Thiocyanate in excess develops goiter followed by auto immune thyroid diseases even after effective salt iodization in a rural community of north east India

PURPOSE

Salt iodization in Manipur of north-east India failed to prevent endemic goiter, therefore an in depth study carried out to evaluate thyroid functions of goitrous subjects in a randomly selected region.

METHODS

Goiter survey conducted in children and women of reproductive ages by palpation followed by measurement of urinary iodine, thiocyanate and house-hold salt iodine to evaluate iodine nutritional status and consumption pattern of bamboo-shoots (BS). In all grade-2 goitrous subjects, free thyroxine, triiodothyronine, TSH, TPO and Tg antibodies, thyroid volume and echogenecity by ultrasonography and cytomorphology of thyroid by FNAC studied.

RESULTS

Study population was 2486 children and 1506 women, goiter prevalence was 12.59% and 16.27% respectively; median urinary iodine and mean thiocyanate were 166 µg/l and 0.729 ± 0.408 mg/dl while salt iodine was ≥30 ppm. Serum thyroid hormones and TSH profiles of all grade-2 goitrous subjects showed 16.21% were subclinically hypothyroid, 2.16% overt hypothyroid, 4.86% subclinically hyperthyroid and 6.48% overt hyperthyroid, serum TPO- and Tg-antibodies found positive in 41.62%. Ultrasonographic results showed 24% had enlarged thyroid and 86.4% hypoechoic. Cytomorphological studies showed prevalence of colloid goiter (41.08%), lymphocytic thyroiditis (37.83%), Hashimoto's thyroiditis (8.10%), autoimmune thyroiditis (4.32%), sub-acute thyroiditis (2.16%) and 1.62% each papillary, medullary carcinoma, simple diffused hyperplasia and adenomoid nodular goiter.

CONCLUSIONS

Grade-2 goitrous individuals in this mild goiter endemic region were affected by hypo- and hyperthyroidism with hypoechoic thyroid and thyroiditis. Thiocyanate that originates from BS even in presence of adequate iodine developed goiter and led goitrous population towards such diseases.

[Interleukin-6 in endemic goiter patients in the south Ural region]

The cytokine and thyroid status was studied in patients with endemic goiter (EG) depending on thyroid function. IL-6 correlated with free T3 levels (a negative relationship) in hyperthyroidism, with IL-2 and IFN-gamma levels in EG patients with euthyroidism, and with IL-1beta, IL-2, IL-8, IL-10, and IFN-gamma in hypothyroidism. The EG patients with high IL-6 levels showed positive relationships to IL-2 and thyroid peroxidase antibodies and a negative relationship to free T3. In these patients, IL-6 acted to stimulate the secretion of antithyroid antibodies, which is a risk of autoimmune thyroiditis.

Thyroid autoimmunity role in the evolution of endemic goiter in rural area, Fars, Iran

BACKGROUND

WHO reports indicate no iodine insufficiency in Iran, however, goiter is still endemic in Fars Province. This study evaluates the role of thyroid autoimmunity in the evolution of endemic goiter.

METHODS

A total of 516 permanent residents of Akbarabad County of the Kavar area in Fars Province, Iran were selected by simple random sampling. Patients with thyroid malignancy and dysfunction, and those who consumed drugs affecting thyroid function were excluded. After signing a written consent form and undergoing a thyroid examination, 5 cc of blood were drawn to measure free T3 and T4 (RIA), TSH (IRMA), and anti-thyroid peroxidase (competitive RIA) levels. Moreover, samples of 50 cc morning urine were collected for the measurement of urinary iodine excretion (UIE; chloridric acid digestion). Data were analyzed by SPSS (version 13). P<0.05 was significant.

RESULTS

The prevalence of goiter was 38.4% by WHO classification. The prevalence of children with UIE 2-4.9 µg/dL was 5.8%, which indicated sufficient iodine intake. Goiter was more prevalent in females, as well as in patients with positive anti-TPO or higher TSH titers (P<0.01). The prevalence of positive anti-TPO was higher in goiterous patients than healthy persons (P=0.002), which increased with an increase in age, grade of thyromegaly or TSH (P<0.02). Regression analysis showed the odds ratio for diagnosing goiter in females was 2.4 (P<0.001), in those with positive anti-TPO it was 1.87 (P=0.03) and in those with TSH>5.2 mIU/mL the odds ratio was 2.74 (P=0.01). In adolescents compared to children the odds ratio was 0.36 (P=0.01) and the odds ratio in adults to children was 0.33 (P=0.001).

CONCLUSION

This study indicates that despite normal UIE, goiter is endemic in Akbarabad County. Some degree of goiter endemicity may be due to thyroid autoimmunity.

The role of thyroid autoantibodies in the etiology of endemic goiter in schoolchildren of Isfahan, Iran

BACKGROUND

Eleven years after the initiation of universal salt iodization program in Iran, the prevalence of goiter is still high in some areas.

AIM

To investigate the role of thyroid autoimmunity in the etiology of residual goiter in schoolchildren of Isfahan, Iran.

MATERIAL AND METHODS

In a cross-sectional study, 2331 schoolchildren were selected by multi-stage random cluster sampling. Thyroid size was estimated in each child by inspection and palpation. Urinary iodine concentration (UIC), serum anti-thyroperoxidase antibody (anti-TPO Ab), and anti-thyroglobulin antibody (Anti-Tg Ab) were measured.

RESULTS

Overall, 32.9% of children had goiter. The median UIC was 1955.5 microg/dl. There was significant difference in prevalence of positive anti-TPO Ab in goitrous (grade 2) and non-goitrous children (9.7 vs 3.7%, p= 0.02). Goitrous children had higher prevalence of positive anti-Tg Ab than non-goitrous ones (15.1 vs 3.1%, p<0.001).

CONCLUSIONS

According to the present study, goiter is still a public health problem in this region. This study suggests that thyroid autoimmunity is among the contributors of goiter persistence after elimination of iodine deficiency in Isfahan.

TSH-receptor and adhesion molecules in autoimmune thyroid disease

Using a human TSH receptor (TSH-R) cDNA probe we investigated TSH-R expression levels in 20 human thyroid fragments by Northern blot analysis: 14 Graves' disease, 2 Hashimoto's disease, 3 endemic goiter and 1 healthy thyroid gland. TSH-R expression was low in those thyroids where expression of the major histocompatibility complex class I (MHC I), class II (MHC II) and intercellular adhesion molecule 1 (ICAM-1) was high, whereas expression of the endothelial leukocyte adhesion molecule 1 (ELAM-1) bore no relation to TSH-R expression. In situ hybridization showed that next to lymphocytes (MHC II), thyroid cells (MHC II, ICAM-1) and endothelial cells (ICAM-1, ELAM-1) were the source of transcripts of these T-cell activating antigens. We conclude that next to MHC I and II, the expression of additional T-cell activating antigens such as ICAM-1 and ELAM-1 play a role in the initiation of auto-immune thyroid disease.

