EXPRESSION OF THE HERMES-1 (CD44) AND ICAM-1 (CD54) MOLECULE ON THE SURFACE OF THYROID-CELLS FROM PATIENTS WITH GRAVES-DISEASE

From studies of binding of Cr-51-labeled T cells to human thyroid mono layers, we have postulated the existence of tissue ''homing-like'' rec eptors on thyroid cells in patients with Graves' disease (GD). In this study we have investigated whether the CD44 (Hermes-1) protein, well known as a putative human lymphocyte homing receptor, is expressed on thyroid cells in patients with GD, and if so whether its expression is influenced by interferon-gamma (IFN-gamma). Cell surface CD44, as wel l as CD54 (ICAM-1), another putative homing receptor, antigens were an alyzed by flow cytometry and immunohistochemistry. CD44 and CD54 were both expressed on thyroid cells from untreated patients with GD, which , in the case of CD44, appeared as two peaks. IFN-gamma treatment enha nced the expression of the CD54 protein on Graves' thyroid cells and i nhibited the expression of the larger of the two CD44 peaks, but not t he other. Only small amounts of CD44 and CD54 were detected on normal thyroid cells, neither of which was affected by IFN-gamma. The CD44 pr otein was also demonstrated on both GD and normal thyroid cells by imm unohistochemistry. These findings suggest that CD44, and possibly CD54 , may induce putative adhesion pathways that lead to the homing of lym phocytes to the thyroid in patients who develop Hashimoto's thyroiditi s and Graves' disease.