The pathogenic role of circulating Hashimoto's Thyroiditis‐derived TPO‐positive IgG on fetal loss in naïve mice

Problem Antibody‐mediated autoimmune diseases, such as autoimmune thyroid diseases (ATD), systemic lupus erythematosus (SLE), and antiphospholipid syndrome (APS), often are associated with recurrent fetal loss. One of the ATD is Hashimoto's thyroiditis which recently showed association with complications of pregnancy with increased levels of circulating autoantibodies reactive with epitopes on thyroid tissue such as thyroid peroxidase (anti‐TPO). In retrospective study of sera analyses in patients with Hashimoto's thyroiditis, all patients had mainly elevated circulating anti‐TPO autoantibodies. Aim We assessed the potential of human anti‐TPO highly positive IgG, derived from patients with Hashimoto's thyroiditis sera associated with complications of pregnancy, to cause directly complications of pregnancy in murine model. Method of study Naïve ICR female mice, infused intravenously with 100 μg of anti‐TPO‐positive IgG, showed increased fetal loss and embryo small for date (P