Data mining-based statistical analysis of biological data uncovers hidden significance: clustering Hashimoto's thyroiditis patients based on the response of their PBMC with IL-2 and IFN-γ secretion to stimulation with Hsp60

The pathogenesis of Hashimoto's thyroiditis includes autoimmunity involving thyroid antigens, autoantibodies, and possibly cytokines. It is unclear what role plays Hsp60, but our recent data indicate that it may contribute to pathogenesis as an autoantigen. Its role in the induction of cytokine production, pro- or anti-inflammatory, was not elucidated, except that we found that peripheral blood mononucleated cells (PBMC) from patients or from healthy controls did not respond with cytokine production upon stimulation by Hsp60 in vitro with patterns that would differentiate patients from controls with statistical significance. This "negative" outcome appeared when the data were pooled and analyzed with conventional statistical methods. We re-analyzed our data with non-conventional statistical methods based on data mining using the classification and regression tree learning algorithm and clustering methodology. The results indicate that by focusing on IFN-γ and IL-2 levels before and after Hsp60 stimulation of PBMC in each patient, it is possible to differentiate patients from controls. A major general conclusion is that when trying to identify disease markers such as levels of cytokines and Hsp60, reference to standards obtained from pooled data from many patients may be misleading. The chosen biomarker, e.g., production of IFN-γ and IL-2 by PBMC upon stimulation with Hsp60, must be assessed before and after stimulation and the results compared within each patient and analyzed with conventional and data mining statistical methods.

Prognostic significance of thyroglobulin antibody epitopes in differentiated thyroid cancer

CONTEXT

Thyroglobulin antibodies (TgAbs) are surrogate markers of disease recurrence or persistence in differentiated thyroid cancer (DTC). However, the prognostic significance of TgAb heterogeneity in DTC has not been investigated.

OBJECTIVE

To evaluate the relationship between TgAb epitope specificities and clinical outcomes in DTC patients.

DESIGN

We studied 61 TgAb-positive patients with DTC, post-thyroidectomy and remnant ablation (7 males, 54 females; age-range 16-80 years, median follow-up duration 8.9 years). TgAb epitope reactivities were mapped using a panel of 10 thyroglobulin (Tg) monoclonal antibodies delineating six antigenic Tg clusters in competitive ELISA studies. Sera from 45 patients with Hashimoto's thyroiditis (HT) and 22 TgAb-positive healthy subjects served as autoimmune and healthy controls. Tg was measured by immunoradiometric assay (IRMA), electrochemiluminescence immunoassay (ECLIA), and RIA, while TgAbs was measured by ELISA and ECLIA methods.

RESULTS

Samples from 26 DTC patients showed TgAb epitope restriction similar to HT patients, while 35 patients exhibited nonspecific reactivity comparable to healthy controls. DTC patients with epitope restriction had higher rates of recurrent/persistent disease (81% vs 17%, P < .001), higher median TgAb concentration (887.0 vs 82.0 kIU/L; P < .001), and a higher prevalence of thyroid lymphocytic infiltration (71.4% vs 26.8%; P < .001) compared to patients with nonspecific reactivity. Samples with epitope restriction also had a lower median Tg-IRMA/RIA ratio (3.0% vs 36.0%; P < .001) denoting greater degrees of Tg assay interference.

CONCLUSIONS

TgAb epitope restriction is associated with a less favorable prognosis than nonspecific reactivity in DTC patients. TgAb epitope specificities may have prognostic value in DTC.

Ultrasonographic appearance of focal Hashimoto's thyroiditis: A single institution experience

The purpose of this study was to determine the ultrasonographic (US) appearance of focal Hashimoto's thyroiditis (FHT). Thirty-seven FHT patients and 60 consecutive patients with 60 papillary thyroid carcinomas (PTC) that were confirmed by cytology or histopathology between January 2011 and December 2013 were analyzed. Using the results of color Doppler imaging, US findings were retrospectively reviewed. Inter-group differences in size, internal content, echogenicity, echo texture, shape, boundary, margin, calcifications, fine echogenic septa, and blood flow were statistically assessed. The US appearances of the FHTs examined were: solid (100%), hypoechoic (97%), heterogeneous (68%), ovoid-to-round shape (73%), well-defined boundary (95%), smooth margin (89%), and hypervascular (46%). Ovoid-to-round shape, well-defined boundary, fine echogenic septa, and hypervascularity were significantly more prevalent for FHTs than for PTCs (p < 0.05). Ovoid-to-round shape and fine echogenic septa have a higher specificity and positive predictive value. FHTs show a spectrum of US appearances, making FHT diagnosis cumbersome. Fine echogenic septa are highly specific for FHT. Ovoid-to-round shape, well-defined boundary and hypervascularity may possibly be associated with FHT.

