Interleukin-6, tumour necrosis factor and soluble tumour necrosis factor receptors in women with pre-eclampsia

Generalised maternal endothelial cell dysfunction appears to be an underlying problem in pre-eclampsia presumed to be caused, directly or indirectly, by one or more circulating factors derived from the placenta. Recently it has been suggested that tumour necrosis factor (TNF) may play an important role in pre-eclampsia and contribute to endothelial activation. This study was designed to investigate this proposal.

Plasma TNF-alpha, IL-6 and both forms of soluble TNF receptors (p55 and p75 TNF-R) have been measured by ELISA in 31 pre-eclamptic patients and 31 pregnant controls matched for age, parity and gestational age.

Levels of IL-6, TNF-alpha and soluble TNF-R (p55 and p75) were significantly higher in pre-eclamptic patients, compared with age and gestation matched controls with a wide variation in levels between pre-eclamptic individuals. There was a correlation between levels of IL-6 and TNF or TNF-R and between TNF and TNF-R levels. However, when the pre-eclamptic patients were subdivided on the basis of the severity of their disease, the median values of plasma concentrations of IL-6, TNF-alpha and TNF-R were all higher in the group with lower platelet counts.

These new findings are consistent with the concept that the maternal syndrome of pre-eclampsia is associated with endothelial dysfunction and provide evidence that at least part of this dysfunction could arise from excessive release of TNF-alpha into the circulation.