Fig. 1.

Illustration of our hypothesized model, showing that environmental or genetic triggers may act directly to affect TH17/Treg balance in the brain, the periphery, and the placenta. In the placenta, this imbalance is connected to pregnancy morbidities (such as preeclampsia) and to endocrine dysregulation; in the periphery, to autoimmune disease; and in the brain (crossing in from the periphery across the blood-brain barrier), to depression and anxiety.