IL4 and dry eye syndrome: To further define differences in gene expression between normal and psoriatic KCs, we scored the expression amounts of known cytokine response signatures by using a series of reference signature gene lists derived from population RNA-seq of cultured keratinocytes exposed to multiple cytokines including IL-17A, IL-4, IL-13, TNF-α, IFN-α, and IFN-γ (Figure S6D; Table S6; STAR Methods) (Tsoi et al., 2019).