Acute exacerbation of Hashimoto thyroiditis mimicking anaplastic carcinoma of the thyroid: A complicated case

The fibrous variant of Hashimoto thyroiditis is uncommon, accounting for approximately 10% of all cases of Hashimoto thyroiditis. We report a case of this variant that behaved like a malignant neoplasm. The patient was a 69-year-old man who presented with a right-sided anterior neck mass that had been rapidly growing for 2 weeks. Fine-needle aspiration cytology revealed clusters of large multinucleated cells suggestive of an anaplastic carcinoma. A week after presentation, we ruled out that possibility when the mass had shrunk slightly. Instead, we diagnosed the patient with an acute exacerbation of Hashimoto thyroiditis on the basis of laboratory findings. We performed a right thyroid lobectomy, including removal of the isthmus, to clarify the pathology and alleviate pressure symptoms. The final diagnosis was the fibrous variant of Hashimoto thyroiditis, with no evidence of malignant changes. Physicians should keep in mind that on rare occasions, Hashimoto thyroiditis mimics a malignant neoplasm.

Cytotechnologist performance for screening microfollicular atypia in indeterminate thyroid fine-needle aspirates

INTRODUCTION

We previously identified a high level of accuracy among our cytotechnologists (CTs) for identifying nuclear atypia in thyroid fine-needle aspiration (FNA) specimens. Herewith, we present our CT performance at screening for microfollicular atypia.

METHODS

8,814 thyroid FNA specimens were identified in our archives, all screened by 1 of 11 CTs and signed out by a cytopathologist. A subsample of cases was categorized either as atypia of uncertain significance (AUS) with microfollicular proliferation (AUS-F) or suspicious for a follicular neoplasm (SFN).

RESULTS

The agreement rate was low between CTs and cytopathologists for SFN and AUS-F. Only 55.8% of SFN screening diagnoses were upheld; 27.9% were downgraded to AUS, 10.4% were downgraded to benign, and 5% were upgraded. Of AUS-F screening diagnoses, 35.5% were upheld, 33.7% were downgraded to benign, and 20.2% were upgraded to SFN. Among all cases, two-step discrepancies were uncommon.

CONCLUSION

Most disagreements were one-category discrepancies between AUS-F and SFN. The evaluation of microfollicular atypia is challenging given that certain follicular lesions cannot be definitively diagnosed on cytology, a high level of subjectivity is involved in the interpretation of such lesions, and the presence of nuclear or Hurthle cell atypia may complicate the diagnosis.

Expression of papillary thyroid carcinoma-associated molecular markers and their significance in follicular epithelial dysplasia with papillary thyroid carcinoma-like nuclear alterations in Hashimoto's thyroiditis

The aim of this study was to evaluate the expression of papillary thyroid carcinoma (PTC)-associated tumor markers in follicular epithelial dysplasia showing PTC-like nuclear alterations (FED) in Hashimoto's thyroiditis (HT) and to explore the relationship between HT and PTC. In this study, 43 PTC, 18 HT with FED and 16 peritumoral benign thyroid tissues were immunohistochemically analyzed for CK19, galectin-3, HBME-1, CD56, claudin-1 and NGAL expression. Our research revealed that in HT, the expression of CK19, galectin-3, HBME-1, claudin-1 and NGAL was focal and limited to FED, while CD56 was strongly positive in FED and most Hürthle cells. The stain intensity of CK19, claudin-1 and NGAL in FED decreased compared with PTC, but were significantly higher than that in peritumoral benign thyroid tissues (all P < 0.0125). For galectin-3, HBME-1 and CD56, no statistically significant difference was detected between HT and peritumoral benign thyroid tissues (all P > 0.05). In conclusion, In HT, FED might be a precancerous condition closely associated with PTC development as they have overlaps in cytological and immunomarker profiles, indicating that in patients with HT, under prolonged stimuli from chronic inflammation, part of follicular epithelia may show regeneration, hyperplasia, Hürthle cell metaplasia and dysplasia, eventually malignant transformation. Hence, long term follow-up and regular inspection would be necessary for Hashimoto's thyroiditis with FED.

