Possible pathogenetic relevance of interleukin-1 beta in "destructive" organ-specific autoimmune disease (Hashimoto's thyroiditis)

The role of cytokines and vitamin D in vitiligo pathogenesis

Vitiligo is a pigment-related disease with a global prevalence of 0.2% to 1.8% associated with considerable burden on quality of life. The treatment is still a challenge because of relapses and/or incomplete re-pigmentation. Although the exact cause is still unclear, its pathogenesis seems to be justifiable with the autoimmune theory, supported by the results of clinical research. In this narrative review, we aimed to summarize the evidence related to cytokines and vitiligo development. This review is consisted of English articles published in PubMed and Google Scholar concerning levels of inflammatory mediators, especially interleukins, in vitiligo patients over the last 20 years. References of relevant articles were also considered for review. Crucial role of dysregulated levels of interleukins and their synergistic function to each other, in the onset or progression of the disease is evident. The theory of autoimmune vitiligo is reinforced by the results of the studies in the literature, due to the association of pathogenesis with increased secretion of pro-inflammatory mediators and reduction of anti-inflammatory mediators. Decreased vitamin D levels may have a considerable role in vitiligo development by affecting Th1- and Th17-related immune responses. Cytokines play an important role in the pathogenesis or progression of the disease. Moreover, we believe that decreased vitamin D level has a considerable role in vitiligo development by affecting Th1- and Th17-related immune responses.

Lymphocyte infiltration and thyrocyte destruction are driven by stromal and immune cell components in Hashimoto's thyroiditis

Hashimoto's thyroiditis (HT) is the most common autoimmune disease characterized by lymphocytic infiltration and thyrocyte destruction. Dissection of the interaction between the thyroidal stromal microenvironment and the infiltrating immune cells might lead to a better understanding of HT pathogenesis. Here we show, using single-cell RNA-sequencing, that three thyroidal stromal cell subsets, ACKR1⁺ endothelial cells and CCL21⁺ myofibroblasts and CCL21⁺ fibroblasts, contribute to the thyroidal tissue microenvironment in HT. These cell types occupy distinct histological locations within the thyroid gland. Our experiments suggest that they might facilitate lymphocyte trafficking from the blood to thyroid tissues, and T cell zone CCL21⁺ fibroblasts may also promote the formation of tertiary lymphoid organs characteristic to HT. Our study also demonstrates the presence of inflammatory macrophages and dendritic cells expressing high levels of IL-1β in the thyroid, which may contribute to thyrocyte destruction in HT patients. Our findings thus provide a deeper insight into the cellular interactions that might prompt the pathogenesis of HT.

Causal associations of autoimmune thyroiditis and papillary thyroid carcinoma: mRNA expression of selected nuclear receptors and other molecular targets

Potential causal associations of autoimmune thyroiditis (AIT) and papillary thyroid carcinoma (PTC) have been studied previously. The mRNA expression patterns of thyroid hormone receptors (TR), retinoid receptors (RAR), rexinoid receptors (RXR), dihydroxyvitamin D₃ receptors (VDR), and progesterone receptors (PR) in PTC tissue of patients without autoimmune thyroiditis (PTC/AIT-) and in PTC tissue of patients with coexisting AIT (PTC/AIT+) have been investigated in order to judge whether the observed changes may take part in the promotion and progression of thyroid cancer. Tumours with or without AIT were classified histologically and the semiquantitative PCR was performed. The results revealed that there was decreased expression of TRα, TRβα, RARα and PR mRNA in PTC/AIT+ tumours when compared with PTC/AIT- tumours. Decreased expression of RARα in PTC/AIT+ was detected when compared with PTC/AIT- patients. A similar effect of AIT was observed with a decrease in RARγ expression in PTC/AIT+ patients. On the other hand, there was an increased expression of VDR in thyroid tumours (PTC/AIT+) when compared with PTC/AIT-. PR mRNA was decreased in the thyroid tumours of PTC/AIT+ patients when compared with PTC/AIT- patients. In addition, there was an increased expression of MKi67 and complement C3 in PTC of PTC/AIT+ when compared with PTC/AIT-. In the PTC/AIT+ group, a decreased level of IGF-1 mRNA was found when compared with the PTC/AIT- group. According to the significant differences of the studied markers in PTC/AIT+ compared with PTC/AIT-, it was indicated that AIT may be a predisposing factor for the development of PTC.

