Pathogenetic relevance of HLA class II expressing thyroid follicular cells in nontoxic Goiter and in Graves' disease

Antithyroid drugs inhibit in vivo HLA-DR expression in thyroid follicular cells in Graves' disease

Antithyroid drugs have been reported to reduce the expression of HLA-DR in thyrocytes in Graves' disease, but only circumstantial evidence has been provided about their in vivo immunologic effects. This present study was designed to examine the in vivo immunologic effect of antithyroid drugs on thyroid follicular cells. The study was conducted on 25 patients who had Graves' disease in remission or in activity and who were or were not receiving treatment (7 in overt thyrotoxicosis, 6 patients in remission, and 12 patients under medication). HLA-DR expression in thyroid biopsies was verified by immunohistochemistry. The follicular cells of all patients in overt thyrotoxicosis expressed HLA-DR whereas those of patients in remission were negative for HLA-DR. HLA-DR was also not expressed in all patients under medication, but this did not correlate with the clinical evolution after thyroid drug withdrawal. In conclusion, antithyroid drugs inhibit follicular cell HLA-DR expression in Graves' disease, when thyrotoxicosis is controlled. This suggests that additional mechanisms not involving HLA-DR play a role in thyroid autoimmune disease.

Autoimmune and non-autoimmune thyroid diseases have different patterns of cellular HLA class II expression

CONTEXT

Surface HLA-DR antigen is usually only expressed by antigen-presenting cells (APC). In autoimmune thyroid disease, follicle cells function as APC, thus expressing HLA-DR. However, non-autoimmune thyroid diseases may also express surface class II antigens.

OBJECTIVE

To evaluate the presence and pattern of HLA class II expression in autoimmune and non-autoimmune thyroid disorders.

DESIGN

Retrospective: histopathological and immunohistochemical analysis.

LOCATION

Referral center, university hospital.

SAMPLE

Ten histologically normal thyroids, 11 Graves' disease, 7 Hashimoto's thyroiditis, 10 atoxic multinodular goiter and 3 toxic adenomas were analyzed by immunohistochemistry, using a monoclonal antibody anti-HLA-DR.

MAIN MEASUREMENTS

The presence of these antigens in thyroid follicular cells and their relation to inflammatory infiltrate was evaluated. The pattern of HLA-DR expression in thyroid follicular cells was analyzed: membrane, cytoplasmic or both.

RESULTS

Although HLA-DR antigens were sparsely present in one of the 8 normal thyroids, in 6 of the 9 atoxic multinodular goiter and in 2 of the 3 toxic adenomas a net positivity could be seen in large areas. In all 5 Hashimoto's thyroiditis and in 7 of the 10 Graves' disease cases. This expression occurred in follicle cells either in contact with inflammatory cells or not. In non-autoimmune thyroid disease, HLA-DR positivity was essentially cytoplasmic, whereas in Graves' disease and Hashimoto thyroiditis it was mainly in cell membranes.

CONCLUSIONS

It is suggested that the HLA class II expression on the surface of follicle cells could be related to auto-antigen presentation to the immune system by these cells, leading to inflammation.

Suppressive effects of anti-inflammatory agents on human endothelial cell activation and induction of heat shock proteins

BACKGROUND

Studies from our laboratory have shown that the earliest stages of atherosclerosis may be mediated by an autoimmune reaction against heat shock protein 60 (Hsp60). The interactions of Hsp60-specific T cells with arterial endothelial cells (EC) require expression of both Hsp60 and certain adhesion molecules shown to be induced simultaneously in EC by mechanical and other types of stress. Recently, it was shown that suppression of T cell-mediated immune responses by cyclosporin A (CyA) enhanced atherosclerotic lesion formation in mice. In contrast, aspirin was found to lower the risk of myocardial infarction in men. These conflicting observations may be due to different effects of anti-inflammatory agents on adhesion molecule and Hsp expression in EC, respectively.

MATERIAL AND METHODS

In the present study, we analyzed the effects of CyA, aspirin, and indomethacin on T cell proliferation using a proliferation assay. To explore the expression of adhesion molecules, monocyte chemoattractant protein-1 (MCP-1), and Hsp60 in human umbilical vein endothelial cells (HUVECs), Northern blot analyses were used. To examine the activation status of the transcription factors nuclear factor kappaB (NF-kappaB) and heat shock factor-1 (HSF-1), electrophoretic mobility shift assays were performed.

RESULTS

With the exception of indomethacin, the used immunosuppressive and anti-inflammatory agents significantly inhibited T cell proliferation in response to influenza virus antigen in a dose-dependent manner. Interestingly, CyA and indomethacin did not suppress tumor necrosis factor-alpha (TNF-alpha)-induced adhesion molecule expression on HUVECs, whereas aspirin had an inhibitory effect. These observations correlated with the modulation of NF-kappaB activity in EC. All agents tested induced expression of Hsp60 6 hr after application. In addition, aspirin and indomethacin, but not CyA, induced Hsp70 expression in HUVECs that correlated with induction of HSF-1 activity.

