Intra-amniotic infusion of IL-6 results in the infiltration of macrophages in the chorion trophoblast cell layer of rhesus monkeys [145], the expression of TNF-α converting enzyme (TACE), which is essential for the release of TNF-α, increases in the fetal membranes with chorioamnionitis as compared to those from normal pregnancies, and in parallel there is an increased infiltration of monocytes/macrophages within the choriodecidua tissues [233]. This evidence concerns the gene IL6 and chorioamnionitis.