Objectives: Intercellular adhesion molecule-1 (ICAM-1), a 80-110 kD glycoprotein, has been found to be a ligand for the lymphocyte function associated antigen-1 (LFA-1) molecule and has important roles in inflammatory and immune mediated mechanisms. ICAM-1 is expressed on thyroid follicular cells of patients with Hashimoto disease and cultured thyroid monolayer cells derived from the thyroid surgical specimen. In addition to the expression of ICAM-1 on the surface of cells, soluble variants of several adhesion molecules have been reported.
Methods: We evaluated the circulating ICAM-1 in sera of representative autoimmune thyroid disease, Hashimoto and Graves' disease, and analyzed correlations between circulating ICAM-1 and thyroid-directed autoantibodies. Sera were collected from 58 patients with autoimmune thyroid disease, 28 patients with Graves' disease and 30 patients with Hashimoto disease. Serum concentrations for circulating ICAM-1 were determined with sandwitch enzyme immunoassay.
Results: Compared with normal individuals, mean serum concentrations for circulating ICAM-1 were significantly elevated in patients with Hashimoto disease and antithyroperoxidase-positive Graves' disease. Patients with antithyroperoxidase-positive Graves' disease revealed significantly higher serum circulating ICAM-1 concentrations than antithyroperoxidase-negative Graves' disease. Circulating ICAM-1 showed significant positive correlation with serum titers of antithyroglobulin and antithyroperoxidase antibody (r = 0.44, n = 28, p = 0.009, and r = 0.55, n = 28, p = 0.001 respectively). There was a significant positive correlation between circulating ICAM-1 levels and serum antithyroperoxidase level in the group of autoimmune thyroid disease and also circulating ICAM-1 levels were significantly correlated with serum antithyroperoxidase antibody levels in antithyroperoxidase antibody-positive Graves' disease(r = 0.55, n = 28, p = 0.001) and in Hashimoto disease (r = 0.5, n = 30, p = 0.002). The thyrotropin binding inhibiting immunoglobulins(TBII) showed no significant correlation with circulating ICAM-1 levels.
Conclusions: In the present study, high serum levels of ICAM-1 were associated with autoimmune thyroid disease. Graves' disease and Hashimoto disease and positively correlates with levels of antithyroperoxidase antibody.