Suppressor T-lymphocyte deficiency in Graves' disease and Hashimoto's thyroiditis.

The involvement of cell-mediated immunity in the pathogenesis of Graves' disease (GD) and Hashimoto's thyroiditis (HT) was investigated by employing a modified migration inhibition factor test using preparations of isolated T-lymphocytes. The migration of T-lymphocytes from patients with GD and HT in response to crude human thyroid antigen was significantly inhibited compared to the migration of T-lymphocytes from normal subjects. This response was organ specific. When normal T-lymphocytes were mixed with GD or HT T-lymphocytes in ratios varying from 1:9 to 1:1, the migration inhibition activity of the GD or HT T-lymphocytes in response to thyroid antigen was abolished, but was not abolished when two different GD or HT T-lymphocyte preparations were mixed. Mitomycin C inhibited this suppressive effect of normal T-lymphocytes in vitro, but did not influence the migration inhibition activity of the antigen-sensitized GD or HT T-lymphocytes. On the other hand, the migration inhibition of GD and HT T-lymphocytes was prevented by puromycin. There thus appears to be activity in normal T-lymphocytes which can suppress the ability of GD and HT T-lymphocytes to respond to the thyroid antigen, which is lacking in the GD and HT T-lymphocytes themselves. Our results are consistent with the hypothesis that there is a defect in suppressor T-lymphocyte function in GD and HT.

Correlation between thyrotropin-displacing activity and human thyroid-stimulating activity by immunoglobulins from patients with Graves' disease and other thyroid disorders.

Several reports have been published on the anti-TSH receptor antibody in putative autoimmune thyroid disorders using a radioreceptor assay. We have carried out correlative studies between the ability of serum immunoglobulins to displace radiolabeled TSH from the thyroid plasma membrane receptor [TSH-displacing activity (TDA)] and that of actual stimulation of the human thyroid gland [human thyroid-stimulating activity (hTSA)] in Graves' and other thyroid diseases and in control subjects. TDA was assayed by the use of a radioligand technique, while the activation of adenylate cyclase in human thyroid slices was measured as an index of hTSA. The same immunoglobulins were employed for both assays. In this series, positive TDA and hTSA values were found in 70.4% and 81.5% of the samples in active untreated Graves' disease, respectively. Samples from normal persons and from several patients with toxic nodular goiter gave generally negative results in both assays; in a small proportion of patients with either subacute thyroiditis or Hashimoto's thyroiditis, the TDA was positive but hTSA proved to be negative. In Graves' disease (including those patients on propylthiouracil) in remission and treated with 131I, the correlation between TDA and hTSA was not significant (r = 0.309; P greater than 0.1); even when the procedures were compared in the untreated group alone, there was no significant correlation between the two activities (r = 0.309, P greater than 0.1). These studies indicate that 1) significant TDA and hTSA are observed in Graves' disease; nevertheless, the correlation between them is not significant; 2) the hTSA assay appears to be more sensitive and specific than the TDA assay; and 3) TDA may not be synonymous with thyroid stimulation.

T-lymphocyte sensitization in Graves' and Hashimoto's diseases confirmed by an indirect migration inhibition factor test.

T-Lymphocyte sensitization in Graves' disease (GD) and Hashimoto's thyroiditis (HT) was studied by an indirect migration inhibition factor test using normal T-lymphocytes as second stage indicator cells. In the first stage, mononuclear cells or T-lymphocytes, fractionated by the standard Ficoll-Hypaque procedure from the blood of patients with untreated GD and HT, were cultured in Eagle's medium containing thyroid antigen, and their cell-free supernatants were saved. Normal T-lymphocytes as second stage indicator cells were packed in capillary tubes and placed in planchettes with the above supernatants to complete the indirect migration inhibition factor test. Inhibition of the migration of indicator T-lymphocytes was demonstrated when either GD or HT culture supernatants were employed. Moreover, there was a good correlation between the indirect using the culture supernatants and the direct migration inhibition factor test using mononuclear cells or T-lymphocytes. On the other hand, in both direct and indirect migration inhibition factor tests using mononuclear cells and mononuclear cell culture supernatants, respectively, in the presence of human liver antigen as a nonspecific antigen, there was no significant difference between controls and patients. From these results, we can conclude that GD and HT T-lymphocytes are sensitized to thyroid antigen and produce the lymphokine, migration inhibition factor, into the supernatant when exposed to this antigen.

