Self-recognition and the role of fetal microchimerism.

The course and severity of the autoimmune thyroid diseases (AITD) is known to be influenced by pregnancy as evidenced by disease suppression during pregnancy and initiation, or exacerbation, of disease postpartum. AITD is also known to affect both fertility and pregnancy outcome as evidenced by increased fetal loss. However, the precise mechanisms of this influence have not been fully understood. Here we have reviewed the mechanisms of self-recognition thought to be active in AITD and we have included recent information on the potential role of fetal microchimerism (exposure of paternal antigen to the mother during and after pregnancy).