Preeclampsia is a serious complication of pregnancy. Target organs include the vascular system, the liver, kidney and brain. Hypertension and proteinuria are basic for the diagnosis of the syndrome. The immune intolerance in preeclampsia involves the Fas-FasL system. Soluble Fas which prevents the binding between membrane form of Fas and FasL is elevated in preeclampsia and may be responsible for the protection of maternal immune cells from apoptosis and consequently lead to increased apoptosis in trophoblasts.