Induction of thyroid autoantibody production: synergistic effect of B cell mitogen combined with T cell mitogen.

In vitro production of thyroglobulin autoantibodies (TgAb) and thyroid microsomal autoantibodies (McAb) by peripheral blood mononuclear cells (PBMC) stimulated with the B cell mitogen Staphylococcus aureus Cowan I (SAC) and the T cell mitogen pokeweed mitogen (PWM) was examined in 35 normal subjects (NC) and 64 patients with autoimmune thyroid disease (AITD) using an enzyme-linked immunosorbent assay technique. Low concentrations of SAC plus PWM resulted in a synergistic effect on thyroid autoantibody production as well as nonspecific immunoglobulin G production. With such maximal stimulation, TgAb production was detected in all PBMC preparations from serum TgAb-positive patients with AITD; TgAb production was also detected in some NC (46%) and serum TgAb-negative patients with AITD (39%), but the levels of TgAb production were low. Similarly, McAb production was marked in PBMC preparations from serum TgAb-negative but McAb-positive patients. TgAb-secreting cells were also detected in NC by the plaque-forming cell (PFC) assay. The response patterns of PBMC to mitogen (Nil, PWM, and SAC plus PWM) in terms of TgAb production varied among serum TgAb-positive patients with AITD, but not among NC and serum TgAb-negative patients with AITD. Serum TgAb titers were significantly correlated with the in vitro production of TgAb by PBMC with no stimulation (r = 0.64; n = 99; P less than 0.001), with stimulation by PWM (r = 0.75), and with stimulation by SAC plus PWM (r = 0.87); the correlation coefficient increased with the efficiency of stimulation of B cell differentiation. Similar results were found for McAb production. These data suggest that 1) optimal in vitro thyroid autoantibody production occurs with B cell mitogen (SAC) acting synergistically with T cell mitogen (PWM); 2) sufficient numbers of resting B lymphocytes specific for Tg or microsomal antigens are present in some NC PBMC; 3) stages of thyroid-specific B cell differentiation in PBMC vary among serum thyroid autoantibody-positive patients with AITD; and 4) the potential of PBMC to produce thyroid autoantibodies may correlate with the capacity of thyroid-derived lymphocytes. Thus, the circulating lymphocytes may provide a useful vehicle by which sequential changes occurring at the tissue level may be examined.

Studies of HLA-DR expression on cultured human thyrocytes: effect of antithyroid drugs and other agents on interferon-gamma-induced HLA-DR expression.

There have been conflicting reports on whether antithyroid drugs (ATD) act as immunosuppressive agents in patients with autoimmune thyroid disease. While some have claimed that methimazole (MMI) affects the immune system directly, we and others have suggested that its apparent immunosuppressive activity is due to its ability to inhibit thyrocyte, rather than immunocyte, activity. To further address the question, we studied the action of ATD on interferon-gamma (IFN gamma)-induced HLA-DR expression on thyrocytes in tissue culture. We used a cytotoxicity assay, using chromium-51-labeled Graves' disease (GD) thyrocytes and normal thyrocytes incubated sequentially with a monoclonal antibody against HLA-DR and complement, with a cytotoxicity index as the measure of thyrocyte HLA-DR expression. MMI and propylthiouracil (PTU) were added along with 200 U/mL IFN gamma to thyrocytes cultured for 10-14 days. IFN gamma or supernatants from leukoagglutinin-stimulated peripheral blood mononuclear cells (PBMC) stimulated thyrocyte HLA-DR expression; however, the addition of MMI or PTU to either the PBMC or thyrocytes caused no inhibition of the IFN gamma or PBMC IFN gamma stimulation of thyrocyte HLA-DR expression, using either normal or GD thyrocytes. Potassium perchlorate and sodium iodide also had no effect on IFN gamma-induced thyrocyte HLA-DR expression. TSH (either bovine or human) did not induce HLA-DR expression on thyrocytes by itself, but did enhance IFN gamma-induced HLA-DR expression in normal, but not GD, thyrocytes; once again, the further addition of MMI or PTU did not inhibit the enhancing effect of TSH on thyrocyte HLA-DR expression. Low concentrations of TSH binding inhibitory immunoglobulin (TBII; 100 micrograms/mL) did not alter the cytotoxicity index, but at 400 micrograms/mL or more it enhanced HLA-DR expression on normal, but not GD, thyrocytes in a manner similar to TSH; like TSH, it did not induce thyrocyte HLA-DR expression by itself. Moreover, addition of MMI to the combination of IFN gamma and TBII did not inhibit the response of thyrocytes in terms of HLA-DR expression. We conclude that ATD do not alter thyrocyte HLA-DR expression in vitro; however, the ATD may still cause immune effects in vivo secondary to their influence on thyroid hormone formation or synthesis or by inhibition of thyroid antigen presentation which indirectly may result in an immunomodulatory effect. While TSH and TBII similarly enhanced the IFN gamma-induced expression of HLA-DR on normal thyrocytes, they did not do so in GD thyrocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Nontoxic nodular goiter and papillary thyroid carcinoma are not associated with peripheral blood lymphocyte sensitization to thyroid cells.