Uterus globulin associated protein 1 (UGRP1) is a potential marker of progression of Graves' disease into hypothyroidism

Approximately 20% of Graves' disease (GD) patients may result eventually in hypothyroidism in their natural course. Uterus globulin-associated protein 1 (UGRP1) was associated with GD in our previous study. Here we investigated the role of UGRP1 in the development of autoimmune thyroid disease (AITD). The results showed that UGRP1 was expressed in the thyrocytes of most Hashimoto's thyroiditis (HT) patients and a proportion of GD patients (293 HT and 198 GD). The pathologic features of UGRP1-positive thyrocytes resembled "Hürthle cells", and were surrounded by infiltrated leukocytes. The positivity rate of TPOAb in UGRP1-positive GD patients was much higher than that in -negative GD patients. Moreover, UGRP1 was co-expressed with Fas and HLA-DR in the thyrocytes of AITD patients. We also found IL-1β but not Th1 or Th2 cytokines was able to upregulate the expression of UGRP1. Our findings indicated that UGRP1 may be a novel marker in thyrocytes to predict GD patients who develop hypothyroidism.

Upregulated tissue expression of T helper (Th) 17 pathogenic interleukin (IL)-23 and IL-1β in Hashimoto's thyroiditis but not in Graves' disease

T helper (Th) 17 cells and interleukin (IL)-17 play a significant role in the pathogenesis of autoimmune thyroid disease (AITD). However, it has recently become clear that Th17 cells are more heterogeneous and exhibit two different phenotypes, whereas IL-23 and IL-1β are crucial for the generation of pathogenic Th17 lymphocytes. We aimed to investigate the association between IL-17 and Th17-promoting cytokines in AITD by studying the immunoexpression patterns of IL-17, IL-23, and IL-1β in thyroid tissue. Following thyroidectomy, 29 patients with AITD (21 cases of Hashimoto's thyroiditis (HT) and 8 cases of Graves' disease (GD)) and 18 patients with colloid goiter, as controls, were enrolled in this study, and immunohistochemistry was performed. The expression level of IL-17 in thyrocytes was significantly higher in HT and GD patients than in colloid goiter patients. Immunopositivity for both IL-23 and IL-1β was significantly increased in HT patients compared to GD and colloid goiter patients. However, no difference was found between IL-23 or IL-1β expression in patients with GD and colloid goiter. A positive correlation between IL-17 and IL-23 as well as IL-17 and IL-1β expression was observed in HT patients (r = 0.574, p = 0.007 and r = 0.461, p = 0.036, respectively). In the GD group, IL-17 was positively correlated with IL-1β (r = 0.817, p = 0.013) but not with IL-23 expression. We found increased IL-23 and IL-1β expression in the HT group but not in the GD group. Furthermore, both interleukins were correlated with IL-17 immunopositivity in thyroid tissue, suggesting that pathogenic Th17-promoting cytokines may play a role in HT pathogenesis.

