It is possible that syncytiotrophoblast could synthesize and release excessive amounts of proinflammatory cytokines such as TNF-alpha or IL-6 [31], but an analysis of production from chorionic villous explants failed to show the expected increase in protein or mRNA for TNF-alpha, IL-6, IL-1alpha, and IL-1beta in tissue from preeclampsia compared to that from normal pregnancy [32]. Here, IL6 is linked to preeclampsia.