Mitogenic response of peripheral blood lymphocytes from patients with Graves' disease incubated with solubilized thyroid cell membranes containing TSH receptor and with thyroglobulin

Abstract

Transformation of peripheral blood lymphocytes (PBL) in response to solubilized TSH receptor and to human thyroglobulin (hTG) was carried out in patients with Graves' disease (GD). Mean stimulation index (SI) in response to solubilized TSH receptor was significantly increased only in hyperthyroid GD patients (SI = 3.0 +/- 1.8 SD, n = 13, p less than 0.025) when compared to normal subjects (SI = 1.5 +/- 0.8 SD,n = 14). All other subgroups of GD patients (i.e., euthyroid GD patients after treatment as well as those with/without ophthalmopathy or TSH-displacing antibody [TDA]) showed a tendency to elevated mean SI, which, however, was never significantly increased. In contrast, patients who were suspected of having a "disseminated autonomy" showed a tendency to decreased mean SI compared to GD patients. The mitogenic response of PBLs induced by solubilized TSH receptor could be suppressed by incubation of antigen and PBLs with bTSH. Control experiments with purified protein derivate of tuberculin(PPD) as stimulating antigen revealed, however, that bTSH itself suppresses the mitogenic response of PBLs and that the decrease of SI in this experiment is not due to blockage of the antigenic determinants of the TSH receptor protein. Human thyroglobulin (hTG) produced no significant increase in the SI of PBLs. Only 9 out of 47 GD patients showed an SI higher than the mean of normals + 2 SD. All those patients, however, who showed an elevated SI ( greater than 2.0) also revealed an increased SI with solubilized TSH receptor.