Caveolin-1 regulates autophagy activity in thyroid follicular cells and is involved in Hashimoto's thyroiditis disease

Hashimoto's thyroiditis (HT) is considered a T helper-type 1 (Th1) cytokine-dominant autoimmune thyroid disease. Caveolin-1 (Cav-1), a part of the thyroxisome multiprotein complex, is localized at the apical pole of thyrocytes and is indispensable for synthesis of thyroid hormones and modulation of oxidative stress in order to avoid cell damage and apoptosis. Reduced autophagy induces thyroid follicular cells (TFC) apoptosis by activating reactive oxygen species (ROS) in HT patients. Nevertheless, whether Cav-1 has roles in the regulation of autophagy remains largely unclear. In this study, we examined Th1 cytokines and Cav-1 expression in HT thyroid tissues, determined the effects of interleukin-1beta (IL-1β) and interferon-gamma (IFN-γ) on Cav-1 and autophagy activity in TFC, and investigated the association between Cav-1 and autophagy activity in vitro. Our results indicate that higher levels of IL-1β and IFN-γ and lower levels of Cav-1 were expressed in thyroid tissues of HT patients than in those of normal controls. Cav-1 mRNA and protein levels were significantly decreased in TFC exposed to IL-1β and IFN-γ, accompanied by decreased expression of autophagy-related protein LC3B-II. Interestingly, small interfering RNA (siRNA)-mediated Cav-1 knockdown in TFC reduced LC3B-II protein expression. Taken together, these results suggest that lack of Cav-1 expression inhibited autophagy activity in TFC exposed to Th1 cytokines (IL-1β and IFN-γ), which might be a novel pathogenetic mechanism of HT.

Association of IFN-γ : IL-10 Cytokine Ratio with Nonsegmental Vitiligo Pathogenesis

Background and Objectives. Cytokines regulate immune response and inflammation and play a crucial role in depigmentation process of vitiligo. The present study aimed to estimate the serum levels of pro- and anti-inflammatory cytokines, IFN-γ and IL-10, and their ratios in nonsegmental vitiligo patients and healthy individuals from India. Methods. Blood samples were collected from 280 subjects and serum IFN-γ and IL-10 levels were measured using standard ELISA. Results. Nonsegmental vitiligo patients showed increased levels of IFN-γ (12.4 ± 3.2 versus 9.9 ± 4.4 pg/mL) and decreased levels of IL-10 (9.3 ± 1.7 versus 11.5 ± 5 pg/mL) compared to controls. Ratio of IFN-γ : IL-10 differed significantly from patients to controls (p < 0.05). IFN-γ concentrations and IFN-γ : IL-10 ratio varied significantly with respect to clinical variants, disease stability, and social habits (smoking and alcohol consumption) and showed a positive correlation with disease duration. Family history of vitiligo was significantly associated with IFN-γ : IL-10 ratio but not with their individual levels. Conclusion. The ratio of IFN-γ : IL-10 serum levels may be considered as one of the promising immunological markers in nonsegmental vitiligo. This is the first study considering multiple aspects in relation to ratio of cytokine levels. Similar studies with large samples are warranted to confirm our observations.

Impact of lithium alone and in combination with antidepressants on cytokine production in vitro

Lithium is an important psychopharmacological agent for the treatment of unipolar as well as bipolar affective disorders. Lithium has a number of side effects such as hypothyroidism and aggravation of psoriasis. On the other hand, lithium has pro-inflammatory effects, which appear beneficial in some disorders associated with immunological deficits, such as human immunodeficiency virus (HIV) infection and systemic lupus erythematosus (SLE). Therefore, immunological characteristics of lithium may be an important consideration in individualized therapeutic decisions. We measured the levels of the cytokines interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-22, IL-17 and tumour necrosis factor (TNF)-α in the stimulated blood of thirty healthy subjects supplemented with lithium alone, the antidepressants citalopram, escitalopram or mirtazapine alone, the combination of each antidepressant with lithium, and a no drug control. These drugs were tested under three blood stimulant conditions: murine anti-human CD3 monoclonal antibody OKT3 and the 5C3 monoclonal antibody (OKT3/5C3), phytohemagglutinin (PHA), and unstimulated blood. Lithium, alone and in combination with any of the tested antidepressants, led to a consistent increase of IL-1ß, IL-6 and TNF-α levels in the unstimulated as well as the stimulated blood. In the OKT3/5C3- and PHA-stimulated blood, IL-17 production was significantly enhanced by lithium. Lithium additionally increased IL-2 concentrations significantly in PHA-stimulated blood. The data support the view that lithium has pro-inflammatory properties. These immunological characteristics may contribute to side effects of lithium, but may also explain its beneficial effects in patients suffering from HIV infection or SLE.