We tested the claim that uni- and multinodular goiter (UNG and MNG) and papillary carcinoma (PC) of the thyroid are autoimmune thyroid diseases (AITD) similar to Graves' disease (GD) and Hashimoto's thyroiditis (HT). The expression of HLA-DR on cultured thyroid epithelial cells (thyrocytes) from UNG, MNG, and PC after coculture with autologous peripheral blood mononuclear cells (PBMC) was compared with that on GD and HT cells. The thyrocytes also were cultured with interferon-gamma (IFN gamma) alone. A cytotoxicity assay involving 51Cr-labeled thyrocytes, anti-HLA-DR, and complement was used to determine HLA-DR expression. Stimulation of thyrocytes with 200 U/mL IFN gamma induced HLA-DR (expressed as a cytotoxicity index) equally well on all thyrocytes [AITD (n = 6): IFN gamma, 23.8 +/- 7.7 (+/- SD); unstimulated, 3.6 +/- 2.0; UNG (n = 6), MNG (n = 9), and PC (n = 5): IFN gamma, 22.5 +/- 4.7; unstimulated, 4.0 +/- 3.0]. When cocultured with autologous PBMC, the values were: AITD, 24.9 +/- 10.1; UNG, MNG, and PC, 3.8 +/- 3.7 (P less than 0.001). The supernatants from the AITD cocultures had higher IFN gamma concentrations (by RIA) than those from the other cocultures. We conclude that in UNG, MNG, and PC, the peripheral blood helper T-lymphocytes are not sensitized to thyrocyte membrane antigen(s); consequently, little if any IFN gamma is produced in cocultures, and hence, there is no increase in thyrocyte HLA-DR expression, unlike the situation in AITD (GD and HT). Thus, UNG, MNG, and PC are not primarily autoimmune in nature, as defined by a lack of sensitization of the PBMC of such patients to thyroid antigen(s).

Thyroid antigen stimulates lymphocytes from patients with Graves' disease to produce thyroid-stimulating immunoglobulin (TSI).

Circulating lymphocytes from patients with Graves' disease and from control subjects were cultured in vitro alone, with normal human thyroid tissue homogenates, and with other nonthyroid human tissue homogenates. The supernatants of these cultures were assayed for human thyroid-stimulating activity by incubation with human thyroid slices in which increases in cAMP levels were then measured. Human thyroid stimulator activity was demonstrated in 16 out of 20 experiments in which lymphocytes from patients with active untreated Graves' disease (with hyperthyroidism) were cultured with normal thyroid homogenate, in 4 out of 17 experiments when control lymphocytes were similarly cultured, and in one out of 12 experiments in which the lymphocytes from the patients with Graves' disease were cultured with liver or gastric mucosa homogenate. Thyroid-stimulating activity was abolished by precipitation of the globulin from the supernatant by goat anti-human globulin serum. These results demonstrate that normal human thyroid tissue homogenates can specifically stimulate most lymphocytes from patients with Graves' disease and lymphocytes from a few normal subjects to produce human thyroid-stimulating immunoglobulins in vitro. This suggests that the human thyroid-stimulating immunoglobulins are auto-antibodies to normal thyroid constituents, but the possiblity that an antigenic change in the thyroid initiates the disease cannot be entirely excluded. The findings suggest that the prime change in Graves' disease is immunologic, perhaps a failure of immunological suppression.

Thyrocyte HLA-DR expression and interferon-gamma production in autoimmune thyroid disease.