Thyroid autoantibodies in women with and without thyroid disorders in an iodine-replete area

To compare the prevalence of positive autoantibodies in patients with thyroid disorders and healthy subjects in an iodine-replete area of the Islamic Republic of Iran, we studied 930 women in a clinic-based study: 698 patients (286 hypothyroid, 140 hyperthyroid, 272 with simple goitre) and 232 healthy women. Serum thyroxine (T4), triiodothyronine (T3), thyroid stimulating hormone, and anti-thyroid antibodies were measured. Positive autoantibodies were detected in 75.5% of patients with hypothyroidism, 73.6% of those with hyperthyroidism, 48.9% of those with simple goitre and 35.8% of the control group (P < 0.001). Autoimmunity may have a role in the genesis of common thyroid disorders.

Goiter rate, serum thyrotropin, thyroid autoantibodies and urinary iodine concentration in Tehranian adults before and after national salt iodization

Goiter rate, serum TSH, antithyroperoxidase (TPOAb), antithyroglobulin (TgAb) antibodies, and urinary iodine concentration (UIC) were evaluated 10-11 yr prior (1983-1984) and 5-6 yr after (1999-2000) national salt iodization in Iran. Pre- and post-iodization groups consisted of 465 and 1426 adults aged > or =20 yr, respectively, selected by random cluster sampling in Tehran province. Total, grade 1 and grade 2 goiter rates were 65.2, 53.1, and 12.1% in 1983-1984 vs 25.2, 15.5, and 9.7% in 1999-2000 (p<0.0001). Median serum TSH was 1.5 mIU/l in 1983-1984 vs 0.8 mIU/l in 1999-2000 (p<0.0001). Median TSH also decreased in 20-29, 30-39, 40-49, 50-59, and > or =60- yr-adults in 1983-1984 vs 1999-2000 (p<0.0001). In 1983-1984, positive TPOAb and positive TgAb were detected in 3.2 and 4%, respectively, using agglutination test. Corresponding values were 12.5 and 16.8% using immunoenzymometric assay in 1999-2000. Overt and subclinical hypothyroidism was present in 0 and 32.8/1000 in 1983-1984 vs 3.5 and 21.7/1000 in 1999-2000, respectively. Overt and subclinical hyperthyroidism was detected in 4.4 and 4.4/1000 in 1983-1984 vs 0.7 and 5.6/1000 in 1999-2000, respectively. Subclinical hypothyroidism in males was significantly more frequent in 1983-1984 vs 1999-2000 (odds ratio 5.02, 95% confidence interval 1.72-14.68; p=0.004). Salt iodization resulted in adequate UIC, decrease in serum TSH and subclinical hypothyroidism in males, and an increase in thyroid autoantibodies without significant change in thyroid abnormalities. Benefits of iodine supplementation far outweigh its hazards in Tehranian adults.

The role of iodine in the evolution of thyroid disease in Greece: from endemic goiter to thyroid autoimmunity

The thyroid gland is dependent on dietary iodine for the production of thyroid hormones, normal iodine requirement being about 150-200 microg/day. Long-term deficiency in iodine intake is associated with the development of goiter. When the prevalence of goiter in a population rises above 5-10%, the problem is considered endemic. Greece is a country with a recent history of moderate iodine deficiency, endemic goiter being prevalent in the 1960s in inhabitants of mountainous regions. Despite recognition of the problem, an iodine prophylaxis program was never officially implemented. Instead, "silent iodine prophylaxis" took place during the 1980s and 1990s with Greece's improvement in socioeconomic conditions. This resulted in the elimination of iodine deficiency and a parallel decrease in the prevalence of goiter among schoolchildren in formerly iodine deficient areas. However, the transition from iodine deficiency to iodine sufficiency or excess was followed by the emergence of autoimmune thyroiditis, especially among young girls, indicating that exposure to excess iodine may trigger thyroid autoimmunity. Thus, the modification of an environmental factor, ie dietary iodine, over the last 40 years in Greece has been associated with changes in the phenotypic expression of thyroid disease from endemic goiter to goiter associated with autoimmune thyroiditis.

Prevalence of antithyroid microsomal antibody in thyroid patients of endemic goitre area

The region of greater Mymensingh known for iodine endemicity, recently came under iodine supplementation as a result of mandatory universal iodination of salt program. Autoimmune thyroid diseases (AITD) are among the most common human autoimmune disorders & presence of autoantibodies to the microsomal antigen (AntiMCAb) is a hallmark of disease activity. Both iodine deficiency & iodine supplementation precipitate increase rate of autoimmunity to the thyroid gland. Study was undertaken to determine prevalence of AntiMCAb positive cases among patients with various thyroid diseases. High resolution ultrasound (HRUS), serum thyroid hormone assays & scintiscan were used to classify the thyroid patients into 8 categories. 221 patients were studied during the stipulated period of 3 months. Male patients were 60 & female patients were 161. Age ranged from 11 to 65 years with median age 29.4 years. AntiMCAb test were done with radioimmunoassay (RIA). 126 patients had antimicrosomal antibody (57.01%). All form of hypothyroid (atrophic, goitrous, Hashimoto's) have very high rate of AntiMCAb positive cases. Highest 89.28% were seen in patients showing feature of Hashimoto's thyroiditis or generalized feature of AITD in HRUS with hypothyroidism, followed had 61.29% positive cases, However, antithyroid antibody was found in all form of thyroid disorders. Nodular goiter had 21.73% antiMCAb positive cases. AntiMCAb found positive at the rate of 33.33% in euthyroid patients with HRUS feature of AITD & diffuse euthyroid goiter, 40% in subclinical hypothyroid, 40% in subclinical hyperthyroid. Female rated higher in range of antimicrosomal antibody positivism. 59% of all thyroid patients among female subjects were AntMCAb positive, where as 51.67% male thyroid patients were positive. Highest number of positive cases found in the 30-35 age group. No definite pattern, however, was observed among age distribution. 20 age matched sample from patients unsuspected of thyroid disease shows 10% AntiMCAb positive compared to 73.33% of the same among same age group of thyroid patients. Frank Hashimoto's thyroiditis with positive antiMCAb and hypothyroidism were all detected by HRUS.

[Role of some environmental factors in the development of endemic goiter (a review)]

The review presents possible causes of endemic goiter since only iodine deficiency fails to explain such a great spread of this disease. Etiological factors of endemic goiter, such as the imbalance of trace elements, the use of contaminated drinking water, the toxic action of chemicals, exposure to ionizing radiation, genetic factors, are discussed. Prevalence rates of endemic goiter in Russia and other countries of the world are presented. The causes of a significant increase in the incidence of this disease are discussed.

[Iodine therapy for iodine deficiency goiter and autoimmune thyroiditis. A prospective study]

PROBLEM

There is epidemiological and clinical evidence that iodine may induce or promote the manifestation of autoimmune thyroiditis. For this reason it is important to know if substitution of alimentary iodine deficiency or iodine treatment of endemic goitre can cause formation of thyroid antibodies. On the other hand the practical importance of this phenomenon should be evaluated.

