Serum markers of macrophage activation in pre-eclampsia: no predictive value of soluble CD163 and neopterin

Background. Alternatively activated macrophages expressing the CD163 and CD206 surface receptors are the dominant immune-cell type found in the placenta. The placental number and distribution of macrophages is altered in pre-eclampsia, and the generalised inflammatory reaction associated with pre-eclampsia might lead to shedding of soluble CD163 into the circulation. Methods. Serum samples from 18 women with pre-eclampsia and 90 normal pregnancies were obtained from a longitudinal study of 955 pregnant women at Randers County Hospital, Denmark. sCD163 and Neopterin were measured by ELISA on samples collected in weeks 18, 28, 32, and 38 of pregnancy. Results. sCD163 levels in pregnancy ( 2 - 3 mg/l) were similar to previously measured levels in non-pregnant women, and did not increase from week 18 to 38. There was a tendency towards higher sCD163 in week 38 in pre-eclamptic women compared to healthy women. Neopterin increased throughout pregnancy in both healthy ( from median 5.4 to 6.7 nmol/l, p < 0.0001) and pre-eclamptic women ( from 5.0 to 8.0 nmol/l, p < 0.0001), but there were no differences between groups at any time-point. sCD163 correlated to neopterin in both the control ( r = 0.25, p < 0.0001) and in the pre-eclampsia group ( r = 0.32, p = 0.011). C-reactive protein was higher in pre-eclampsia than in healthy pregnancies by week 38 ( 159 versus 91 nmol/l, p = 0.0189). Conclusions. The macrophage serum-markers sCD163 and neopterin are not pre-symptomatic nor prognostic markers for pre-eclampsia.