Radioimmunoassay for estimation of thyroglobulin in human serum.

A specific double antibody radioimmunoassay has been develop for the measurement of thyroglobulin in human serum. Human thyroglobulin was purified by combined DEAE-cellulose and affinity chromatography using Sepharose 4B-bound Concanavalin A. Sensitivity of test serum was 10 ng/ml. Thyroglobulin was not detectable in half of normal subjects, and half showed values between 10 and 180 ng/ml. In the patients with simple goiter and secondary hypothyroidism, serum thyroglobulin was usually in the normal range. In Hashimoto's thyroiditis, many sera having precipitating antibodies or high hemagglutination antibodies for thyroglobulin showed a high thyroglobulin concentration in serum probably due to a false positive reaction. In hyperthyroidism, an increased thyroglobulin level was observed in 64% of patients. However, there was no correlation between serum thyroglobulin and thyroxine levels in untreated hyperthyroidism. Serum thyroglobulin was increased significantly in some cases for several weeks after isotope therapy for the hyperthyroidism.     

Thyroid function and antimicrosomal antibody during the course of silent thyroiditis

The thyroid function and antithyroidal antibody were studied in 17 patients with silent thyroiditis unrelated to pregnancy. The antimicrosomal hemagglutination antibody (MCHA) was negative in ten of them (group I) and was positive in seven (group II). At one month after the thyrotoxicosis, thyroid function became normal in both groups. At two months after the onset of thyrotoxicosis, in group I T4 (8.1 +/- 1.8 micrograms/dl, Mean +/- SD), T3 (113 +/- 25 ng/dl) and TSH were normal. At that time T4 (2.8 +/- 2.2 micrograms/dl) was significantly decreased (p less than 0.001) compared with those of group I and the levels of TSH were strikingly increased in 6 patients in group II. The level of T3 (96 +/- 29 ng/dl) in group II was not different from that of group I. Therefore MCHA was negative in patients who did not develop hypothyroidism and MCHA was positive in patients who developed hypothyroidism. The development of hypothyroidism two months after thyrotoxicosis and positive MCHA are correlated. The Tg was elevated in 7 out of 13 patients (54%) with negative antithyroglobulin hemagglutination antibody and in the remainder was normal during thyrotoxicosis. The discrepancy between the level of Tg and thyroid hormones was discussed.     

Five patients with painless thyroiditis simultaneously developed in a nursery school

Painless (silent) thyroiditis (PT) occurred simultaneously in 1 male and 4 females aged 21 to 52 years working at a nursery school. Clinical symptoms did not include goiter, or pain or tenderness of the neck in any of the patients but were characterized by edema of the lower legs as well as palpitation and loss of body weight as observed in subacute thyroiditis. General blood analysis showed that all patients were negative for C-reactive protein (CRP) and 3 had mild impairment of liver function. Examination of thyroid function suggested transient thyrotoxicosis accompanied by a marked reduction in radioactive iodine uptake (RAIU), but antithyroglobulin hemagglutination antibody (TGHA) and antithyroid microsomal hemagglutination antibody (MCHA) were negative in all patients. Examination of various viral antibodies showed no significant changes in their titers. Thyrotoxicosis was transient and disappeared without treatment or by glucocorticoid administration. Our results suggested that PT observed in this study was caused by some environmental factor. The possibility of an unidentified virus as a factor cannot be ruled out.     

Clinical studies on thyroidal autoantibodies.

