INTRATHYROIDAL LYMPHOCYTES IN AUTOIMMUNE THYROID-DISEASES

Aiming to assess the autoimmune origin of certain thyroid diseases, we studied the phenotypic composition and the ability of intrathyroidal lymphocytes to a re-induce HLA-DR expression on autologous thyrocytes coming from patients with graves's disease, nodular goiter and papilla ry thyroid carcinoma. Lymphocytes coming only from graves's disease pa tients were capable of reinduce HLA-DR expression on autologous thyroc ytes (24.1 +/- 13.6 vs 1.5 +/- 2.54% in nodular goiter and carcinoma), as interferon gamma did (17.4 +/- 8.34%). Phenotypic characterization showed a significant decrease of T-CD3 (total lymphocytes) and T-CD4 (helper) in lymphocytes coming from patients with nodular goiter and c arcinoma, and a marked reduction of T-CD8 (suppressor) in lymphocytes coming from patients with graves disease. Thus the T-CD4/T-CD8 ratio v aries according to the etiology of the thyroidal disease. The lack of suppressor activity would explain why cells coming only from patients with graves disease, show marked HLA-DR expression. These findings giv e little support to the autoimmune origin hypothesis for nodular goite r and thyroid carcinoma.