PRESENCE OF BOTH STIMULATING AND BLOCKING TYPES OF TSH-RECEPTOR ANTIBODIES IN SERA FROM 3 PATIENTS WITH PRIMARY HYPOTHYROIDISM

A case report of three patients with primary hypothyroidism who had potent TSH‐binding inhibitor immunoglobulins (TBII) and both thyroid stimulating (TSAb) and thyroid stimulation‐blocking antibodies (TSBAb) has been described. Two patients displayed symptoms and signs indistinguishable from those in primary myxoedema (cases 1 and 2), and another patient had a history of Graves'disease (case 3). TBII, TSAb and TSBAb activities were 90.0, 1084.2 and 94.5% in case 1, 91.5, 826.6 and 95.8% in case 2, 76.0, 230.0 and 95.0% in case 3, respectively (normal range, < 11.0%, < 145.0 and < 22.0%, respectively. The results indicate that both stimulating and blocking types of TSH‐receptor antibodies exist in these patients. The possible mechanism whereby hypothyroidism developed has been discussed. Copyright © 1990, Wiley Blackwell. All rights reserved