Evidence for a polarized Th1 response in the maternal circulation in women with preterm labor and intra-amniotic inflammation/infection

OBJECTIVE: Most work examining the immune response to intra-amniotic infection has focused on the study of amniotic fluid (AF) cytokines. An adequate characterization of the full range of maternal pro- and antiinflammatory cytokines is lacking. This is important, because of emerging evidence that complications of infection result from an anti-inflammatory response. The purpose of this study was to characterize the maternal cytokine response in women with preterm labor with and without intra-amniotic infection/inflammation (IAI). STUDY DESIGN: This study focused on patients with preterm labor in the following groups: 1) term delivery (n = 157); 2) preterm delivery without IAI (n = 126); and 3) IAI (n = 50). IAI was defined as a positive AF culture or an elevated AF WBC count. Maternal plasma concentrations of interleukin (IL)-1b, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, interferon gamma, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor alpha were determined. A p!0.05 was considered significant. RESULTS: 1) Patients with IAI had higher plasma concentrations of IL-6 than those without IAI who delivered preterm [median: 12.5 pg/ml, range: 0-355.5 vs.7.4 pg/ml, range: 0.74-179.3; p = 0.04), and those who delivered at term (median: 5 pg/ml, range: 0-541.4; p = 0.01); 2) Patients with IAI had higher plasma concentrations of IL-8 than those who delivered at term (median:11.1 pg/ml, range: 0.29-82 vs. median: 6 pg/ml, range: 0.4-84.3; p = 0.02) but not than those without IAI who delivered preterm (median: 7.9, range: 1.3-90.2; pO0.05); and 3) There were no significant differences in the plasma concentrations of the rest of the cytokines (11 of 13) among groups. CONCLUSION: IL6 and IL8 are increased in the maternal circulation in cases of intra-amniotic infection/inflammation. The lack of a demonstrable anti-inflammatory response is in sharp contrast to what has been reported in non-pregnant patients