We examined the expression of HLA-DR antigen induced by mitogen, mitogen-free supernatants from mitogen-stimulated peripheral blood mononuclear cells (PBMC), or autologous and allogeneic PBMC on thyrocytes cultured for 1-2 weeks (precultured) before the addition of the stimulant. Leucoagglutinin (LAG) and concanavalin A, but not lipopolysaccharide induced HLA-DR expression on thyrocytes from normal subjects (NC) and patients with Graves' disease (GD) and Hashimoto's thyroiditis (HT). The degree of DR expression induced by LAG was significantly less in GD than in NC thyrocytes. This response was dependent on contaminating T cells, especially suppressor-cytotoxic T (Ts/c) cells, NK cells, and HLA-DR+ cells, but not helper-inducer T (Th/i) cells or B cells, in the thyrocyte cultures. OKT3 monoclonal antibody, which activates T cells specifically in the presence of monocytes, also induced thyrocyte HLA-DR expression. Furthermore, interferon-gamma (IFN-gamma) was detected in culture supernatants from LAG-stimulated thyrocytes. Anti-IFN-gamma monoclonal antibody eliminated the ability of LAG to induce HLA-DR. Mitogen-free supernatants from mitogen-stimulated PBMC also induced thyrocyte HLA-DR expression, which was inhibited by anti-IFN-gamma. The supernatants of concanavalin A- or LAG-stimulated PBMC from either untreated or recently treated patients with GD or hypothyroid HT induced less thyrocyte DR expression than NC PBMC. Indeed, the levels of IFN-gamma in supernatants from such patients were lower than those in NC, and the correlation between DR expression and IFN-gamma levels was significant. This IFN-gamma production by PBMC required Th/i cells, NK cells, and HLA-DR+ cells. Before the addition of autologous or allogeneic PBMC, only precultured HT thyrocytes expressed HLA-DR, whereas GD and NC thyrocytes did not. The induction or enhancement of DR expression on autologous thyrocytes by direct coculture with PBMC occurred within 8 days in GD and HT, but not in NC. There was a significant correlation between the serum titer of antithyroid microsomal antibodies and the degree of DR expression. Allogeneic normal PBMC also induced DR expression on NC and GD thyrocytes within 8 days, the effect on the latter being more pronounced than with autologous GD PBMC. Thyrocyte HLA-DR expression induced by autologous GD PBMC and allogeneic normal PBMC required monocytes. Th/i, and NK cells and was blocked by anti-IFN-gamma. However, the enhancement of thyrocyte DR expression by autologous HT PBMC did not require monocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Thyroid-stimulating hormone (TSH) binding to extrathyroidal human tissues: TSH binding to extrathyroidal human tissues: TSH and thyroid-stimulating immunoglobulin effects on adenosine 3',5'-monophosphate in testicular and adrenal tissues.

Binding of [125I]bovine TSH to human thyroid, testicular, fat, adrenal, liver, kidney, pancreas, and lung cell membranes has been studied. The first four tissues were found to have comparable high affinity constant values; the rest of the tissues lacked high affinity sites. With the exception of fat tissue, the capacities of the high affinity sites of the first four tissues were similar. Bovine TSH concentrations of 100-20,000 microIU/ml stimulated increased cAMP production in human cryopreserved testicular slices. Forty percent of the specimens of thyroid-stimulating immunoglobulin (TSI) from Graves' disease sera also increased human testicular cAMP production. In addition, bovine TSH caused a significant rise in cAMP in the whole decapsulated rat testis. Twenty-five percent of the TSI specimens tested also induced such responses. The rat adrenal gland responded with increased cAMP production to concentrations of 1,000 microU/ml bovine TSH. The physiological significance of high affinity bovine TSH and TSI binding and subsequent cAMP production in nonthyroidal tissues in not known. However, since these stimulators are present in hypothyroidism and hyperthyroidism, respectively, it is possible that the pathophysiological effects of this binding could be of some importance.

Effect of human chorionic gonadotropin on human thyroid tissue in vitro.

Thyroid stimulating substances other than TSH have been found in certain disease states associated with hyperthyroidism. The thyroid stimulator associated with the thyrotoxicosis of trophoblastic disease is uncertain; however, recent evidence suggests a role for hCG. To explore the thyroid stimulating properties of hCG further, we examined the ability of hCG to displace [1252]TSH from receptors on human thyroid membrane and to generate cyclic-AMP (c-AMP) from human thyroid slices. Human chorionic gonadotropin at a concentration of 40 IU/ml displaced labeled TSH from human thyroid membranes and, at a concentration of 69 IU/ml, hCG caused the generation of c-AMP in thyroid slices. These results suggest that hCG can bind to the TSH receptor on thyroid cells and can stimulate them to produce c-AMP at concentrations of hCG within the range that is found in trophoblastic disease.

