Expression Of Fas And FasL In Serum And Placenta In Preeclampsia

Background Preeclampsia is a common obstetric complication, affecting about 7-10% pregnant women. The etiology of preeclampsia is unknown..Abnormal activation of the immune system may play an important role in the pathogenesis. The Fas receptor ,a type I transmembrane protein belonging to the the tumor necrosis factor receptor family ,is expressed on numerous cell types. In contrast,FasL(ligand for Fas),a type II transmembrane protein, is limited to certain leukocytes and tissues with immune privilege. Both exist in vivo by forms of mFas/mFasL and sFas/sFasL.The FasL expressed on surface of effector cells then binds to Fas on the target cells and induces apoptosis.The Fas/FasL system induces apoptosis of activated lymphocytes in the tissues,giving them the characteristics of an immune-privileged site.FasL expression in trophoblast cells and Fas-FasL interaction may contribute to maintenance of immune privilege in pregnancy by inducing apoptosis of activated lymphocytes,thus preventing a deleterious immune reonse towards the conceptus.The disorder of Fas/FasL expressions at fetal-maternal interface would damage the fetal maternal immune balance.Abnormal expression of Fas/FasL,may be one of the important mechanisms of etiology of pre-eclampsia. To date,the results of investigations related to the expression of Fas/FasL on placenta in patients withpre-eclampsia are disparity. The immunologic mechanism between Fas /FasL and PEremains largely unknown.Objective To observe the serum and placental levels of Fas and FasL inpreeclampsia .To study the relationship between Fas/FasL and PE, and to investigatethe immunologic mechanism of the disease.Methods 40 pregnant women with preeclampsia and 39 healthy pregnant womenwere recruited and samples of serum and placentas were collected. Western blot wasused to detect the expression of Fas and FasL in placentas, and the ELISA method tothe concentration of soluble Fas and FasL in serum.Results Serum levels of soluble Fas in PE group were significantly higher than thatof healthy pregnant women (2.11±0.95ng/ml versus 1.57±0.60ug/ml, P<0.05), andserum levels of soluble FasL of PE group were significantly higher in comparisonwith controls (4.43±1.90 pg/ml versus 3.48±1.53pg/ml, P<0.01). But, there were nosignificant differences in Fas and FasL levels in placentas between PE group andhealthy pregnant women (P>0.05 for both).Conclusions The change of Fas/FasL is closely associated with preeclampsia, andelevated soluble Fas and FasL may play an important role in the pathogenesis of thedisease. Abnormal expression of Fas/FasL system, which weakens the immunologictolerance of the mother to her fetus, might be one of the important mechanisms ofpreeclampsia.