Functional Fas ligand expression in thyrocytes from patients with Graves' disease.

Fas/Fas ligand (FasL) interaction has been suggested to play a role in the pathogenesis of Hashimoto’s thyroiditis. This manuscript addressed a role for Fas/FasL interaction in the pathogenesis of Graves’ disease (GD). Apoptosis was detected in 0.5–5.0% of GD thyrocytes, but not in normal thyrocytes from patients with adenoma (N). Fas was constitutively expressed on the basement membrane of both GD and N thyrocytes. Thyrocytes expressed Bcl-2 constitutively in both GD and N thyrocytes. FasL was detected at the messenger ribonucleic acid level in thyroid tissue and cultured thyroid cells by Northern blotting and RT-PCR. FasL protein was detected in the cytoplasm and basolateral surface of thyrocytes from GD, but not in N. Cell surface expression of FasL on cultured thyrocytes disappeared within 48 h after their isolation. However, it was retained by culturing the cells with a matrix metalloproteinase inhibitor. Coculture with thyrocytes induced apoptosis of Fas transfectants, which was blocked by an anti-F...