In an attempt to clarify autoimmune nature of Grave's disease and Hashimoto's thyroiditis, thyroidal autoantibodies have been studied on 86 cases of Grave's disease, 54 cases of Hashimoto's thyroiditis, 31 cases of simple goiter, 11 cases of primary hypothyroidism a-d 22 cases of thyroid neoplasia as well as on 364 healthy subjects. Two kinds of tanned red cell hemagglutination tests were carreid out on each case. One method using refined human thyroglobulin for sensitization of sheep red cells has been found to be specifice for anti-thyroglobulin antibody and to be frequently positive in Hashimoto patients. However, in another method using human thyroidal microsomes (purified by ultracentrifugation) as sensitizing antigen, some heterogenous antibodies including anti-thyroglobulin antibody might be detected together with the antibody against the antigen proper to thyroidal micorsome (HF antigen)which is derived from hyperfunctioning thyroidal follicular cells of Grave's patients. hAnti-HF antibody is frequently detected both in Hashimoto and Grave's patients. In other thyroid diseases the titers of both thyroidal autoantibodies were generally low, though higher than in healthy subjects. The effect of aging on thyroidal autoantibodies in healthy subjects was clearly observed in females but not in males. From the results of these two test, it is possible to speculate that high=columnar and hyperfunctioning thyroidal follicular cells might exist focally in most cases of Hashimoto's thyroiditis.     

Experimental autoimmune thyroiditis in mice chronically treated from birth with anti-IgM antibodies

The role of T lymphocytes in the pathogenesis of experimental autoimmune thyroiditis in mice is well established while the role of B lymphocytes is unclear. Mice with thyroid lesions have thyroglobulin antibodies whereas these antibodies can occur in mice immunized with Tg that do not develop thyroid lesions. To determine whether thyroglobulin antibodies are necessary for the development of the thyroid infiltrates with mononuclear cells, which are characteristic for experimental autoimmune thyroiditis, AKR mice chronically treated from birth with goat anti-mouse IgM antibodies were immunized with mouse thyroglobulin in Freund's complete adjuvant when they were 7 weeks old. Control mice, similarly immunized, were chronically injected from birth with normal goat gamma-globulin. Three weeks after immunization, all mice were sacrificed, thyroglobulin antibodies in the serum were measured by hemagglutination assay and enzyme-linked immunosorbent assay, and thyroid pathology was assessed. The serum concentration of IgG and IgM, the percentage of B and T lymphocytes in the spleen (flow cytometry), and the in vitro proliferative response of spleen lymphocytes to stimulation by PHA, LPS, and Tg were also measured. All mice treated with anti-IgM antibodies did not have detectable thyroglobulin antibodies but 63% of these mice and 88% of control mice (all of which had thyroglobulin antibodies) had thyroid lesions. Mice treated with anti-IgM antibodies that did not have thyroid lesions had a more pronounced depression of B lymphocytes than similarly treated mice that had thyroid lesions. These experiments suggest that thyroglobulin antibodies are not necessary for the development of thyroid infiltrates with mononuclear cells. B lymphocytes could still participate in the production of experimental autoimmune thyroiditis by presenting thyroglobulin to helper T lymphocytes.     

Detection of thyroid microsomal and thyroglobulin antibodies by new sensitive radioimmunoassay in Hashimoto's disease; comparison with conventional hemagglutination assay

We evaluated clinical usefulness of thyroid microsomal antibody (MCAb) and thyroglobulin antibody (TGAb) measured by new sensitive radioimmunoassays (RIA). These assays are simple and reproducible; the intra- and inter-assay coefficients of variation were 3.6-6.8% and 6.6-13.2% in the MCAb assay, and 3.2-7.7% and 7.6-12.3% in the TGAb assay, respectively. In 126 patients with Hashimoto's disease, the antibody activity determined by this RIA correlated with that determined by the hemagglutination assay (HA) (r = 0.848 for MCAb, r = 0.686 for TGAb, p less than 0.001). MCAb was detected by RIA in all of 115 HA-positive and 4 of 11 HA-negative patients, and TGAb by RIA in all of 84 HA-positive and 29 of 42 HA-negative patients: the prevalence of MCAb was 94% and that of TGAb was 90% in the disease. Moreover, some showed high antibody activity only in RIA. In another group of 14 patients with biopsy-proved Hashimoto's disease with no antibody activity by routine HA tests, serum MCAb was detected in 3 (21%), TGAb in 11 (79%), and both activities in 2 (14%). Our results indicate that (1) the RIA tests are more sensitive than the conventional HA test, and that (2) the present RIA test for TGAb is more sensitive than that for MCAb in detecting autoimmune abnormalities, especially in patients with biopsy-proved Hashimoto's disease who give negative results in the HA test.     