Suppressor T lymphocyte dysfunction in Graves' disease: role of the H-2 histamine receptor-bearing suppressor T lymphocytes.

The allo-suppressor effect of normal T lymphocytes on the production of migration inhibition factor by sensitized T lymphocytes of Graves' disease in response to human thyroid antigen has been studied further by a modified migration inhibition factor test employing purified T lymphocyte preparations. The production of migration inhibition factor was consistently abolished when normal T lymphocytes were mixed with the Graves' disease lymphocytes in various ratios (1:9, 2:8, and 5:5). However, pretreatment of the normal T lymphocytes with cimetidine (an H-2 histamine receptor antagonist) led to a demonstrable loss in their allo-suppressor properties, whereas pretreatment with chlorpheniramine (an H-1 histamine receptor antagonist) had no such effect. These studies indicate that a subset of normal T lymphocytes bearing H-2 histamine receptors suppresses the production or release of migration inhibition factor by sensitized T lymphocytes, and further suggest the possibility that there may be an abnormality in the H-2 receptors on Graves' disease suppressor T lymphocytes. It is conceivable that this defect is fundamental in the pathogenesis of Graves' disease.

Separate induction of MHC and thyroid microsomal antigen (McAg) expression on thyroid cell monolayers: enhancement of lectin-induced McAg expression by interferon-gamma.

Interferon-gamma (IFN gamma) induced the expression of the MHC class II antigens HLA-DR and -DQ on 1- to 2-week-old thyrocytes from normal thyroid tissue and thyroid tissue from patients with autoimmune thyroid disease; it also enhanced the expression of B2-microglobulin, which is associated with MHC class I molecules. However, the expression of thyroglobulin and thyroid microsomal antigen (McAg) was not detected after IFN gamma stimulation. Autologous and allogeneic peripheral blood mononuclear cells had the same ability as IFN gamma to induce antigen expression when cocultured with thyrocytes. In contrast, leucoagglutinin (LAG) induced McAg as well as HLA-DR and B2-microglobulin expression on thyrocytes, but not thyroglobulin expression. Concanavalin A and pokeweed mitogen also induced McAg expression. The time course of LAG induction of McAg was not always correlated with that of HLA-DR. Anti-IFN gamma, antiinterleukin-2 receptor, and anti-HLA-DR monoclonal antibodies inhibited LAG or peripheral blood mononuclear cell induction of HLA-DR expression, but not LAG induction of McAg expression. Anti-HLA-DR reduced the IFN gamma induction of HLA-DR. INF gamma enhanced thyrocyte McAg expression induced by LAG, especially when thyrocytes were incubated with IFN gamma for 24 h before LAG stimulation. In contrast, in the absence of LAG stimulation, IFN gamma suppressed already present spontaneous McAg expression. TSH did not induce McAg and HLA-DR expression on DR-negative thyrocytes, but enhanced weak DR expression induced by other stimulants, e.g. IFN gamma or lectins. These data suggest that in vitro induction mechanisms of MHC class I and II antigens and McAg are different; MHC antigens are induced by IFN gamma, whereas McAg is induced by lectin, probably acting on thyrocytes directly; and IFN gamma has an enhancing effect on LAG-induced thyrocyte McAg expression.

In vitro induction of anti-thyroid microsomal antibody-secreting cells in peripheral blood mononuclear cells from normal subjects.

