Production and properties of novel human thyroid cancer specific monoclonal antibodies

Monoclonal antibodies (TCM-7, -9 and -12) against human thyroid differentiated cancers were established by screening with human thyroid cancers, normal and benign thyroid tissue, and normal human serum protein. A monoclonal antibody (TCM-9) with strong specificity for human thyroid cancer but not for Graves' disease, adenoma or normal thyroid, was shown to recognize a 300 K protein but not to bind to native or mature human thyroglobulin. When TCM-9 was used in immunohistochemical staining tests on more than 30 types of non-thyroid lesions, no reactivity of TCM-9 was observed except with skin immature teratoma, lip squamous carcinoma and stomach adenocarcinoma, which revealed weak reactivities. TCM-9 also showed strong reactivity with two undifferentiated thyroid cancer cell lines and one tissue specimen. Thus TCM-9 is a novel monoclonal antibody against the thyroid cancer.

Circumvention of the induction of resistance in murine experimental autoimmune thyroiditis by recombinant IL-1 beta

Murine experimental autoimmune thyroiditis (EAT) is induced in genetically susceptible mice by immunization with mouse thyroglobulin (MTg). We have previously shown that raising the level of circulatory MTg for greater than or equal to 2 to 3 days, by the i.v. injection of soluble MTg or the infusion of thyroid-stimulating hormone, rendered these mice resistant to subsequent EAT induction. The Ag-specific resistance was mediated by CD4+ Ts cells, and the induction of unresponsiveness could be interfered with by injecting the T cell adjuvant poly(A).poly(U) 3 h after MTg pretreatment. To dissect further the cytokine signals involved in circumventing the induction of resistance, the effect of human rIL-1 beta was examined. As with poly(A).poly(U), mice given 4000 or 10,000 U or rIL-1 beta 3 h after deaggregated MTg (dMTg) were not resistant to EAT induced with MTg and adjuvant. Moreover, mice given 90,000 U or rIL-1 beta after dMTg and then immunized displayed very severe thyroiditis, strong in vitro proliferative response, and high antibody titers, compared with immunized controls, indicating a dose-dependent effect of rIL-1 beta. The intermediate dose of 10,000 U or rIL-1 beta was selected to determine the importance of time interval between dMTg and rIL-1 beta administration. Interference with the induction of suppression was more efficacious when rIL-1 beta was given at 3 h than at 24 h, but at 24 h it was no more effective than 4000 U given at this interval. In contrast, mice given 10,000 U of rIL-1 beta 3 h before dMTg and then challenged developed MTg antibodies but little thyroiditis, demonstrating that the interference with suppression of autoantibody responses can occur without altering the induction of suppression of thyroiditis. The injection of rIL-1 beta also led to a sharp but transient rise in serum IL-6. The short t1/2 of IL-6 suggests that any role played by IL-6 would require critical timing. Murine rIL-2 given at 1 and 2 days after dMTg had a minimal effect on induced resistance. Lastly, immunization of dMTg-pretreated mice with MTg and rIL-1 beta did not induce EAT, demonstrating that rIL-1 beta could not interfere with established suppression. Thus, the intervention by rIL-1 beta in MTg-induced suppression occurs at a critical time, early after the injection of dMTg but before the establishment of resistance.

