Elevation of amniotic fluid interleukin 6 (IL-6), IL-8 and granulocyte colony stimulating factor (G-CSF) in term and preterm parturition.

We determined the levels of inflammatory cytokines such as interleukin 6 (IL-6) granulocyte-colony stimulating factor (G-CSF) and IL-8 in the amniotic fluids from women with premature or term delivery. Cytokines were detectable even in the absence of apparent infection (group 1), but much higher cytokine levels were found in cases of intrauterine infection, particularly in cases of premature delivery (group 2). In cases of term delivery (groups 3-5), all of the cytokine levels showed c. 3- to 4-fold increase during labor pain (group 4) and an 8- to 13-fold increase in the presence of endotoxin (group 5), in comparison with the levels in cases where neither factor was present (group 3). Regarding infection, the cytokine levels were 20- to 30-fold higher in chorioamnionitis-positive premature delivery group (group 2), than in the infection-negative group (group 1). All the cytokines were simultaneously induced in amniotic fluid by labor pain and infection, and a significant positive correlation was observed among these three cytokine levels. In-vitro culture system and immunohistochemical study indicated that the cytokines in the amniotic fluid appeared to originate from trophoblasts and decidual cells. Thus, infection and labor pain may trigger the production of inflammatory cytokines at term as well as premature delivery and the determination of these cytokine levels will be a good indication for the prediction of the presence of intrauterine infection.