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

Objective: To investigate the effect of antiphospholipid antibodies on eico sanoid production by human decidual cells and the in vitro interaction betw een 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 Gynec ology 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 antiphospholipi d antibodies, and eicosanoids (prostaglandin [PG] E-2, PGF(2 alpha), and th romboxane B-2) were assayed by RIA after 24 hours of culture. In vitro inte ractions between antiphospholipid antibodies and secretory phospholipase A( 2) were investigated with use of a modified ELISA for phospholipase A(2). R esult(s): Antiphospholipid antibodies reduced eicosanoid release from decid ual cells in a dose-dependent fashion. In vitro assays showed that antiphos pholipid antibodies bound secretory phospholipase A(2) and that a competiti on 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 decid ual function, we suggest that an interaction between antiphospholipid antib odies and secretory phospholipase A(2) occurring in vivo might impair impor tant cellular communications at the decidual level in the antiphospholipid antibody syndrome. (Fertil Steril(R) 1999;71:342-6. (C) 1999 by American So ciety for Reproductive Medicine.)