Vestibular disorders in euthyroid patients with Hashimoto's thyroiditis: role of thyroid autoimmunity

INTRODUCTION

A relationship between vestibular disorders and thyroid autoimmunity independently from thyroid function has been postulated.

AIM

To shed more light on the actual relationship between vestibular lesions and Hashimoto's thyroiditis (HT) regardless of thyroid function.

METHODS

Forty-seven patients with HT (89·4% F; aged 48·3 ± 12·7 years), 21 with multinodular goitre (MNG; 57·1% F; 54·1 ± 9·8 years) and 30 healthy volunteers (56·7% F; 50·7 ± 13·9 years) were enrolled. Inclusion criteria were the presence of normal thyroid function tests and no clinical history of vestibular dysfunction. Each subject was submitted to complete vestibular evaluation [Caloric Test, Vestibular evoked myogenic potentials (VEMPs), Head Shaking Test (HST)].

RESULTS

52·2% of HT patients showed an alteration of VEMPs and 44·7% of caloric test (P < 0·0001 for both). None of the MNG patients showed any vestibular alteration, while one healthy control showed an altered caloric test. A correlation was found between vestibular alterations of HT patients and the degree of serum TPOAb level, not affected by age and serum TSH value. By logistic regression analysis, the absence of thyroid autoimmunity significantly reduced the risk of vestibular alterations: HR 0.19 (95%CI: 0·003-0.25, P = 0·0004) for caloric test; HR 0·07 (95%CI: 0·02-0·425, P < 0·0001) for VEMPs; and HR 0·22 (95%CI: 0·06-0·7, P = 0·01) for HST.

CONCLUSION

In euthyroid HT patients, a significant relationship between subclinical vestibular damage and the degree of TPOAb titre was documented. This finding suggests that circulating antithyroid autoantibodies may represent a risk factor for developing vestibular dysfunction. An accurate vestibular evaluation of HT patients with or without symptoms is therefore warranted.

Increased differentiation of Th22 cells in Hashimoto's thyroiditis

As Th22 subsets are identified, their involvement in the pathogenesis of numerous autoimmune diseases has become apparent. In this study, we investigated differentiation of Th22 cells in the autoimmune thyroid diseases including Hashimoto's thyroiditis (HT) and Graves' disease (GD). Besides, we also explored the involvement of Th22 cells in an iodine-induced autoimmune thyroiditis (AIT) model (i.e., NOD.H-2(h4) mice). In HT patients, we showed the level of circulating Th22 cells correlated with the level of serum IL-22, and was significantly higher than in GD patients and healthy control subjects. Levels of serum IL-6, a major Th22 cell differentiation effector, were also higher in HT, and correlated with Th22 cells concentration. Peripheral blood mononuclear cells isolated from HT patients produced larger amounts of IL-6 in vitro than did those isolated from other groups. Furthermore, unlike those from GD patients, T lymphocytes from HT patients showed an enhanced differentiation in vitro into Th22 cells in the presence of recombinant IL-6 and TNF-α. In addition, levels of circulating Th22 cells and titers of thyroid peroxidase antibody were positively correlated in HT patients. In NOD.H-2(h4) mice, higher numbers of Th22 cells were observed in the spleens of the AIT group, while splenocytes of this group also produced larger amounts of IL-6 and IL-22 in vitro compared with the control. Intra-thyroid infiltrating IL-22+ lymphocytes were significantly increased in mice of the AIT group compared with the control. Our results indicate that Th22 cells may contribute to the pathogenesis of HT.

Eosinophilic replacement infiltrates in cystic Hashimoto's thyroiditis: a potential diagnostic pitfall

A 50-year-old woman underwent a fine-needle aspiration biopsy for progressive enlargement of the left thyroid lobe which was cystic and solid on ultrasound exam. The smears contained innumerable eosinophilic leukocytes along with lymphocytes, Hurthle cells, cells from a papillary thyroid carcinoma (PTC), and atypical glandular and squamous cells. The cytologic interpretation was Hashimoto's thyroiditis (HT), suspicious for epithelial neoplasm. The associated diagnostic comment stated concern for a sclerosing mucoepidermoid carcinoma with eosinophilia (SMECE) arising in a PTC. Thyroidectomy demonstrated a PTC, HT with multiple lymphoepithelial cysts, and extensive multifocal infiltrates of eosinophils, generally confined to the cyst walls. As the cytologic findings mimicked a SMECE, we report these specimens as a most unusual diagnostic pitfall.

