In vitro regulation of antithyroglobulin synthesis by lymphocytes of patients with Hashimoto's disease by an antigen-specific "suppressor factor" derived from cultured normal human T-lymphocytes.

Suppressor factors (SF) elaborated by peripheral blood T-lymphocytes in culture from normal subjects activated by thyroglobulin as well as those from patients with Hashimoto's thyroiditis (HT), were tested for their ability to modulate antithyroglobulin synthesis by cultured HT-lymphocytes. A micro ELISA system and a micro reverse haemolytic plaque assay system were employed to detect antithyroglobulin and antithyroglobulin secreting B-lymphocytes respectively. In the latter system, the SF from normal T-lymphocytes caused suppression of thyroglobulin-specific plaque formation by HT lymphocytes while the "SF" from HT T-lymphocytes did not cause any suppression in most of the cases studied. A "SF" obtained by using liver antigen as a non-specific antigen, did not cause suppression of plaques. These results were highly significant (p less than 0.001). Although differences were seen with and without SF in the ELISA system, they were not statistically significant, likely due to a lack of sensitivity of the ELISA system as compared with the plaque assay. These observations imply that the HT-lymphocytes were deficient in thyroid antigen specific T-suppressor cell function and/or numbers to begin with and that the added normal SF afforded the signal necessary to the helper T-cells to suppress antibody synthesis by the B-lymphocytes. It is thus inferred that there is a defect in antigen-specific suppressor T-lymphocyte function in Hashimoto's thyroiditis.