Serum concentration of IL-6, IL-2, TNF-α, and IFNγ in Vitiligo patients

Background:

Vitiligo is an acquired depigmenting disorder characterized by the loss of functional melanocytes from the epidermis. Although the etiology of vitiligo is unknown, over the last few years, substantial data from clinical research has greatly supported the ‘Autoimmune theory’ and this is supported by the frequent association of vitiligo with disorders that have an autoimmune origin, including Hashimoto's thyroiditis, Graves disease, type 1 insulin-dependent diabetes mellitus, and Addison's disease. As cytokines are important mediators of immunity, there is evidence to suggest that they play a major role in the pathogenesis of autoimmune diseases.

Aim:

Keeping this in view we have assayed sera for cytokine IL-6, IL-2, Tumor necrosis factor (TNF)-α, and IFNγ in 80 cases of vitiligo and compared it with healthy subjects, in order to find out whether they play a role in the pathogenesis of vitiligo or not.

Materials and Methods:

Serum IL-6, IL-2, TNF-α, and IFNγ were done by the indirect enzyme linked immunosorbent assay (ELISA).

Results:

The mean serum IL-6 and IL-2 levels in the patient group were significantly higher when compared with those of the normal controls. The mean serum IFNγ level in patients with vitiligo was significantly lower than that in the control group. There was no significant difference in the serum level of TNF-α between vitiligo and healthy controls.

Conclusion:

An increase in the production of proinflammatory cytokines such as IL-6 and IL-2 in vitiligo patients may play an important role in melanocytic cytotoxicity. Thus, we speculate that the cytokine production of epidermal microenvironment may be involved in vitiligo.

Association of the -31C/T functional polymorphism in the interleukin-1beta gene with the intractability of Graves' disease and the proportion of T helper type 17 cells

Interleukin (IL)-1beta is a proinflammatory cytokine and has been implicated in the pathogenesis of several autoimmune diseases. To evaluate the hypothesis that the functional -31C/T polymorphism (rs1143627) in the gene encoding IL-1beta is associated with the intractability and the severity of autoimmune thyroid diseases, we genotyped this polymorphism in 64 patients with intractable Graves' disease (GD), 28 GD patients in remission, 49 patients with Hashimoto's disease (HD) who developed hypothyroidism (severe HD), 28 untreated euthyroid HD patients (mild HD) and 59 healthy volunteers. The -31T allele, which is related to the high producibility of IL-1beta, was significantly more frequent in patients with intractable GD than in those with GD in remission (P = 0.0017; odds ratio 2.8; 95% confidence interval 1.5-5.3), although there was no difference in this frequency between two groups of HD patients. We showed additionally that the proportion of IL-17-producing T helper type 17 (Th17) cells, whose differentiation and proliferation are promoted by IL-1beta, was higher in autoimmune thyroid disease patients with the T allele than in those with CC genotypes. In conclusion, our data indicated that the T allele of -31C/T polymorphism in the IL1B gene was involved in the intractability of GD, and this involvement may arise through the differentiation and proliferation of Th17 cells.

Cytokines in Thyroid Autoimmunity

The role of cytokines in the pathogenesis of autoimmune thyroid disease (ATD) has been extensively investigated over the past years. In patients with ATD, these molecules can be found in both the thyroid and sites of extrathyroidal complications of the disease. Cytokines can affect the autoimmune process through a number of mechanisms including recruitment of inflammatory cells and upregulation of molecules essential for perpetuation of the inflammatory response in the affected site. In addition, cytokines can interfere with thyroid hormone synthesis, implicating them directly in thyroid dysfunction found in ATD patients. Also, these molecules can modulate the function of cells in orbital tissue, which results in localised oedema, indicating a central role for cytokines in the development of proptosis, the cardinal feature of thyroid associated ophthalmopathy.

