Toll-like receptor-2 and -4 in the chorioamniotic membranes in spontaneous labor at term and in preterm parturition that are associated with chorioamnionitis

Objective The Toll-like receptor-2 and -4 recognize microbial products that are associated with gram-positive and gram-negative bacteria, respectively. This study examined Toll-like receptor-2 and -4 expression in fetal membranes in response to labor at term and histologic chorioamnionitis. Study design Immunohistochemistry and real-time quantitative reverse transcriptase-polymerase chain reaction were used to examine the chorioamnion from patients with (1) preterm labor and intact membranes, (2) preterm premature rupture of membranes who were delivered ≤34 weeks of gestation, and (3) women at term with or without labor. All groups were stratified on the basis of the presence of histologic chorioamnionitis. Results Toll-like receptor-2 expression was significantly higher in patients with chorioamnionitis than in patients without this condition (all P< .05). The Toll-like receptor-2 and -4 messenger RNA amounts were significantly higher in membranes from women at term with spontaneous labor than women who were not in labor (P = .001 and .002, respectively). Toll-like receptor-2 expression was polarized to the basal surface of amniotic epithelial cells in patients without chorioamnionitis, but this distribution was lost in the presence of inflammation. Conclusion Spontaneous labor at term and preterm delivery with histologic chorioamnionitis, regardless of the membrane status (intact or ruptured), are associated with an increased expression of Toll-like receptor-2 and -4 in the chorioamniotic membranes. These observations have implications for understanding the biologic nature of innate immunity.