Objective: To investigate the potential association between serum inflammatory cytokine levels and thyroxine replacement dose in patients with Hashimoto disease.
Patients and methods: The study included 40 patients (12 men) with a mean age of 56.52±6.12 years who had hypothyroidism due to Hashimoto disease. Serum Interleukin-1b (IL-1b), Tumour Necrosis Factor-alpha (TNF-alpha) and Interleukin-6 (IL-6) levels, as well as TSH, fT3 and fT4 were measured (ELISA).
Results: Serum IL-6 showed a significant positive correlation both with total thyroxine replacement dose (r=0.551, P=0.001) and with dose per kilogram of body weight (r=0.482, P=0.002). There was also a significant negative linear correlation between serum IL-6 and T3 (r=−0.322, P=0.043), as well as between serum IL-6 and T3/T4 ratio (r=−0.332, P=0.036). A further significant (r=0.419, P=0.007) positive association was demonstrated between IL-6 and TNF-alpha. However, no association was found between T3 or T3/T4 ratio and TNF -alpha or IL-1b.
Conclusions: In patients with Hashimoto disease serum IL-6 levels are positively associated with thyroxine replacement dose and negatively associated with fT3 and fT4. These results are possibly attributable to the inhibitory effect of IL-6 on deiodination of T3 and imply a role for IL-6 in determining thyroxine replacement dose among these patients.
01 - 05 Apr 2006
European Society of Endocrinology