Ductal Metaplasia in Chronic Lymphocytic Thyroiditis as a Manifestation of Phylogenic Regression to an Exocrine Structure

From a morphologic and functional point of view the thyroid can be considered as both an exocrine and endocrine organ. Firstly, thyroglobulin is secreted at the apical pole of the thyrocyte. Secondly, after endocytosis thyroglobulin is lysed and T3 and T4 are secreted at the basal pole into the bloodstream. However, usually exocrine glands are constituted of 2 well separate components: an acinus/alveolar component and an exocrine duct component. Under particular conditions such as chronic injury the acinus/alveolar component is rapidly destroyed, whereas the ductal component seems to be far more resistant and can proliferate giving rise to a tubular network described as "ductulus reaction" or "ductal metaplasia." Normal exocrine ducts and metaplastic ducts exhibit common genetic and phenotypic features directly related to their tubular morphology. In this study, we describe in lymphocytic autoimmune thyroiditis the appearance of ductal-like structures which displayed the features of ductal metaplasia.

Thyroid cancer and the immune system: a model for effective immune surveillance

Differentiated thyroid cancers, including papillary and follicular variants, are a useful model with which to examine interactions between cancer and the immune system. Differentiated thyroid cancers are detected in only 20,000 individuals annually in the USA, but thyroid microcarcinomas (< 1 cm in diameter) are far more common. This suggests that the immune system might restrain the growth of these microcarcinomas. On the clinical level, patients with lymphocytes that infiltrate into papillary thyroid cancer have improved survival, supporting the notion that immune system activation might improve this. Together, these observations suggest that the growth and distant spread of thyroid carcinoma are suppressed by mechanisms of immune surveillance, possibly involving lymphocytes, macrophages and their secreted products. In this review, we examine the general hypothesis of immune surveillance and the data pertaining to the roles of lymphocytes, dendritic cells and cytokines in the immune response against thyroid cancers.

The role of Fas mediated apoptosis in preeclampsia

It has become clear in recent years that apoptosis is a normal process in trophoblast turnover during pregnancy. Increased trophoblast apoptosis has been observed in the placenta of women with preeclampsia, serum from women with preeclampsia has been found to induce increased trophoblast sensitivity to Fas-mediated apoptosis, and serum from women with preeclampsia has elevated levels of various chemokines, growth factors and cytokines that are involved in the regulation of apoptosis. This review highlights the importance of apoptosis in normal placental development and explores the mechanisms whereby Fas-mediated apoptosis may play a role in conditions related to abnormal placentation, such as preeclampsia.

In vitro modulation of inflammatory cytokine and IgG levels by extracts of Perna canaliculus

Background

Inflammation is a predominant characteristic of autoimmune diseases which is characterized by the increased expression of pro-inflammatory cytokines. Soon to be published work from our laboratory has shown that ingestion of Perna canaliculus prevents the development of autoimmune diseases such as Systemic Lupus Erythematosus and rheumatoid arthritis in laboratory animals. The current paper attempts to illustrate how Perna can alleviate inflammation by modulating inflammatory cytokines, cyclooxygenase enzymes and Immunoglobulin-G (IgG) levels.

Methods

In the present study, hydrochloric acid [HCl] and Tween-20 were used to develop extracts of Perna. These extracts were assayed for protein content. Increasing concentrations of these extracts were then tested in cell culture for modulation of inflammatory cytokine, cyclooxygenase enzymes and IgG levels. Parallel tests were run using an available glycogen extract of Perna as a comparison to our in-house laboratory preparations.

