The increased maternal serum levels of IL-6 are associated with the severity and onset of preeclampsia

► We analysed IL-6 levels in early onset, late onset preeclampsia and severe and mild preeclampsia. ► Higher levels of IL-6 were seen in both early onset and late onset, and in severe preeclampsia. ► There was no difference in the level of IL-6 between early onset and late onset preeclampsia. ► Higher levels of IL-6 were not seen in mild preeclampsia. Preeclampsia is a complex disease of pregnancy with both feto-placental and maternal factors contributing to its pathogenesis. Although the cause of this disease is uncertain, imbalance between pro-and anti-inflammatory cytokines has been implicated in the pathogenesis of preeclampsia. Increased levels of the inflammatory cytokine IL-6 has been postulated to be involved in some ways in the pathogenesis of preeclampsia. However studies investigating whether levels of IL-6 in the maternal circulation differ between the disease severities or between times of onset of preeclampsia, or between preeclamptic pregnancies that are or are not complicated by fetal growth restriction (FGR) are limited. 104 women with preeclampsia and 75 health pregnant women were included into this study. The levels of IL-6 in maternal circulation were measured by enzyme-linked immunosorbent assay (ELISA). The levels of IL-6 in serum were significantly increased in women with preeclampsia in early onset and late onset preeclampsia compared to gestation matched health pregnant women. In addition, the levels of IL-6 were significantly increased in women with severe preeclampsia, but not with mild preeclampsia compared to gestation matched health pregnant women. Furthermore there was no correlation in IL-6 levels between preeclamptic with or without FGR. Our data shows increased level of circulating IL-6 levels in both women with early onset or late onset preeclampsia and in women with severe preeclampsia. These results suggest the excessive maternal inflammatory response in preeclampsia.