Immunofluorescence staining indicated that DDX5 protein was highly expressed in epidermal keratinocytes from healthy skin of humans and mice (Fig. 1h–k), but was almost undetectable in whole lesional skin from patients with AD and psoriasis and MC903- or IMQ-treated mice (Fig. 1h–k), indicating a reduction in keratinocyte DDX5 in inflamed skin in humans and mice. This evidence concerns the gene DDX5 and Alzheimer disease.