IL-17C: A Unique Epithelial Cytokine with Potential for Targeting across the Spectrum of Atopic Dermatitis and Psoriasis.

Both atopic dermatitis (AD) and psoriasis are characterized by complex inflammatory circuits that may be regulated through "feed-forward" mechanisms in the epidermis that amplify cellular immune responses through production of keratinocyte-derived cytokines and inflammatory mediators. IL-17C is a unique cytokine that is produced by keratinocytes and that is involved in such synergistic loops that may be responsible for amplifying the inflammation in both diseases. This may ultimately lead to induction of S100As and other molecules that accompany epidermal hyperplasia. Thus, antagonism of IL-17C may be beneficial in both psoriasis and AD patients. The IL-17C neutralizing antibody MOR 106 was able to inhibit both T helper type 2 cells and T helper type 17/T helper type 22-skewed inflammatory loops that drive different features of AD and psoriasis. The therapeutic potential of IL-17C antagonism in AD is supported by a recently reported small phase 1 clinical trial in patients with AD.