Increased levels of serum macrophage colony-stimulating factor before the onset of preeclampsia.

Macrophage colony-stimulating factor (M-CSF) is known to play a central role in maintaining pregnancy. The present study determined whether the increase in serum M-CSF levels preceded the onset of preeclampsia. Blood was collected from 110 normotensive pregnant women at risk for preeclampsia who were carrying single fetuses at about 30 weeks of gestation. After centrifugation, serum was stored at -20 degrees C until assay. Eighteen women developed preeclampsia at a later stage of pregnancy (group 1), while 88 women continued to have normotensive pregnancies until delivery. Thirty-four of the 88 women with normotensive pregnancy who were matched for age and parity were selected to form a control group (group 2). Serum M-CSF levels were determined by the sandwich ELISA method using three antibodies. Serum level of M-CSF was 1,266 U/ml (median) in group 1 and 1,082 U/ml in group 2. Serum M-CSF levels were significantly higher in group 1 than in group 2 (p < 0.0002). Increased levels of serum M-CSF markedly precede the development of clinical manifestations of preeclampsia. High serum M-CSF levels support M-CSF elevation in the placenta. This elevation at 30 weeks of gestation may be associated with placental hypoxia, which is considered the cause of preeclampsia.