PATIENTS AND METHODS

During a prospective study we examined 209 patients with endemic non-toxic goitre and 53 healthy people. For treatment were used 200 micrograms iodine/d (n = 119), 500 micrograms iodine/d (n = 27), 1.5 mg iodine/week (n = 41), 150 micrograms iodine/d plus 75 to 100 micrograms T4/d (n = 26), 100 micrograms iodine plus 100 micrograms T4/d (n = 24). The observation took 1 year with a 3-month interval for check ups including clinical examination, ultrasound, TSH, T3, fT4, TPO- and thyreoglobuline antibodies and urinary iodine.

RESULTS

After 12 months 7.5% of iodine treated persons had produced antibodies, most of them at low levels. In healthy people we found increased antibody-levels in 3.8%, in patients with goitre in 9.0%, in patients with nodular goitres in 11.1%. 500 micrograms iodine caused the most antibody reaction in 14.8%. People treated with 200 micrograms iodine/d showed positive antibody levels in 5%. T4 seems to reduce antibody-reactions. Pathological antibody-levels were not found in patients with combined iodine/T4- and single-T4 therapy. Among the 22 primary pathological antibody levels only 4 increased further (18.2%). Three of them belonged to the group of 5 persons treated with 500 micrograms iodine/d. Primary high antibody values were normalized in 5 patients (22.7%). Hypothyroid disturbances were not found. Ultrasound did not show any alterations, and the reduction of thyroid volumes in antibody-positive patients was not affected. Median urinary iodine excretion during the observation-interval was 5.2 to 7.2 micrograms/dl.

CONCLUSIONS

Possible antibody reactions have no clinical importance at all. Individual cases must be observed. Low iodine doses should be preferred. Combined iodine/T4 treatment seems to have an advantage regarding immunological thyroidal reactions.

Elevated anti-galactosyl antibody titers in endemic goiter

Anti-Gal is a human polyclonal antibody that constitutes approximately 1% of the circulating immunoglobulin G (IgG), interacts specifically with the mammalian carbohydrate alpha-galactosyl epitope. Furthermore, it was found to mimic in vitro thyrotropin (TSH) effects regarding stimulation for cyclic adenosine monophosphate (cAMP) synthesis, 125I uptake, and cellular proliferation on cultured porcine thyrocytes and on Graves' disease thyrocytes, but not on normal human thyrocytes. As immune activation in sporadic and endemic goiters might play a secondary role in regulating thyrocyte proliferation and function, we evaluated anti-Gal titers in endemic goiter. Serum was obtained from 109 Chagas'-negative patients living in an endemic goiter area of Brazil (Grao Mogol, MG) and 160 controls. The patients were divided into 3 groups, according to their goiter size (World Health Organization [WHO] classification): grade 0 (group 1, n = 24), grade I-II (group 2, n = 41), and grade III-IV (group 3, n = 44). Anti-Gal was assessed by a radioimmunological procedure (results expressed as the percentage of bound radioactivity/total activity [%B/T]). The antibody titer was significantly more elevated in group 1 (mean +/- SEM: 9.27%+/-0.80%), in group 2 (mean +/- SEM: 16.17%+/-0.97%), and in group 3 (20.97%+/-1.30%) than in normal controls (6.46%+/-0.33%). Analysis of the male and female data separately for anti-Gal titer did not substantially alter these results. We concluded that the anti-Gal titer is higher in patients with endemic goiter and presented a possible relationship with the size of goiter. Whether these antibodies contribute to the pathogenesis of the disease needs further clarification.

[Endemic goiter in Latium: environmental and genetic factors]

Most studies on the pathogenesis of endemic goiter focus above all on iodine deficiency. In some endemic goiter areas (i.e. Nigeria) there is no evidence of iodine deficiency; therefore, we suggest the taking into account of various factors, both environmental and non-environmental. We report the results of two studies carried out in three different areas in Latium: one of them (Cerveteri, RM) could be classified as high prevalence of goiter area, while the two others (Roccasecca dei Volsci, LT and Castel San Pietro Romano, RM) are true endemic goiter areas. The role of environmental factors, radioactivity and electromagnetism, foodstuff, the hydrogeological and chemical composition of natural water and the importance of genetics are here discussed, assuming that the endemic goiter could have a multifactorial pathogenesis.

[Epidemiologic and immunologic parameters in the assessment of endemic goiter in the Orenburg region]

Epidemiological investigations were carried out in 2328 children in the districts of the Orenburg district. Iodine deficiency was detected in the children living in the districts having low concentrations in the water and foodstuffs. There was a deviation of immunological parameters from the normal values in the children of the same districts.

Effects of low level radiation from the Chernobyl accident in a population with iodine deficiency

To determine the effects of low dose radiation from 131I and 137Cs resulting from the Chernobyl disaster on the expression of endemic goiter in children, we studied children in regions with and without evidence of radiocontamination but comparable iodine insufficiency. We included 89 children in the study (radiocontaminated) region (SR) and 116 in the control region (CR) because they were either fetuses, infants, or pre-adolescents at the time of exposure. We evaluated thyroid dimensions by clinical examination and ultrasound; thyroid function by hormonal levels, and thyroglobulin measurement; histology of the thyroid by fine needle aspiration; and thyroid autoimmunity. SR subjects had 5 times the frequency of thyroid enlargement as those from CR, greatest in the younger patients. There were no instances of clinically apparent thyroid dysfunction. Antithyroid microsomal and antithyroglobulin antibodies were present in a markedly greater percentage of SR subjects. Fine needle biopsy demonstrated greater cellular proliferation in samples from SR.

CONCLUSIONS

We have demonstrated findings of autoimmune thyroid disease at markedly increased frequency in a population of children with poor iodine nutriture who were exposed to low level radiation, compared to a more iodine deficient population not so exposed. These results suggest that low level radiation may induce thyroid gland changes in children who have inadequate iodine intake nutriture and reinforce the importance of adequate dietary iodine.

[General pathology of trace element deficiency]

According to the authors' concept, different forms of trace element deficiency show some general rules of development. All of them are followed by a decrease of immune resistance. Trace element deficiency is never isolated, it is always characterized by trace element unbalance and is followed by a considerable disturbance of metabolism (mineral, lipid, carbohydrate and protein) with relevant manifestations. Reduced immune resistance and pluriglandular endocrinopathy create the conditions for various malignancies.

Growth stimulating antibodies in endemic goitre: a reappraisal

OBJECTIVE

Previous studies, using a variety of methods, have reported growth-promoting immunoglobulins (IGs) in a large proportion of patients with endemic goitre. We sought to determine whether thyroid growth-promoting immunoglobulins (TGI) are present in the serum of Indian patients with endemic goitre.

DESIGN

IgG was prepared by protein G-Sepharose affinity purification and added to FRTL-5 thyroid cells in the presence of suboptimal concentrations of TSH.

PATIENTS

We studied 30 sequential patients with endemic goitre and 16 euthyroid controls without a goitre from the same area.

MEASUREMENTS

Two assays for thyroid cell growth were used: 3H-thymidine incorporation, and flow cytometric measurement of the proportion of cells in the S phase and G2/M phase of the cell cycle.