Analysis of triiodothyronine and thyroxine-binding autoantibodies in chickens susceptible to autoimmune thyroiditis

This report reveals a surprisingly high incidence of thyroid hormone (T3 and T4) autoantibodies (THA) and thyroglobulin autoantibodies in a closed flock of untreated Cornell strain (CS) White Leghorn chickens. This flock is closely related to the Obese strain chicken, which develops a severe spontaneous autoimmune thyroiditis. A sensitive electrophoretic autoradiographic assay for THA was developed. This assay was applied to the study of autoantibodies to T3 and T4 in the sera of adult female CS chickens. Of 109 females, 29.4% had antibodies to T3 and 18.4% had antibodies to T4. The incidence of thyroglobulin antibodies, determined by passive hemagglutination, was 15.6%. The presence of THA affected RIA measurements because serum T3 and T4 hormone concentrations appeared elevated in those birds with moderate to high antibody levels. There was major variance in the electrophoretic heterogeneity of the THA from individual chickens; i.e., some of the sera contained antibodies to T3 or T4 that appeared to be monoclonal, whereas other sera exhibited polyclonal multi-banded patterns. To determine if antibodies reactive with T3 and T4 (which are haptens) were generated by antibody responses to the T3/T4 sites on the thyroglobulin molecule, competitive binding assays were performed to determine the relative binding affinities of the antibodies for the haptens (T3/T4) and the "hapten-conjugate" (thyroglobulin). In these assays, thyroglobulin competed with the haptens, thus supporting the above hypothesis.     

Elevated prolactin to cortisol ratio and polyclonal autoimmune activation in Hashimoto's thyroiditis.

Cortisol and prolactin, which are considered to have an immunomodulatory effect, and selected autoantibodies were determined in Hashimoto's thyroiditis. 37 patients (8 males and 29 females) (54 +/- 13.8 years) and an equal number of sex- and age-matched normal subjects (52.6 +/- 14.2 years) were studied. None of the 74 subjects suffered from any other immunological, infectious, hepatic, renal or malignant diseases. Patients with Hashimoto's thyroiditis exhibited significantly higher (p < 0.016) prolactin values (14.0 +/- 3.8 ng/ml) than did control subjects (6.5 +/- 1.3 ng/ml). In contrast, cortisol levels were lower in Hashimoto's thyroiditis (13.5 +/- 3.2 microg/dl) vs. normal state (16.0 +/- 1.13 microg/dl), (p < 0.05). The prevalence of anti-TPO and anti-Tg antibodies was 100 % and 43 % in the patients with Hashimoto's disease. In contrast, no subject of the control group was positive for anti-TPO, although 9 subjects (24 %) were positive for anti-Tg autoantibodies. The percentage of positive autoantibodies to nucleus, smooth-muscle, and parietal cells in the patients (36.0, 10.9 and 18.5 %, respectively) was higher than that in healthy group (11.0 and 0 % respectively). Notably, neither group was positive for antibodies against double-stranded DNA or mitochondria. In conclusion, our results provide evidence for a polyclonal activity in Hashimoto's thyroiditis, an organ-specific autoimmune disease, associated with an altered prolactin-adrenocortical status. Such information should initiate longitudinal studies to clarify the exact time sequence of these events related to the disease's activity.     