Results

Tween-20 Perna extracts were found to be more stable and less toxic in cell culture than HCl digest of Perna. They also assayed higher in protein content that HCl extracts. Although both extracts inhibited IgG production in V2E9 hybridomas, Tween-20 extracts were more consistent in IgG suppression than HCl extracts. Overall Tween-20 extracts effectively decreased levels of TNF-α, IL-1, IL-2 and IL-6 as observed using cytokine bioassays. Twenty micrograms of Tween-20 Perna extracts induced such significant decreases in inflammatory cytokine production that when tested on sensitive cell lines, they very nearly abolished the decrease in viability induced by these cytokines. Tween-20 extracts effectively inhibited both COX-1 and COX-2 cyclooxygenase activity. As a comparison, the glycogen extract also demonstrated a similar though weaker effect on COX-1 and COX-2 enzymes. The active components of both extracts (Tween-20 and glycogen) were observed to possess molecular weights above 100 kDa. Although the anti-cytokine activity of the Tween-20 extract was destroyed by Proteinase-K treatment, the anti-COX-1 and anti-COX-2 activity of both the extracts were not sensitive to protease treatment.

Conclusion

We have successfully demonstrated modulation in the levels of inflammatory cytokines, cyclooxygenase enzymes and immunoglobulins by our in-house laboratory preparations of Perna canaliculus, whereby suggesting an immunomodulatory role of Perna canaliculus in regulating inflammation.

Detection and characterization of RANK ligand and osteoprotegerin in the thyroid gland

Receptor activator of NF-kappaB (RANK) ligand (RANKL) and osteoprotegerin (OPG) play essential roles in bone metabolism and immune responses. RANKL activates RANK, which is expressed by osteoclasts and dendritic cells (DC), whereas OPG acts as its decoy receptor. The role of RANKL and OPG in thyroid physiology is unclear. Northern analysis revealed pronounced OPG mRNA levels in normal human thyroid. By contrast, RANKL mRNA levels were most abundant in lymph node and appendix, and low in the thyroid. In the human thyroid follicular cell line XTC and in primary human thyroid follicular cells, OPG mRNA levels and protein secretion were upregulated by interleukin (IL)-1beta (33-fold), tumor necrosis factor (TNF)-alpha (eightfold), and thyrotropin (TSH) (threefold). RANKL mRNA was stimulated in XTC by IL-1beta and TNF-alpha, but inhibited by TSH. Conditioned medium harvested from IL-1beta-treated XTC (containing high concentrations of OPG) inhibited RANKL-induced CD40 upregulation and cluster formation of DC. OPG mRNA levels were three times more abundant in surgical thyroid specimens of Graves' disease as compared to other thyroid diseases. Our data suggest that RANKL and OPG are produced in the thyroid gland by thyroid follicular cells, are regulated by cytokines and TSH, and are capable of modulating dendritic cell functions. Thus, these cytokines may represent important local immunoregulatory factors involved in the pathogenesis of autoimmune thyroid diseases.

Increased interleukin-6 and granulocyte-macrophage colony stimulating factor levels in the sera of patients with non-segmental vitiligo

BACKGROUND

Although the cause of vitiligo is unknown, an autoimmune theory has been proposed, and there is now convincing evidence that cytokines have an important role in pathogenesis of autoimmunity.

OBJECTIVE

To study the possible role of interleukin-1, beta (IL-1 beta), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-alpha) and granulocyte-macrophage colony stimulating factor (GM-CSF) in the pathogenesis of vitiligo.

METHODS

The authors measured the serum levels of the above-mentioned cytokines from 50 patients with the vitiligo compared with 20 healthy volunteers, employing the method of radioimmunoassay.

RESULTS

The results showed that the serum levels of both IL-6 and GM-CSF of the patients with both focal type and generalized type of vitiligo, and the serum level of IL-1 beta of the generalized type,were significantly, higher than those of normal controls in the patients with segmental vitiligo, the serum levels of all the cytokines tested were not significantly different from those of the normal controls. The GM-CSF levels of both focal type and generalized type, and the IL-6 level of the generalized type in progressive stage were significantly higher than those in stable state.

CONCLUSION

It is speculated that IL-6 and GM-CSF may be involved in the autoimmune mechanism of non-segmental vitiligo. However, more evidence is required before a definite conclusion can be drawn.

