Relationship of long-acting thyroid stimulator to the clinical features and course of Graves' disease

Abstract

Long-acting thyroid stimulator (LATS) determinations were performed in the serum of 439 subjects. A positive LATS response was found in 1 per cent of those without thyroid disease, in 9 per cent of those with thyroid disorders other than Graves' disease and in 53 per cent of those with active Graves' disease. Only 16 per cent of the patients with inactive Graves' disease had LATS in their serum and there was a significant negative correlation between the presence of LATS and the duration of inactivity of the disease. Analysis of the association of LATS with each of the three major manifestations of Graves' disease (hyperthyroidism, ophthalmopathy and dermopathy), individually and in various combinations, revealed that LATS was most closely associated with the number of manifestations present, rather than with any individual manifestation. The incidence was lowest (47 per cent) in patients with only one of the three organ systems involved; it was 63 per cent in those with two organs actively involved and 89 per cent in those with all three involved. The presence or absence of hyperthyroidism was statistically associated with the presence of LATS only when it was the sole active manifestation of the disease, and the addition of ophthalmopathy was similarly unrelated to the incidence of LATS when ei her other manifestation was present and active. Only dermopathy showed a statistically significant association with LATS regardless of the presence or absence of other features. Sixty per cent of the patients with dermopathy had very high concentrations of LATS. The incidence of LATS was higher in patients previously treated for hyperthyroidism than in those never treated. Serial LATS determinations were performed in seventy-four patients and results compared prospectively with the clinical course of the patient's disease, including dermopathy and ophthalmopathy. In the majority of patients LATS decreased during the period of study, including those who received no specific treatment. Ophthalmopathy either stabilized or improved in most patients, either following treatment or spontaneously. The course of ophthalmopathy usually paralleled the course of LATS. Patients with persistently very high or moderately high levels of LATS, or those who showed a change from no detectable LATS to very high levels, had a relatively poor prognosis in regard to ophthalmopathy. The course of hyperthyroidism did not parallel the course of LATS. There was no prognostic significance in a single LATS determination, even when the serum concentration of LATS was very high. Serial LATS determinations were of prognostic value. Eighteen patients were treated with glucocorticoids for severe, progressive ophthalmopathy. Following treatment LATS decreased markedly in seven of the eight patients who had LATS in their serum. However, the presence or absence of LATS prior to therapy was not helpful in determining whether a patient would respond to glucocorticoid therapy. In thirteen of the eighteen patients ophthalmopathy improved. The possible role of LATS in the pathogenesis of Graves' disease is discussed in the light of the observed in errelationships.