When shC and shPML HF cells were infected with UV-inactivated HCMV (UV-HCMV), the mRNA levels of ISGs, such as ISG54, CXCL10, PKR, ISG15, and USP18 were less efficiently induced in PML-knockdown cells than in control cells (Fig. 1A). This evidence concerns the gene USP18 and hydrops fetalis.