RESULTS

Both assays were shown to detect growth produced by TSH and by thyroid stimulating antibodies in IgG preparations from 3 patients with Graves' disease. There was no significant increase in either 3H-thymidine incorporation or the distribution of cells in S or G2/M phase with IgGs from endemic goitre patients, and no difference between the effects of these IgGs and those from the normal subjects.

CONCLUSIONS

Thyroid growth-promoting immunoglobulins cannot be detected in Indian patients with endemic goitre.

Prevalence of anti-thyroid peroxidase antibodies in autoimmune and nonautoimmune thyroid disorders in a relatively low-iodine environment

We evaluated the prevalence of antithyroid peroxidase antibodies (anti-TP0 Ab) in 402 patients with thyroid disease and 30 healthy controls by a commercial radioimmunoassay (RIA) and compared the results with the passive hemagglutination (HA) method. The patients in the study had autoimmune thyroid disorders (AITD) such as Graves' disease and Hashimoto's disease or had nonautoimmune thyroid diseases (NAITD) such as thyroid cancer, congenital goiter, endemic goiter, and nodular goiter. Subjects were recruited from a population with a mild iodine deficiency (Sao Paulo, Brazil). The effect of specific therapy (for either thyrotoxicosis or chronic thyroiditis) on the circulating anti-TPO levels was also investigated. Positive anti-TPO Ab was detected in 89.9% of the patients with AITD as compared with a prevalence of positive tests of only 4.8% in patients with NAITD. Positive microsomal antibody (M Ab) was found in 68.4% of the patients with AITD and in 6.4% of the patients with NAITD. A positive and significant correlation was obtained between M Ab and anti-TPO Ab. A positive anti-TPO test with negative anti-M was found in 14.1% of the patients with AITD but in only 4.3% of the patients with NAITD and normal controls. These results suggest that anti-TPO Ab by RIA is more sensitive and specific than M Ab by HA. In patients with AITD, anti-TPO Ab levels usually decreased after treatment, suggesting that this parameter could be used in the follow-up of these thyroid disorders.

Failure to detect thyroid growth-promoting activity in immunoglobulin G of patients with endemic goiter

The [3H]thymidine incorporation assay in FRTL-5 cells was used to measure thyroid growth-stimulating antibody in the purified immunoglobulin G (IgG) fraction of patients with endemic nontoxic goiter (grade I-III) living in Italy (n = 34) or Peru (n = 37). IgG of euthyroid nongoitrous subjects living in the same endemic area (n = 25) and from an area of sufficient iodine intake were used as controls. Bovine TSH (10 mU/L) and thyroid-stimulating antibody of Graves' disease produced a significant increase in [3H]thymidine incorporation and DNA content in FRTL-5 cells. IgG from Italian or Peruvian patients with endemic goiter produced a small increase in [3H]thymidine incorporation in FRTL-5 cells (131 +/- 54% and 165 +/- 57%, respectively), which was indistinguishable from that obtained with IgG from normal nongoitrous subjects residing in endemic or nonendemic areas (167 +/- 80% and 161 +/- 36%, respectively). For comparison 18 of 25 (72%) IgG of hyperthyroid patients with Graves' disease produced clear-cut increases in [3H]thymidine incorporation (1142 +/- 1065%) and DNA content (219%) in FRTL-5 cells. IgG from patients with endemic goiter, at variance with Graves' IgG, did not cause an increase in DNA in FRTL-5 cells. All Graves' IgG that stimulated [3H]thymidine incorporation in FRTL-5 cells also stimulated cAMP production in this culture system, whereas no adenylate cyclase stimulation was produced by IgG from patients with endemic goiter. The prevalence of thyroglobulin antibody and thyroperoxidase antibody in endemic goiter patients did not differ from that in control subjects residing in the same iodine-deficient area. Our data show that sera of endemic goiter patients are devoid of thyroid growth-stimulating antibody and thyroid-stimulating antibody activities. These observations argue against a direct role of thyroid autoimmunity in the development of goiter in iodine-deficient areas.

Incidence of thyroid autoantibodies in the endemic goiter

The aim of our study was to investigate the incidence of thyroid autoantibodies (TA) in the endemic region of the north-eastern Poland. The mean titres of ATMA and TGAb were measured in 1508 randomly chosen persons aged 3 to 68 yrs. ATMA or TGAb were positive in 17% of the population studied. Frequency and mean titres of TA were observed to increase with age. Autoantibodies were more frequently noted in persons with parenchymatous goiter. There was no correlation between the incidence of autoantibodies and goiter enlargement, however, the highest percentage of TGA was noted in people with large thyroid (III). TA were also found in 10% of the subjects without goitre. Our results do not confirm the hypothesis that thyroid autoantibodies play a key role in the pathogenesis of endemic goiter.

The effect of treatment with levothyroxine or iodine on thyroid size and thyroid growth stimulating immunoglobulins in endemic goitre patients

OBJECTIVE

We assessed the effect of levothyroxine or iodine on thyroid size and on thyroid growth stimulating immunoglobulins in endemic goitre patients.

DESIGN

Levothyroxine or iodine was given orally in an open randomized prospective study (100 and 200 micrograms respectively).

PATIENTS

Thirty-seven euthyroid patients with diffuse iodine deficiency goitres and thyroid growth stimulating immunoglobulins were studied.

MEASUREMENTS

Thyroid size, thyroid growth stimulating immunoglobulins (mitosis arrest assay), basal TSH, free T3, free T4, thyroid anti-microsomal antibodies, antithyroglobulin antibodies, anti-TSH receptor antibodies and urinary iodine excretion were measured.

RESULTS

Thyroid size decreased significantly in both groups, in the levothyroxine group more than in the iodine treated group. Thyroid growth stimulating immunoglobulins levels also decreased significantly in both groups. Between groups there was no statistically significant difference. A statistically significant correlation between thyroid growth stimulating immunoglobulins reduction profiles and goitre size reduction could not be established. TSH levels became suppressed in the levothyroxine group while the T4 values rose; in the iodine treated group TSH levels stayed constant as did T4. None of the patients developed thyroid microsomal or thyroglobulin auto-antibodies and/or hyperthyroidism during the treatment.

CONCLUSIONS

Levothyroxine as well as iodine was effective in reducing thyroid size as well as thyroid growth stimulating immunoglobulins levels in endemic goitre patients. Since in both groups TSH levels were not related to thyroid size reduction, other factors than TSH suppression must be responsible for the observed thyroid size reduction. Iodine itself by virtue of its antiproliferative action on thyrocytes may have had a direct action on the goitre reduction during iodine treatment; however, the levothyroxine dose, containing less iodine, had a similar effect. A complicated picture hence emerges with regard to factors involved in the shrinkage of iodine deficiency goitre during thyroxine or iodine therapy. These findings indicate that TSH and thyroid growth promoting immunoglobulins are not the only influences on the size of endemic goitres, although it cannot be excluded that these two factors contribute to influence the pathogenetic process.

