Antiphospholipid antibodies inhibit prostaglandin release by decidual cells of early pregnancy: possible involvement of extracellular secretory phospholipase A 2

Abstract

Objective: To investigate the effect of antiphospholipid antibodies on eicosanoid production by human decidual cells and the in vitro interaction between antiphospholipid antibodies and secretory phospholipase A 2. Design: Cultures of human decidual cells from early pregnancy. Setting: All decidual specimens were obtained from the Obstetrics and Gynecology Department of the Catholic University, Rome, Italy. Patient(s): Patients were undergoing operative laparoscopy for extrauterine pregnancy, with a period of amenorrhea ranging from 6 to 9 weeks. Intervention(s): Decidual samples were collected at laparoscopy by routine uterine curettage. Main Outcome Measure(s): Decidual cells were incubated with antiphospholipid antibodies, and eicosanoids (prostaglandin [PG] E 2, PGF 2α, and thromboxane B 2) were assayed by RIA after 24 hours of culture. In vitro interactions between antiphospholipid antibodies and secretory phospholipase A 2 were investigated with use of a modified ELISA for phospholipase A 2. Result(s): Antiphospholipid antibodies reduced eicosanoid release from decidual cells in a dose-dependent fashion. In vitro assays showed that antiphospholipid antibodies bound secretory phospholipase A 2 and that a competition occurred between antiphospholipid antibodies and secretory phospholipase A 2 for the common substrate cardiolipin. Conclusion(s): In light of the critical role played by eicosanoids in decidual function, we suggest that an interaction between antiphospholipid antibodies and secretory phospholipase A 2 occurring in vivo might impair important cellular communications at the decidual level in the antiphospholipid antibody syndrome.