Cytokine production and visualized effects in the feto-maternal unit. Quantitative and topographic data on cytokines during intrauterine disease.

BACKGROUND

A large array of cytokines show high activity in amniotic fluid. Attempts have been made to quantify the concentrations or to track rising levels for diagnostic purposes when examining disturbances of the feto-maternal unit. However, the kinetics of cytokine production in the amniotic fluid are not well understood, and there is lack of knowledge about concomitant levels in fetal and maternal blood.

EXPERIMENTAL DESIGN

The presence of cytokines in fetal and placental cells was demonstrated by immunohistochemistry using mAb. Cytokines were quantified by enzymimmunoassay in amniotic fluid and fetal and maternal blood. This was done with regard to two disease states that quite frequently complicate the course of pregnancy, namely chorioamnionitis and intrauterine growth retardation. The cytokines examined were G-CSF, GM-CSF, TNF-alpha, IL-1, IL-6, and IL-8.

RESULTS

In chorioamnionitis, all cytokines, except GM-CSF, were elevated about 100 times in the amniotic fluid. An accompanying increase in maternal and fetal blood was only found for IL-6 and G-CSF; IL-8 was elevated in fetal blood only. Intrauterine growth retardation was characterized by elevated levels of TNF-alpha in the amniotic fluid, whereas G-CSF, GM-CSF, and IL-1 beta were significantly reduced. Immunohistochemistry showed that under normal conditions the cytokines are to be found in a characteristic distribution in certain cell types in the fetus, the placenta, and the placental bed. With rising concentrations, more cells seemed to be recruited for cytokine production, especially macrophages and decidual cells. In chorioamnionitis, fetal extramedullary granulopoiesis was augmented, and in intrauterine growth retardation, erythropoiesis as well as granulopoiesis were depressed.

CONCLUSIONS

Not only inflammatory disease but also intrauterine growth retardation is characterized by a changing cytokine pattern. Alterations in fetal hematopoiesis observed at postmortem examination of perinatal deaths can be correlated to changes in cytokine production within the feto-maternal unit.