[Autoimmune thyroid pathology of pregnancy and puerperium. Prevalence in a zone of endemic goiter and its impact on the newborn]

The aim of this work was to study the prevalence of thyroid disease in pregnant and puerperal women and newborns in Pirque (Chile) and its possible relation to iodine intake or autoimmune disease. Two hundred twenty eight women with 13.4 +/- 3.4 weeks of pregnancy were examined initially and in 223, laboratory tests were performed. Goiter was found in 107 women. Although all women were euthyroid, those with goiter had higher serum levels of T3 and T4. Nineteen women had positive anti-thyroid antibodies and urinary iodine excretion was > 100 micrograms/g creatinine in 87.2%. Within 2 and 57 weeks after delivery (mean 13.5 weeks), 183 women were reexamined and in 175 laboratory tests were performed. Serum T3 continued to be higher in those with goiter. Fifteen women with positive anti-thyroid antibodies during pregnancy continued to have positive titres; of these, two had a post partum thyroiditis and one a graves disease. Two hundred three newborns were examined and no one had goiter or elevated TSH. It is concluded that there is a high frequency of goiter among pregnant and puerperal women from Pirque, that iodine intake is normal and that there is a low frequency of post partum thyroiditis.

Expression of various MHC class II molecules and of intracellular adhesion molecule-1 (ICAM-1) on focal clusters of dendritic cells in iodine deficiency goitres

Thyroid sections from 18 consecutive euthyroid patients undergoing surgery for iodine deficiency goitre were investigated by means of immunohistochemistry and immunofluorescence, evaluating the expression of MHC class II antigens (HLA-DR, -DP, -DQ, and RFD1) and intercellular adhesion molecule-1 on the formerly described clusters of dendritic cells, as well as on thyrocytes. Eleven of 18 iodine deficiency goitres contained clusters of dendritic cells. These clusters appeared to express only HLA-DR in two cases; in nine of 12 cases they showed a differential expression of class II molecules in the following frequency: HLA-DR > DQ and/or -DP > RFD1. These dendritic cells also were ICAM-1+. In four of 18 iodine deficiency goitres, thyroid epithelial cells showed MHC class II expression in several combinations, but were ICAM-1-. In normal thyroids and in nodular goitres from inhabitants of the endemic area not having an actual iodine deficiency, only sparse clusters of dendritic cells were found; these cells were only HLA-DR+. Follicle lining cells were negative for the MHC class II molecules. In normal thyroids from an area with sufficient iodine supply, no clusters of dendritic cells were seen. The few dendritic cells observed were lying isolated in the interstitium and only positive for HLA-DR and ICAM-1; epithelial cells were negative for the studied markers. These data show clusters of dendritic cells in thyroids of inhabitants of an endemic area. When goitre is accompanied by iodine deficiency at the moment of operation, there appears to be activation of these dendritic cells and of thyroid epithelial cells.

Use of FRTL-5 for the study of thyroid antibodies involved in goitrogenesis

Some authors have suggested a role of autoimmunity in the pathogenesis of iodine deficiency disorders (IDD). For this purpose we have searched for thyroid adenylate cyclase stimulating antibody (TSAb) and thyroid growth stimulating antibody (TGSAb) in patients with endemic goiter (EG) and endemic cretinism (EC). Immunoglobulins G preparations (IgGs) were tested in FRTL-5 cells. TSAb were calculated as percent of cAMP increase over basal production and TGSAb were expressed as percent of increase of 3H-thymidine incorporation and DNA content in FRTL-5 cells. Our results show that IgGs from goitrous patients were devoid of TSAb and TGSAb activities, while in the same conditions IgGs from patients with Graves' disease had the ability to stimulate cAMP production and 3H-thymidine incorporation in FRTL-5 cells. These data argue against a direct role of TSAb and TGSAb in the pathogenesis of IDD.

[Behavior of thyroid autoantibodies in persons inhabiting an endemic goiter area]

The study was aimed at investigating the occurrence of thyroid autoantibodies (ATMA and TGA) in persons inhabiting the area of goiter endemy of mild degree. The survey comprised 1508 persons of age ranging from 3 to 68 years. The subjects studied have been divided into the groups taking into account age, sex, degree of thyroid enlargement (according to WHO, 1974), and the characteristics of the goiter. The occurrence of ATMA or TGA antibodies was demonstrated in 17% of the subjects. An increase in the incidence and titer of thyroid autoantibodies with age was observed. The occurrence of thyroid autoantibodies was observed more frequently in the subjects with parenchymatous goiter. No correlation was found between the incidence of the antibodies and goiter size. Thyroid autoantibodies have also been found in 10% of subjects without goiter. The results obtained do not indicate convincingly the role of the thyroid autoantibodies in the pathogenesis of endemic goiter.

Thyroid growth stimulating immunoglobulins in sporadic and endemic colloid goitre

Several methods have been described to measure immunoglobulins stimulating the growth of thyroid cells in vitro, the so called Thyroid Growth stimulating Immunoglobulins (TGI). The methods make use of either Ig-stimulated guinea pig thyroid (organ) cultures (the cytochemical bioassays; growth is measured via Feulgen-densitometry or pentose shunt analysis), the culture of Ig-stimulated rat or porcine thyroid follicles (growth is measured via 3H-thymidine incorporation), or of Ig-stimulated rat FRTL-5 cells (growth is measured via 3H-thymidine incorporation, or counting the number of mitoses in arrest). The various methods have now been validated: (a) the data obtained with TGI preparations in the Feulgen Cytochemical Bioassay (CBA's) correlate well with those obtained in the FRTL-5 mitosis arrest assay with the same TGI preparations, (b) the growth stimulation can not be ascribed to hormonal contaminations of the used Ig preparations, since protein A-sepharose purified IgG is active in the assays and since anti human IgG's neutralize the growth stimulating effects of the preparations. Using the assays TGI has been found positive in goitrous Graves patients, in sporadic goitre patients and in endemic goitre patients. Particularly, patients complaning of recurrent goitre after thyroidectomy or with recent goitre growth are TGI positive. TGI occurs in sporadic goitre in the absence of TSH-receptor antibodies. The autoimmune-prone animal model of the BB rat also proved to be TGI-positive; the animal shows an increased thyroid glandular weight. Both the histomorphology of human goitres as well as the goitre of the BB rat indicate that the dendritic cell plays a prominent role in initiating the thyroid autoimmune reaction.