Secretion of immunoglobulin G (IgG) and IgM antithyroid microsomal antibodies (AMA) was induced in vitro by coculturing non-T cells (B lymphocytes) and autologous CD4 (helper/inducer) cells from normal subjects stimulated with pokeweed mitogen (PWM) or a combination of human thyroid microsomal antigen (McAg) and Staphylococcus aureus Cowan I (SAC) strain. With PWM stimulation, AMA production was induced in more IgM-secreting cells (AMA-M) than IgG-secreting cells (AMA-G). However, McAg plus SAC stimulation resulted in similar numbers of AMA-G- and AMA-M-secreting cells. PWM induced a significantly greater number of both AMA-M (and generalized IgM)-secreting cells than did McAg plus SAC, while the number of AMA-G-secreting cells induced by the two stimuli were similar. There were no significant differences between autologous or allogeneic CD4 cells from normal subjects or patients with autoimmune thyroid disease (AITD) when cocultured with B cells from normal subjects in terms of helper activity in the induction of AMA-M- or IgM-secreting cells with PWM stimulation. However, with McAg plus SAC, CD4 cells from patients with AITD induced a significantly greater number of AMA-M-secreting cells than did autologous or allogeneic CD4 cells from normal subjects. There was no difference in helper activity between autologous and allogeneic normal CD4 cells in the induction of generalized IgM-secreting cells regardless of the stimulus used. Normal autologous or allogeneic CD8 (suppressor/cytotoxic) cells cocultured with normal B cells and autologous CD4 cells suppressed the induction of AMA-M-secreting cells by PWM stimulation. On the other hand, CD8 cells from patients with AITD suppressed the induction of AMA-M-secreting cells significantly less effectively. All CD8 cells suppressed the induction of IgM-secreting cells equally well. We conclude that 1) B lymphocytes from normal subjects are capable of producing autoantibodies in vitro in the presence of CD4 cells; 2) the helper activity of CD4 cells from patients with AITD to induce AMA-M secreting cells is greater than that of normal CD4 cells with thyroid antigen stimulation; and 3) this helper activity may be due to relatively impaired suppressor activity in thyroid antigen-specific CD8 cells from patients with AITD, whereas the immunoregulatory function of CD8 cells from normal subjects appears to play an important role in the maintenance of self-tolerance.

Studies of the effect of suppressor T lymphocytes on the induction of antithyroid microsomal antibody-secreting cells in autoimmune thyroid disease.

The suppressor function in CD8 (suppressor/cytotoxic) T lymphocytes from patients with autoimmune thyroid disease and normal subjects has been studied. CD8 and CD4 (helper/inducer) cells were separated by the panning method. Patient's non-T cells and autologous CD4 cells were cultured with or without autologous or allogeneic CD8 cells in the presence of either pokeweed mitogen or Staphylococcus aureus strain Cowan 1 plus human thyroid microsomal antigen. Antithyroid microsomal antibody (AMA) and total immunoglobulin G (IgG)-secreting non-T cells were measured by enzyme-linked immunosorbent spot assay. With pokeweed mitogen stimulation, the suppressor effect of CD8 cells from patients with serum AMA on the induction of AMA (of IgG type)-secreting cells was significantly less than that of CD8 cells from normal subjects. CD8 cells from patients with no serum AMA suppressed the induction of AMA-secreting cells as much as did normal CD8 cells. CD8 cells from both patients and normal subjects suppressed the induction of IgG-secreting cells equally well. On the other hand, with the combination of S. aureus strain Cowan 1 and human thyroid microsomal antigen (1 mg/L) stimulation, CD8 cells from both normal subjects and patients only slightly suppressed the induction of IgG-secreting cells. However, under these circumstances, once again, CD8 cells from both normal subjects and patients with no serum AMA suppressed the induction of AMA-secreting cells, whereas CD8 cells from patients with serum AMA suppressed the induction of the AMA-secreting cells significantly less. Higher TMc concentrations enhanced the suppressor effect of CD8 cells from patients with serum AMA on the induction of AMA-secreting cells. Furthermore, Concanavalin A, when added to the stimuli described above, further inhibited the induction of both AMA- and IgG-secreting cells by CD8 cells from patients with serum AMA. There thus appears to be a relative defect of antigen-specific suppressor T lymphocyte function in CD8 cells from patients with autoimmune thyroid disease, which may result in the presence of autoantibody-secreting cells in those patients.

Graves' disease in pregnancy years after hypothyroidism with recurrent passive-transfer neonatal Graves' disease in offspring. Therapeutic considerations.

