ABSTRACT
According to the theory of in vitro radioassay, using TSHAb as binder and 125I-staphylococcal protein A (125I-SPA) as tracer agent, a new method for detecting the abnormal immunoglobulin (aIgG) in the sera of patients with Graves disease (GD) was reported. In the initial study of the method, the most appropriate interacting conditions of TSHAb with aIgG were explored and compared with ELISA using ganglioside (GLS) as a binder. The relationship between aIgG and thyroid-stimulating imunoglobulin(TSI) was probed into. The results showed that TSHAb could interact specifically with aIgG in vitro; but it could not interact with IgG from sera of normal subjects, systemic lupus erythematosis (SLE) patients and diabetic patients. With aIgG as an evaluating index, the mean value in 29 normal subjects was 1. 06?0. 17. When the sera of 72 patients with GD in different clinical stages were studied, the aIgG index was positive in 83% of untreated GD patients (n = 24), in 12% of GD patients in clinical remission (n = 25) and in 82% of relapsed GD patients (n = 23). Very significant difference was observed between normal subjets and untreated and relapsed patients with GD (P