H. Schleusener

Classification of Hypothyroidism in Evaluating Patients after Radioiodine Therapy by Serum Cholesterol, T3-Uptake. Total T4, FT4-Index, Total T3, Basal TSH and TRH-Test*

. During a follow-up examination of patients after radioiodine therapy for thyrotoxicosis, 128 patients without recurrent hyperthyroidism were investigated for the clarification of different degrees of hypothyroidism. The clinical diagnosis and the conventional tests for circulating thyroid hormones were compared to the estimation of serum thyroid stimulating hormone (TSH), and to the thyrotropin-releasing hormone (TRH) test, which was performed with 500 μg synthetic TRH I.V., and referred to age and sex specific normal ranges. Moreover, serum triiodothyronine (T3) was estimated by radioimmunoassay. Results: 1. A gradual classification of biochemical group-differences gave more significant discrimination than a division into groups based on clinical impression. Different grades of severity of hypothyroidism could be demonstrated by highly significant differences of free thyroxine index (FT4-Index) between the 1st group of patients with low FT4-Index and a 2nd group with raised basal TSH (and normal FT4-Index), between the 2nd group and a 3rd group with an elevated value of Δ TSHmax (and normal FT4-Index and basal TSH), and between the 3rd group and a 4th group of biochemically normal reacting patients and controls. There was a less significant difference with very considerable overlap between clinically established groups. 2. T3-uptake, total T4 and FT4-Index are not sufficient for detecting hypothyroidism in individual patients, although their group-differences are significant in biochemical classification. 3. Neither between clinical nor between biochemical groups was there any significant correlation with serum cholesterol. 4. Triiodothyronine can be normal or elevated in a situation with low T4 and raised TSH concentrations. Conclusions: Evidence could be given that hypothyroidism is a graded phenomenon. Its classification by biochemical data is more reasonable than a clinical division. Advancing severity of hypothyroidism after radiation therapy is compensated during a certain period by supplementary production of triiodothyronine. As thyroid hormone concentration in patients with pathological serum TSH or TRH-test is significantly lower than in euthyroid patients or in controls, replacement therapy in early stages of hypothyroidism also seems reasonable.

Relations between serum levels of TSH, TBG, T4, T3, rT3 and various histologically classified chronic liver diseases

Serum levels of TSH, thyroxine-binding globulin (TBG), T4, T3 and reverse T3 (rT3) were measured in 36 patients with fatty liver disease, 11 patients with chronic persistent hepatitis, 17 patients with chronic active hepatitis, and 29 patients with liver cirrhosis. TBG was significantly above normal levels in both groups of chronic hepatitis, the slight concomitant T4 and T3 increase was significant only for Tt in chronic persistent hepatitis. A significant decrease in T4 and T3 concentration was found in fatty liver disease and in hepatic cirrhosis. A shift in T4 conversion to rT3 could exclusively be demonstrated for the group of hepatic cirrhosis, reflected by a significant increase in rT3. As our findings indicate normal TSH levels and a lack of clinical signs of hypothyroidism in chronic liver disease, the possibility of diverse regulating changes must be considered.

Interferon-γ protects human thyroid epithelial cells against cell-mediated cytotoxicity

Abstract Interferons have been shown to have antagonistic effects on cell-mediated cytotoxicity. In the present study, we investigated various types of immunologically mediated cytotoxic reactions with a 51 chromium release assay, using human thyroid cells as targets, which were cultured in the presence and absence of interferon-gamma (IFN-γ). Antibody-dependent cellmediated cytotoxicity (ADCC), natural killer (NK) cell-mediated cytotoxicity, autologous lymphocyte-mediated cytotoxicity (ALC) were measured utilizing thyroid tissue, sera and lymphocytes from patients with autoimmune thyroid disease as well as from normal subjects. ADCC, determined with sera from patients with Hashimotos thyroiditis, was reduced by 70 % when the thyroid target cells were cultured in the presence of 1000 U human IFN-γ/ml culture medium. Similarly, natural killer cell-mediated cytotoxicity, as well as autologous lymphocyte-mediated cytotoxicity, was significantly reduced after pretreatment of thyroid target cells with 500-1000 U IFN-γ/ml culture medium. Although it is known that IFN-γ renders target cells resistant to NK cell-mediated lysis, this is the first report on this effect using human epithelial cells, which may have major implications for the suggested role of IFN-γ in the induction and perpetuation of autoimmune thyroid disease.

