Patients with PN at baseline have previously been found to show an upregulation in epithelial mesenchymal transition, especially compared with patients with psoriasis or atopic dermatitis.18 Epithelial mesenchymal transitioning, a process commonly elevated in inflammation and mediated by TGF-β, leads to tissue fibrosis if overactivated and may reflect a decrease in dermal fibrosis among the nemolizumab group compared with the placebo group.43 This evidence concerns the gene TGFB1 and psoriasis.