Placental expression of a novel primate-specific splice variant of sFlt-1 is upregulated in pregnancies complicated by severe early onset pre-eclampsia.

sFlt-1 is increased in the placenta and serum of women with pre-eclampsia. A novel primate-specific splice variant has recently been discovered, but its expression in severe pre-eclampsia has yet to be reported. We investigated placental expression of the previously described variant, sFlt-1/sFlt-i13, and the novel variant, sFlt-e15a, in pregnancies complicated by severe early onset pre-eclampsia (n = 14) and HELLP (haemolysis, elevated liver enzymes and a low platelet count) syndrome (n = 8). There was significant upregulation of both variants in pre-eclampsia and HELLP syndrome compared with normotensive term (n = 35) and preterm controls (n = 8). We conclude that the novel primate-specific splice variant of sFlt-1 is highly expressed in both severe pre-eclampsia and HELLP.