TNF-α May Exert Different Antitumor Effects in Response to Radioactive Iodine Therapy in Papillary Thyroid Cancer with/without Autoimmune Thyroiditis.

Autoimmune thyroiditis (AIT) may impair radioiodine (I) uptake in papillary thyroid cancer (PTC). Finding the mechanisms that govern immune cells during I therapy of PTC with concomitant AIT (PTC + AIT) could provide a rationale. Our study aimed to evaluate the effects of I on anti-thyroglobulin antibodies (TgAb), matrix metalloproteinase-9 (MMP-9) and its tissue inhibitor TIMP-1 and tumor necrosis factor-α (TNF-α) and its receptors TNFR1 and TNFR2, in PTC and PTC + AIT patients. Peripheral blood was collected from 56 female patients with PTC and 32 with PTC + AIT before and 4 days after I (3.7 GBq). The serum levels of TgAb, MMP-9, TIMP-1, TNF-α, TNFR1 and TNFR2 were measured by ELISA. The mean radioactivity of blood samples collected after I intake was higher in the PTC + AIT group than in PTC ( < 0.001). In the PTC + AIT group, TNF-α/TNFR1 and TNF-α/TNFR2 ratios decreased by 0.38-fold and 0.32-fold after I and were positively correlated with the MMP-9/TIMP-1 ratio (r = 0.48, = 0.005, and r = 0.46, = 0.007). In the PTC group, TNF-α/TNFR1 and TNF-α/TNFR2 ratios increased by 3.17-fold and 3.33-fold and were negatively correlated with the MMP-9/TIMP-1 ratio (r = -0.62, < 0.001 and r = -0.58, < 0.001). Our results demonstrate that TNF-α may exert different antitumor effects in response to I therapy depending on the patient's immune profile.