Immunomodulation in Normal Pregnancy and Pre-Eclampsia

Abstract

Wegmann et al proposed that in normal pregnancy there is bias of the maternal immune system away from potentially damaging type-1 inflammatory responses towards type-2 responses. The corollary of this hypothesis is that a bias towards type-1 responses will be detrimental to pregnancy. Many of the features of the maternal syndrome of pre-eclampsia could be caused by inappropriate activation of maternal inflammatory cell responses. To investigate this we have used flow cytometry to analyse markers of inflammation (CD11b, CD64, CD62L, HLA-DR and intracellular reactive oxygen species (iROS) in leucocytes from non-pregnant, normal pregnant and pre-eclamptic women. Although there was significantly lower expression of CD62L and significantly higher levels of iROS in pre-eclampsia compared to normal pregnant women, the differences between pre-eclampsia and normal pregnancy were in many respects less startling than those between normal pregnant and non-pregnant controls. Compared to samples from non-pregnant women, leucocytes from normal pregnant women showed significantly higher levels of CD lib, CD64 and iROS. Thus we were able to confirm and extend the concept that there is a generalised change in circulating leucocytes, during pre-eclampsia, characteristic of inflammation. But the new observation, that normal pregnancy itself is already characterised by such a response was unexpected, and leads to a new perspective of immunomodulation in pregnancy.