Nelson and colleagues found that activation of TLR3 by polyriboinosinic-polyribocytidylic acid (polyI: C), simulating the viral dsRNA in keratinocyte cell culture (Takada et al., 2017), causes a loss of Keratin1 and filaggrin (markers of differentiated keratinocytes) and an increase in the expression of Lgr5 and Lgr6 HF progenitor markers as well as Krt15 (Nelson et al., 2015). Here, LGR5 is linked to hydrops fetalis.