Identification of a thyroiditogenic sequence within the thyroglobulin molecule

Thyroglobulin (Tg)-specific T cells are important in the induction of experimental autoimmune thyroiditis (EAT), but the nature and the number of the Tg T cell epitopes involved in the disease process are unknown. Through the use of computerized algorithms that search for putative T cell epitopes, a 17-mer peptide (TgP1) was identified within the known portion of the rat Tg sequence (corresponding to amino acids 2495 to 2511 of the human Tg sequence) that induced strong mononuclear cell infiltration of the thyroid in classic EAT-susceptible murine strains such as SJL, C3H, and B10.BR and low or undetectable infiltration in EAT-resistant strains such as BALB/c and B10. TgP1 appears to be phylogenetically conserved since it is completely homologous to its bovine counterpart and differs at a single amino acid position from its human analogue. After priming with TgP1 in vivo, significant proliferative T cell responses to TgP1 in vitro were observed only with lymphocytes from susceptible (high responder) strains, thus correlating proliferative capacity with EAT induction. TgP1-primed T cells did not respond to intact mouse Tg (MTg) or rat Tg in vitro and, conversely, T cells primed in vivo with MTg or rat Tg did not respond to TgP1 in culture, suggesting that TgP1 is comprised of non-immunodominant T cell determinants. TgP1 was defined as a serologically nonimmunodominant epitope as well, since in vivo priming of all strains with MTg led to strong MTg-specific IgG responses but no TgP1-specific responses in ELISA assays. This was not due to lack of immunogenic B cell determinants on TgP1, however, because peptide challenge of EAT-susceptible strains elicited TgP1-specific IgG that also cross-reacted with MTg and rat, human, bovine, and porcine Tg. The data demonstrate that TgP1 delineates nonimmunodominant but highly immunogenic determinants at both the T and B cell level, which may play an important role in the development of autoimmune thyroiditis.

Clinical meaning of circulating antithyroglobulin antibodies in differentiated thyroid cancer: a prospective study

In recent studies of patients with differentiated thyroid cancer (DTC), an association between the persistence of tumor and the presence of circulating anti-thyroglobulin antibodies (TgAbs) have been described. The aim of the present study was to evaluate TgAb variations before and after total thyroid ablation and to correlate TgAb levels to the outcome of disease. Forty-three patients with DTC were studied (35 female, 8 male; 33 patients had papillary cancer and 10 follicular cancer). Tumor was intrathyroid in 20 cases, had spread to the lymph nodes in 19 and to the lungs in 4. All patients underwent total thyroidectomy and 131I therapy, and were then treated by suppressive doses of L-thyroxine. After a mean follow-up of 3.55 yr, TgAbs became undetectable in 24 patients (all were considered tumor-free), whereas TgAbs remained elevated in 19 cases. In 5 of these 19 patients, disease progression or persistence was documented (to the lymph nodes in three and to the lungs in two). TgAb levels were higher in patients with persistent disease in comparison with those tumor-free. Serum thyroglobulin (S-Tg) results were only elevated in the two patients with persistent disease in the lungs. Our data suggest that TgAbs determination may give some additional information to the follow-up of patients with DTC: the disappearance of TgAbs after therapy seems to represent a favorable prognostic factor, while the persistence of circulating TgAbs, particularly at high levels and in the absence of detectable S-Tg, may be representative of disease.

Postparathyroidectomy transient thyrotoxicosis

Three patients are described who had spontaneously resolving transient thyrotoxicosis after resection of a parathyroid adenoma without thyroidectomy or an apparent thyroid abnormality before or during surgery. All had documented thyrotoxicosis that developed within 2 weeks after surgery, which was clinically symptomatic in two of three patients. The thyrotoxicosis was associated with subnormal radioactive iodine thyroid uptake when performed in the two symptomatic patients and was consistent with a postsurgical inflammatory etiology secondary to thyroid gland trauma during parathyroidectomy. In all patients, the clinical and biochemical evidence of thyrotoxicosis resolved within 2 months. Antithyroglobulin and antimicrosomal antibodies were not detected in the two patients who had a complete recovery 3 months after surgery. However, in the patient who had autoimmune thyroiditis, hyperthyroidism due to Graves' disease subsequently developed 19 months after parathyroidectomy and was associated with increasing titers of antithyroglobulin and antimicrosomal thyroidal autoantibodies. From these observations, we conclude that 1) spontaneously resolving transient thyrotoxicosis of varying severity may occur in some patients after parathyroidectomy, which could be secondary to intraoperative thyroid gland manipulation, and 2) while the occurrence of subsequent Graves' hyperthyroidism in a patient with underlying autoimmune thyroiditis may have been a coincidence, this observation also raises the possibility that thyroidal autoantigen released during parathyroidectomy may trigger the reactivation of autoimmune thyroid disease in a predisposed subject.

