Binding of solubilized human TSH-receptor protein by peripheral blood lymphocytes of patients with Graves' disease.

Peripheral blood lymphocytes (PBL) from patients with hyperthyroidism due to Graves' disease (GD) were investigated for the ability to bind radioiodinated TSH receptor protein as hypothetical autoantigen (ABL). Thyrotropin-displacing antibody (TDA)-positive patients, who relapsed and were investigated shortly after starting antithyroid drug therapy, as well as TDA-positive patients with a first diagnosis of GD, who were investigated before starting therapy, showed significantly increased numbers of ABLs (0.2 +/- 0.17%, p less than 0.01 and 0.15 +/- 0.08%, p less than 0.001, respectively) when compared to controls (0.018 +/- 0.016%). In contrast, TDA - negative patients had no significant increase of ABLs (0.08 +/- 0.09%). Preincubation of PBLs with excess unlabelled antigen and nylon wool filtration of PBLs, reduced the number of ABLs markedly. Blocking of the binding sites on the lymphocytes with anti-Ig serum and blocking of the antigen itself by TSH depleted PBLs almost totally from ABLs. The present data indicate that: i) there are lymphocytes of B-cell characteristics capable of binding TSH-receptor; ii) there is a correlation between appearance of ABLs in hyperthyroid GD patients and the detection of TDA in patients' sera; iii) in Hashimoto, toxic nodular goiter and in some normals, a small amount of TSH receptor binding ABLs are detectable.