The thyroid "microsomal" antigen is an epitope on the thyrotropin receptor

Antimicrosomal antibodies are present in the sera of most patients with autoimmune thyroiditis, and Graves' disease. It has, in general, been difficult to separate antimicrosomal activity from that directed against the thyrotropin (TSH) receptor in Graves' IgG preparations. The "microsomal" antigen has been localized to the endoplasmic reticulum and microfollicular aspect of thyrocytes; its structure is however unknown. In an attempt to identify the thyroid microsomal antigen, we studied the interaction of Hashimoto's IgG with high microsomal antibody titre and negative for thyroglobulin with purified thyroid plasma and light microsomal membranes. We allowed Hashimoto's, Graves', and control IgGs to bind to protein blots of thyroid plasma membranes resolved on SDS-PAGE under non-reducing conditions. All seven Hashimoto's IgG at a concentration of 2 mg/ml interacted with an M approximately 197,000 polypeptide corresponding to the TSH holoreceptor. By contrast to Graves' IgG (which were positive at 1 mg/ml), however, this binding was not blocked by pretreatment of the protein blots with TSH. Normal IgGs showed no binding at concentrations of up to 2 mg/ml. Both Hashimoto's and Graves' IgG interacted with TSH-affinity column-purified receptor preparations. Two of the Hashimoto's IgGs induced adenylate cyclase activation in thyroid plasma membranes, three inhibited TSH-stimulated enzyme activation, and two were without effect. Two classes of autoantibodies, other than TSH receptor directed, were encountered; one class raised to antigens common to all seven patients and another class unique to individual patients, eg, Mr 210,000 and Mr 20,000 polypeptides. We propose that the TSH receptor has multiple epitopes (functional domains), and the one to which antimicrosomal antibody bind is likely to be spatially separated from that with which Graves' IgG and TSH interact. Differences in affinity or number of sites allows for the demonstration of Graves' IgG against a background of antimicrosomal antibody.     

Cytomorphologic aspects of thyroiditis. A study of 51 cases with functional, immunologic and ultrasonographic data

Fine needle aspiration provided material for detailed cytomorphologic study in 51 cases of thyroiditis, 40 of which were diagnosed as Hashimoto's (autoimmune) thyroiditis. Of these 40 cases, 22 were found to be euthyroid on clinical examination and radioimmunoassay (RIA), 10 were hyperthyroid and 8 were hypothyroid. Of the 11 cases of subacute thyroiditis, 4 were thyrotoxic and 7 were euthyroid. Radioactive iodine uptake (RAIU) showed decreased to negligible uptake in ten and normal uptake in one case of subacute thyroiditis, whereas all of the thyrotoxic cases of Hashimoto's thyroiditis showed markedly increased RAIU. Echography showed a hypoechoic or anechoic pattern in most of the cases. Antimicrosomal and/or antithyroglobulin antibodies were positive in 25 cases of Hashimoto's thyroiditis and in 1 case of subacute thyroiditis. The cytologic features that characterized subacute thyroiditis were the presence of multinucleated giant cells and a polymorphonuclear and lymphocytic population associated occasionally with epithelioid-cell granulomas. Hashimoto's thyroiditis was characterized by Hürthle-cell changes and a significant lymphoid population consisting of mature and transformed lymphocytes, often impinging on follicular cells. There was an overlap in the cytomorphologic features between some cases of Hashimoto's and subacute thyroiditis. In such cases, the final diagnosis was arrived at by an integrated approach incorporating all of the diagnostic parameters available.     

IgA and IgG antigliadin,IgA anti-tissue transglutaminase and antiendomysial antibodies in patients with autoimmune thyroid diseases and their relationship to thyroidal replacement therapy

Celiac disease is a chronic illness of the small bowel caused by gliadin intolerance in genetically predisposed subjects. The aim of this study was to investigate serum levels of IgA and IgG antigliadin antibodies, IgA antiendomysial antibodies, and IgA anti-tissue transglutaminase antibodies in 169 patients with autoimmune thyroid diseases, i.e. chronic thyroiditis and Graves' disease. Antiendomysial antibodies were positive in 2 out of 169 persons (1.18%), IgA antigliadin antibodies in 15.98%, IgG antigliadin antibodies in 51.48%, and IgA anti-tissue transglutaminase in 14.79%. The prevalence of positivity was higher compared to the 1312 control blood donors described in our previous study (Vancíková et al. 2002) (p<0.05). Patients with chronic thyroiditis treated with a high replacement dosage of levothyroxin (125-200 microg daily) had higher serum levels of IgA antigliadin antibodies in comparison with patients treated with a lower dosage (50-100 microg daily) (medians: 13.00 vs. 19.69, p=0.033). We found a negative correlation of IgA anti-tissue transglutaminase antibodies and total calcium serum levels (r = -0.480, p=0.0236, n=22). We can conclude that in persons with autoimmune thyropathy there is a high prevalence of positive antigliadin, anti-tissue transglutaminase and antiendomysial antibodies. Latent celiac disease may lead to impaired resorption of therapeutically administered levothyroxine, calcium, or other substances.     

