IL‐1β induces thymic stromal lymphopoietin and an atopic dermatitis‐like phenotype in reconstructed healthy human epidermis

2 polarization. Recent studies suggest that IL-1β contributes to the development of AD skin inflammation. Here, we have investigated the impact of IL-1β signalling on the epidermal homeostasis of both healthy subjects and AD patients [with functional filaggrin (FLG) alleles], with particular attention to TSLP production and keratinocyte differentiation. In healthy reconstructed human epidermis (RHE), IL-1β promoted (i) robust secretion of TSLP in an NF-κB-dependent manner and (ii) a significant decrease in the expression of filaggrin and other proteins of the epidermal differentiation complex. These effects were prevented by treatment of RHE with the anti-IL-1β mAb canakinumab and by the IL-1 receptor antagonist anakinra. Interestingly, RHE generated from AD donors behaved like that of healthy individuals and showed comparable responses to IL-1β signals. Collectively, our results suggest that IL-1β may be an early key mediator for the acquisition of an AD phenotype through induction of TSLP and alteration of the epidermal homeostasis. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.