Conversion of autoimmune hypothyroidism to hyperthyroidism

BACKGROUND

Graves' disease and Hashimoto's thyroiditis are the two autoimmune spectrum of thyroid disease. Cases of conversion from hyperthyroidism to hypothyroidism have been reported but conversion from hypothyroidism to hyperthyroidism is very rare. Although such cases have been reported rarely in the past we are now seeing such conversions from hypothyroidism to hyperthyroidism more frequently in clinical practice.

CASE PRESENTATION

We are reporting three cases of middle aged Asian females who presented with classical symptoms of hypothyroidism and the investigations showed elevated thyroid stimulating hormone with positive thyroid antibodies. Diagnosis of autoimmune hypothyroidism was made and thyroxine replacement therapy was initiated. Patients became asymptomatic with normalization of thyroid stimulating hormone level. After few years they developed symptoms of hyperthyroidism with suppressed thyroid stimulating hormone level. Over replacement of thyroxine was considered and the dose of thyroxine was decreased, but they remain symptomatic. After gradual decrease in the dose of thyroxine it was stopped finally. Even after few months of stopping thyroxine, the symptoms of hyperthyroidism did not improve and the biochemical and imaging modalities confirmed that the patients have developed hyperthyroidism. Anti-thyroid treatment was then started and the patients became symptom free.

CONCLUSION

High index of suspicion should be there for possible conversion of hypothyroidism to hyperthyroidism if a patient with primary hypothyroidism develops persistent symptoms of hyperthyroidism. Otherwise it can be missed easily considering it as an over replacement with thyroid hormone.

Circulating microRNAs in autoimmune thyroid diseases

CONTEXT

Autoimmune thyroid diseases (AITDs), including Graves' disease (GD) and Hashimoto's thyroiditis (HT), are the most common autoimmune diseases. MicroRNAs (miRNAs) are small noncoding RNAs, which can play pivotal roles in immune functions and development of autoimmunity. Recently, it has been recognized that identification of circulating miRNAs can provide important and novel information regarding disease pathogenesis and clinical condition. However, the role circulating miRNAs in AITD has not yet been described.

OBJECTIVE

The aim of this study was to characterize the different circulating levels of miRNA in patients with AITD.

DESIGN AND METHODS

Sixty-four participants who met the criteria for HT or GD and healthy subjects were recruited. Microarrays were used to analyse the expression patterns of miRNA in serum obtained from patients with HT and GD and healthy subjects. After analysing the microarray data, four interesting miRNAs (miR-16, miR-22, miR-375 and miR-451) were selected and validated by quantitative real-time PCR.

RESULTS

Several miRNAs were observed to be differently expressed in serum from patients with AITD compared with healthy subjects by microarray analysis. Further analysis consistently showed that serum levels of miR-22, miR-375 and miR-451 were increased in patients with HT. On the other hand, the serum levels of miR-16, miR-22, miR-375 and miR-451 were increased in patients with GD compared with healthy subjects.

CONCLUSIONS

We revealed that different levels of serum miRNAs were associated with GD and HT, which may play a role in the pathogenesis of these diseases.

Is lymphocytic thyroiditis a unique type or merely a type of Hashimoto's thyroiditis?

AIM

Objective of the study was to clarify the role of apoptosis in the pathogenesis of lymphocytic thyroiditis (LT) and the existence of difference between Hashimoto's thyroiditis (HT) and LT.

METHODS

We evaluated levels of antithyroglobulin and antithyroperoxidase antibodies, the apoptosis by in situ Cell Death Detection-TUNEL and the expression of Bcl2 and Bax by immunohistochemistry in thyroid tissues from 16 patient with HT, 10 with LT and 10 with euthyroid goiter-EG (control group).