Clinical, laboratory and immunologic effects of the treatment of endemic goiter with T4, T3 and KI

We treated 204 patients with endemic nontoxic goiter with T4, T3 and KI, singly or in combination. Definitely nodular goiters were excluded, since the possibility of autonomy would be increased. Goiter size was evaluated before and 6 months after treatment clinically in a blind way, i.e. the observer (always the same) did not know either the pretreatment goiter size or the treatment the patient had received. At the same time various laboratory parameters were recorded. All the active treatments (but not placebo) resulted in a highly significant decrease in the gland size. The effectiveness decreased in the following order: 1) T3 50 micrograms/d (most effective), 2) (T4 50 micrograms/d + T3 12.5 micrograms) x 2, 3) T4 150 micrograms + iodide 150 micrograms/d, 4) T4 75 micrograms + T3 18.75 micrograms/d, 5) T4 200 micrograms/d, 6) T3 37.5 micrograms/d, 7) Iodide 300 micrograms/d, 8) T4 150 micrograms/d, 9) Iodide 150 micrograms/d (least effective) and 10) Placebo (not effective). The results show that T4 200 micrograms and T3 50 micrograms are roughly equipotent, and slightly more effective than 300 micrograms of Iodide. Taking into consideration the side effects (increase in pulse rate, shortening of the Achilles tendon reflex) did not change the order of effectiveness in an important way. The clinical outcome correlated in general with the suppression of the 131I uptake (r = 0.220, p = 0.03) and the TRH test (r = 0.248, p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

[Antithyroid antibodies and endemic goiter]

Relationship between thyroid autoantibodies and endemic goiter have been studied in 164 subjects from three different areas of endemic goiter: 91 patients and 31 healthy controls from Central Sardinia, 23 patients from Northern Latium, and 19 patients from Southern Latium. In subjects with endemic goiter from Sardinia higher levels of thyroid autoantibodies were present as compared to the healthy controls; microsomal fraction autoantibodies titer was higher than antithyroglobulin autoantibodies. In subjects from the two other endemic goiter areas the antimicrosomal and antithyroglobulin autoantibodies were absent, with the exception of one patient with basedow's goiter. It is suggested that some of the areas classified as positive for endemic goiter are indeed characterized by an extensive genetic predisposition to lymphocytic chronic thyroiditis complicated by nodular goiter.

Chromatographically purified immunoglobulin G of endemic and sporadic goiter patients stimulates FRTL5 cell growth in a mitotic arrest assay

A strain of differentiated rat thyroid cells (FRTL5) in continuous culture was used to study the presence of thyroid growth-promoting immunoglobulins (TGI) in the serum of patients with endemic and sporadic euthyroid goiters. To identify true in vitro cell proliferation a microscopic mitotic arrest assay was used. Immunoglobulins G (IgGs) were prepared with QAE-Sephadex A-50 or protein-A-Sepharose. A positive growth stimulation index was found in IgG preparations of 65 of 71 patients with endemic goiter and in 9 of 14 IgG preparations of patients with sporadic goiter. IgG preparations of 15 control subjects from an area where endemic goiter due to iodine deficiency does not occur and of 18 subjects without iodine deficiency and without thyroid enlargement living in the endemic area did not stimulate FRTL5 cell growth. FRTL5 cell growth stimulation with IgGs of these euthyroid goiter patients could only be detected when IgG was tested in combination with a small dose of TSH. Immunoprecipitation with polyclonal and monoclonal antihuman IgG was able to abolish the growth-promoting effects. In 32 blinded samples the Feulgen cytobiochemical assay, formerly used to detect TGI, was compared with the FRTL5 mitotic arrest assay. The two methods showed similar results. Our observations of chromatographically purified IgG promoting thyroid cell proliferation in vitro provide good evidence that IgG was responsible for thyroid cell growth in vitro and suggest that autoimmune growth mechanisms may be involved in the pathogenesis of both endemic and sporadic goiters.

Thyroid autoimmunity in endemic goitre caused by excessive iodine intake

The pathophysiology of endemic goitre caused by excessive iodine intake is not well defined. By interacting with the immune system, iodine excess may trigger the development of autoimmune thyroid disease such as lymphocytic Hashimoto's thyroiditis (LT). In an attempt to examine this further, we compared the presence of thyroid autoantibodies in 29 goitrous children, from an iodine excess area, and in 26 healthy children, from an iodine sufficient area, of north central China. Serum was tested for antimicrosomal (MAb), anti-thyroglobulin (TgAb), second colloid antigen antibodies (CA2-Ab) and TSH binding inhibitory immunoglobulins (TBII). Affinity chromatographically purified IgG was tested for thyroid growth-stimulating activity (TGI) by two different methods: a sensitive cytochemical bioassay (CBA) using guinea-pig thyroid explants and a mitotic arrest assay (MAA) employing a continuous rat thyroid cell line (FRTL-5). We found no increased prevalence of LT in patients with endemic iodine goitre. The levels of MAb, TgAb and CA2-Ab did not differ significantly between the two groups of children. Further, TBII were not present in either group. Thyroid growth-stimulating immunoglobulins (TGI) were the major autoantibodies found in children with goitres caused by iodine excess. In the CBA, 12 of 20 (60%) goitrous children and 0 of 12 (0% P less than 0.05) healthy children were positive for TGI. Similar results were found in the MAA, and a good correlation between results of the CBA and MAA was found (P = 0.003). Maximal TGI activity in dose-response CBA showed a good relation with clinical goitre size (r = 0.63; P less than 0.05) indicating a possible pathophysiological role for these antibodies. We conclude that endemic iodine goitre is not associated with Hashimoto's lymphocytic thyroiditis. Nevertheless, autoimmune growth factors such as TGI may play a primary role in the pathogenesis of thyroid growth in this condition.

The prevalence of immunological abnormalities in endemic simple goitre

Thyroid growth stimulating immunoglobulins microsomal antibodies and antibodies against thyroglobulin were determined in patients with simple goitre (n = 20) and controls (n = 6) living in an iodine deficient area. In addition, lymphocytic infiltration of thyroid tissue, the amount of the various lymphocyte subsets (Leu 4+, Leu 3a+, and Leu 2a+ T-cells as well as B1+ B cells) in the thyroid gland, as well as the expression of the histocompatibility antigen HLA-DR on thyrocytes and intrathyroidal T-lymphocytes were examined. Goitrous patients were subdivided into two groups according to their individual iodine supply estimated by iodine excretion values, and immunological parameters were compared between patients with low (group A, iodine excretion less than 70 micrograms/24 h) and with higher (group B, iodine excretion greater than 100 micrograms/24 h) iodine supply. Thyroid growth stimulating immunoglobulins and antithyroid antibodies were equally prevalent in the two patient groups, but were absent in controls. Lymphocytic infiltration of thyroid tissue was present to a comparable extent in patients of groups A and B, but to a distinctly lower degree in control persons. Intrathyroidal T-lymphocyte subsets did not differ between patients and controls. B-lymphocytes, germinal centres as well as DR+ thyrocytes were detected in goitrous patients of both groups, but never in control persons. Thus, immunological abnormalities frequently occur in patients with simple goitre and do not depend upon individual iodine supply.

Immunological features of endemic goiter

Some immune aspects of simple endemic goiter have been studied through a comparison of IgG, IgA, IgM, kappa and lambda chains, and C3 and C4 in the peripheral blood of 59 patients operated on for goiter and the peripheral blood of 49 normal controls. The median IgM was lower in the goiter blood. The incidence of thyroglobulin (Tg) and microsomal (Mi) antibodies (Abs) was 20.3% in goiter blood and that of nonthyroid autoAbs was 37%. Active and total rosetted blood lymphocytes were counted and OKT3, OKT4, OKT8, Leu 1, Leu3a, Leu2b, T DR+, and NK cell populations were classified. Helper T cells were occasionally decreased when goiter was associated with lymphocytic thyroiditis. The NK percentage was sometimes higher in goiter blood, whereas the T DR+ percentage was not significantly different in the two groups. Lymphocyte infiltration (LI) was noted in 32% of goiters (about 5% with a diffuse and nodular pattern). A prevalence of helper/inducer cells was observed among the infiltrating T cells. HLA-DR antigen (Ag) positive epithelial cells were seen, not only in LI areas. Granular deposits of IgG, IgA, IgM, and C3 on the follicular basal membrane were stained in 6.7% of goiters Patterns histologically and immunologically similar to those in Hashimoto's thyroiditis may therefore be observed in long-standing simple endemic goiter, suggesting that an autoimmune mechanism may be involved in its pathogenesis.

