol. When the analysis was restricted to untreated GO patients, a correlation was found between CAS and both total (p = 0.04) and LDL-cholesterol (p = 0.03), after adjustment for GO duration.
In patients with a short duration of hyperthyroidism, total and LDL-cholesterol correlate with the presence of GO, suggesting a role of cholesterol in the development of GO. Depending on GO duration, total and LDL-cholesterol correlate with GO activity, suggesting a role of cholesterol in the clinical expression of GO.
According to Rundle's curve, Graves' ophthalmopathy (GO) worsens during an initial phase up to a peak of maximum severity, then improves and reaches a static plateau, with the activity curve ...preceding the severity curve by a few months. To our knowledge, no studies have tried to replicate Rundle's curve, and very few have investigated the natural history of GO. Here, we studied GO natural history retrospectively and tried to identify factors that may affect it.
A total of 65 patients with untreated GO underwent an eye assessment after a median of seven months after the appearance of GO and then after a median of 40 months. The primary endpoints were the variation of the single GO features and of the NOSPECS score, as well as the overall outcome of GO. The secondary endpoint was the influence of several variables (age, sex, smoking, GO and thyroid disease duration, thyroid treatment, thyroid status, thyroid volume, anti-TSH receptor autoantibodies) on the outcome of GO.
The majority of patients had mild, minimally active GO, and only five had a Clinical Activity Score (CAS) >3. There was a significant reduction of CAS (p<0.0001) and NOSPECS (p=0.01) between the first and last observation, with a timing pattern resembling Rundle's curve. This difference was confirmed even when patients with a CAS >3 at first observation were excluded. At the last observation, 50.8% of patients had improved, 33.8% had remained stable, and 15.4% had worsened moderately or substantially. The overall outcome of GO was not affected by any of the variables under examination.
In confirmation of Rundle's observations, untreated GO improves spontaneously with time in the majority of patients, with an activity peak between 13 and 24 months, which may have implications in determining the proper timing of GO treatments.
Objective: To report on 2 patients with moderate to severe Graves ophthalmopathy (GO) who developed dysthyroid optic neuropathy following levothyroxine (LT4) withdrawal in preparation for 131I ...treatment for thyroid carcinoma.Methods: Two patients referred to a center for the treatment of thyroid diseases were evaluated.Results: Patient 1, a 55-year-old woman, had active (clinical activity score CAS, 5 out of 7 moderate to severe GO. After LT4 withdrawal, her left eye visual acuity decreased from 10/10 to 1/10, and her omolateral visual field was impaired. Euthyroidism was rapidly restored and GO was treated with intravenous glucocorticoids. Nevertheless, as the patient's visual acuity was still impaired, orbital decompression was performed. Patient 2, a 50-year-old man, had active (CAS, 3 out of 7) moderate to severe GO. After LT4 withdrawal, the patient developed a right dysthyroid optic neuropathy. His visual acuity decreased from 10/10 to 4/10, and his omolateral visual field was impaired. After prompt restoration of euthyroidism and treatment with intravenous glucocorticoids, normalization of his visual acuity was achieved.Conclusion: In moderate to severe GO, dysthyroid optic neuropathy may be precipitated in thyroidectomized patients following LT4 withdrawal, even if triiodothyronine at doses that do not prevent elevated serum thyroid-stimulating hormone concentrations are administered, suggesting that hypothyroidism should be carefully avoided in patients with such grades of GO.Abbreviations: CAS clinical activity score DON dysthyroid optic neuropathy GD Graves disease GO Graves ophthalmopathy LE left eye LT4 levothyroxine RE right eye rhTSH recombinant human thyroid-stimulating hormone T3 triiodothyronine TRAb thyroid-stimulating hormone receptor autoantibody TSH thyroid-stimulating hormone TTA total thyroid ablation
Context:
Serum thyroglobulin (Tg), the marker of residual tumor in papillary thyroid carcinoma, can be underestimated in patients with Tg autoantibodies (TgAb). TgAb are due to a coexistent ...lymphocytic thyroiditis (LT) or the papillary thyroid carcinoma per se. TgAb assays are highly discordant.
Design:
We evaluated 141 patients with a clinical diagnosis of nodular thyroid disease, 32 of Hashimoto's thyroiditis, and four of Graves' disease, who underwent total thyroidectomy for an associated papillary thyroid carcinoma. Patients were classified as papillary thyroid carcinoma-lymphocytic thyroiditis (PTC-T) and papillary thyroid carcinoma (PTC) according to the presence or absence of LT on histology. Tg was measured before thyroid remnant ablation, when it is expectedly detectable, by an immunometric assay (IMA) and TgAb by three noncompetitive IMA and three competitive radioimmunoassays (RIA). The number of lymphocytes was compared with TgAb concentration.
Results:
Seventy-two of 177 patients (40.7%) were classified as PTC-T and 105 (59.3%) as PTC. Although the tumor stage was similar in the two groups, Tg was undetectable in more PTC-T (37 of 72) than PTC (12 of 105) (P < 0.01), and Tg values were lower in the former (0; 0–4.7 ng/ml) (median; 25th to 75th percentiles) than in the latter group (9.7; 2.7–24.2) (P < 0.01). Accordingly, the percent of positive TgAb by the six assays resulted in higher PTC-T (29.2–50.0%) than PTC (1.9–6.7%) (P < 0.01). Among 49 patients with undetectable Tg, TgAb were more frequently positive by IMA (57.1–63.3%) than RIA (30.6–42.9%). The number of lymphocytes correlated with TgAb concentration in all six assays (0.34 < Rho < 0.46) (all P < 0.01).
Conclusions:
In papillary thyroid carcinoma, LT on histology must be carefully searched for because it is frequently associated with TgAb and therefore mistakenly low or undetectable Tg. TgAb can be missed by some assays. In absence of LT, TgAb are rare.
Clinically overt Graves' orbitopathy (GO) is associated with Graves' disease (GD) in approximately 95% of cases, whereas the remaining 5% is observed in patients with hypothyroid autoimmune ...thyroiditis (AT) or without overt thyroid dysfunction (euthyroid GO). However, it is not known whether there is a difference in terms of GO phenotype between patients with GD and those with hypothyroid AT or without thyroid dysfunction, and hence this is investigated here.
The study design was to evaluate retrospectively all consecutive patients with a recent manifestation of GO, seen at their first visit to a tertiary referral center over a period of 10 years. In total, 358 GO patients were studied, and all of them underwent GO assessment.
Of the 358 patients studied, 341 had hyperthyroid GD, 10 had AT with hypothyroidism, and seven had euthyroid GO. Age, sex, and smoking habits were similar in the three groups, as was the time since GO was first noticed (GO duration). The vast majority of patients had moderate to severe, active GO, as expected in a tertiary referral center. Exophthalmometry, eyelid width, clinical activity score (CAS), diplopia, and visual acuity did not differ between patients with GD and those with AT or euthyroid GO, suggesting that the GO phenotype was similar. Accordingly, the NOSPECS score did not differ between the three groups.
The phenotype of GO is similar regardless of the underlying thyroid disease. Because this study was performed in a tertiary referral center, this conclusion can be restricted only to patients who develop moderate to severe GO.
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