RESULTS

It was found that apoptosis of thyrocytes in HT (mean 3.05%, SD 1.29%) and LT (mean 2.70%, SD 1.17%) was statistically significantly higher than EG (mean 0.56%, SD 0.23%), but the difference in the percentage of thyrocytes between HT and LT was not statistically significant. In HT the percentage of apoptotic infiltrating lymphocytes (mean 0.59%, SD 0.23%) was smaller than in EG (mean 2.26%, SD 1.42%), but it showed no significant difference in comparison to LT. The expression of Bax in infiltrating lymphocytes in HT (mean 0.72%, SD 0.34%) was statistically significantly higher than LT (mean 0.11%, SD 0.06%). The level of thyroglobulin was lower in HT compared to LT (P<0.01) and compared to EG (P<0.01). The level of antithyroglobulin/antithyroperoxidase antibodies was higher in HT compared to LT (P<0.01) and compared to EG (P<0.01). There was no statistically significant difference in the level of thyroglobulin and level of antibodies between LT and EG.

CONCLUSION

These results suppose that apoptosis represents one of significant mechanisms in the pathogenesis of both HT and LT and that LT probably differs from HT.

Is Hashimoto's thyroiditis a prognostic factor for thyroid papillary microcarcinoma?

AIM

The relationship between papillary thyroid carcinoma (PTC) and accompanying Hashimoto's thyroiditis (HT) has been investigated extensively. However, there is no agreement among the authors. We aimed with this study to investigate this relationship in a limited subtype of PTC called papillary thyroid microcarcinoma (PTMC).

PATIENTS AND METHODS

Between January 1999 and December 2012, 1923 thyroids were surgically resected in two referral centers and thoroughly inspected for evidence of PTMC. Of these patients, 172 who were diagnosed with PTMC had demographic and pathological features recorded.

RESULTS

Fourteen patients (8.1%) were found to have CLN metastases. Eleven (78.6%) of the patients with CLN metastases had tumors larger than 5 mm, and 3 (21.4%) patients with CLN metastases had small tumors (≤ 5 mm), but there was no statistical significance (p > 0.05). Accompanying Hashimoto's thyroiditis (HT) was detected in 67 (39%) patients. The CLN metastasis rate was slightly higher in cases with HT in surrounding thyroid tissue. However, there was no statistical significance; the CLN rate was 6.7% (n=7) in patients without thyroiditis and 10.4% (n=7) with Hashimoto's thyroiditis. Insufficient FNA results in patients with thyroiditis were associated with HT (p < 0.05).

CONCLUSIONS

Surgeons and other clinicians who play a role in the treatment of thyroid cancers should be aware that some PTMC cases may show a worse course, as with some PTCs, contrary to expectations.

Pathologic spectrum of lymphocytic infiltration and recurrence of papillary thyroid carcinoma

PURPOSE

The aim of this study was to investigate the prognosis of papillary thyroid carcinoma (PTC) patients according to different pathologic grades of lymphocytic thyroiditis (LT).

MATERIALS AND METHODS

This study included 144 PTC patients who underwent total thyroidectomy with radioactive iodine remnant ablation therapy. Pathologic grades of LT were separated at two points, chronic lymphocytic thyroiditis (CLT) and Hashimoto thyroiditis (HT). Patients were divided into two groupings according to the presence of the diseases (Grouping 1; patients with CLT or HT and without CLT or HT, Grouping 2; patients with HT and without HT). The groupings were compared according to recurrence, clinicopathologic and ultrasound (US) characteristics, and disease free survival.

RESULTS

Of 144 patients, 41 had CLT and 19 had HT. There were 10 patients (6.9%) with tumor recurrence. In both groupings, the presence of calcification was more frequently associated with patients with LT (p=0.041 and 0.047, respectively). In Grouping 2, the mean age at diagnosis was older in patients without HT compared to patients with HT (p=0.032). On multivariate analysis, the presence of LT was not an independent predictor of recurrence in both groupings. For both groupings, pathologic tumor size and taller than wide shape on US were independent predictors of recurrence. The presence of LT in PTC patients did not affect recurrence.

CONCLUSION

There was no relationship between PTC prognosis and different grades of LT. Pathologic tumor size and taller than wide shape on ultrasound were independent predictors of PTC recurrence regardless of concurrent LT.