Effect of human thyroglobulin on the production of platelet activating factor from peripheral blood mononuclear cells from patients with autoimmune thyroid diseases

Platelet activating factor (PAF), a phospholipid mediator, has been found to play a role in immune reactions, as well as in many pathophysiological alterations in certain disorders. To determine whether there might be a potential role of PAF in the development of autoimmune thyroid diseases (AITD) we have measured in vitro production of PAF by cultures of pokeweed mitogen-stimulated peripheral blood mononuclear cells (PBMC) obtained from 13 patients with Hashimoto's thyroiditis (HT) and 22 patients with Graves' disease (GD), as well as 18 normal control subjects. Similarly, the levels of PAF in cultures of PBMC after relevant [human thyroglobulin (Tg) and human thyroperoxidase (TPO)] antigenic stimulation in the same preparations were measured by a RIA kit. The basal values of PAF were significantly higher in the PBMC preparations from HT patients than in other two groups. In HT preparations, but not in controls, Tg antigen significantly increased the production of PAF. In GD preparations the response to Tg antigen was also present, but the release of PAF did not reach the levels in control group of preparations. Significantly lower values of PAF production were found in preparations from hyperthyroid GD when compared to the results of preparations from GD patients who were euthyroid and to the results of normal control preparations. The type of treatment and chronicity of disease may also have played some role in these findings, since those treated with radioactive iodine had lower values than those patients who became euthyroid using only antithyroid drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of thyroid function and anti-thyroid autoantibodies in systemic sclerosis

Parameters of thyroid metabolism, and the presence of anti-thyroid antibodies were investigated in 43 patients with systemic sclerosis. Anti-thyroid antibodies were detected in 14 cases. Elevated levels of anti-thyroglobulin antibodies were determined in 4 cases, anti-thyroid peroxidase (TPO) antibodies in 11, and anti-microsomal antibodies in 5. The detection of anti-TPO antibodies gave the most remarkable information about the presence of autoimmune thyroiditis. The patients with anti-TPO and/or reduced T3 concentration tended to have secondary Sjögren's syndrome. Our results provide further evidence that anti-thyroid antibodies might be responsible for the remarkable appearance of autoimmune thyroiditis in systemic sclerosis.

A case of hypothyroidism with simultaneous presence of stimulating type anti-thyrotropin (TSH) receptor antibodies and anti-thyroxine (T4) autoantibodies

We have examined a hypothyroid patient with stimulating type anti-thyrotropin (TSH) receptor antibodies and without blocking type anti-TSH receptor antibodies. Although she had high serum TSH (240 microU/ml) and low free triiodothyronine (FT3, 0.49 pg/ml) concentrations, which agree with physical findings of hypothyroidism, she had an unusually high free thyroxine (FT4) concentration (3.56 ng/dl). Incubation of her serum with 125I-T4, followed by precipitation with 12.5% polyethylene glycol (PEG) disclosed a higher binding of 125I-T4 (34.4%) than in normal controls, being 5-7%. In addition, binding of 125I-T4 to her serum gamma-globulin was completely displaced by the addition of unlabelled T4. From these results it was concluded that her serum contained anti-T4 autoantibodies. Treatment with synthetic T4 was begun and her thyroid function was monitored by sensitive TSH radioimmunoassay (RIA) and RIA of FT4 after PEG treatment. Since both sensitive TSH RIA and FT4 RIA results after PEG treatment give results concordant with the physical findings, it was concluded that both of the RIA results are useful for the evaluation of thyroid function in patients with thyroid hormone autoantibodies.

