As soon IL-22 has been described to target keratinocytes, it has been observed that the cytokine induces a “psoriasis-like” phenotype on RHE, that is, hyperplasia with a thickening of the spinous layer and a disappearance of the granular layer [6, 11], and that the expression and secretory patterns of IL-22-treated keratinocytes resembled most of the features of psoriatic lesions [54]. Here, IL22 is linked to psoriasis.