Serum Soloble Fas in Autoimmune Thyroid Disease / 대한내분비학회지

ABSTRACT

The Changes of soluble Fas levels in Patients with Autoimmune Thyroid Diseases BACKGROUD Apoptosis was observed in thyroid tissue from Hashimoto disease but not those from Graves disease. Recently Fas and Fas ligand interactions among thyrocytes were suggested to development of clinical hypothyroidism in Hashimoto disease.Soluble Fas produced as the form lacking the tranmembrane domain due to alternative splicing, is supposed to inhibit Fas-Fas ligand interaction and blocks Fas mediated apoptosis. METHODS: In tbis study, we measured serum soluble Fas to determine the possible involvement of this molecule in the autoimmune thyroid disease by enzyme linked immunosorbant assay in 29 patients with Graves disease, 30 patients with Hashimotos disease and 19 normal controls. RESULTS: Compared with normal subjeets (4.26 +/- 1.00 U/mL), soluble Fas was not increased in patients with Graves disease (4.23 +/- 1.14 U/mL, p>0.05) but it was increased in throtoxic Graves patients (4.70 +/- 1.26 U/mL, p<0.05) compared to euthyroid Graves (3.72 +/- 0.73 U/mL, p<0.05) and normal subjects (4.26 +/- 1.00 U/mL, p<0.05). The euthyroid and hypothyroid patients with Hashimoto disease showed low soluble Fas levels, 2.94 +/- 0.54 U/mL and 2.74 U/mL, respectively compare to the patients with Graves disease and normal subjects. The thyroid hormone levels to (T3 T4 and free T4) showed positive correlation with the serum titers of antithyroid autoantibodies, antithyroglobuin antibodies, antiperoxidase antibodies and thyrotropin binding inhibitor immunoglobulins. CONCLUSION: We found that the patients with thyrotoxic Graves disease had increased level of serum soluble Fas and the patients with Hashimoto disease showed low levels of soluble Fas compared to normal controls. Increased soluble Fas in Graves disease suggests increased expression of alternatively spliced Fas mRNA variant and decreased soluble Fas in Hashimoto disease suggests decreased Fas mRNA variant and increased full length membrane Fas, so these findings are related to the promotion of apoptosis of thyroid cells during autoimmune reaction in Hashimotos disease.