Anti-thyroglobulin anti-idiotypic antibodies in sera of patients with Hashimoto's thyroiditis and Graves' disease

The objective of this study was to find naturally occurring anti-idiotypic (anti-Id) antibodies to anti-human thyroglobulin (anti-hTg) idiotype in sera of patients with autoimmune thyroid disease. Sera from patients with Hashimoto's thyroiditis (HT), Graves' disease (GD), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE) and sera from normal subjects were tested for the presence of anti-Id antibodies against mouse anti-hTg monoclonal antibodies (McAb) in indirect ELISA and in indirect solid-phase RIA. Microtitration plates were coated with six McAb, five of them directed against different epitopes on hTg molecule, and then incubated with patients' sera. The bound antibody was detected with either peroxidase or 125I-labeled anti-human IgG. The specific positive reaction was observed in four of 40 patients with HT, in two of 26 patients with GD, in seven of 58 patients with RA, and in none of 20 normal subjects. The detected binding was due to the presence of anti-hTg anti-Id antibodies and not to Tg-anti-Tg circulating immune complexes, as the positive sera did not contain hTg when resolved on SDS-PAGE, nor did they bind to all anti-hTg McAb tested. The binding was dose dependent, and titers of anti-Id antibodies varied from 1:243 to 1:2187. The binding could be inhibited up to 50% by hTg, but not by the thyroid microsomal antigen, indicating that some of those anti-Id might represent the internal image of the antigen. Serum from the patient 3403, showing the strongest reactivity against McAb A-3, was chosen for IgG purification and F(ab')2 fragment isolation. The 3403 F(ab')2 fragment, but not the Fc fragment, was found to react specifically with four mouse anti-hTg McAb but not with the control mouse IgG. Thus, the obtained results permit the conclusion that anti-hTg anti-Id antibodies could occur naturally during the course of thyroid autoimmune disorders.     

Anterior pituitary cell antibodies detected in Hashimoto's thyroiditis and Graves' disease

An immunofluorescence study using unfixed cryostat sections of rat pituitary glands was carried out on sera from 34 patients with Hashimoto's thyroiditis, 28 patients with Graves' disease, 10 patients with thyroid adenoma and 50 healthy subjects. After absorption of sera with rat liver tissues, 19 of 34 patients retained reactivity to anterior pituitary cell antibodies (PCA, 55.8%). On the other hand, immunofluorescence in anterior pituitary cells was faint and detected in only 2 of 28 patients with Graves' disease (7.1%) after absorption of their sera with rat liver aceton powder. A similar result was also obtained when PCA were compared in the sera of Hashimoto's thyroiditis and Graves' disease with high titers of thyroid microsomal autoantibodies. PCA were detected neither in the sera of patients with thyroid adenoma nor in the healthy subjects. The present study suggests that PCA were considerably more prevalent in Hashimoto's thyroiditis than in Graves' disease.     

