Ia+ T cells in new onset Graves' disease.

The Ia (immune-associated, DR) antigen is a cell surface glycoprotein which is absent on normal circulating T lymphocytes but present on activated T lymphocytes. We studied the expression of this antigen on circulating T lymphocytes from patients with untreated hyperthyroid Graves' disease. All patients (n = 33) with recent onset hyperthyroid Graves' disease studied had an increased percentage and number of circulating Ia+ T cells. Patients with non-Graves's hyperthyroidism or Graves' disease patients more than 1 yr after thyroid ablation had normal values for Ia+ T cells. Other cell surface activation antigens, recognized by monoclonal antibodies 4F2 and 5E9, were not present on circulating T cells in patients with Graves' disease. The 100% positivity for increased numbers of Ia antigen-bearing T cells in hyperthyroid Graves' disease contrasts with our finding of 70% positivity in another HLA-DR-associated disease, recent onset type I diabetes mellitus. The pathogenic significance of these cells is not known, but they seem to represent selective activation of the immune system in patients with untreated hyperthyroid Graves' disease.

Duke Scholars

Author Barton Ford Haynes Medicine, Duke Human Vaccine Institute