ABSTRACT
Background: Graves disease is an autoimmune disease caused by TSH receptor antibodies. Thyrotropin binding inhibitor immunoglobulins(TBII) are detected in most Graves patients, but some patients have no TBII activities in their sera. It is unknown whether the clinical features of TBII-positive patients are different from those of TBII-negative patients. Methods: To evaluate the prevalence of TBII-negative Graves' patients and its clinical differences from TBII-positive patients, we examined TBII by radioreceptor assay in 686 consecutive untreated Graves patients. We found 84 TBII-negative patients(15 men and 69 women, mean age ±EM: 40.9±.4 years) and compared their clinical characteristics with 87 TBII-positive patients (22 men and 65 women, mean age±EM: 39.9±.5 years) who were selected randomly from the same patients group. Results: In this study, TBII was undetectable in 12.2% of patients with Graves' disease(84 of 686). TBII-negative group had a less weight loss than TBII-positive group. However, there was no significant differences in age, sex ratio, prevalence of ophthalmopathy, duration of illness and positive rate of family history for thyroid diseases between TBII-negative and