Down-regulation of the auto-aggressive processes in patients with hypothyroid Hashimoto's thyroiditis following substitutive treatment with L-thyroxine

• Published in: European cytokine network Vol. 20; no. 1; p. 27
• Main Authors: Guclu, Feyzullah, Ozmen, Bilgin, Kirmaz, Cengiz, Kafesciler, Sabriye Ozkaya, Degirmenci, Papatya Bayrak, Taneli, Fatma, Hekimsoy, Zeliha
• Format: Journal Article
• Language: English
• Published: France 01.03.2009
• Subjects: Adolescent; Adult; Aged; Autoantibodies - blood; Autoimmunity - drug effects; Cytokines - blood; Down-Regulation - drug effects; Down-Regulation - immunology; Female; Hashimoto Disease - drug therapy; Hashimoto Disease - etiology; Hashimoto Disease - immunology; Humans; Interferon-gamma - blood; Interleukin-12 - blood; Interleukin-2 - blood; Interleukin-4 - blood; Middle Aged; Thyroid Hormones - blood; Thyroxine - therapeutic use; Young Adult
• ISSN: 1952-4005
• DOI: 10.1684/ecn.2009.0147

Hashimoto's thyroiditis is a chronic, organ-specific autoimmune disease. It is the most common cause of primary hypothyroidism during the adolescent period, via autoimmune thyroid tissue destruction, affecting 2% of the population. The pathogenesis of Hashimoto's thyroiditis involves a complex interaction between predisposing genetic and environmental factors. In this study, we wanted to investigate the role of cytokines such as IL-2, IL-4, IL-12 and IFN-gamma in the pathogenesis of the disease, and the changes to cytokine levels brought about by treatment with L-thyroxine. Sixty five female patients, aged 18-73 years with Hashimoto's thyroiditis, referred to the Celal Bayar University Medical Faculty Endocrinology out-patients clinic, were included in this study. After a 10-12 week period of L-thyroxine treatment, all patients were restored to the euthyroid state. At the beginning and end of the treatment period, serum-free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), autoantibodies against thyroid peroxidase (anti-TPO), autoantibodies against thyroglobulin (anti-Tg) levels were measured using a chemiluminecent, immunometric method, and cytokine levels were measured using ELISA. There was a statistically significant decrease in the serum levels of TSH (p < 0.0001) and a concomitant increase in FT4 serum levels (p < 0.0001). Also, during the post-treatment period, serum levels of anti-Tg (p < 0.01) and anti-TPO (p < 0.001) were significantly lower than during the pre-treatment period. A statistically significant decrease was shown for interleukin (IL)-12 serum levels during the post-treatment period (p < 0.001). However, the decrease in interferon (IFN)-gamma serum levels was not statistically significant (p = 0.276). On the other hand, no change was demonstrated in serum IL-2 and IL-4 levels (p = 0.953 and p = 0.313, respectively) after treatment with L-thyroxine. Considering that our study involved a 10-12 week period of treatment, the statistically significant decrease in serum IL-12 levels, and the statistically non-significant decrease in IFN-gamma levels, might indicate that a T helper type 1 inflammatory process had been halted or slowed down.