CONCLUSION

Our results show that the tested agents (except indomethacin) are inhibitors of the T cell-mediated immune response, as expected, that aspirin is an effective suppressor of adhesion molecule expression, and that all three agents can induce Hsp60 in HUVECs. These data provide the molecular basis for the notion that (1) part of the anti-atherogenic effect of aspirin may be due to the prevention of the adhesion of sensitized T cells to stressed EC; (2) that part of the atherosclerosis-promoting effect of CyA may be due to its potential as an inducer of Hsp60 expression and its inability to down-regulate adhesion molecule expression on EC; and (3) that down-regulation of MCP-1 expression by aspirin may result in decreased recruitment of monocytes into the arterial intima beneath stressed EC.

Human leukocyte antigens associated with hyperthyroid Graves ophthalmology in Japanese patients

PURPOSE

To evaluate the association of human leukocyte antigen (HLA) types in Japanese patients with Graves ophthalmopathy.

METHODS

Japanese patients with severe ophthalmopathy (48 patients) and patients without ophthalmopathy (46 patients) were selected prospectively from 234 consecutive patients with hyperthyroid Graves disease. The criteria for severe ophthalmopathy were proptosis of 19 mm or more, or a 3-mm difference in exophthalmometry measurement between the two eyes, or diplopia at the primary eye position. The criteria for the absence of ophthalmopathy were proptosis of 16 mm or less, no diplopia, no lid retraction, and no thickening of extraocular muscles. Serologic HLA typing of class I and II antigens was performed in the two patient groups. The frequency of each HLA antigen in the two patient groups was compared to that in 767 unrelated normal healthy Japanese controls.

RESULTS

The frequencies of HLA-DR14 and DQ1 were significantly higher in the patient group with severe ophthalmopathy (35% and 75%, respectively) than in healthy controls (4% and 43%, respectively; corrected P < .05), and also greater than in the patient group without ophthalmopathy (13% and 55%, respectively; P < .01). On the other hand, the frequencies of HLA-B35, B54, DR4, and DQ4 were significantly higher in the patient group without ophthalmopathy (23%, 23%, 43%, and 30%, respectively) than in the patient group with severe ophthalmopathy (13%, 15%, 25%, and 19%, respectively; P < .01).

CONCLUSIONS

HLA-DR14 and DQ1 antigens may be genetic markers of predisposition to the development of severe ophthalmopathy. In addition, HLA-B35, B54, DR4, and DQ4 may be genetic markers of resistance to severe ophthalmopathy. Variation in the severity of ophthalmopathy associated with Graves disease may depend, in part, on the presence or absence of particular HLA antigens.

The possible role of the immune system in Alzheimer's disease

Currently, there is little doubt that the immune system plays a role in the neurodegenerative process in Alzheimer's disease (AD). Inflammatory proteins such as complement components, enzymes, eicosanoids, and cytokines are found in association with cerebral amyloid plaques and may exacerbate the fundamental pathology of AD, by stimulating Amyloid beta (A beta) production, supporting its aggregation and increasing its cytotoxicity. Activated microglia and astrocytes are the main source of these proteins, and A beta may trigger their release. Interestingly, there are also indications that the immune system may play a protective role against the development of AD. Microglial cells have been shown to degrade A beta, and recent evidence suggests that autoreactive A beta-specific T cells may be relevant to the elimination of the peptide. This mechanism seems, however, impaired in the majority of patients with AD. The immune system seems thus to represent a natural line of defense against the accumulation of dangerous amyloidogenic substances. Impairment of this specific immunological defense mechanism and the failure to eliminate a toxic metabolite can be the basis for a chronic nonspecific inflammatory process in the brain, as described above. AD is a good example how an immune response initially aiming at maintaining the integrity of the body may fail and consequently lead to tissue destruction and neuronal loss.

Influenza vaccination in a healthy geriatric population: preferential induction of antibodies specific for the H3N2 influenza strain despite equal T cell responsiveness to all vaccine strains

Cellular as well as humoral immune reactivity were studied in healthy young (< 30 years; n = 12) and older (> 65 years; n = 12) individuals before as well as 1 month after immunization with a trivalent whole virus influenza vaccine. Before vaccination, peripheral blood mononuclear cell proliferation in response to in vitro stimulation with each of the virus strains was low in both groups. No antibodies against either the H1N1 or the B strain were found in most individuals, while 91% of the young and 75% of the elderly persons had low but protective antibody titres to the H3N2 strain. Vaccination led to a significant enhancement of peripheral blood mononuclear cell reactivity to all three influenza strains in both age groups. However, there was a significant difference in the humoral immune response between the groups. While there was a vigorous antibody response to all three vaccine strains among young persons, protective titres against the H1N1 and the B strains were only just reached in the old. In contrast, antibody production to the H3N2 strain was most abundant in the majority of elderly individuals, leading to significantly higher titres in the old than in the young group. In conclusion, the results demonstrate the preferential induction of antibodies to one particular influenza strain despite equal T cell recruitment to all vaccine strains in healthy aged individuals after immunization with a trivalent influenza vaccine. Our findings underline the complexity of immunological alterations to be expected after vaccination in healthy elderlies.

