IA-POSITIVE LYMPHOCYTES-T IN RECENTLY DIAGNOSED IDIOPATHIC ADDISONS-DISEASE

The Ia (DR, immune-associated) antigen is absent on normal circulating T lymphocytes, but present on activated T lymphocytes. Utilizing monoclonal antibody L243, the expression of this glycoprotein on circulating T lymphocytes was studied in 5 patients with recent-onset idiopathic Addison''s disease, 1 patient with recent-onset adrenal hemorrhage, and 9 patients with long-standing adrenal insufficiency (5 with idiopathic Addison''s disease and 4 after bilateral adrenalectomy for Cushing''s disease). The patient with adrenal hemorrhage and the 9 patients with long-standing adrenal insufficiency had percentages of circulating Ia-positive T cells within the normal range. All 5 patients with recent-onset idiopathic Addison''s disease had an elevated percentage of circulating Ia-positive T cells (7-29%). The expression of Ia antigen on T cells in recent-onset idiopathic Addison''s disease probably reflects immunologic activation, which may be of pathophysiologic importance.