Characterization and sequencing of a 40-amino-acid peptide from human thyroglobulin inducing experimental autoimmune thyroiditis

We previously demonstrated that: a) a cytotoxic T cell hybridoma (HTC2) was able to induce lysis of syngeneic macrophages pulsed with either porcine thyroglobulin (pTg) or the tryptic fragments (TF) from pTg less than 10 kDa (M(r)) and that b) these low M(r) pTg TF included pathogenic epitopes because their injection into CBA/J mice induces thyroid lymphocytic infiltration typical of experimental autoimmune thyroiditis. Therefore the biochemical analysis of the TF preparation from pTg less than 10 kDa M(r) was undertaken and the characterized peptides were tested for their ability to be recognized or not by HTC2 cells. The sequencing of the selected peptides showed a 70% sequence homology with a portion of human thyroglobulin (hTg). The lack of a published sequence of pTg led us to synthesize a 40-amino acid peptide (F40D) similar to that portion of hTg. This F40D peptide was able to generate lymphocytic infiltrations in CBA/J mice thyroid glands, as was the native pTg molecule. Although the lymphocytic infiltrations were similar in the pTg or F40D-immunized mice, auto-antibodies to pTg or to hTg were only detectable in mice immunized with pTg. In contrast, autoantibodies levels to F40D peptide were significantly increased in serum from mice in which EAT had been induced by the F40D peptide. This highly hydrophobic peptide shows a M(r) of 4,492 kDa; it is located at the end of the second-third of the thyroglobulin molecule and up to now represents a unique sequence from the hTg molecule inducing experimental autoimmune thyroiditis.

Radioimmunoassay for ceronapril, a new angiotensin-converting enzyme inhibitor, and its application to a pharmacokinetic study in healthy male volunteers

Ceronapril is a member of a new chemical class of angiotensin-converting enzyme inhibitors being developed by The Bristol-Myers Squibb Pharmaceutical Research Institute. A radioimmunoassay (RIA) has been developed for the measurement of ceronapril in biological fluids. The RIA has a range of 0 to 500 ng/ml and has the sensitivity to detect 1.0 ng/ml of ceronapril. Satisfactory zero binding and sensitivity were obtained after a 2-h incubation at room temperature or overnight at 4 degrees C. Separation of the antibody-bound and free radiolabel was achieved by employing polyethylene glycol-goat anti-rabbit gamma-globulin separant. A quantitative recovery of the exogenous analyte was obtained at all concentrations of ceronapril tested. Intraassay coefficients of variance (CV's) were 3.9% and 4.6% for the low and medium controls, respectively. A highly significant statistical correlation between RIA and [14C]TLRC was observed for both plasma and urine samples. Clinical samples from the ascending dosage studies have been analyzed by the ceronapril RIA. The maximum concentration and the area under the plasma concentration-time curve did not increase in a dose-proportional manner for doses above 100 mg.

New antigenic clusters on human thyroglobulin defined by an expanded panel of monoclonal antibodies

Twenty-seven hybridomas secreting monoclonal antibodies (mAb) directed against new antigenic clusters on human thyroglobulin (hTg) were obtained by fusion of the mouse myeloma P3-X63-Ag8 653 with spleen cells from BALB/c mice immunized with a mixture of hTg and six anti-hTg mAb with the aim of masking the corresponding antigenic clusters previously reported. Fourteen mAb were selected, produced in ascitic fluid and characterized. All these mAb were of the IgG1 subclass. Five new antigenic clusters on the hTg molecule were defined by the 14 mAb, extending the initial antigenic map of hTg to 11 clusters. These mAb were used in an attempt to probe the interaction between hTg and the autoantibodies from patients with Hashimoto's thyroiditis who do not recognize antigenic cluster II, a cluster whose recognition by anti-hTg autoantibodies is significantly associated with thyroid disorders.

