Soluble intercellular adhesion molecule-1 (sICAM-1) in Graves' disease

The aim of this study was to determine the level of sICAM-1 in sera of hyperthyroid and euthyroid patients with Graves' disease and find correlation between thyroid function, anti-TSH receptor as well as anti-thyroid antibodies. Comparative determination of sICAM-1, TSH and thyroid hormones, anti-TSH receptor- as well as anti-thyroglobin-, anti-thyroid peroxidase antibodies was made in sera of Graves' patients. Thirty patients with untreated hyperthyroid Graves' disease (12 had infiltrative ophthalmopathy) were studied before and after methimazole treatment. sICAM-1 was measured by ELISA using monoclonal antibodies to human ICAM-1. The sICAM-1 was significantly elevated in hyperthyroid Graves' patients (738.9 +/- 151 ng/ml) compared to controls (212 +/- 42 ng/ml) (p < 0.0001). Both in hyperthyroid and euthyroid Graves' groups with infiltrative ophthalmopathy the sICAM-1 proved to be higher than those without ophthalmopathy. Correlations were observed between sICAM-1 and serum thyroxine, triiodothyronine and anti-TSH receptor antibodies (r = 0.91, 0.83 and 0.61, respectively). There was, however, no association of serum ICAM-1 levels with anti-thyroid peroxidase or anti-thyroglobulin antibodies. It was concluded that elevation of sICAM-1 can be the consequence of hyperthyroidism and the autoimmune processes mediated by anti-TSH receptor antibodies as well as cytokines. The elevated level of sICAM-1 might be important both in regulation of autoimmune mechanism and "homing" phenomenon of lymphocytes in Graves' disease.