Taking into account (a) the preferential cytokine environment in AD vs psoriatic lesions and (b) those of these cytokines able to target keratinocytes [14], we design in vitro experiments aiming to culture NHEK and RHE with an IL-22, TNFα, IL-4, and IL-13 mix or an IL-22, TNFα, and IL-17 mix, with the objective to, respectively, mimic AD and psoriasis epidermis. The gene discussed is IL17A; the disease is psoriasis.