10 years experience with consecutive measurement of thyrotropin binding inhibiting antibodies (TBIAb)

In the present study we reviewed 230 patients in whom thyrotropin-binding inhibiting antibodies (TBIAb) follow-up determinations had been performed up to 10yr after hyperthyroidism had first developed. In 104 patients, Graves’ophthalmopathy occurred at some time in the course of the observation period. Fourty-four of these patients with Graves’ ophthalmopathy had at least one, and up to four relapses after each one-year course of antithyroid drug therapy with methimazole. The addition of TBIAb-positive results over an observation period of 1–10 yr showed positive cumulative findings in 95% of the 44 patients with recurrences of Graves’ disease. A single TBIAb determination during hyperthyroidism showed positive results in 70%. A detailed breakdown showed that TBIAb was detectable during all hyperthyroid phases in 48% of the patients with ophthalmopathy. Thirty-four per cent of the patients had sometimes positive, sometimes negative TBIAb findings in the various hyperthyroid states. In 18% of the patients, TBIAb was not detected in any of the hyperthyroid phases. However, some of these patients became TBIAb-positive for the first time during antithyroid drug therapy or during a remission confirmed by a suppression test. Only 2 of the 44 patients never had TBIAb positive results at any time during the observation period. In those patients without ophthaJmopathy during the observation period, the “cumulative” frequency of TBIAb was 74% for patients with diffuse goiter and 52% for patients with diffuse-nodular goiter. However, in patients with ophthalmopathy, there was no difference in TBIAb detectability between those patients with a diffuse and those with a diffuse-nodular thyroid. The data presented in this study are discussed with regard to the heterogeneity of hyperthyroidism and in view of the possible value of TBIAb in predicting the course of Graves’disease.

Solubilized TSH-receptor: its usefulness for the radioligand receptor assay for TSH and TSH-displacing antibody

The usefulness of solubilized TSH-receptor for measuring TSH and TSH-displacing antibodies (TDA) in a radioligand receptor assay (RRA) was investigated. Crude thyroid membranes were solubilized with Triton X-100. A soluble protein fraction was isolated by DEAE-Sephadex A-50 ion-exchange chromatography. The binding of 125I-TSH to the solubilized fraction was studied. It was maximal after 45 min at 37 C, whereas at 4C a similar binding was observed after at least 17 h. The binding was inhibited by Ca2+and Mg2+ with concentrations higher than 1 mM and by NaCI in the concentration range 17–150 mM. No inhibition of binding was found with normal serum up to 100 μI. In contrast, 1.5 μI of a Graves’ disease serum showed significant inhibition. Using the system to measure TSH in serum, as low as 10 μU TSH could be estimated. Compared to an RRA using thyroid membrane fractions, the sensitivity for TSH in serum as well as for TDA is increased at least tenfold in our system.

Natural cytotoxicity of peripheral blood leukocytes from normal subjects and patients with Hashimoto's thyroiditis against human adult and fetal thyroid cells

Natural cytotoxicity of human peripheral blood leukocytes against fetal and adult human thyroid cells was investigated in vitro. Natural killer (NK) cell activity was determined at various effector: target cell ratios in a standard 51Cr release assay with human thyroid cells as targets. The effector cells were unfractionated peripheral blood mononuclear cells obtained by Hypaque-Ficoll gradient centrifugation. We have demonstrated that peripheral blood leukocytes from normal subjects and patients with Hashimotos thyroiditis exhibit natural cytotoxicity against both human fetal and adult thyroid cells. This was effector: target cell ratio and incubation time dependent. Although there was a tendency for increased killing of fetal thyroid cells by peripheral blood leukocytes from patients with Hashimotos thyroiditis compared to age/sex matched normal subjects this was not significant and there were no significant differences between the two groups for killing of adult thyroid cells. A possible role for natural cytotoxicity in progressive thyroid tissue destruction in Hashimotos thyroiditis is discussed.