Thyroid growth immunoglobulins in large multinodular endemic goiters: effect of iodized oil

Iodized oil (IO) was administered to 10 goitrous patients recently emigrated to São Paulo (SP) from iodine deficiency areas and to 42 goitrous patients from 2 Brazilian chronic iodine deficiency regions, Loreto and Luziania (L). Thyroid growth-promoting immunoglobulin G (IgG) thyroid-stimulating antibody, serum thyroglobulin (Tg), TSH, and thyroid hormones were measured before and 1 yr after IO administration. In all patients there was a remarkable reduction of gland mass associated with a significant decrease (P less than 0.01) in both basal serum Tg and peak Tg levels after bovine TSH administration. The mean percent Tg increase after bovine TSH treatment was reduced to 82% above basal levels compared with 224% before IO. Mean serum TSH levels, elevated only in the L group [7.3 +/- 11 (+/- SD) microU/ml] decreased to the normal range after IO (2.5 +/- 2.1 microU/ml). Serum T3 and T4 concentrations did not change greatly. Tests for microsomal antibodies were negative before and after IO. IgG concentrates of serum obtained before and after IO were tested for their ability to stimulate incorporation of [3H]thymidine into DNA or to increase intracellular generation of cAMP in FRTL-5 cells. Thymidine incorporation activity was found in 8 of 10 patients from SP [316 +/- 37% (+/- SEM); range, 140-480%] and 25 of 42 patients in the L group (mean, 206 +/- 14; range, 120-500%) before IO. Stimulation of thymidine incorporation reflected true growth-promoting activity, as confirmed by experiments measuring cell number, was not accounted for by TSH in the preparation, and reflected IgG action because it was abolished by absorption with antihuman IgG. IgG from only 1 patient in group SP and 4 patients in group L stimulated intracellular production of cAMP in FRTL-5 cells. All patients except 1 in both groups had no IgG stimulation (less than 120%) of growth-promoting activity 1 yr after IO treatment. There was a significant positive correlation between thyroid growth-promoting activity and serum Tg concentrations (r = 0.58; P less than 0.001), but no significant correlation was found with other parameters (TSH, T4, and T3). We conclude that growth-promoting IgGs lacking ability to stimulate cAMP production may play a role in the large multinodular goiters due to chronic iodine deficiency.

Assay for thyroid growth stimulating immunoglobulins: stimulation of [3H]thymidine incorporation into isolated thyroid follicles by TSH, EGF, and immunoglobulins from goitrous patients in an iodine-deficient region

Estimations were carried out of [3H]thymidine incorporation during culture of isolated porcine thyroid follicles in the presence of standard TSH or epidermal growth factor (EGF) both alone and together with anti-TSH or anti-EGF serum, and of immunoglobulins fractionated from the sera of patients from our endemic goitre area with iodine deficiency. A significant stimulation of thymidine incorporation was exerted by TSH when thyroglobulin was present in the culture medium, and also by EGF. TSH stimulation was abolished by anti-TSH serum, in contrast to the effect of EGF. Anti-EGF serum, on the other hand, blocked the effect of EGF, but not that of TSH. The sera of 20 out of 72 patients (27%) with euthyroid goitre (not operated on) and of ten out of 26 patients (38%) with recurrent euthyroid goitre contained immunoglobulins stimulating thyroid growth (TGI). There was no correlation of TGI with other thyroid antibodies. TGI have to be regarded as a pathogenetic factor of euthyroid goitre also in patients from an endemic region especially in recurrent cases.

Iodized oil treatment for endemic goiter does not induce the surge of positive serum concentrations of anti-thyroglobulin or anti-microsomal autoantibodies

Forty-three goitrous patients (grade II and III, WHO classification), living in areas of chronic iodine deficiency, were treated with an injection of iodized oil (470 mg iodine). Serial measurements of serum thyroid hormone levels after the therapy revealed increasing concentrations of both hormones, with a significantly lower serum T3/T4 ratio, and progressively significantly lower serum TSH mean values. Serum Tg mean value, initially elevated (58 +/- 9 ng/ml), decreased after 6 months and returned to the normal range at 36 months of therapy. In none of the examined patients (except for one subject with positive autoantibodies before therapy), it was observed the surge of positive anti-thyroglobulin or anti-microsomal autoantibodies after the iodized oil. We conclude that iodized oil therapy does not induce an abnormal autoimmune reaction in endemic goiter patients.

[Iodine and delayed immunity]

Iodine was and is sometimes used therapeutically in various pathologies where the immune mechanism is known to play a dominant role. It has in fact been administered to patients with tubercular granulomatous, lepromatous, syphilitic and mycotic lesions where it facilitates cure. This effect does not depend on iodine's action on the micro-organism responsible. Iodine may also be used in Villanova-Panol Panniculitis, in erythema nodosum, in nodular vasculitis, erythema multiforme and Sweet's syndrome. Oral iodine is also very effective in the lymphatic-cutaneous form of sporotrichosis. In order to establish a relationship between dietary iodine and immune response, 607 infants residing in an area of endemic goitre were studied: 215 were given Lugol solution (2 drops a week for about 8 months) and 392 not. The immune response was assessed by the skin test method using tetanic toxoid and a clear correlation was shown between this and lymphocyte stimulation and monocytic chemotaxis tests. The test was considered positive when an infiltration of at least 5 mm in diameter was shown after 48 hours (in the U.S. 80% of paediatric cases aged 2-10 years old were positive). A significant difference was noted in the average diameter of the infiltrations after the tetanic toxoid skin test in the two groups considered (P less than 0.001). The results appear to indicate that an adequate iodine intake is necessary for normal retarded immune response. The molecular mechanism by which iodine increases immune response is still to be decided.

