Organ Antibodies After Local Irradiation

Radioiodine treatment for hyperthyroidism is followed by an increase in the thyroid humoral antibodies (2). This increase is temporary (3, 11, 16), lasting about one year, after which there is a gradual drop to below the pretherapy values (3). The increase is due to the radiotherapy, since it is not found after other forms of treatment for hyperthyroidism, such as subtotal thyroidectomy (3, 7). The rise in humoral thyroid antibodies after radioiodine therapy has also been observed in euthyroid patients (4). The question is whether this increase in thyroid antibodies is a manifestation of a general nonspecific increase in the humoral antibodies or a sign of a specific immunologic reaction directed only against the irradiated tissue. It should be possible to decide which of these two explanations is the correct one if it were known whether radioiodine therapy produces an increase in antibodies also against other tissues than the thyroid and whether there is an increase in the thyroid antibodies also after intensive, local irradiation of other tissues. The object of the present study was to elucidate these problems. Material The study was performed in 129 consecutive cases of hyperthyroidism and 47 euthyroid patients, who were examined before radioiodine therapy and two to twelve months afterward, and on 86 cases of carcinoma of the cervix or corpus uteri, who were examined before and two to twelve months after intracavitary application of radium. No patients with known auto-immune disease were included in the group given radioiodine therapy, and no patients with known auto-immune or thyroid disease were included in the radium-treated group. Methods The methods used for radioiodine therapy were the same as described previously (3, 4). In radium treatment for tumors of the corpus or cervix uteri, as in radioiodine therapy, an extremely large radiation dose is supplied to a small area and only a small dose to the rest of the body. Irradiation with radium was given in two local applications at intervals of about three weeks. The total dose on the surface of the mucous membrane was 20,000 to 30,000 R and at 2 cm depth 4,000 to 5,000 R. Some of the patients had also received external 60CO therapy. The method has been described by Kottrneier (12). Antibodies to bovine gamma globulin and to human 7S gamma globulin were examined by the tanned-cell passive hemagglutination test (1). Antibodies to parietal cells were examined with the indirect immunofluorescent test (10, 19, 20), using unfixed sections of rat gastric mucosa. Antibodies to nuclear antigens were examined by the same technic (8, 9), with acetone-fixed sections of human thyroid. The test sera were heated to 56°C for thirty minutes and diluted one to five before incubation on the tissue sections.