Percutaneous intranodular ethanol injection: a new treatment for autonomous thyroid adenoma

Established methods for definitive ablation of autonomous thyroid nodules are surgery and radioiodine. Since it has been demonstrated that percutaneous ethanol injection can inactivate parathyroid adenomas and small hepatocellular carcinomas, we started a trial of this treatment in patients with autonomous thyroid nodules. Twenty-eight patients, 22 toxic and 6 nontoxic, all with undetectable thyrotropin serum levels and suppressed extranodular tissue on scintigraphy, were treated. Treatment consisted of percutaneous intranodular ethanol injection under ultrasound guidance. The total amount of alcohol injected ranged from 0.4 to 2.2 times the estimated nodule volume, divided into 4 to 9 injections performed at 2 to 7 day intervals. Most patients were treated with a single cycle of injections, but 7 of them required 2 cycles. The signs and symptoms of hyperthyroidism disappeared in all cases. Apparently complete cure (normal serum free thyroid hormones, thyrotropin in basal conditions and after thyrotropin releasing hormone, reactivation of extranodular tissue on scintigraphy with nodule no longer visible) was obtained in 17 patients (13 after 1 cycle and 4 after 2 cycles). Partial cure (normal serum free thyroid hormone levels, detectable thyrotropin levels with normal or blunted response to thyrotropin releasing hormone and partial reactivation of extranodular tissue on scintigraphy with nodule or parts of it still visible) was obtained in 10 patients (8 after 1 cycle and 2 after 2 cycles). In 1 patient with a very large nodule thyrotropin levels remained undetectable, but thyroid hormone levels eventually became normal. No recurrences were observed after a follow-up of 12 to 32 months (mean 20 months). No serious side effects were encountered. A clinically valuable result was obtained in all patients. These data suggest that this form of treatment could constitute an alternative to surgery and radioiodine for the ablation of autonomous thyroid nodules.

Conserved natural humoral immunity to thyroglobulin in patients with multiple myeloma

We studied humoral immunity to human thyroglobulin (hTg) during the course of multiple myeloma (MM). In this report, we describe the anti-hTg antibody activity in the sera of patients with MM. Among 63 sera tested, 28 (44%) had IgG anti-hTg autoantibodies (aAb), 16 (25%) exhibited IgM aAb, and six (9%) had IgA anti-hTg aAb. For the majority of sera the anti-hTg autoantibody activity was associated with more than one immunoglobulin class. IgG anti-hTg antibodies were observed in 9/11 patients with IgA MM and in 19/40 patients with IgG MM. The IgM anti-hTG antibody activity was found in the sera of 11 patients with IgG MM. These results show that the anti-hTg activity in these patients is associated with residual polyclonal immunoglobulins. However, in the serum of one patient presenting a double monoclonal gammopathy (IgG and IgA lambda MM), the anti-hTg activity was carried by both the IgG lambda and the IgA lambda molecules, suggesting that in this case the activity was due to the monoclonal immunoglobulin itself. We also studied the epitopic specificity pattern of all these anti-hTg aAb. Only three sera recognized one antigenic region on hTg, suggesting that the majority of the anti-hTg aAb in MM patients were directed against antigenic regions other than those recognized by our panel of murine mAb. In conclusion, our results demonstrated that humoral immunity to hTg is maintained in MM patients. These data contrast with the well-documented suppression of immunity to foreign, especially bacterial, antigens described in MM.

The sonographic appearances in postpartum thyroiditis

During the postpartum period about 50% of women with circulating thyroid autoantibodies develop a transient autoimmune thyroiditis. To determine the sonographic appearances in postpartum thyroiditis (PPT), serial ultrasound (US) scans of the thyroid were performed in 135 postpartum women who were divided into three clinical groups: Group 1, 37 antibody positive subjects who developed PPT; Group 2, 28 antibody positive subjects in whom thyroid function remained normal; Group 3, 70 antibody negative controls. Thyroid hypoechogenicity was observed in 14/31 patients (45%) who were scanned between 4 and 8 weeks postpartum and who subsequently developed PPT (Group 1) compared with 4/24 patients (17%) in Group 2 (P less than 0.05) and 1/65 patients (1.5%) in Group 3 (P less than 0.001). In antibody positive patients, the positive predictive value of an abnormal scan during this period was 78%. Between 15 and 25 weeks postpartum thyroid hypoechogenicity was present in 32/37 patients (86%) in Group 1 compared with 11/28 patients (39%) in Group 2 (P less than 0.001) and 2/70 patients (3%) in Group 3 (P less than 0.001). Sonographic abnormality persisted beyond 32 weeks postpartum in 36/41 antibody positive patients (87%) who had exhibited thyroid hypoechogenicity earlier during the study and who had late scans. The characteristic US appearance in PPT is thyroid hypoechogenicity. The role of sonography in the prediction, diagnosis and follow up of patients with PPT is discussed.

