Cytokine release from placental endothelial cells, a process associated with preterm labour in the absence of intrauterine infection

There is currently a great deal of interest in the role that cytokines may play in the processes mediating preterm as well as normal term labour. In c ase of preterm delivery a cause-effect relationship between infection, unco ntrollable preterm labour, and increased uterine cytokine concentrations is widely accepted, but there is considerable information that increased uter ine cytokine release is also a condition in normal term labour and preterm labour not due to infection. Thereby, the exact cellular sources of cytokin e production have not yet been identified. In the present study, the author s used immunohistochemical analysis to localize interleukin 1 beta (IL-1 be ta), interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) immu noreactivity within trophoblastic villi and fetal membranes. In the absence of chorioamnionitis, uncontrollable preterm labour, and also normal term l abour was associated with strong immunoreactivity for IL-1 beta and IL-6 in the endothelial cells within trophoblastic villi. In contrast, preterm del ivery accompanied by histologically confirmed chorioamnionitis, was not ass ociated with increased expression of cytokine antigens within endothelial c ells of the fetal vascular system, but strong cytokine activity was found i n polymorphonuclear cells infiltrating the amniochorionic membranes. Theref ore, the data suggest two well-defined subgroups among patients delivering preterm. Thereby, increased uterine cytokine concentrations may be realized in both groups, but the,cellular sources of cytokine production may be dif ferent. (C) 1999 Academic Press.