Binding of solubilized human TSH-receptor protein by peripheral blood lymphocytes of patients with Graves’ disease

Peripheral blood lymphocytes (PBL) from patients with hyperthyroidism due to Graves’ disease (GD) were investigated for the ability to bind radioiodinated TSH receptor protein as hypothetical autoantigen (ABL). Thyrotropin-displacing antibody (TDA)-positive patients, who relapsed and were investigated shortly after starting antithyroid drug therapy, as well as TDA-positive patients with a first diagnosis of GD, who were investigated before starting therapy, showed significantly increased numbers of ABLs (0.2 ±0.17%, p<0.01 and 0.15 ± 0.08%, p<0.001, respectively) when compared to controls (0.018 ± 0.016%). In contrast, TDA — negative patients had no significant increase of ABLs (0.08 ± 0.09%). Preincubation of PBLs with excess unlabelled antigen and nylon wool filtration of PBLs, reduced the number of ABLs markedly. Blocking of the binding sites on the lymphocytes with anti-lg serum and blocking of the antigen itself by TSH depleted PBLs almost totally from ABLs. The present data indicate that: i) there are lymphocytes of B-cell characteristics capable of binding TSH-receptor; ii) there is a correlation between the appearance of ABLs in hyperthyroid GD patients and the detection of TDA in patients’ sera; iii) in Hashimoto, toxic nodular goiter and in some normals, a small amount of TSH receptor binding ABLs are detectable.

ANTIBODY DEPENDENT CELL MEDIATED CYTOXICITY (ADCC) IS A FREQUENT FINDING IN CHILDREN WITH ACQUIRED AND NEONTAL HYPOTHYRODISM (NH)

In children with autoimmune thyroiditis and hypothyroidism thyreoglobulin (Tab) and microsomal antibodies (Mab) are present, but not in children with NH. In contrast, thyroid growth blocking antibodies have been detected frequently in newborns with connatal hypothyroidism by our and other groups. This study presents data on cytotoxic thyroid autoantibodies in children with hypothyroidism. ADCC was measured using a 51Cr- release assay in human thyroid cells (JCEM 59: 734, 1984). 12 of 37 (32%) NH newborns were positive for this antibody, 6 of 12 (50%) older children with NH T4-treated for more than 4 years, and 4 of 4 children (100%) with autoimmune thyroiditis were positive, too. ADCC studies in 29 mothers of 37 NH newborns revealed positive titers in 7 (28%), and these had delivered 6 of 12 positive newborns. In addition, 2 of 7 mothers of older NH children with positive titers were positive for ADCC. 2 mothers and their NH newborns were also positive for Mab and Tab. We conclude that ADCC is a frequent finding not only in acquired but also in NH which might be of pathogenetic significance. The persistence of ADCC in older children suggests independent antibody production in the fetus and newborn. Since ADCC in inflammatory autoimmune thyroiditis leads to destruction of thyroid tissue accompanied by hypothyroidism, similar etiological factors {e.g. viral, HLA, environmental) may be responsible for the destruction of the fetal organ.

Thyroid Growth Blocking Antibodies in Congenital Hypothyroidism

The causes of transient and permanent congenital hypothyroidism (CH) have not been entirely clarified, although there is increasing evidence that these diseases might be the result of an Immunological disorder. Thyroid growth blocking antibodies (TGBAb), detected in the sera of affected infants and their mothers, might suggest that the development and maturation of the fetal thyroid gland might be suppressed by these antibodies. Recently, Drexhage et al. 1 described TGBAb in patients with primary myxedema. Applying the same technique, van der Gaag et al. 2 detected thyroid growth blocking antibodies in about 50% of infants with congenital hypothyroidism.

Autoimmune and Autonomous Toxic Goiter: Differentation and Clinical Outcome After Drug Treatment

Our own data presented in this paper are taken from investigations of a multi center prospective study*, in which the following colleagues participate: Althoff (Frankfurt), Badenhoop (Mannheim), Benker (Essen), Beyer (Mainz), Bd’rner (Wiirzburg), Bogner (Berlin), Bretzel (GieBen), Fiek (Berlin), Finke (Berlin), GrSf (Berlin), Grebe (GieBen), Ifengst (Miinster), Hensen (Berlin), Holl (Berlin), Hopf (Berlin), Hufner (Heidelberg), Joseph (Marburg), Jungmann (Frankfurt), Kahaly (Mainz), Kotulla (Berlin), Koppenhagen (Berlin), Mtiller-Eckardt (GieBen), Pickardt (Miinchen), Raue (Heidelberg), Reiners (WCirzburg), Reinwein (Essen), Schatz (GieBen), Schleusener (Berlin), Schoffling (Frankfurt), Schumm (Frankfurt), Schwander (Berlin), Schwedes (Mannheim), Seif (TUbingen), Usadel (Mannheim), WLtte (Miinchen), Ziegler (Heidelberg)