The forces driving autoimmune disease

There are two classes of autoimmune disease, organ-specific and non-organ specific or systemic. That cells producing autoantibodies are selected by antigen is strongly suggested by the presence of mutations and high affinity antibody. T-cells are pivotal in all forms of autoimmunity as evidenced by the therapeutic benefit of anti-T-cell monoclonals such as anti-CD4, and the frequent development of high affinity IgG autoantibodies. The production of anergic T-cells by the use of non-depleting anti-CD4 in the presence of antigen is discussed with particular reference to its potential for immunological intervention in autoimmune disease. It is possible to identify T-cell epitopes in organ-specific autoimmunity using pathogenic T-cell clones or hybridomas to identify the peptide sequences which are reactive. Antigen-specific therapy may ultimately be based on such peptide epitopes. The specificity of the T-cells in systemic autoimmunity is still obscure, but there is some evidence that reactivity with certain germ-line idiotypes can lead to the development of systemic autoimmunity. The possibility of stimulating B-cells specific for auto-antigens such as DNA becomes feasible if a complex of antibody and DNA is taken up by these specific B-cells and processed idiotype is presented to T-helpers specific for those idiotype epitopes. Evidence is presented that there may be pre-existing defects in the target organ in certain organ-specific disorders, and the evidence for a glycosylation defect in the IgG in patients with rheumatoid arthritis is explored. It is noted that the spouses of probands with rheumatoid arthritis is explored. It is noted that the spouses of probands with rheumatoid arthritis also tend to have this glycosylation defect and this raises the possibility of an effect due to an environmental factor, such as a microbial infection. Molecular mimicry of autoantigens by microbes can stimulate autoreactive cells by their cross-reactivity. It is emphasized that cross-reaction which gives rise to the priming of autoreactive T-cells could give rise to the establishment of a chronic autoimmune state. In animals with normal regulatory immune systems, such induced autoimmunity is ultimately corrected and it is only in animals where there are defects in regulation, that autoimmunity persists. Thus, there are many factors giving rise to autoimmunity, and the diseases are rightly regarded as multifactorial in origin.

Prevalence of autoantibodies to thyroglobulin, thyroxine, or triiodothyronine and relationship of autoantibodies and serum concentrations of iodothyronines in dogs

Assays were developed to detect and measure autoantibodies (AA) to thyroglobulin (Tg) and to the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). An ELISA to detect AA to Tg was developed, using purified canine Tg as the antigen and goat anti-canine IgG conjugated with alkaline phosphatase as the second antibody. A highly charged agarose electrophoresis assay was used for determination of AA to T4 and T3. Sera from dogs (n = 119) with clinical signs consistent with hypothyroidism were tested for AA to Tg, T4, and T3. Autoantibodies to at least 1 of the 3 thyroid antigens were detected in 58 of the 119 (48.7%) sera tested. Autoantibodies to Tg were detected more frequently in samples with low serum concentrations of thyroid hormones than in samples with normal concentrations. The presence of AA to T4, T3, or both was not significantly associated with low thyroid hormone concentrations, but this lack of association may have been attributable to binding of AA in the measurement of thyroid hormones by radioimmunoassay.