Hashimoto's thyroiditis pathology and risk for thyroid cancer

BACKGROUND

Hashimoto's thyroiditis (HT) has been found to coexist with differentiated thyroid cancer (DTC) in surgical specimens, but an association between the two conditions has been discounted by the medical literature. Therefore, we performed this study to determine any potential relationship between HT and the risk of developing DTC.

METHODS

We collected data for thyrotropin (TSH), thyroxine (T4), thyroid peroxidase antibody (TPO-Ab) titers, surgical pathology, and weight-based levothyroxine (LT4) replacement dose for patients who were referred for thyroid surgery. Patients with HT at final pathology were studied further. To estimate thyroid function, patients with preoperative hypothyroid HT (Hypo-HT) were divided into three equal groups based on their LT4 replacement: LT4-Low (<0.90 μg/kg), LT4-Mid (0.90-1.43 μg/kg), and LT4-High (>1.43 μg/kg). A group of preoperatively euthyroid (Euth-HT) patients but with HT by pathology was also studied. All subjects were also grouped based on their TPO-Ab titer in TPO-high (titer >1:1000) or TPO-low/negative (titer <1:1000 or undetectable) groups. The relationship of HT and DTC was studied extensively.

RESULTS

Of 2811 subjects, 582 had HT on surgical pathology, 365 of whom were Euth-HT preoperatively. DTC was present in 47.9% of the Euth-HT, in 59.7% of LT4-Low, 29.8% of LT4-Mid, and 27.9% of LT4-High groups. The relative risk (RR) for DTC was significantly elevated for the Euth-HT and LT4-Low groups (p<0.001), but not for the LT4-Mid or LT4-High replacement dose groups. TPO-low/negative status conferred an increased RR in the Euth-HT and LT4-Low replacement dose groups (p<0.001 both), while TPO-high status decreased it in Euth-HT group (p<0.05) and made it nonsignificant in the LT4-Low group.

CONCLUSIONS

HT pathology increases the risk for DTC only in euthyroid subjects and those with partially functional thyroid glands (LT4-Low) but not in fully hypothyroid HT (LT4-Mid and LT4-High). High TPO-Ab titers appear to protect against DTC in patients with HT.

Coexistence of papillary thyroid cancer and Hashimoto thyroiditis in children: report of 3 cases

This report documents 3 pediatric papillary thyroid carcinoma cases with associated Hashimoto thyroiditis. In all 3 cases, hypoechoic nodules accompanied by multiple echogenic spots were noted on sonography of the thyroid. Hashimoto thyroiditis was suspected on the basis of positive thyroid autoantibody test results and pathologic examinations of thyroidectomy specimens, which revealed chronic thyroiditis with lymphocytic infiltration as the background of papillary thyroid carcinoma development. The potential for papillary carcinoma development warrants close follow-up, and meticulous sonographic examinations must be performed in children with Hashimoto thyroiditis.

Lymphocytic profiling in thyroid cancer provides clues for failure of tumor immunity

Thyroid cancers are usually surrounded by a significant number of immune-reactive cells. Tumor-associated lymphocytes as well as background lymphocytic thyroiditis are frequently mentioned in pathology reports of patients who have undergone surgery for thyroid cancer. The nature of this lymphocytic reaction is not well understood. The fact that cancer can survive in this adverse microenvironment is indicative of immune regulation. We characterized the lymphocytic infiltration that accompanies thyroid cancer and compared it with that present in thyroid autoimmunity. We found that double-negative (DN) T cells were significantly more abundant in thyroid cancer than in thyroid autoimmunity. Although FOXP3(+) regulatory T cells were also present, DN T cells were the dominant cell type, associated with thyroid cancer. Furthermore, upon stimulation, the DN T cells associated with cancer remained unchanged, while the few (<5%) DN T cells associated with thyroid autoimmunity increased in numbers (>20%). CD25 expression on DN T cells remained unchanged after stimulation, which indicates that the increase in the absolute number of DN T cells in thyroid autoimmunity was at the expense of inactivation of single-positive T cells. We concluded that in the setting of thyroid cancer, DN T cells appear to suppress tumor immunity. In contrast, in thyroid autoimmunity, DN T cells were barely present and only increased at the expense of inactivated, single-positive T cells upon induction. Together, these findings indicate that thyroid cancer-associated DN T cells might regulate proliferation and effector function of T cells and thereby contribute to tumor tolerance and active avoidance of tumor immunity.