Intense expression of the b7-2 antigen presentation coactivator is an unfavorable prognostic indicator for differentiated thyroid carcinoma of children and adolescents

Previous observations suggest that an immune response against thyroid carcinoma could be important for long-term survival. We recently found that infiltration of thyroid carcinoma by proliferating lymphocytes is associated with improved disease-free survival, but the factors that control lymphocytic infiltration and proliferation are largely unknown. We hypothesized that the antigen presentation coactivators (B7-1 and B7-2), which are important in other immune-mediated thyroid diseases, might be important in lymphocytic infiltration of thyroid carcinoma. To test this, we determined B7-1 and B7-2 expression by immunohistochemistry [absent (grade 0) to intense (grade 3)] in 27 papillary (PTC) and 8 follicular (FTC) thyroid carcinomas and 9 benign thyroid lesions. B7-1 and B7-2 were expressed by the majority of PTC and FTC (78% of PTC and 100% of FTC expressed B7-1; 88% of PTC and 88% of FTC expressed B7-2). B7-1 expression was more intense in PTC (1.4 +/- 0.2; P = 0.01) and FTC (2.6 +/- 0.2; P < 0.001) than in benign tumors (0.57 +/- 0.30) or presumably normal adjacent thyroid (0.07 +/- 0.07) and was more intense in carcinoma that contained lymphocytes (1.95 +/- 0.21) than in carcinoma that did not (1.08 +/- 0.26; P = 0.016). B7-2 expression was of similar intensity in benign and malignant tumors (PTC, 1.6 +/- 0.2; FTC, 2.1 +/- 0.4; benign, 1.86 +/- 0.4), but was more intense than in presumably normal adjacent thyroid (0.64 +/- 0.25; P </= 0.013). B7-2 expression also correlated with the number of tumor-associated lymphocytes per high power field (r = 0.38; P = 0.02). Recurrence developed exclusively from tumors that expressed B7-2, and intense B7-2 expression was associated with a reduced probability of remission (P = 0.04). In conclusion, these data support the hypothesis that the antigen presentation coactivators B7-1 and B7-2 may be important for lymphocytic infiltration and the immune response against thyroid carcinoma.

Immunoassay of anti-thyroid autoantibodies: high analytical variability in second generation methods

The use of highly sensitive immunometric methods in clinical laboratories to assay anti-thyroid antibodies has progressively expanded in recent years but it is not known whether the new techniques have improved the analytical variability connected with the preceding methodologies. The Italian Society of Laboratory Medicine Study Group on Autoimmune Diseases conducted a collaborative study with the biomedical industry to evaluate the degree of standardization of the new analytical procedures. Twelve companies agreed to participate in the study on the search for anti-thyroglobulin (anti-Tg) and anti-thyroperoxidase (anti-TPO) antibodies in nine sera from patients with autoimmune thyroiditis, and in six sera from patients with non-autoimmune thyroid disease; ten immunometric and three immunofluorescence methods were employed. Agreement of qualitative results was close to 90% for anti-Tg and 97% for anti-TPO, with no important differences between the methods; variability of the quantitative results, expressed as CV% of absolute (in lU/ml) and relative (in cut-off concentration multiples) values was 93.9% and 102.3%, respectively, for anti-Tg, and 75.5% and 62.9%, respectively, for anti-TPO. These findings show that despite the progressive improvement in the analytical techniques, the variability between methods for the assay of anti-Tg and anti-TPO is still unexpectedly high, and probably due to several factors such as uncertainty in defining the positive cutoff concentration, absence of adequate international reference preparations, modality of autoantigen purification, and analytical variability in the assay procedures.

A role for IL-15 in driving the onset of spontaneous autoimmune thyroiditis?