Symptoms and signs of severe hypothyroidism developed in a young woman at age 15. These symptoms progressed for a year; at age 16, she was found to have a firm goiter, thyroid autoantibodies, very low serum thyroxine and high thyrotropin values, indicating autoimmune thyroiditis with hypothyroidism. She received L-thyroxine, 0.20 mg per day, and was well until age 24 when she became pregnant. In the first trimester, manifestations indicative of hyperthyroidism developed; these were only ultimately recognized immediately after delivery of a 32-week still-born goitrous baby. Despite the discontinuation of thyroxine therapy, the hyperthyroidism persisted and was confirmed as Graves' disease by elevated thyroxine, triiodothyronine, and radioactive iodine uptake values, a diffuse scanning result, and the presence of thyroid-stimulating antibody. The patient was treated with propylthiouracil and became pregnant while receiving that regimen. Later, several months after delivery, the patient was treated with radioactive iodine, ultimately became hypothyroid, and has been treated ever since with thyroxine. She became pregnant again and, because of the continuing high titers of thyroid-stimulating antibody, received propylthiouracil, 100 mg daily, commencing in the third trimester of pregnancy, to avoid probable fetal hyperthyroidism due to the transplacental transfer of thyroid-stimulating antibody. In each of the last two pregnancies, when the infants were born, they seemed normal (because of the transplacental effect of propylthiouracil), but passive-transfer neonatal hyperthyroidism developed in each within 10 days after delivery, ultimately requiring treatment by conventional means. This case illustrates the following points: (1) Hyperthyroidism occasionally develops years after hypothyroidism. (2) In young women, high titers of thyroid-stimulating antibody may produce fetal and neonatal passive-transfer hyperthyroidism even at a time when the mother herself is no longer hyperthyroid; transplacental treatment of the fetus by maternal propylthiouracil ingestion may thus be necessary during the last trimester, but only when there is a high degree of probability that the fetus is at risk. (3) Because the infants had been protected in utero by the placental transfer of propylthiouracil, neonatal hyperthyroidism did not develop until several days after delivery.(ABSTRACT TRUNCATED AT 400 WORDS)

Lack of effect of methimazole on thyrocyte cell-surface antigen expression.

The nature of the immunosuppressive effect of antithyroid drugs has been a subject of controversy. It has been claimed that these agents exert a direct effect on the immune system, although we and others have suggested that the drugs affect the thyroid cells primarily with consequent reduced thyrocyte-immunocyte signalling. This may occur from reduced thyroid hormone production and/or reduced antigen presentation by the thyrocytes to local T lymphocytes. Using a cytotoxicity assay system, with chromium-51 labelling, monoclonal antibodies against thyroperoxidase (TPO) and HLA-DR, and complement, we have measured the expression of TPO and HLA-DR on cultured normal human thyroid cells; we have also measured thyroglobulin (Tg) release by radioimmunoassay into the medium of the cultured cells. The thyroid cells were stimulated with TSH or thyrotropin binding inhibitory immunoglobulin (TBII) for 48 hours before measuring for TPO induction, and with interferon gamma (IFN-gamma) (with or without TSH or TBII) for thyrocyte HLA-DR expression. A dosage of 1.6 milliunits per ml of TSH resulted in a significant increase in TPO expression on thyrocytes when compared with control unstimulated thyroid cells (p less than 0.001). The concentrations of Tg released into the medium with TSH or TBII were also significantly higher than those of the control thyrocytes. IFN-gamma at 200 units per ml induced HLA-DR expression, but did not induce thyrocyte TPO expression, or Tg release. Addition of the antithyroid drug, methimazole (MMI), at different concentrations, in addition to the other stimulators, IFN-gamma, TSH, or TBII, did not result in any inhibition of TPO, Tg release, or HLA-DR expression on the thyroid cells. It would thus appear that the pathways for stimulation for the expression of TPO and HLA-DR appear to be different. Finally, MMI does not cause its immunosuppressive effect by any reduction of thyroid antigen expression or release.

Demonstration of the production of human thyroid-stimulating immunoglobulins (HTSI) by Graves' lymphocytes cultured in vitro with phytohaemagglutinin (PHA).

The lymphocytes from patients with Graves' disease or from healthy subjects have been cultured in vitro either alone or with phytohemagglutinin (PHA). After six days the culture supernatants have been assayed for their human thyroid-stimulating activity by measuring increases in adenosine 3',5' monophosphate (cyclic AMP) in human thyroid slices with which the supernatants have been incubated. Significant levels of human thyroid stimulator activity were found in the culture in which Graves' lymphocytes were cultured with PHA. This activity has been abolished by precipitation of the IgG from the culture supernatant with goat antihuman IgG serum. In contrast, when Graves' lymphocytes were cultured alone, or when control lymphocytes were cultured either alone or with PHA, there was no overall significant production of human thyroid-stimulating immunoglobulin (HTSI). It is concluded that Graves' lymphocytes can be stimulated by PHA to produce HTSI in vitro. Since PHA is known to stimulate only the T lymphocytes, which do not themselves elaborate immunoglobulins as the B lymphocytes do, the above observations indicate a cooperation between T and B lymphocytes in the production of HTSI, at least in this system.