Elevations of group II phospholipase A(2) concentrations in serum and amniotic fluid in association with preterm labor

OBJECTIVE: The purpose of this study was to determine whether the elevation of secretory group II phospholipase Ag concentration in the serum and amni otic fluid in preterm labor is associated with intrauterine inflammation. STUDY DESIGN: Serum and amniotic fluid were collected from women with prete rm delivery (<37 weeks' gestation; n = 38) and term delivery (n = 20). Phos pholipase activity was measured with a highly sensitive system that was bas ed on reverse-phase high-performance liquid chromatographic separation of 9 -anthracenylmethyl derivatives of fatty acids released by phospholipase AP The concentrations of immunoreactive isozymes (group I or II) of secretory phospholipase A(2) were assayed with a radioimmunoassay kit with a monoclon al antibody against human pancreatic phospholipase A(2) and splenic IIA pho spholipase A(2). Localization of immunoreactive group II phospholipase A(1) in the amniotic membrane was determined by immunostaining visualized with the Vectastain ABC (Vector Laboratories, Inc, Burlingame, Calif) method. RESULTS: Enzymatic activities of phospholipase A(2) in the serum and amniot ic fluid specimens obtained from patients in preterm labor with chorioamnio nitis were significantly higher than those in specimens from patients in te rm labor. Significant elevations of phospholipase A(2) activities were obse rved in patients with preterm labor without histologically evident chorioam nionitis. The activity of phospholipase A(2) was clearly correlated with th e concentration of the immunoreactive group II phospholipase A(2). Group II phospholipase A(2) was localized in amniotic cells obtained from patients with a pathologically determined diagnosis of chorioamnionitis. The predict ive value for chorioamnionitis of the group II phospholipase A(2) concentra tion was relatively higher than the predictive values of the concentrations of C-reactive protein and interleukins 6 and 8. CONCLUSION: Significant elevations of group II phospholipase A(2) concentra tions were detected in the serum and amniotic fluid of women with preterm l abor. Group II phospholipase A(2) concentration may be a useful indicator f or preterm labor, and phospholipid metabolism is certainly activated both i n preterm labor and in apparent inflammatory diseases.