Loss of tissue-specific autoantigens in thyroid tumours

MODIFICATION OF CELL ANTIGENS DURING AMINOAZO DYE CARCINOGENESIS IN RAT LIVER

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Granulomatous and lymphocytic thyroiditis associated with a follicular adenoma

A 44-year-old woman came to medical attention with right thyroid lobe enlargement and weight loss. Thyroid scan and ultrasound demonstrated a nodule in the right thyroid lobe; a right hemithyroidectomy was performed. Histologic examination documented granulomatous and lymphocytic thyroiditis associated with a follicular adenoma. No inflammation was apparent within the adenoma. The parallels between granulomatous thyroiditis and lymphocytic thyroiditis, including presumed viral initiation and deranged immunologic function, suggest that granulomatous thyroiditis may evolve into chronic lymphocytic thyroiditis; this case may be an example of such a transition. It is proposed that thyroid follicular adenomas have different antigenicity, which may account for the conspicuous absence of inflammation within the tumor.

Peroxidase activity in benign nodular lesions and carcinoma in the rat thyroid induced by N-nitrosobis (2-hydroxypropyl) amine and phenobarbital

Nodular lesions induced by N-nitrosobis (2-hydroxypropyl) amine (BHP) and phenobarbital (Pb) in F344 rat thyroid were histologically divided into 2 categories, benign lesions and carcinoma. Benign lesions were subclassified into 3 types mainly based on histological characteristics and localization of peroxidase (PO). The type 1 lesion showed localization of PO almost identical with that of the group 1 rat thyroid. Type 2 was characterized by an intense reaction product of PO in the cytoplasm but a weak one on the surface of the microvilli, and type 3 exhibited localization of PO opposite to that of type 2. Carcinoma proliferated in papillary, follicular and poorly differentiated patterns and developed as de novo carcinoma with the highest incidence, although a considerable number of carcinomas coexisted with benign type 3 lesions. A majority of these carcinomas lacked the reaction product for PO. These results suggest that benign nodular lesions, especially types 2 and 3, show hyperactivity of PO synthesis reflecting their response to excessively secreted TSH, whereas carcinoma is autonomous, because of marked inhibition of PO synthesis even in the presence of TSH hypersecretion.

Cytotoxic assay of circulating thyroid peroxidase antibodies

This study describes an assay for the detection of cytotoxicity for thyroid cells in serum of patients with autoimmune thyroiditis. Quantitative measurement may be performed by DNA or [3H] leucine incorporation determinations. The cytotoxic effect is localized in the gamma-globulin fraction, and is complement-mediated. It is thyroid specific i.e. it is not observed with fibroblasts and patients with other autoimmune diseases (patients with lupus erythematosis or glomerulonephritis) do not have cytotoxic antibodies directed against thyroid cells. The thyroid cytotoxicity is related to the presence of antimicrosomal antibodies and the effect of circulating antibodies is inhibited by human thyroid peroxidase. These results strengthen the possible implication of circulating antithyroid peroxidase antibodies in thyroid damage observed in autoimmune thyroiditis.

Thyroid carcinoma in benign thyroid diseases. An analysis from minute carcinoma

The relative frequency of thyroid carcinoma in benign thyroid diseases such as toxic diffuse goiter (toxic goiter), adenomatous goiter (goiter), adenoma, and chronic thyroiditis (thyroiditis) was studied using 3,219 surgically removed thyroid glands. Coexistence of carcinoma and benign diseases was found in 257 glands. Among them, 157 glands had minute carcinoma (diameter of cancer nodule is smaller than 10 mm) and 100 glands had advanced carcinoma (larger than 10.1 mm in diameter). The incidence of carcinoma including minute carcinoma was 29.4% in goiter (98/333), 21.0% in thyroiditis (11/53), 8.6% in adenoma (55/638), and 5.3% in toxic goiter (98/1852). Chi-square test also revealed that the rate of carcinoma not only advanced carcinoma but also minute carcinoma was higher in goiter than in the other diseases (P less than 0.01, respectively). Among the patients aged under 39, the incidence of advanced carcinoma and minute carcinoma in thyroiditis were the highest, respectively (83% and 100% in thyroiditis, 9.0% and 11.4% in goiter, 2. 6% and 1.9% in adenoma, and 0.7% and 3.4% in toxic goiter), however, among the patients aged over 40, they were secondary lower and the lowest, respectively (19% and 16.8% in goiter, 5.2% and 7.5% in adenoma, 4.2% and 6.7% in thyroiditis, and 1.4% and 7.5% in toxic goiter). We concluded that adenomatous goiter accompanies carcinoma more frequently than other benign thyroid diseases and the high incidence of carcinoma in chronic thyroiditis is probably due to a preoperative selection of the patients.

Autoantigens in an immunological network

An autoantigen network, consisting of all non-lymphoid cells and a subset of peripherally located autoregulatory lymphocytes, is proposed. By equilibrating a web of idiotypic stimulation (helper activity) and antiidiotypic inhibition (suppressor activity) directed at each tissue differentiation antigen, this network quantitatively limits autoantigen expression and thereby regulates the differentiation and growth homeostatic processes these autoantigens mediate. Perturbations of the network's dynamic equilibrium secondary to viral infection, somatic mutation, or interaction with environmental agents would clinically manifest themselves as autoimmune tissue destruction, benign or malignant nonlymphoid neoplasia, and lymphoproliferative disorders.

Tumour specific T-like antigen of human breast carcinoma

An autoantibody response against a breast carcinoma tumour specific neoantigen is described. The antigen, which was present in 6 of 11 breast carcinomata examined, was shown to have similarities to the T antigen of DNA virus induced animal tumours. In addition a different antigen (or antigenic determinant) was shown to be present in one breast carcinoma. This was not strictly tumour specific, being present in lower concentration in normal breast from the same individual.