Probing the normal and autoimmune B cell repertoire with Epstein-Barr virus. Frequency of B cells producing monoreactive high affinity autoantibodies in patients with Hashimoto's disease and systemic lupus erythematosus

The frequency of cell precursors producing Ig of different classes and Ag-binding activities were determined, using EBV-infection and limiting dilution assays, in healthy subjects and patients with autoimmune disease. A large proportion of circulating B cells from healthy subjects were committed to the production of IgM antibodies that were polyreactive and bound a variety of self- and exogenous Ag, i.e., IgG Fc fragment, ssDNA, thyroglobulin, thyroid microsomal Ag, insulin, and tetanus toxoid. Similar frequencies of these polyreactive antibody-producing cells were found in patients with Hashimoto's disease and SLE. In contrast, significantly higher frequencies of cell precursors producing monoreactive IgG autoantibodies to thyroid Ag (thyroglobulin and thyroid microsomal Ag) and ssDNA were found in Hashimoto's disease and SLE patients, respectively. Calculation of the Kd revealed that monoclonal polyreactive antibodies were in general low affinity (Kd, 10(-3) to 10(-7) mol/liter), whereas monoclonal monoreactive autoantibodies were high affinity (Kd, 10(-9) to 10(-11) mol/liter). The detected frequency and high affinity of the monoreactive autoantibodies in Hashimoto's disease and SLE patients were comparable to those of anti-tetanus toxoid and anti-insulin IgG mAb produced by B cell clones from vaccinated healthy subjects and insulin-treated patients with insulin-dependent diabetes mellitus, respectively. These findings support the hypothesis that the autoimmune B cell repertoire in patients with organ-specific and systemic autoimmunity is shaped by Ag-driven responses rather than merely reflecting a polyclonal B cell activation.     

Production of IL-10 and IL-12 in CD40 and interleukin 4-activated mononuclear cells from patients with Graves' disease

We investigated the effect of T cell-dependent B cell activation on the production of IL-10 and IL-12 by peripheral blood mononuclear cells (PBMCs) obtained from patients with Graves' disease vs Hashimoto's thyroiditis, type 1 diabetes or normal controls. Incubation of PBMCs, from each of the subject groups, with a combination of anti-CD40 monoclonal antibodies and interleukin 4 (IL-4)-activated B cells, as shown by an increased level of soluble CD23. There was also a notable increase in the number of CD23(+)cells in PBMCs from patients with Graves' disease as compared to the other subject groups. This combination of B cell stimulants increased production of IL-10 in PBMCs obtained from patients with Graves' disease relative to those patients with Hashimoto's thyroiditis, type 1 diabetes, or the control subjects. The production of IL-12 showed wide variation that depended on the basal IL-12 level. In subjects with a low basal IL-12 level there was a positive correlation between the production of IL-12 and that of IL-10 from PBMCs stimulated with anti-CD40 antibodies plus IL-4. On the contrary, in the patients with a high basal IL-12 level, no change or a decrease of IL-12 production was observed after the stimulation. Thus, T cell-dependent B cell activation via a CD40 pathway triggers the overproduction of IL-10 and overcome the effect of IL-12 to shift the Th(1)/Th(2)balance to Th(2)dominance in patients with Graves' disease but not in Hashimoto's thyroiditis or type 1 diabetes.     

Decreased nerve growth factor levels in hyperthyroid Graves' ophthalmopathy highlighting the role of neuroprotective factor in autoimmune thyroid diseases

Nerve growth factor (NGF), which is a neurotrophic factor, is involved in autoimmune and inflammatory processes. Serum NGF levels were investigated in 131 patients with autoimmune (95 with Graves' disease, of whom 57 had ophthalmopathy, 19 with Hashimoto's thyroiditis) and nonimmune thyroid diseases (17 with toxic nodular goitre), and 20 controls. NGF levels were measured via enzyme-linked immunosorbent assay. Twenty-nine positive cases for NGF were detected: 21 cases in Graves' disease, 7 cases in Hashimoto's thyroiditis, no case in toxic nodular goitre and one case in controls. NGF levels were higher in patients with Graves' disease and particularly with Hashimoto's thyroiditis compared with controls (1786.47+/-34.79 pg/ml and 1996.27+/-77.71pg/ml vs 1579.16+/-57.45pg/ml, P<0.049 and P<0.0001, respectively). Increased NGF levels associated with Graves' hyperthyroidism and correlated with FT(3) (P<0.01). Patients with the presence of antibodies against TSH receptor showed higher NGF levels than those with no antibodies (1938.61+/-56.44pg/ml vs 1712.12+/-54.22pg/ml, P<0.009). Decreased NGF levels were demonstrated in hyperthyroid Graves' ophthalmopathy compared with those without eye symptoms (1746.65+/-51.98pg/ml vs 1910.47+/-55.62pg/ml, P<0.036). NGF may be involved in the pathomechanism of autoimmune thyroid diseases. Decreased NGF levels in hyperthyroid Graves' ophthalmopathy highlight the importance of NGF in the neuroprotection of orbital tissues.     

