A leading role for the immune system in the pathophysiology of preeclampsia.

Preeclampsia syndrome is characterized by inadequate placentation, because of deficient trophoblastic invasion of the uterine spiral arteries, leading to placental hypoxia, secretion of proinflammatory cytokines, the release of angiogenic and antiangiogenic factors and miRNAs. Although immune-system alterations are associated with the origin of preeclampsia, other factors, including proinflammatory cytokines, neutrophil activation, and endothelial dysfunction, are also related to the pathophysiology of this syndrome. The pathophysiology of preeclampsia may involve several factors, including persistent hypoxia at the placental level and the release of high amounts of STBMs. DAMP molecules released under hypoxic conditions and STBMs, which bind TLRs, may activate monocytes, DCs, NK cells, and neutrophils, promoting persistent inflammatory conditions in this syndrome. The development of hypertension in preeclamptic women is also associated with endothelial dysfunction, which may be mediated by various mechanisms, including neutrophil activation and NET formation. Furthermore, preeclamptic women have higher levels of nonclassic and intermediate monocytes and lower levels of lymphoid BDCA-2(+) DCs. The cytokines secreted by these cells may contribute to the inflammatory process and to changes in adaptive-immune system cells, which are also modulated in preeclampsia. The changes in T cell subsets that may be seen in preeclampsia include low Treg activity, a shift toward Th1 responses, and the presence of Th17 lymphocytes. B cells can participate in the pathophysiology of preeclampsia by producing autoantibodies against adrenoreceptors and autoantibodies that bind the AT1-R.