The obese strain (OS) of chickens, which suffers from spontaneous autoimmune thyroiditis, is an excellent animal model for Hashimoto's thyroiditis and provides a unique opportunity to investigate the mechanisms underlying and driving the onset of the disease. Following recent advances in cloning chicken cytokines, we can now begin to investigate the role of cytokines in driving the lymphoid infiltration of the thyroid seen in these birds from day 7 posthatch. Using real-time quantitative RT-PCR, we characterized the expression of IFN-gamma, IL-1beta, IL-2, IL-6, IL-8, IL-15, and IL-18 in thyroids from OS birds and control CB line birds, both in the embryo just before hatch (embryonic day 20) and at 3 and 5 days posthatch. All of these cytokines were up-regulated compared with levels in thyroids from CB birds, at least at some time points, with some evidence for coordination of regulation, e.g., for the proinflammatory cytokines IL-1beta and IL-8. Only IL-15 was up-regulated at all time points. IL-15 was also shown to be up-regulated in spleens of OS birds at embryonic day 20 and 5 days posthatch, suggesting that IL-15 is constitutively up-regulated in this line of birds. This could explain the general immune system hyperreactivity exhibited by OS chickens and may be a factor driving the lymphoid infiltration of the thyroid.

Inflammatory cytokine regulation of TRAIL-mediated apoptosis in thyroid epithelial cells

Death receptor-mediated apoptosis has been implicated in target organ destruction in chronic autoimmune thyroiditis. Depending on the circumstances, inflammatory cytokines such as IL-1, TNF and IFNgamma have been shown to contribute to either the induction, progression or inhibition of this disease. Here we demonstrate that the death ligand TRAIL can induce apoptosis in primary, normal, thyroid epithelial cells under physiologically relevant conditions, specifically, treatment with the combination of inflammatory cytokines IL-1beta and TNFalpha. In contrast, IFNgamma is capable of blocking TRAIL-induced apoptosis in these cells. This regulation of TRAIL-mediated apoptosis by inflammatory cytokines appears to be due to alterations of cell surface expression of TRAIL receptor DR5 and not DR4. We also show the in vivo presence of TRAIL and TRAIL receptors DR5 and DcR1 in both normal and inflamed thyroids. Our data suggests TRAIL-mediated apoptosis may contribute to target organ destruction in chronic autoimmune thyroiditis.

IL-10 kinetics in thyroiditis-prone BB/Wor rats

Cytokines modulate the course of autoimmunity, but their role in the evolution of spontaneous disease is unclear. This study compared the cytokine kinetics of T cell cultures from thyroiditis (LT)-prone NB line BB/Wor rats with those of Wistar (Wis) rat controls following activation with the thyroid-specific antigen thyroglobulin (Tg) or Concanavalin A (Con A).

DESIGN

T cell enhanced splenocytes from 60 day old Wis and NB rats were activated with 0.5 microg/ml rat thyroglobulin (Tg) or Con A in the presence of homologous irradiated splenocytes as antigen presenting cells (APC's). In addition, the effect of APC's was determined in a crisscross experiment which examined NB T cell responses to Con A in the presence of Wis APC's. ELISA and RT-PCR were used to examine IL-2, IL-4, IL-10, TNFalpha, IFNgamma, IL-I0 concentrations and mRNA expression in the supernatant and cells from parallel cultures harvested at specific intervals. Frozen thyroids from 60 day old NB, Wis and Fisher rats were examined for the presence of IL-10 by immunohistochemistry. T cell proliferation was measured by 3H thymidine uptake.

RESULTS

Following activation with either Tg or Con A, IL-10 concentrations exceeded IFNgamma in NB rat cultures, but IFNgamma exceeded IL-10 in Wis cultures. Wis splenocytes significantly enhanced NB T cell proliferation and cytokine responses to Con A. Thyroids from 60 day NB rats contained IL-10, but no IFNgamma. There was no IL-10 in thyroids from Wistar or Fisher rats.

CONCLUSION

Splenocyte responses in LT-prone BB/Wor rats favor IL-10 production. Future investigations will examine the source of intrathyroidal IL-10 and its role in LT.