Primary and secondary alterations of immune reactivity in the elderly: impact of dietary factors and disease

The function of the immune system declines with age. It is the aim of the present review to demonstrate that it makes sense to distinguish between primary and secondary alterations of immune reactivity in the elderly. Primary changes occur as the result of an age-dependent intrinsic decline of immune responsiveness. They also occur in healthy persons, i.e. persons selected according to the criteria of the SENIEUR protocol of the European Community's Concerted Action Program on Aging (EURAGE). T lymphocytes are hereby more severely affected than B cells or antigen presenting cells, possibly due to the involution of the thymus, which is almost complete at the age of 60. Secondary immunological changes occur as the result of environmental factors including diet, drug intake, physical activity etc. or are alternatively due to underlying diseases. In this article, the effects of high lipid intake as well as the impact of diseases, such as for instance Alzheimer's disease and atherosclerosis, will be addressed. The results underline the complexity of immunological alterations to be expected in old age. Changes in the aging immune system represent an opportunity for increased frequency and severity of disease and endanger the protective effect of vaccination.

Antigen presentation by interferon-gamma-treated thyroid follicular cells inhibits interleukin-2 (IL-2) and supports IL-4 production by B7-dependent human T cells

The consequence of recognition of antigen on antigen-presenting cells that are induced to express major histocompatibility complex (MHC) class II molecules following an inflammatory process is still not clear. In this study, we have investigated the outcome of antigen presentation by epithelial cells and we have used as a model thyroid follicular cells (TFC) that are known to express MHC class II molecules in autoimmune thyroid diseases and acquire the capacity to present autoantigens to T cells infiltrating the thyroid gland. The result show that MHC class II-expressing TFC were unable to stimulate a primary T cell alloresponse, using CD4+ T cells from three HLA-mismatched responders. Phenotypic analysis showed that TFC, after incubation with interferon-gamma, do not express the costimulatory molecules B7-1 (CD80) and -2 (CD86). Addition of murine DAP.3 cells expressing human B7-1 (DAP.3-B7) to cultures containing peripheral blood CD4+ T cells and DR1-expressing TFC led to a proliferative response, suggesting that the failure of TFC to stimulate a primary alloresponse was due to a lack of co-stimulation. Similarly, HLA-DR-restricted, influenza-specific T cell clones dependent on B7 for co-stimulation did not respond to peptide presented by TFC; again the lack of response could be overcome by co-culture of TFC with DAP.3-B7. Furthermore, recognition of antigen on TFC inhibited interleukin-2 (IL-2) production in the B7-dependent T cells. In contrast, in T helper type 0 (Th0) T cells, IL-4 release was not affected by TFC presentation. In addition, antigen presentation by TFC favored IL-4 production relative to IL-2 production by B7-independent Th0 clones. These results suggest that antigen presentation by MHC class II+ TFC may induce tolerance in autoreactive Th1 cells but may simultaneously favors a Th2 response in uncommitted T cells, and thereby support autoantibody production.

Identification of thyroid stimulating hormone receptor-specific T cells in Graves' disease thyroid using autoantigen-transfected Epstein-Barr virus-transformed B cell lines

The importance of thyrotropin receptor (TSHR) agonist antibodies in the manifestations of Graves' disease (GD) is recognized. There are, however, no convincing reports of TSHR-specific T cells. We have previously cloned T cells specific for thyroglobulin and thyroid peroxidase (TPO) from GD lymphoid infiltrates and used autologous EBV-transformed B cell lines (EBVL) transfected with an expression vector encoding TPO to efficiently detect TPO-specific T cells. Here we used EBVL transfected with TSHR to seek TSHR-specific T cells in the GD infiltrates, after cloning the in vivo activated T cells without antigen. 3 out of 30 clones responded vigorously and reproducibly to EBVL-TSHR, with a mean stimulation index > 7. Their release of IL-2, IL-4, and IL-10 after stimulation with soluble anti-CD3 and phorbol ester was indistinguishable from the other clones from this thyroid. However, they produced relatively little IFN gamma (median IL-4/IFN gamma ratio of 0.80) compared with the other clones (median IL-4/IFN gamma ratio 0.06). Thus, this new potent method of antigen presentation, using autoantigen-transfected EBVL, has permitted the first unequivocal identification of TSHR T cells in GD thyroid, with distinct Th0/Th2 characteristics, unlike previously cloned TPO-responsive cells which have Th1 characteristics.

