Poster session I Clinical obstetrics, epidemiology, fetus, medical-surgical complications, neonatalogy, physiology/endocrinology, prematurity: Abstracts 87 - 236| Volume 208, ISSUE 1, SUPPLEMENT , S57-S58, January 01, 2013

102: Postpartum elevation of Toll-like receptor 1: innate immune system activation persists beyond the prototypical postpartum period


      Toll-like receptors are important mediators of the innate immune system that recognize structurally conserved protein sequences that are expressed by specific microorganisms. TLR 1 recognizes triacyl lipoproteins which are specifically expressed by bacteria. Immune system dysfunction may be causal or serve as a stimuli to preterm labor. There is limited information regarding basal expression of TLR 1 during pregnancies not affected by preterm labor. In this study, our objective was to investigate whether TLR 1 expression in healthy pregnant women changes longitudinally during a pregnancy and postpartum.

      Study Design

      We prospectively evaluated TLR expression in dendritic cells (DCs) of 20 healthy women during the 1st trimester (Collection 1), 2nd trimester (Collection 2), the day of delivery (Collection 3) and 6 weeks postpartum (Collection 4). TLR1/2 expression on DCs was measured by multicolor flow cytometry. TLR levels from each collections were compared to non-pregnant controls and to the postpartum collection. ANOVA and T-tests were used to assess statistical significance.


      Basal expression of TLR 1 was elevated throughout pregnancy in all trimesters and the postpartum collection relative to a non-pregnant cohort (p<0.001). TLR 1 expression was highest postpartum compared to the non-pregnant controls with mean TLR 1 expression being 78% (p< 0.001) above the non-pregnant control level.


      TLR 1 is elevated during pregnancy and postpartum in uncomplicated pregnancies. Since TLR 1 ligands are specifically associated with bacteria, we hypothesize that basal expression of TLR 1 increases following transient exposure to bacteria at delivery and remains elevated into the postpartum period. Postpartum TLR 1 levels have not yet returned to non-pregnant control levels suggesting that immune system adaptations persist beyond the prototypical puerperal stage. This information may be useful for future studies evaluating TLR 1 and preterm labor.
      Tabled 1Percentage increase in TLR 1 positive cells when compared to non-pregnant controls
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