Maternal plasma-soluble ST2 concentrations are elevated prior to the development of early and late onset preeclampsia – a longitudinal study

<b>Objective:</b> The objectives of this study were to determine (1) the longitudinal profile of plasma soluble ST2 (sST2) concentrations in patients with preeclampsia and those with uncomplicated pregnancies; (2) whether the changes in sST2 occur prior to the diagnosis of preeclampsia; and (3) the longitudinal sST2 profile of women with early <i>or</i> late preeclampsia. <b>Materials and methods:</b> This longitudinal nested case–control study included singleton pregnancies in the following groups: (1) uncomplicated pregnancies (<i>n</i> = 160); and (2) those complicated by early (&lt;34 weeks, <i>n</i> = 9) and late (≥34 weeks, <i>n</i> = 31) preeclampsia. sST2 concentrations were determined by enzyme-linked immunosorbent assays. Mixed-effects models were used for the longitudinal analysis. <b>Results:</b> (1) Plasma sST2 concentration profiles across gestation differed significantly among cases and controls (<i>p</i> &lt; 0.0001); (2) women with early preeclampsia had higher mean sST2 concentrations than controls at &gt;22 weeks of gestation; cases with late preeclampsia had higher mean concentrations at &gt;33 weeks of gestation (both <i>p</i> &lt; 0.05); and (3) these changes started approximately 6 weeks prior to clinical diagnosis. <b>Conclusions:</b> Maternal plasma sST2 concentrations are elevated 6 weeks prior to the clinical diagnosis of preeclampsia. An increase in the maternal plasma concentration of sST2 may contribute to an exaggerated intravascular inflammatory response and/or the Th1/Th2 imbalance in some cases.