TNF and preeclampsia: The exact mechanism of how IL-2 decreased PPET is unknown; however, IL-2 along with several other cytokines, such as IL-17 and TNF-α, and the autoantibody to the AT1 receptor (AT1-AA) are abundant in preeclampsia, and all have some effect to regulate ET-1, which except for IL-17, corresponds with their effect on blood pressure [37–40].