TPO-Ab positivity, often used as a marker of thyroid autoimmunity, has been associated with elevated pro-inflammatory cytokines, including interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) (19, 20), which can have systemic effects beyond the thyroid gland (21, 22). This evidence concerns the gene IL6 and autoimmune thyroid disease.