Preeclampsia is a human specific pregnancy complication. In this project we investigate if infection with HHV-6 is an underlying cause. To do this we infect human placental cells with the viruses. We want to know if viral infection alters DNA methylation, mRNA levels and microRNAs. Cells from 8 placentas have been infected with the viruses and un-infected cells are controls, in total we have 48 samples that have been analyzed with three different methods.