Clinical observations have reported the presence of anti-thyroid peroxidase (TPO) antibodies in some vaccinated individuals (Colafrancesco et al., 2013), and experimental models have demonstrated that administration of thyroglobulin (Tg) or TPO can induce autoimmune thyroiditis in mice, suggesting these autoantigens play a critical role in HT pathogenesis (Pyzik et al., 2015). This evidence concerns the gene TPO and hematocrit.