Psoriasis is a common inflammatory skin disease resulting from dysregulation of the IL-23/TWe studied whether estradiol, a female hormone, plays protective roles in imiquimod-induced psoriatic inflammation in mice by regulating neutrophil and macrophage functions.Wild-type mice and conditional knockout mice were ovariectomized, supplemented with placebo or estradiol pellets, and an imiquimod-containing cream applied.Mice without endogenous ovarian hormones exhibited exacerbated psoriatic inflammation including increased production of IL-17A and IL-1β, which was reversed by exogenously added estradiol. The suppressive effect of estradiol on the production of IL-1β and IL-17A was abolished in mice lacking estrogen receptors in neutrophils and macrophages (Esr1Our results suggest a novel mechanism for sex-dependent differences in psoriasis clinical phenotypes that may shed new light on the pathology of psoriasis.