Effects of type I-interferons on human thyroid epithelial cells derived from normal and tumour tissue

Long term interferon (IFN) therapy is frequently associated with side effects which affect the thyroid gland such as hypothyroidism and thyroiditis. We have therefore tested the ability of type I-IFNs to exert direct effects on primary cultures of human thyroid epithelial cells: (i) Type I-IFNs (IFN-alpha 2b and IFN-omega) inhibit cell proliferation as determined by [3H]thymidine incorporation with a half-maximal effect at approximately 1 ng/ml (50 pM). Inhibition of cell growth is observed in cells derived from normal thyroid as well as neoplastic tissue (autonomous and non-secreting adenoma; follicular, papillary and anaplastic carcinoma). (ii) Over a similar concentration range, type I-IFNs suppressed thyroglobulin release by thyroid cells. (iii) IFN-alpha 2b stimulated surface expression of major histocompatibility class (MHC) I but not MHC II molecules, while IFN-gamma enhanced the expression of both MHC I and MHC II molecules. This effect of IFN-gamma, but not that of IFN-alpha 2b was antagonized by suramin. (iv) Incubation of thyroid cells with IFN-alpha 2b also resulted in increased cell surface levels of the intercellular adhesion molecule 1 (ICAM-1). These findings demonstrate that type I-IFNs directly affect thyroid function and explain related side effects of these cytokines. In addition, our results provide a rational basis for the possible use of type I-IFNs in the treatment of patients with advanced thyroid cancer for whom no therapeutic alternative exists.

Retrobulbar T cells from patients with Graves' ophthalmopathy are CD8+ and specifically recognize autologous fibroblasts

Graves' ophthalmopathy is an autoimmune condition characterized by T cell infiltration of the retrobulbar tissue. Phenotypic and functional analysis of these infiltrating cells may provide insight into the pathogenesis of the disease. IL-2-responsive cells were therefore grown out of the retrobulbar tissue from two patients with severe Graves' ophthalmopathy undergoing orbital decompression surgery, and six T cell lines were established and characterized. They consisted predominantly of CD8 + CD45RO+ cells and secreted IL-4, IFN-gamma, and IL-10 upon activation. When screened for their antigen reactivity, all lines proliferated in response to stimulation with autologous retrobulbar fibroblasts in an HLA class I-restricted manner, but did not recognize autologous peripheral blood mononuclear cells, crude eye muscle extract, allogeneic cells, or purified protein derivate of Mycobacterium tuberculosis. In contrast, PBMC from the same patients responded readily to purified protein derivate of Mycobacterium tuberculosis and allogeneic PBMC, but did not recognize autologous fibroblasts. Interestingly, only one of the six retrobulbar T cell lines displayed cytotoxicity towards its specific target cell population. These results suggest that the retrobulbar fibroblasts are a major T cell target in Graves' ophthalmopathy. Pronounced cytokine production in the absence of target cell cytotoxicity may explain fibroblast proliferation, glycosaminoglycan secretion, and secondary eye muscle enlargement in this condition.

Immunoglobulin A in Graves' orbital tissue: deoxyribonucleic acid amplification by polymerase chain reaction

A role for IgA autoantibodies in Graves' ophthalmopathy is suggested by the presence of immunoglobulins of this class in Graves' orbital tissue, as detected by immunohistochemistry. We, therefore, investigated the possibility of using the polymerase chain reaction (PCR) to amplify IgA immunoglobulin genes from plasma cells infiltrating Graves' eye tissue. Template cDNA was reverse-transcribed from orbital muscle (M) mRNA of one patient (#7) and from orbital connective tissue/fat (F) mRNA of two patients (#1 and #7), both undergoing surgery for exophthalmos because of severe infiltrative ophthalmopathy. Preliminary studies to establish the PCR procedure were performed for kappa light chain DNA amplification. With the very small amount of orbital tissue template available, the sensitive "hot start" modification of the PCR was necessary to amplify significant amounts of kappa light chain DNA. Using this procedure, IgA heavy chain DNA was amplified from both connective tissue/fat (F7) and muscle (M7) cDNA of patient #7. The DNA yield was less for IgA than for IgG using the same template. There was no significant IgA (or IgG) DNA product using the connective tissue/fat cDNA of patient #1. While not implying that IgA-infiltrating plasma cells are specific for Graves' orbital tissue, our studies nevertheless demonstrate the feasibility of amplifying the genes coding for IgA antibodies from Graves' orbital tissue plasma cells. Expression of these immunoglobulin genes in future studies will make it possible to determine the antigen specificity of the antibodies expressed by Graves' orbital tissue plasma cells.

Epithelial cells bearing class II molecules stimulate allogeneic human colonic intraepithelial lymphocytes

HLA-DR+ gut epithelial cells may present antigen to intraepithelial lymphocytes (IEL). This study aimed to isolate an IEL population from the human colon to activate CD3 + IEL by a human colonic epithelial cell line (HT-29), bearing different concentrations of class II antigen (HLA-DR). IEL were isolated by a mechanical method from six patients with ulcerative colitis (UC) and from 14 control patients. IEL were cocultured with HT-29 which had been induced to express class II molecules by gamma-interferon (IFN-gamma) in a dose dependent manner. The phenotype and the subsequent expression of activation markers by the IEL were determined to two colour flow cytometry. The IEL population had a CD4/CD8 ratio similar to that seen in tissue sections. In the mixed cell culture, the degree of IEL activation showed a positive correlation with the degree of HLA-DR expression by the HT29 cells and the IEL secreted a IFN-gamma like factor that in turn stimulated the HT-29. Thus, depending on their expression of HLA molecules, colonic epithelial cells are able to activate CD3+CD8+IEL.

