741: Changes in the cytokine TRAIL during pregnancy: a potential explanation for the susceptibility of pregnant women to the effects of infection

741 Changes in the cytokine TRAIL during pregnancy: a potential explanation for the susceptibility of pregnant women to the effects of infection Piya Chaemsaithong, Roberto Romero, Tamara Stampalija, Zhong Dong, Lami Yeo, Edgar Hernandez-Andrade, Sonia Hassan, Tinnakorn Chaiworapongsa NICHD/NIH/DHHS, Perinatology Research Branch, Detroit, MI, Wayne State University School of Medicine, Department of Obstetrics and Gynecology, Detroit, MI OBJECTIVE: Pregnancy is characterized by activation of the innate immune response and suppression of adaptive immunity, which promotes fetal immune tolerance. Pregnant women with infection develop sepsis and acute respiratory distress syndrome (ARDS) more frequently than non-pregnant women. The cytokine TRAIL (Tumor necrosis factor-Related Apoptosis-Inducing Ligand), has been implicated in the tolerance of the fetus. Knock-out mice for TRAIL have delayed neutrophil apoptosis and resolution of the inflammation after an injection of endotoxin. The aim of this study was to determine if maternal plasma concentrations of the soluble form of TRAIL (sTRAIL) change during normal pregnancy and pregnancy with acute infection. STUDY DESIGN: A cross-sectional study was conducted to include women in the following groups: 1) non-pregnant (n 23); 2) normal pregnant (n 93); and 3) pregnant with acute pyelonephritis (n 23). Plasma concentrations of sTRAIL were determined by ELISA. RESULTS: 1) Normal pregnant women had a lower mean plasma sTRAIL concentration than non-pregnant women (31.5 10.1 pg/mL vs. 53.3 12.5 pg/mL; p 0.001); 2) plasma sTRAIL concentrations did not change with gestational age (Pearson correlation -0.1; p 0.4); 3) the mean plasma concentration of sTRAIL was significantly lower in pregnant women with acute pyelonephritis than in those with normal pregnancy (19.8 8.2 pg/mL vs. 31.5 10.1 pg/ mL; p 0.001); and 4) patients with positive blood and urine cultures had a significantly lower sTRAIL concentration than those with only a positive urine culture (13.5 7.7 pg/mL vs. 24.7 4.6 pg/mL; p 0.001). CONCLUSION: 1) Pregnancy is associated with a lower maternal plasma sTRAIL concentration; and 2) patients with acute infection during pregnancy had a lower maternal plasma concentration of sTRAIL than those without evidence of infection. We propose that TRAIL may contribute to the increased risk of sepsis in pregnant women with an infection. 742 Racial differences in vaginal flora and cytokine concentrations during pregnancy Brenna Anderson, Riana Dutt, Christina Raker Alpert Medical School of Brown University/Women & Infants’ Hospital, Division of Maternal Fetal Medicine, Providence, RI, Alpert Medical School of Brown University/Women & Infants’ Hospital, Division of Research, Providence, RI OBJECTIVE: Pregnant women may be at increased risk of HIV acquisition. This risk appears greatest among non-Caucasian women. Our objective was to investigate racial differences in local and systemic immunity in the genital tracts of pregnant Caucasian and non-Caucasian women. STUDY DESIGN: Pregnant women at low risk for immune disruption, ages 18-35 were enrolled in a prospective observational cohort at 14 weeks gestation. Exclusion criteria included history of medical or obstetrical complications, recent infections, vaginal symptoms, tobacco use, or fetal anomalies. Study visits were conducted each trimester and postpartum. Semi-quantitative vaginal cultures were performed at a reference laboratory. Concentrations of cervical cytokines, serum Creactive protein (CRP), and vaginal secretory leukocyte protease inhibitor (SPLI) were measured via multiplex bead assay and standard ELISA and compared between Caucasian and non-Caucasian women. Categorical variables were compared by Fisher’s exact test, and continuous variables were compared between groups by the Wilcoxon rank-sum test. RESULTS: 47 pregnant women were included, 21 non-Caucasian and 26 Caucasian, only one of whom had evidence of asymptomatic bacterial vaginosis by Amsel criteria. In the second trimester, non-Caucasian women were more likely to be colonized with Gardnerella vaginalis (62% vs. 25%, p 0.02) and non-pigmented anaerobic gram negative rods (43% vs. 8%, p 0.01) than were Caucasian women. Mycoplasma hominis was more frequently isolated in non-Caucasian women throughout the second (29% versus 4%, p 0.03) and third trimesters (35% versus 6%, p 0.04). Non-Caucasian women had higher median interleukin (IL)-10 concentrations throughout the second (128 pg/mL versus 7 pg/mL, p 0.05) and third trimesters (224 pg/mL versus 7 pg/mL, p 0.05). CONCLUSION: Racial differences in colonization of the genital tract were most apparent in the second trimester, during which non-Caucasian women experienced a greater diversity of microorganisms and increased IL-10.