Expression of cytokine receptors in the placenta in term and preterm labour

Elevated uterine concentrations of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumour-necrosis factor-alpha (TNF-alpha) are suspected to cause increased prostaglandin release from gestational tissues, out little information is available about the expression pattern of cytokine receptors in these tissues. In this study, cytokine receptor positive cells in frozen tissue sections of placentae (n=70) and fetal membranes (n=50) were identified by immunohistological staining with monoclonal antibodies specific for IL-6 receptor, TNF receptors I and II, and IL-1 receptor I. Both subunits of the IL-6 receptor (gp130 and gp80) as well as TNF receptors I and II were expressed by fetal endothelial cells within placental villi, while IL-l-receptor I was detected exclusively in stromal cells of the maternal decidua. The IL-1 receptor I and TNF receptors I and II were expressed in both uterine quiesence and labour, irrespective of gestational age. Immunoreactivity of the gp130 subunit of the IL-6 receptor was found also throughout pregnancy, while the appearence of the gp80 subunit correlated with the presence of term and preterm labour. In case of preterm labour, expression of the gp80 subunit was predominantly detected in the absence of intrauterine infection. Therefore, it is concluded that the de novo expression of the gp80 subunit and consequently the appearance of entire IL-6 receptors in the placenta is associated with spontaneously occurring labour at term and also with preterm occurring labour in the absence of inrauterine infection. (C) 1998 W. B. Saunders Company Ltd.