HLA-DR expression by platelets in acute idiopathic thrombocytopenic purpura

Induction of expression of MHC class II antigens on the surface of cells that do not ordinarily express these proteins has been implicated in the pathogenesis of autoimmunity in diabetes mellitus and autoimmune thyroiditis. Platelets express class I but not class II HLA antigens. In this report, we describe a child with acute idiopathic thrombocytopenic purpura who at the time of the thrombocytopenic episode had class II (HLA-DR) antigens on his platelets. Following recovery, the HLA-DR antigens were no longer present on the platelets. We postulated that class II had been induced on his megakaryocytes by a cytokine such as interferon gamma, and that the induced expression of class II antigens contributed to the autoimmune disorder. To substantiate this possibility we next studied class I and II antigen expression on an erythroleukaemia cell line (HEL), which has many megakaryocytic features. Following treatment of HEL cells with interferon gamma, class I expression was increased and HLA-DR antigens were induced. These observations suggest that cytokine-mediated induced HLA-DR expression may contribute to the pathogenesis of a subset of thrombocytopenias.

Expression of intercellular adhesion molecule-1 in thyroid follicular cells in autoimmune, non-autoimmune and neoplastic diseases of the thyroid gland: discordance with HLA

The presence of intercellular adhesion molecule-1 (ICAM-1) on epithelial cells facilitates their recognition by specific T lymphocytes. To assess the possible role of ICAM-1 in the recognition of thyroid follicular cells by T cells in thyroid autoimmune disease, we investigated the expression of ICAM-1 in thyrocytes from thyroid glands affected by Graves' disease, in glands with non-autoimmune pathology and normal glands using immunofluorescence staining on cryostat sections and on dispersed cell preparations. Sequential tissue sections from glands affected by Graves' disease (n = 15), multinodular goitre (MNG, n = 26), benign nodules (n = 11), primary carcinomas (n = 12) and control thyroid glands (n = 5) were stained for ICAM-1, HLA class I, HLA class II, CD3 and thyroid peroxidase (TPO). Weak and patchy ICAM-1 expression was found in the thyrocytes of 4/15 (27%) Graves' disease and of 1/26 (4%) multinodular goitre glands. In contrast, ICAM-1 expression was detected in the thyrocytes of 5/11 (45%) benign nodules and of 8/12 (67%) thyroid carcinomas in which it was sometimes strong. Thyrocytes in the five control glands were negative. These results correlated well with flow cytometry data from 23 of these glands which showed that ICAM-1 expression in thyrocytes from Graves' patients was, when present, 'dull', while in some malignant thyrocytes it was 'bright'. In preparations of thyrocytes from Graves' disease glands we found a striking discordance between the high levels of expression of HLA class I and HLA class II and the low expression of ICAM-1. This is surprising since in vitro the expression of these three molecules is equally induced by IFN-gamma and TNF-alpha. These results suggest that additional factors are involved in the induction of the inappropriate HLA class II expression observed in the thyrocytes of glands affected by Graves' disease.

T cell activation and antigen presentation in human thyroid autoimmunity

In 1983, a hypothesis concerning the relevance of class II expression and antigen presentation to the induction and maintenance of endocrine autoimmunity was published. This article reviews the evidence that has been marshalled to support this concept, both in man, chiefly in Graves' disease, and in murine systems. New data concerning the multiplicity of thyroid autoantigens recognized by in vivo activated thyroid infiltrating T cells are compatible with this concept since the thyroid epithelial cells are the source of these antigens. Whether other autoimmune diseases also employ the same mechanism remains to be ascertained, as does the initial trigger for the autoimmune process.

Autoantigen recognition by thyroid-infiltrating T cells in Graves disease

Graves disease is a common form of human autoimmune thyroiditis. It shares many pathological features and HLA associations with other, less easily studied, organ-specific autoimmune conditions such as insulin-dependent diabetes mellitus, and hence it is also a useful model for understanding these other diseases. We have previously shown that thyroid-infiltrating T cells in Graves disease that have been recently activated in vivo specifically recognize autologous thyroid epithelial cells. However, the autoantigens involved were not defined. In this study, we have made use of antigen-independent T-cell cloning techniques to show that at least three different thyroid antigens, three different epitopes on a single antigen, and two HLA class II elements are involved in this recognition process in a single individual. This demonstrates that T cells that are present and activated at the site of a human autoimmune disease may show considerable heterogeneity in their recognition of autoantigen on the target tissue. This contrasts with the limited heterogeneity recently reported in some animal models and has potentially important implications for both our understanding of the autoimmune process in humans and the design of immunotherapies to reverse it.

