GRP and atopic eczema: Based on the finding showing that GRP expression was increased in dermal immune cells, afferent nerves, and neurons in skin-innervating DRG of IL-22 transgenic atopic dermatitis murine model and IL-22-treated human keratinocytes [57], IL-22 may be involved in the activation of the GRP receptor pathway, an itch-specific pathway [113,114].