The present study immunolocalized CSF1 and MIF to decidual cells in sections of term decidua, and established that leukocyte-free, cultured decidual cells from first trimester and term placentas synthesize and secrete both chemokines. These findings extend previous observations of CSF1 and MIF expression in early decidua to include term decidua, and suggest that these chemokines are synthesized and secreted by decidual cells throughout pregnancy. Several lines of evidence prompted us to evaluate the effects of TNF and IL1B on term decidual cells. TNF and IL1B are expressed at the fetal-maternal interface.
The mRNA for TNF is present in syncytiotrophoblasts of the first trimester and term placentas and in the decidua at term. Immunoreactive IL1B has been detected in villous and extravillous trophoblasts, whereas TNF and IL1B secretion has been demonstrated in explants of term placentas and decidua.
The current results indicate that TNF and IL1B induce CSF1 output by cultured first trimester and term decidual cells. This finding suggests the existence of a novel autocrine/paracrine mechanism, through which TNF and IL1B enhance the production of the macrophage-targeting chemokine CSF1 in decidual cells throughout pregnancy in vivo.