The immunoregulatory influence of transforming growth factor beta in thyroid autoimmunity: TGF beta inhibits autoreactivity in Graves' disease

The immunoregulatory influence of transforming growth factor beta (TGF beta) was studied in patients with Graves' disease and in normal controls. Special attention was given to determine how TGF beta affects the interaction between thyroid epithelial cells and T lymphocytes. Human recombinant TGF beta 1 (rTGF beta 1) was immunosuppressive in patients with Graves' disease and in controls. In both groups it inhibited the proliferation of peripheral blood mononuclear cells and of peripheral and thyroid derived T cell lines and clones in response to non-specific stimuli. It also decreased the number of serine esterases expressing cytotoxic T cells and suppressed the recognition of thyroid epithelial cells by thyroid autoantigen specific T cell clones. Inhibition of autoantigen recognition was not only observed when rTGF beta 1 was added to the thyroid epithelial cell/lymphocyte co-culture, but was also found when thyroid epithelial cells were preincubated with rTGF beta 1, which was then removed before the initiation of co-culture. This was probably as a result of a decrease in the antigenicity of the target cells, as rTGF beta 1 also suppressed thyroid peroxidase as well as HLA class II autoantigen expression, in cultured thyroid epithelial cells. These results demonstrate that TGF beta may exert a variety of down-regulatory influences in Graves' disease. It may be of importance for the suppression of autoaggression in persons predisposed to autoimmunity; may be quantitatively overrun by immunostimulatory influences in the acute phase of the disease; and may be important for the induction of remission in patients with Graves' disease.

Detection of interleukin-6 and interleukin-1 production in human thyroid epithelial cells by non-radioactive in situ hybridization and immunohistochemical methods

Human endocrine thyroid epithelial cells have been described to produce cytokines in vitro. In order to determine whether they do so in vivo during thyroiditis, parallel studies on mRNA expression with a non-radioactive in situ hybridization technique and immunohistochemical detection for the protein were performed on frozen sections of thyroid samples from autoimmune thyroiditis (Graves' disease and Hashimoto's thyroiditis), non-toxic goitre and normal thyroid tissue. cDNA probes were sulphonated and their hybridization with mRNA was detected with a sulphonyl-specific monoclonal antibody. This signal was amplified and visualized with the alkaline phosphatase-anti-alkaline phosphatase (APAAP) system. The protein products were detected with immuno-purified rabbit F(ab')2 antibody fragments recognizing recombinant human cytokines, visualized by the immunoperoxidase technique. Each sample was studied at the two levels. Both interleukin-6 mRNA and protein were found in the endocrine cells. There was no obvious difference between autoimmune thyroiditis and non-toxic goitre. However, normal thyroid epithelial cells produced less interleukin-6. Interleukin-1 alpha mRNA and its protein were found in epithelial cells from Hashimoto's thyroiditis samples, but not in the others, except one Graves' disease sample, in which only mRNA was detected. Interleukin-1 beta was not detected in these cells, its mRNA was only found in one of the Graves' disease samples. These cytokines were also detected in some infiltrating cells.

Advances in molecular biology. Potential impact on diagnosis and treatment of disorders of the thyroid

Advances in molecular biology research continue to have a major impact on clinical medicine. These advances have provided a means to produce proteins previously available in limited supply and allow for the production of novel proteins that are improved agonists or else antagonists with greater specificity for therapeutic targets. Newer drug delivery systems should facilitate delivery of these proteins. By combining the capabilities to produce drug targets in acceptable quantities with improved methods for determining the three-dimensional structures of these targets, novel organic therapeutic molecules that act on these targets will be designed. Gene transfer therapy using genes that express important proteins or that encode "antisense" RNAs that inhibit the translation of specific mRNAs will soon become a reality. The use of RFLPs and PCR methodologies promises increased means to diagnose specific genetic diseases and infections. Most importantly, molecular biology is helping to understand the mechanisms of disease such that novel diagnostic and therapeutic approaches can be described. These advances are providing an understanding of the mechanisms involved in cancers of the thyroid gland. They have already led to an enhanced understanding of (1) the growth factors that control proliferation of the thyroid gland, (2) the potential steps in thyroid nodule and neoplasia development, (3) particular mutations that may occur as thyroid cancers develop, (4) oncogenes that are expressed in thyroid cancers, and (5) the genetic defects that are responsible for thyroid gland malignancies in the multiple endocrine neoplasia (MEN) syndromes. With the latter, the RFLP technology has already provided an enhanced means to diagnose the disorder. With further progress, enhanced means for diagnosis and treatment should emerge. Molecular biology techniques are contributing to an increased understanding of the mechanisms of development of autoimmune thyroid disease as with Graves' disease and Hashimoto's thyroiditis. The potential role of infections, histocompatibility antigens, thyroid gland and extraglandular antigens, immune modulators, subpopulations of T-cells such as suppressor and helper cells, other cells involved in immune responses, and a combination of influences of several different functions on the thyroid gland are being defined. This knowledge should soon suggest improved means for diagnosis and treatment. Understanding of the function of the thyroid hormone receptors should have clinical importance. This knowledge suggests a means to develop thyroid hormone antagonists that may be used to more rapidly ameliorate the effects of hyperthyroidism and could be useful in nonthyroidal disorders such as cardiac arrhythmias.(ABSTRACT TRUNCATED AT 400 WORDS)

