['To compare mRNA concentrations of corticotrophin-releasing hormone (CRH), placenta specific-1 (PLAC1), and selectin-P in preeclamptic and normal pregnancies.', 'Peripheral blood samples were obtained from 43 pregnant women with preeclampsia and 41 control subjects. Plasma was harvested from samples and RNA extracted. Plasma RNA was analyzed using reverse transcription polymerase chain reaction (PCR) assay. Median concentrations of CRH, PLAC1, and selectin-P mRNA in plasma were compared, to assess possible differences in distribution. Data were also stratified and compared according to clinical severity of preeclampsia. Finally, CRH, PLAC1, and selectin-P were plotted against quantitative distributions of blood pressure and proteinuria.', 'All markers were differently distributed between cases and controls. Median values in subgroups correlated with severity of preeclampsia. All markers correlated with both. Selectin-P was identified as the marker with the highest degree of correlation. No correlation was found between any markers in the control group and proteinuria or blood pressure.'] Are cell-free mRNA concentrations of CRH , PLAC1 , and selectin-P increased in the plasma of pregnant women with preeclampsia?