A major human thyroglobulin epitope defined with monoclonal antibodies is mainly recognized by human autoantibodies

The antigenic nature of 15 anti-human thyroglobulin (hTg) monoclonal antibody (mAb) epitopes was studied by two different approaches. First, we tested two successive protease-digest products of hTg. Only four mAb from the same cluster of reactivity recognized a low-molecular weight peptide, the other mAb only bound native hTg or high-molecular weight digest fractions. Second, these 15 mAb were used to immunoscreen hTg expression libraries. Only the same four mAb revealed immunoreactive clones corresponding to region 1149-1295 on the hTg primary sequence. After subcloning, this antigenic determinant was reduced to a 102-amino acid peptide (hTg region 1149-1250). The two different methodologies were coherent and complementary, and demonstrated that hTg sequence 1149-1250 is the target for this cluster of four mAb. Moreover, anti-hTg autoantibodies which cross-reacted with these mAb bound the 102-amino acid peptide. This epitope was the one most frequently detected by sera from autoimmune thyroid disease. The data confirm the presence of an immunodominant domain in the central part of the hTg molecule and suggest that this mAb epitope may be a powerful probe for the diagnosis of autoimmune thyroid disorders.

Immunity to self-antigens in periodontal disease

Auto-antibody to collagen, previously detected in periodontal disease, may represent either a response to local tissue damage or be the manifestation of a disturbance of the host immune response induced by the periodontal flora and its products. In an effort to distinguish between these two hypotheses, this study was undertaken to determine circulating IgG auto-antibody levels in 41 periodontal-disease patients against 12 self-antigens (salmon DS-DNA, calf SS-DNA, human and bovine thyroglobulin, rabbit proteoglycan, horse myoglobin, bovine myosin, actin, fetuin, human transferrin, cytochrome C, and human Type I collagen) and compare them to those in 21 periodontal disease-free subjects. None of the detected IgG auto-antibody levels were significantly different between periodontal disease and control sera (Mann-Whitney U-test, P greater than 0.05) except for human Type I collagen (P less than 0.05). Fifty-six percent of patients and 38% of controls were "broad responders;" i.e., 50% or more of the auto-antibody levels were higher than the median values of the control group; however, these values were not significantly different using the chi-square test. It was concluded that the destruction of connective tissue components is the primary driving force in the induction of the enhanced auto-antibody response found in periodontal disease. This response is apparently secondary to the primary bacterial infection which remains the major etiologic event.

The evolution of Graves' ophthalmopathy during treatment with antithyroid drug alone and combined with triiodothyronine

We analyzed the evolution of the ophthalmopathy associated with Graves' hyperthyroidism in 45 patients treated with two different antithyroid drug regimens. Group A patients (n = 31) received either methimazole (40-100 mg daily) or propylthiouracil (400-900 mg daily) combined with T3 daily throughout treatment. Group B patients (n = 14) were treated with conventional regimen with lower doses of either methimazole (5-25 mg daily) or propylthiouracil (50-300 mg daily) and no T3 addition. Eye signs and proptosis measurement were evaluated just before the beginning of the treatment and compared with the results after antithyroid drug withdrawal. Improvement of the eye signs considered on grounds of the NOSPECS classification was greater in group A than group B (p less than 0.01). Also, the decrease in proptosis measurement was greater (p less than 0.01) in patients treated with combined regimen (21.5 +/- 2.4 mm to 20.4 +/- 2.3 mm) than in patients receiving conventional therapy (20.4 +/- 1.6 mm to 20.0 +/- 1.7 mm). Serum thyroglobulin concentrations did not correlate with either the severity or the evolution of the ophthalmopathy. Negative serum antithyroglobulin antibody (TgAb) was associated with the improvement of the ophthalmopathy that was noted in 24 out of 27 patients (Chi-Square = 5.84; p less than 0.001). Thus, serum TgAb levels might have some connection with progression of eye signs but serum Tg concentration does not. Our study suggests that in most patients the transition from hyperthyroidism to euthyroidism induced by antithyroid drug therapy is associated with the improvement of the Graves' ophthalmopathy. However, no marked difference can be drawn between the two treatment regimens.

