Problem: The aim of this study was to compare the expression levels of Fas and Fas ligand (FasL) in first-trimester placentas obtained from spontaneous abortions in patients with antiphospholipid antibody syndrome (APS) or factor V (FV) Leiden mutation, compared with values in placentas from induced abortions in patients negative for these conditions.
Method of study: We studied explants from 6- to 10-week-old placentas that had been prepared by collagenase digestion from 10 spontaneous abortions from APS-positive patients, nine spontaneous abortions in patients positive for FV Leiden mutation, and 10 induced abortions. All tissues were analyzed by flow cytometry for expression of Fas and FasL.
Results: Flow cytometric analysis showed that placental FasL expression was significantly lower in abnormal pregnancies than in normal ones. However, no such difference was observed for Fas expression.
Conclusion: FasL on placental cells may be involved in the maintenance of immune privilege, thereby ensuring the safety and growth of placental tissues. Dysregulation of apoptotic mechanisms may play a critical role in spontaneous abortions.