Role of autoimmune and familial factors in goiter prevalence. Studies performed in a moderately endemic area

Abstract

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 North-Western 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 yr) 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), TT3, TT4 and TSH. Prevalence of goiter in schoolchildren was 77.9% and 94.8% in their parents. Mean (+/- SD) 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 that of control subjects matched for sex and age. The frequency in schoolchildren was 4.3%. The presence of goiter in children was unrelated to the presence of thyroid antibodies in parents, whether goitrous or nongoitrous. A higher prevalence of goiter was found in children with goitrous parents as compared to children with nongoitrous parents (p less than 0.005). In conclusion, the frequency of thyroid autoantibodies in the adult population of the endemic area studied was increased, but showed no relation with the presence of goiter. The prevalence of goiter in children was associated with the presence of goiter but not of thyroid autoantibodies in parents. These data suggest that autoimmune phenomena are of limited importance in the development of endemic goiter.

Antigen-Presenting Dendritic Cells as Regulators of the Growth of Thyrocytes: A Role of Interleukin-1 and Interleukin-6

“…Because DC are antigen-presenting cells (APC) par excellence and the only stimulators of naive T lymphocytes, these early DC/M⌽ accumulations were proposed as inducers of the relatively mild thyroid autoimmune reactions, which often later develop in endemic goitre patients (11,12) and iodine-deficient rats (8). Indeed, the first local sign of an autoimmune thyroiditis process is, in all animal models of spontaneous disease studied so far, the accumulation and cluster formation of DC and M⌽ in the thyroid gland (10,13,14).…”

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

“…Moreover, a higher prevalence of antithyroglobulin antibodies has also been described in an area of iodine deficiency in Italy [2]. Further support for the concept that iodine deficiency precipitates thyroid autoimmune reactivity was given by the extraordinary immunohistological picture seen in human iodine deficiency goitres.…”

“…This was also recently established in an experimental animal model of iodine-deficient rats (see Introduction). Other signs of autoimmune reactivity in iodine deficiency are the higher prevalence of antithyroglobulin antibodies in iodine-deficient areas [2] and the presence of thyroid growth-stimulating immunoglobulins in serum IgG of endemic goitre patients [1,12,13]. These latter IgGs have also been described in goitrous Graves' and Hashimoto's patients [14,15].…”

Thyroid Volume Measured by99mTc-Pertechnetate Scintigraphy and Its Relationship with Clinical Parameters in Korean Patients with Autoimmune Thyroiditis

“…23,24) These findings indicate that thyroid autoantibody levels are related to thyroid volume. 25,26) The patients enrolled in the present study had a variety of thyroid statuses-euthyroid, subclinical hypothyroidism, and overt hypothyroidism. We found relationship between a larger thyroid volume and the number of autoantibodies such as TPOAb and TgAb.…”