Tumor necrosis factor-alpha is decreased in the umbilical cord plasma of patients with severe preeclampsia.

We investigated the role of the fetal immune system in pregnancies complicated by preeclampsia by assessing umbilical cord plasma levels of the cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta). Nineteen nulliparous patients with severe preeclampsia composed the study group (group A). A comparison group was comprised of 19 healthy nulliparous patients with uneventful pregnancies (group B). Mixed umbilical cord blood was collected immediately after delivery. Plasma was prepared and all samples were assayed for TNF-alpha and IL-1beta by specific enzyme-linked immunoassays (ELISAs). Data are presented as the median with range of values. The length of labor was similar in both groups. TNF-alpha was detected less frequently in the umbilical cord plasma of preeclamptic patients than in the umbilical cord plasma of control patients (57.9 vs. 89.5%, p < 0.05), and the concentrations of TNF-alpha were significantly lower in the umbilical cord plasma of the preeclamptic patients [20 pg/ml (0-80 pg/mL) vs. 50 pg/mL (0-310 pg/mL), p < 0.05]. Umbilical cord plasma IL-1beta detection rates and concentrations from the preeclamptic and control patients were similar, [15.8 vs. 5.3%, 0 pg/mL (0-40 pg/mL) vs 0 pg/mL (0-10 pg/mL)]. The lower concentrations of TNF-alpha in umbilical cord plasma of patients with severe preeclampsia suggest that release of TNF-alpha by the fetus and mother are independent and may reflect adaptation of the fetus to reduced placental perfusion in preeclampsia.