CD4+ T-cell clones from autoimmune thyroid tissue cannot be classified according to their lymphokine production

In order to define whether CD4+ T cells from autoimmune and non-autoimmune thyroid tissue could be classified according to their mediator production, lymphokine production was studied in 63 thyroid-derived CD4+ T-cell clones from four patients with Graves' disease, one with Hashimoto's thyroiditis, and one with non-toxic goitre (9-12 clones per patient). The production of interleukin 2 (IL-2), gamma interferon (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), lymphotoxin (LT), interleukin 6 (IL-6) and transforming growth factor beta (TGF-beta) was assessed at the mRNA level by slot-blot analysis in unstimulated clones as well as after activation with monoclonal anti-CD3 (OKT3) and IL-2. No lymphokine production was found in unstimulated clones, whereas 56% of the clones produced all six lymphokines simultaneously after stimulation. In the remaining 44% usually not more than one lymphokine was missing from the complete panel. Lymphokine mRNA concentrations varied between different clones and different patients, but, in this small sample, not between the diseases from which the clones were originated. There was a significant correlation between IL-6, LT, and IL-2 mRNA levels and T-cell helper function, which was estimated by the stimulation of thyroid microsomal autoantibody production using autologous peripheral B cells. TGF-beta and IFN-gamma mRNA expression was unrelated to T-cell help. The results demonstrate that intrathyroid T cells from autoimmune and non-autoimmune thyroid disorders cannot be classified according to their lymphokine production, unlike some results with in vitro-induced mouse T-cell clones, where two populations, Th1 and Th2, have been described. Single T cells are capable of producing a whole panel of lymphokines and thus are capable of triggering a multitude of different processes.

T-cell recognition of HLA class II molecules induced by gamma-interferon on a colonic adenocarcinoma cell line (HT29)

HLA class II molecules may be induced on non-lymphoid cells by gamma-interferon (IFN-gamma). We investigated if HLA class II molecules induced by IFN-gamma on the HT29 colonic carcinoma cell line are functional, i.e. if they may be recognized by allogeneic T cells. We found that IFN-gamma-treated HT29 (HT29IFN) cells could not induce primary proliferative responses of peripheral blood T lymphocytes, nor were they able to induce proliferation in T-lymphocyte clones (TLC) specific for HLA class II molecules found on HT29IFN. However, in the presence of exogenous interleukin 2 (IL-2), 1 of 5 DQw8-specific TLC proliferated when restimulated with HT29IFN, and 3 of these 5 TLC could very effectively inhibit the growth of HT29IFN, probably due to a cytotoxic effect. Both the proliferative response and the cytotoxicity were inhibited by anti-DQ MoAb. We conclude that T cells may recognize HLA-DQ molecules on non-lymphoid cells, which may be of relevance for autoimmune diseases, graft-versus-host disease, and possibly for the recognition of malignant cells.

Analysis of intrathyroidal cytokine production in thyroid autoimmune disease: thyroid follicular cells produce interleukin-1 alpha and interleukin-6

Cytokine production was studied in thyroid tissue from patients with Graves' disease, Hashimoto's thyroiditis and non-toxic goitre. The expression of interferon gamma, tumour necrosis factor alpha and beta, interleukin-1 alpha and beta, interleukin-6 and platelet-derived growth factor A chain was assessed by slot-blot analysis of the respective mRNA in freshly isolated tissue samples. All seven cytokines were detected in patients of all groups. Although the respective mRNA levels were, in general, higher in thyroid autoimmune disorders, this appeared to relate to the degree of the lymphocytic infiltration of the thyroid gland at the time of surgery. Purified thyroid follicular cells expressed high levels of interleukin-1 alpha and interleukin-6 mRNA and when established in primary culture, purified thyroid follicular cells from Graves' disease as well as non-toxic goitre produced interleukin-1 alpha and interleukin-6 bioactivity spontaneously. In the case of interleukin-1 this could be further augmented by addition of lipopolysaccharide to the thyroid follicular cell cultures. These results demonstrate that the lymphocytic infiltrate found in autoimmune and non-autoimmune thyroid disorders is associated with cytokine production. Additionally we have shown that intrathyroidal cytokine production is not restricted to thyroid-infiltrating mononuclear cells, but may also involve thyroid follicular cells both in vivo and in vitro. The cytokines produced by thyroid follicular cells may have an important role in stimulating autoantigen specific T cells in vivo as both interleukin-1 and interleukin-6 facilitate T cell activation.