Elevated blood Hsp60, its structural similarities and cross-reactivity with thyroid molecules, and its presence on the plasma membrane of oncocytes point to the chaperonin as an immunopathogenic factor in Hashimoto's thyroiditis

The role Hsp60 might play in various inflammatory and autoimmune diseases is under investigation, but little information exists pertaining to Hashimoto's thyroiditis (HT). With the aim to fill this gap, in the present work, we directed our attention to Hsp60 participation in HT pathogenesis. We found Hsp60 levels increased in the blood of HT patients compared to controls. The chaperonin was immunolocalized in thyroid tissue specimens from patients with HT, both in thyrocytes and oncocytes (Hurthle cells) with higher levels compared to controls (goiter). In oncocytes, we found Hsp60 not only in the cytoplasm but also on the plasma membrane, as shown by double immunofluorescence performed on fine needle aspiration cytology. By bioinformatics, we found regions in the Hsp60 molecule with remarkable structural similarity with the thyroglobulin (TG) and thyroid peroxidase (TPO) molecules, which supports the notion that autoantibodies against TG and TPO are likely to recognize Hsp60 on the plasma membrane of oncocytes. This was also supported by data obtained by ELISA, showing that anti-TG and anti-TPO antibodies cross-react with human recombinant Hsp60. Antibody-antigen (Hsp60) reaction on the cell surface could very well mediate thyroid cell damage and destruction, perpetuating inflammation. Experiments with recombinant Hsp60 did not show stimulation of cytokine production by peripheral blood mononuclear cells from HT patients. All together, these results led us to hypothesize that Hsp60 may be an active player in HT pathogenesis via an antibody-mediated immune mechanism.

The expression of dual oxidase, thyroid peroxidase, and caveolin-1 differs according to the type of immune response (TH1/TH2) involved in thyroid autoimmune disorders

CONTEXT

Hashimoto's thyroiditis (HT) and Graves' disease (GD) are thyroid autoimmune disorders driven by Th1 and Th2 immune responses, respectively. Caveolin-1 (Cav-1), thyroid peroxidase (TPO), and dual oxidase (DUOX) are thought to be part of the thyroxisome, which is essential to maintain thyroid hormone synthesis, at the apical membrane.

OBJECTIVES

To analyze the thyroxisome in HT and GD thyroids, we investigated Cav-1, DUOX, and TPO expression as well as markers of oxidative stress (OS), cell proliferation, apoptosis, and antioxidant defenses. The effects of cytokines on Cav-1 expression were analyzed in vitro.

RESULTS

In HT, the decrease in Cav-1, DUOX, and TPO expression was marked in follicles having the morphological aspect of active follicles in normal glands and thus called active-like follicles. T4 was not detected in the colloid but in the cytoplasm as well as DUOX and TPO. These abnormalities were associated with increased OS and cell damage. In the hypofunctioning follicles of HT and normal thyroids, Cav-1, DUOX, and TPO were not expressed. In GD, they were expressed at the apical pole of thyrocytes, and T4 accumulated in the colloid of all follicles. Th1 cytokines IL-1α/interferonγ decreased Cav-1 expression in vitro, whereas the Th2 cytokine IL-4 had no effect.

CONCLUSION

Th1 cytokine-induced down-regulation of Cav-1 could be responsible for intracytoplasmic T4 synthesis and mislocalization of DUOX and TPO, suggesting an important role for Cav-1 in the preservation of thyroxisome integrity. The thyroxisome's disruption, leading to uncontrolled OS and cell apoptosis, is a key, event in HT pathogenesis.

[A case report of poorly differentiated thyroid carcinoma with contralateral papillary carcinoma]

A 22-year-old female patient complained of neck discomfort for one week. Examination revealed bilateral neck masses. Color doppler ultrasound showed bilateral thyroid masses,which resulted in two thyroid lobes asymmetry. Bilateral cervical enlarged lymph nodes were not found. Thyroid function was normal. Complete left lobe and subtotal right lobe of thyroid gland were resected. The pathological results showed poorly differentiated carcinoma of left thyroid and papillary carcinoma of right thyroid with bilateral Hashimoto's thyroiditis. The patient received resection of residual thyroid and lymph nodes in another hospital, with no tumor or metastasis found. The patient without radiotherapy or chemotherapy was followed up for 34 months, and no progressive lesions were found.