Fetal microchimeric cells in blood and thyroid glands of women with an autoimmune thyroid disease

Persistence of fetal microchimeric cells may result in the development of autoimmune thyroid diseases (AITD) such as Hashimoto thyroiditis (HT) or Graves disease (GD). In women, HT and GD show an increased incidence in the years following parturition. Although fetal cells have already been shown to be more common in the thyroid glands of patients with an AITD compared with controls, these cells haven’t been described in blood of these patients. Our study detected fetal cells in blood of all patients with an AITD. Moreover, fetal cells were immune cells potentially capable of initiating a graft vs. host reaction and suggest a potential role of these cells in the pathogenesis of AITD. Our study indicates the value and need for further research in this field.