Intrathyroidal cytokine production in thyroid disease

The intrathyroidal production of Interferon gamma, tumour necrosis factor alpha and beta, Interleukin-1 alpha and beta, Interleukin-6, platelet-derived growth factor A and of transforming growth factor-beta was analysed in patients with autoimmune and non-autoimmune thyroid disease. Cytokines were assessed indirectly by slot blot mRNA analysis in fresh tissue samples (unpurified cells, infiltrating mononuclear cells and thyroid follicular cells), in thyroid follicular cells in primary culture, as well as in thyroid-derived T-cell clones. The production of Interleukin-1 alpha and beta, Interleukin-6 and transforming growth factor beta was additionally measured by bioassay. Cytokine production by thyroid-infiltrating mononuclear cells generally did not differ between autoimmune and non-autoimmune samples, the whole panel of all cytokines being found in freshly purified cells as well as in thyroid-derived T-cell clones from patient with Graves' disease, as well as with multinodular non-toxic goitre. Thyroid follicular cells produced Interleukin-1 alpha, Interleukin-6 and transforming growth factor beta. Interleukin-1 and Interleukin-6 production did not differ between thyroid follicular cells from autoimmune and non-autoimmune thyroids. Transforming growth factor beta was, however, lower in non-toxic goitre than in Graves' disease and in normal thyroid tissue, but could be increased by exposure of the cells to micromolar concentrations of iodide. This seemed of special interest, as transforming growth factor beta proved to inhibit thyroid follicular cell growth in response to known growth stimuli, such as insulin-like growth factor I or epidermal growth factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Transforming growth factor beta regulates thyroid growth. Role in the pathogenesis of nontoxic goiter

The production and growth regulatory activity of transforming growth factor beta were studied in human thyroid tissue. As estimated by its mRNA expression in fresh tissue samples, transforming growth factor beta was produced in normal and in diseased thyroid glands. Transforming growth factor beta mRNA was mainly produced by thyroid follicular cells and in lesser quantities by thyroid infiltrating mononuclear cells. The concentrations of transforming growth factor beta mRNA were lower in iodine-deficient nontoxic goiter than in Graves' disease and normal thyroid tissue. Transforming growth factor beta protein secretion by cultured thyroid follicular cells was also low in nontoxic goiter, but could be increased by addition of sodium iodide (10 microM) to the culture medium. Recombinant transforming growth factor beta did not affect basal tritiated thymidine incorporation in cultured thyroid follicular cells, but inhibited, at a concentration of 10 ng/ml, the growth stimulatory influence of insulin-like growth factor I, epidermal growth factor, transforming growth factor alpha, TSH, and partly that of normal human serum on cultured thyroid follicular cells. This inhibition was greater in Graves' disease than in nontoxic goiter. These results suggest that transforming growth factor beta may act as an autocrine growth inhibitor on thyroid follicular cells. Decreased transforming growth factor beta production and decreased responsiveness to transforming growth factor beta may be cofactors in the pathogenesis of iodine-deficient nontoxic goiter.

Analysis of T-cell receptor usage in activated T-cell clones from Hashimoto's thyroiditis and Graves' disease

Rearrangements to the T-cell receptor (TcR) beta and gamma gene loci were studied in T cells derived from the thyroid glands of a patient with Hashimoto's (HT) and another with Graves' (GD) autoimmune thyroiditis. The cells studied were freshly isolated mononuclear cells, T-cell lines grown in the presence of anti-CD3 and IL-2 and T-cell clones. Numerous different rearrangements to the constant regions of TcR beta and TcR gamma and in the variable gene region of TcR beta were observed. These findings indicate that the T-cell response in autoimmune thyroiditis is multiclonal and may have implications for the epitopes recognized by autoreactive T cells and for the mechanisms of the disease.

Tumour necrosis factor synergises with gamma interferon on the induction of mRNA for DR alpha chain on thyrocytes from Graves' disease and non toxic goitre

In both thyroid autoimmune diseases Graves' and Hashimoto's thyroiditis, the epithelial thyroid follicular cells (TFC) have been shown to express HLA class II molecules, and can restimulate autoreactive T cells cloned from the diseased tissue. This aberrant class II expression is important in the mechanism of perpetuation of the disease process, therefore we have compared the effect of interferon gamma (IFN gamma) and tumour necrosis factor (TNF alpha) on the HLA-DR alpha mRNA expression of thyroid follicular cells derived from Graves' disease (GD) and a non autoimmune disease, non toxic goitre (NTG). Our results indicate that TNF alpha synergises with IFN gamma in the induction of HLA class II mRNA. There was no consistent difference in DR alpha mRNA expression between the GD and NTG thyroid follicular cell preparations in response to induction by a combination of these lymphokines at various concentrations. Our data suggest that the differences in the level of expression of class II molecules observed in vivo in Graves' disease and non toxic goitre, which is much higher in the former, is probably due to local release of lymphokines by infiltrating T lymphocytes, although other factors may be involved.