By determining the levels of a number of innate immune effectors in the choroid plexus in neonates and adults, they also identified significantly lower levels of the IFN receptor (IFNAR) in the neonate choroid plexus as a cause of susceptibility to HSV-1, providing an increased understanding of HSE pathogenesis in newborns. This evidence concerns the gene IFNAR1 and herpes simplex encephalitis.