Abstract. Recent studies demonstrate that apoptosis is an important process in physiological and pathological cell death. We examined the apoptotic phenomena in thyroid tissues by two methods: immunohistological and in situ end-labeling of fragmented DNA (ISEL). In thyroid tissues from patients with Hashimoto's thyroiditis and thyroid cancer, fragmented nuclear DNA and LeY (apoptosis associated antigen) were observed. In tissues from patients with Graves' disease, LeY and bcl-2 oncoprotein were expressed, but no ISEL positive cells were observed. In contrast, thyrocytes in normal thyroid tissues were not stained with ISEL or anti-L&' antibodies (Abs). Fas antigen (Ag) was expressed in various thyroid tissues, including normal subjects. The clinical meaning of this was not determined. These results suggest that the apoptotic process takes place in Hashimoto's thyroiditis and thyroid cancer, and is overcome in Graves' disease by bcl-2 expression.

No abstract

Painless (silent) thyroiditis (PT) occurred simultaneously in 1 male and 4 females aged 21 to 52 years working at a nursery school. Clinical symptoms did not include goiter, or pain or tenderness of the neck in any of the patients but were characterized by edema of the lower legs as well as palpitation and loss of body weight as observed in subacute thyroiditis. General blood analysis showed that all patients were negative for C-reactive protein (CRP) and 3 had mild impairment of liver function. Examination of thyroid function suggested transient thyrotoxicosis accompanied by a marked reduction in radioactive iodine uptake (RAIU), but antithyroglobulin hemagglutination antibody (TGHA) and antithyroid microsomal hemagglutination antibody (MCHA) were negative in all patients. Examination of various viral antibodies showed no significant changes in their titers. Thyrotoxicosis was transient and disappeared without treatment or by glucocorticoid administration. Our results suggested that PT observed in this study was caused by some environmental factor. The possibility of an unidentified virus as a factor cannot be ruled out.

Antithyroglobulin (anti-Tg) antibodies cytophilic for human monocytes were detected in the serum of 30 of 45 patients with Hashimoto's thyroiditis using the passive rosette technique. These antibodies conferred on normal monocytes the ability to form rosettes with Tg-coated erythrocyres (E-Tg) in vitro. The percentage of E-Tg rosette-forming monocytes was correlated with serum anti-Tg antibody titers measured by tanned sheep red cell hemagglutination. Most serum cytophilic activities were recovered in the immunoglobulin G fraction and were not affected by heating to 56 C for 30 min or ultracentrifugation at 105,000 X g for 60 min. Passive E-Tg rosette formation by monocytes was immunologically specific and was inhibited by the addition of small amounts of free Tg into the medium but was not inhibited by the addition of normal human serum. The anti-Tg antibody-armed monocytes became cytotoxic against Tg-coated chicken erythrocytes and lysed target erythrocytes by an extracellular mechanism. It was suggested that monocytes might be armed by cytophilic antibodies in vivo, since monocytes of patients with Hashimoto's thyroiditis showed increased E-Tg binding (rosette formation) relative to monocytes from control subjects. These findings support the possible pathogenetic involvement of monocytes in human autoimmune thyroiditis.

No abstract