CTLA4 gene polymorphisms in children and adolescents with autoimmune thyroid diseases

Two common forms of autoimmune thyroid diseases are Graves' disease and Hashimoto's thyroiditis. Cytotoxic T lymphocyte antigen 4 (CTLA4) encoded by the CTLA4 gene on chromosome 2q33 plays a role in susceptibility to Graves' disease and is probably important also for Hashimoto's thyroiditis as well as for the other endocrine autoimmune disorders. The CTLA4 locus is the only nonhuman leukocyte antigen locus that has been found in association with Graves' disease repeatedly. Particularly, association of three polymorphic markers of CTLA4 gene, namely, C(-318)T, A49G, and (AT)n dinucleotide repeat, with Graves' disease was demonstrated in most of the population-based investigations. On the other hand, there are few studies to reveal the association of these markers with Hashimoto's thyroiditis. A49G polymorphism was proposed to be associated with Hashimoto's thyroiditis, and C(-318)T was suggested to be not associated. The patient groups consisted of 88 patients (10 males and 78 females; mean age: 14.5 +/- 3.2 years [4.6-21.0 years]) with a previous diagnosis of Hashimoto's thyroiditis and 112 euthyroid volunteers (51 males and 61 females; mean age: 14.1 +/- 2.9 years [5.2-18 years]). The frequency of A/G (A49G) genotype was high and statistically significant in patients with Hashimoto's thyroiditis in comparison with the control group. Although the frequency of C/T [C(-318)T] genotype is not significantly high in children with Hashimoto's thyroiditis according to the control group, the risk of Hashimoto's thyroiditis in A/G genotype group was 4.66 times greater than the group with A/A genotype. In this study, we documented that the A49G polymorphism might increase the susceptibility for Hashimoto's thyroiditis.     

Incidences of antibodies to Yersinia enterocolitica: high incidence of serotype O5 in autoimmune thyroid diseases in Japan

Antibodies to Yersinia enterocolitica serotype O3, O5, O6 and O9 were measured by the micro-agglutination method in 445 healthy subjects and patients with Grave's disease (n = 70), Hashimoto's disease (n = 45) and thyroid tumor (n = 29). In contrast to previous reports, the incidence of antibodies to serotype O3 in each group of patients with thyroid diseases was not significantly different from that in healthy subjects. However, the incidence of antibodies to serotype O5 was significantly higher in patients with Graves' disease (81.4%, P less than 0.001) and Hashimoto's disease (91.1%, P less than 0.001) than in healthy subjects (258.9%). Significantly increased incidence of antibodies to serotypes O6 and O9 was observed only in patients with Hashimoto's disease (40.0% and 51.1% vs healthy subjects 24.7% and 29.9%, respectively). Patients with thyroid tumor showed no increase in any serotype of Yersinia enterocolitica. No correlations was found between the titers of anti-Yersinia antibodies and anti-thyroglobulin or anti-microsomal antibodies. These data indicate an association between thyroid autoimmunity and antibodies to Yersinia enterocolitica. These results are different from those in reports from other countries, suggesting that serotype specificity may be influenced by racial or genetic factors.     