Thyroid autoimmunity and endemic goiter

The goitrogenic role of autoimmune phenomena in endemic goiter is still uncertain. Scanty and discrepant results have been reported in different areas of the world. This prompted us to evaluate the prevalence of circulating thyroid antibodies in an area of northwestern Tuscany during a survey for endemic goiter. The survey was carried out according to the P.A.H.O. criteria in a stable community. In all schoolchildren (n = 142; age range 7-15 years) and in most of their parents (n = 159), thyroid size was evaluated and urine was collected for iodine determination. Blood was drawn for determination of circulating thyroid microsomal (MAb) and thyroglobulin antibodies (TgAb). TSH binding-inhibiting (TBIAb) and thyroid growth-stimulating antibodies (TGSAb), TT3, TT4 and TSH. Prevalence of goiter in schoolchildren was 77.9% and 94.8% in their parents. Mean (+/- S.D.) urinary iodine excretion was 55.0 +/- 2.1 micrograms/24 h. The overall frequency of TgAB and MAB in the adult population was 14.4, statistically higher than of control subjects matched for sex and age. The frequency in schoolchildren was 4.3%. TBIAb and TGSAb were undetectable in all tested cases. The presence of goiter in children was unrelated with the presence of thyroid antibodies in parents, whether goitrous or non-goitrois. A higher prevalence of goiter was found in children with goitrous parents as compared to children with non-goitrous parents (P less than less than 0.005). In conclusion, the frequency of thyroid autoantibodies in the adult population of the endemic area studies was increased, but showed no relation with the presence of goiter.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum autoantibodies and thyroid lymphocytic infiltration in endemic goitre

Patients with thyroid diseases from areas of endemic goitre in Northern Italy were examined for thyroid antibodies by passive haemoagglutination. Of 40 schoolboys with goitre only one had thyroid antibodies (AT) in the blood. Among 182 adults with grade 1-2 goitre, examined within an area of low endemia, the frequency of AT was 7%, not significantly different from that found in the 286 persons with thyroid 'O' living in the same area. Among 181 adults with grade 2-3 goitre, examined within an area of serious endemia, the frequency of AT was 16%; the percentage went up to 24% in 144 patients operated on for goitre. AT frequency was 36% in 87 patients with toxic goitre, more than 70% in 97 patients with Graves' disease and 17% in 60 patients with cancer of the thyroid. AT occurred three times more frequently in women than in men. Microsomal antibodies were more frequently detected than anti-thyroglobulin antibodies: the opposite was true in thyroid cancer. Lymphocytic infiltration (IL) of the gland was observed in 45% of the 464 simple goitres and in 52% of the 60 cancers of the thyroid: it was more frequent and intense in women. Among the 144 patients operated on for goitre the frequency and the titre of AT progressed in parallel with the intensity of the lymphocytic infiltration. Patients with a greater lymphocytic infiltration and higher AT had a higher TSH. Multinodular non-toxic goitre and autoimmune lymphocytic thyroiditis can be present in the same thyroid gland and the clinical expression will depend on which condition predominates.

Detection of thyroid growth immunoglobulins (TGI) by [3H]-thymidine incorporation in cultured rat thyroid follicles

A new bioassay is described for detecting the growth stimulating immunoglobulins (TGI) that contribute to goitre formation in human thyroid autoimmune diseases. It measures the incorporation of tritiated thymidine into intact rat thyroid follicles grown in tissue culture. This radiometric assay demands much less technical skill than the cytochemical bioassays (CBA) previously employed. It has good reproducibility and the techniques and apparatus are available in many clinical laboratories. Immunoglobulins (Igs) from 68% of patients with goitrous Graves' disease were positive, in proportion with goitre size, and this showed no correlation with T3 levels, or three accepted methods for conventional thyroid stimulating antibodies. Non-toxic nodular goitre cases gave positive results in 3/9 who had recurrences after one or more thyroidectomies and in 1/10 cases of familial simple goitre. All normal subjects and all endemic goitre cases were negative as well as 21 cases of sporadic non-toxic nodular goitre. Although it is less sensitive than the 'growth CBA' it clearly emphasizes the essential difference between the intensity of growth stimulus which leads to the regular hyperplasia of thyroid epithelium seen in Graves' thyrotoxicosis and the disorganized and metabolically uncoordinated hyperplasia typical of non-toxic nodular goitre.

Thyroid hormone and immunological studies in endemic goiter

Iodized oil (1 ml im) was given to 58 goitrous patients from a mildly iodine-deficient area in Greece. Goiter size, urinary iodine, and serum T4, T3RU, T3, rT3, TSH, thyroxine-binding globulin (TBG), and thyroid autoantibodies were measured before and 1, 3, and 6 months after the injection. Goiter size decreased. Serum T4 remained relatively constant, but TBG decreased and therefore T3RU and FTI increased. Serum T3 and rT3 initially decreased (P less than 0.001) and then increased at the sixth month (P less than 0.001), both showing roughly parallel changes. Serum TSH, initially normal (1.42 +/- 0.11 (SEM) mU/liter), decreased to 0.65 +/- 0.01 and 0.76 +/- 0.05 mU/liter at the third and sixth month (difference from baseline P less than 0.001). Thyroid autoantibodies, both against thyroglobulin and the microsomal antigen, were undetectable before treatment, but became positive in 42.8% of the patients 3 and 6 months later. Three patients developed transient hyperthyroidism. This occurred 3 or 6 months after treatment, and was associated with high titers of thyroid autoantibodies. These results indicate that: 1) transient hyperthyroidism may occur after the administration of iodized oil, possibly because of thyroid tissue necrosis and leakage of hormones, and 2) serum TBG decreases after iodized oil, a finding not previously reported and one whose cause is not known.

The use of monoclonal antibodies against thyroglobulin in immunoperoxidase techniques

A monoclonal mouse antibody to human thyroglobulin was used in a modified biotin-peroxidase-complex method to demonstrate thyroglobulin in different tissues and tumors of the thyroid gland. Mouse ascites fluid containing monoclonal antibodies could be diluted up to 1:1,600 for detection of thyroglobulin, whereas no staining was observed in a medullary carcinoma. Nonspecific background staining was negligible. These results demonstrate that monoclonal antibodies against thyroglobulin are suitable in the immunohistochemical localisation of thyroid hormones.

[Possible relation between the immune response and thymus-dependence of the immunizing antigens in children in an endemic goiter region]

As a result of serological examination of 7- to 14-year-old children in goiter endemic region it was shown that the activity of diphtheria and tetanus antitoxins is reduced in the initial stage of the thyroid enlargement, but prolonged antistrumin administration prevents this lowering. The relationship between these factors and immune response to polysaccharide antigens of typhoid vaccine was not observed. It is suggested that the dissimilar influence of the enlarged goiter initial forms and antithyroid prophylaxis on antibody genesis, induced by different antigens, is caused by an unequal role of the immune t-system.

[Clinical importance of the leukocyte migration inhibition test in thyroid diseases]

The leukocyte migration inhibition test (LMIT) was used to examine a group of patients with autoimmune thyroiditis and diffuse toxic goiter. The LMIT is likely to be used as an additional histological test for evaluating the correlation between the cellular and humoral types of autoimmunity in thyroid diseases.

[Various indicators of the B-system of immunity in endemic goiter]

Blood serum immunoglobulins (Ig) and the circulating antibodies against thyroglobulin, which are known to characterize the state of the immunity B-system, were investigated in 167 patients with endemic goiter and in 80 healthy persons. A significant elevation in the IgM, IgG, and antithyroglobulin antibody levels was observed in patients with hyperthyroid goiter. An increase in the antibody titre to thyroglobulin and in the IgG level was found in euthyroid goiter cases. The extent of functional activity of the thyroid gland and the presence of ophthalmopathy influenced the incidence and the level of the serum Ig elevation and of the antithyroglobulin antibodies increase.