[Primary hypothyroidism in normal thyroid gland morphology]

A 25 year old patient developed hypothyroidism with antibodies against thyroglobulin, thyroid microsomes and thyrotropin receptors. Thyroid 99m-technetium-uptake was 0%. Ultrasound investigation revealed a normal sized, homogenous thyroid gland. Histology showed lymphocyte infiltration but regular follicles. These results suggest the cause of hypothyroidism to be thyrotropin inhibiting immunoglobulins with no parenchyma-destroying properties.

Thyroid peroxidase antibodies in children with autoimmune thyroiditis

AIMS

To compare the prevalence of thyroid peroxidase antibodies in 25 children with autoimmune thyroid disorders and in 41 children and young adults with type 1 diabetes, and to test the prevalence of thyrotropin receptor antibodies.

METHODS

Two commercially available radioimmunoassays for antibodies to thyroid peroxidase, a commercially available agglutination test of particles coated with thyroid microsomal antigens, and a radioimmunoassay for thyrotropin receptor antibodies were used. Patients and controls were studied.

RESULTS

One of the radioimmunoassays detected thyroid peroxidase antibodies not only in all children with autoimmune thyroid disorders and children and young adults with type 1 diabetes and thyroid microsomal antibodies, but also in 20% of healthy control children without microsomal antibodies. With this thyroid peroxidase assay and with microsomal agglutination, 94% of the children with autoimmune thyroiditis, 71% of those with Graves' disease, and over 90% of those with type 1 diabetes and thyroid dysfunction tested positive. In the other radioimmunoassay for thyroid peroxidase antibodies thyroid peroxidase antibody titres in half or more of the children with microsomal antibodies failed to reach the level of positivity given by the producers. Eighty five percent of children with Graves' disease and 71% of those with autoimmune thyroiditis had thyrotropin receptor antibodies but so did 35% of children studied for other endocrinological disorders such as delayed growth or puberty.

CONCLUSIONS

Testing patients with well characterised disorders of thyroid function and with other endocrine disorders is important in evaluating the efficacy of new diagnostic tests for thyroid autoantibodies.

[Role of immune complexes in thyroid diseases]

To elucidate the immune complex (thyroglobulin-antibody, Tg-Ab) role in thyroid hormone formation, in vitro iodination of Tg--AB immune complex, bovine intact Tg and that of the patient with euthyroid goiter and partially purified AB to Tg were studied. We compared the amount of iodamine acids (MIT, DIT, T4/mole of Tg) forming during iodination in immune complex with other samples. The results suggest that Tg being in complex with antibodies (up to 30-40 mole of antibodies/mole of Tg) is iodinated forming the enough amount of MIT, decreased amount of DIT and T4. A MIT fraction increase is connected with additional iodination of complex antibodies. We suggest that such processes may take place in the patient body and be involved in pathogenesis of thyroid disease.

Protection from experimental autoimmune thyroiditis conferred by a monoclonal antibody to T cell receptor from a cytotoxic hybridoma specific for thyroglobulin

A clonotypic mAb, AG7, has been prepared from splenocytes of CBA/J mice immunized with a cytotoxic T cell hybridoma, HTC2, specific for a pathogenic epitope of the thyroglobulin molecule in association with class I MHC Ag. AG7 binds to HTC2 cells but not to the other T cell hybridomas tested. Moreover, when used in functional studies, AG7 blocks the HTC2 capacity of specific target lysis. It also reacts with a determinant that comodulates with the CD3 Ag present on the surface of HTC2 cells. Immunoprecipitation of 125I-labeled solubilized HTC2 membranes demonstrated two bands located at 90 and 72 kDa under nonreducing conditions, which became a 46-kDa band under reducing conditions. Finally, when AG7 is injected into CBA/J mice, on day -1 before immunization with the pathogenic tryptic fragments of the thyroglobulin molecule, experimental autoimmune thyroiditis is abrogated. Thus, one of the multiple potential mechanisms of the protective immunity against EAT induced by HTC2 cells that we previously proposed, i.e., the generation of anti-clonotypic antibodies to HTC2 TCR, seems apparent.