Analysis of Fas, FasL and Caspase-8 expression in thyroid gland in young patients with immune and non-immune thyroid diseases

INTRODUCTION: Apoptosis, programmed cell death is a regulating mechanism enabling the removal of superabundantly produced and unnecessary at the certain moment cells. Disturbances of the apoptosis regulation contribute to the pathogenesis of many diseases, including autoimmune thyroid disorders. The aim of this study was to estimate expression of proapoptotic Fas/FasL and caspase-8 in thyroid tissues in patients with Graves' disease (GD), non-toxic nodular goiter (NTNG) and Hashimoto's thyroiditis (HT). MATERIAL AND METHODS: Inclusion criteria of Graves' patients were: large goiter, ophthalmopathy, TRAb > 5 U/L, positive titre of anti-TPO and anti-TG antibodies and concentration of TSH < 0.45 microIU/mL for more the 2-3 months from an onset of the disease. Isolated thyrocytes were identified by indirect method: in the first stage mouse monoclonal antibodies (mAbs) anti-TPO were bound to rabbit anti-mouse antibodies IgG (Fab')2 labeled FITC. To obtained cellular suspension mAbs directed against apoptotic Fas/FasL molecules labeled with PE (Phycoerythrin) was added. All investigations were performed on Coulter EPICS XL flow cytometer. Detection of apoptotic proteins was confirmed by Western Blot and immunohistochemistry methods using mAbs in DAB chromogene visuality and marked by Mayer's haematoxylin. Evaluation of caspase-8 expression in thyroid follicular cells was performed by Western Blot test. RESULTS: The analysis of Fas and FasL expression on surface of thyroid follicular cells was higher in patients with Hashimoto's thyroiditis (38%, 26%) in comparison with patients with Graves' disease (18%, 14%). In case of patients with Hashimoto's thyroiditis significantly lower percentage of thyroid tissue infiltrating immune Fas+ (13%) and FasL+ (22%) T cells in comparison with Graves' patients (33%, 43% respectively) was observed . Identification of proapoptotic Fas and FasL molecules in the thyroid follicular cells revealed higher expression of both proteins in patients with GD (++,++) and HT (+++; +++, respectively) in comparison with NTNG patients (+/0; +/0). Caspase-8 expression was detected in band 55 kDa using Western Blot test in patients with thyroid autoimmune diseases. CONCLUSIONS: We conclude that alteration in the expression of proapoptotic proteins in thyroid follicular cells may play a role in pathogenesis of thyroid autoimmune disorders. In addition, suppression of apoptosis in Graves' disease led to increased proliferation of thyroid follicular cells which is responsible for goiter formation.     

Inhibition of experimental autoimmune thyroiditis in mice by anti-I-A antibodies

Experimental autoimmune thyroiditis is induced in mice by immunization with thyroglobulin emulsified in Freund's complete adjuvant. The disease is characterized both by thyroid infiltration with mononuclear cells and by circulating thyroglobulin antibodies. The magnitude of the thyroid infiltration and the titer of thyroglobulin antibodies are controlled by genes in the I-A subregion of the major histocompatibility complex (H-2). We investigated the in vivo effect of monoclonal anti-Ia antibodies on experimental autoimmune thyroiditis in susceptible mice. Antibodies were given around the time of immunization, later after immunization, and to mice with established disease. Monoclonal antibody produced by the hybridoma line 10-3.6 (anti-I-Ak, s, u, v, z, f) completely prevented both production of thyroglobulin antibodies and thyroid infiltrates, when given shortly before or at the time of antigen administration. This effect was dose-dependent and this monoclonal antibody decreased the severity of the disease when given after the antigen challenge but did not fully suppress established thyroiditis. The same antibody markedly decreased the number of B lymphocytes in the spleen and decreased the thyroglobulin-induced spleen cell proliferation when either given in vivo or added in vitro to cell cultures. Antibodies produced by the hybridoma line 11.2.12 (anti-I-Ak) did not show an inhibitory effect on the disease. These experiments suggest that in this model of murine thyroiditis anti-Ia antibodies act on antigen-presenting cells. Furthermore, only one monoclonal antibody, anti-Ia, suppressed the immune response to thyroglobulin, suggesting a possible role for the isotype and specificity of anti-Ia antibody.