We have studied the production of
anti-thyroglobulin autoantibody (ATA) in vitro in patients with autoimmune
thyroid diseases to test the hypothesis that these patients have a deficiency in T suppressor cell function. Lymphocytes were cultured for 7 days with or without pokeweek
mitogen (PWM). ATA and
IgG concentrations in the culture supernatant were measured by
enzyme immunoassays. In 15 patients with
Hashimoto's disease (HD), ATA production in vitro was detected. These patients had very high titers of ATA in their sera. In 5 patients with HD who had low ATA titers in their sera, and in 20 normal individuals, ATA production was not detected. Therefore, ATA production in vitro was positively correlated with ATA concentration in the serum. The stimulating effect of PWM was not clear in ATA production, but apparent in
IgG production. In another experiment,
concanavalin A (Con A) was used to induce T suppressor cells, and the activities of these cells were detected in the PWM driven culture system of fresh lymphocytes. In 5 patients with HD, ATA production was inhibited by Con A induced autologous suppressor cells. And the degree of suppression in ATA production was the same as that seen in
IgG production. Furthermore, in 2 patients we have compared the suppressing effect on ATA production of autologous Con A activated cells with that of normal Con A activated cells. There was no difference between the two. Therefore, we could not demonstrate the defect in Con A induced, non-specific suppressor cell activities in patients with HD. Finally, we cultured the lymphocytes with the specific
antigen, Tg (10-100 micrograms/ml). The responses of ATA production to Tg were variable among patients, which may suggest the variety of the status of presensitized lymphocytes or
antigen specific suppressor cells. Further studies are necessary to elucidate the
antigen specific T cell function in autoimmune
thyroid diseases.