Preeclamptic women have decreased circulating IL-10 values at the time of preeclampsia diagnosis: Systematic review and meta-analysis

A key immunomodulatory cytokine, Interleukin-10 (IL-10), has been shown to be dysregulated in preeclampsia, a pregnancy-specific hypertensive disorder, further characterized by multi-system involvement. However, studies have reported inconsistent findings about circulating IL-10 levels in preeclamptic versus normotensive pregnancies. The aim of the present systematic review and meta-analysis was to assess circulating IL-10 levels in preeclamptic and normotensive pregnancies at two time points: before, and at the time of preeclampsia diagnosis. PubMED, EMBASE and Web of Science databases were searched to include all published studies examining circulating IL-10 levels in preeclamptic and normotensive pregnancies. Differences in IL-10 levels were evaluated by standardized mean differences (SMD). Of 876 abstracts screened, 56 studies were included in the meta-analysis. Circulating IL-10 levels were not different before the time of active disease (SMD: −0.01, 95% confidence interval [CI]: −0.11, 0.08; P = 0.76). At the time of active disease, women with preeclampsia (n=1599) had significantly lower IL-10 levels compared to normotensive controls (n=1998) (SMD: −0.79, 95% CI: −1.22, −0.35; P = 0.0004). IL-10 levels were lower in both early/severe and late/mild forms of preeclampsia. Subgroup analysis revealed that IL-10 measurement methodology (ELISA or multiplex bead array) and the sample type (plasma or serum) significantly influenced the observed differences, with the use of sera paired with ELISA technology providing the best distinction in IL-10 levels between preeclamptic and normotensive pregnancies. These findings support the role of decreased IL-10 levels in the pathophysiology of preeclampsia. Future studies should address the therapeutic potential of IL-10 in preeclampsia.