IL17A and psoriasis: It is found that the level of CCL20 and CCR6+T cells increases greatly in the imiquimod-induced psoriasis mouse model and that CCR6+ γδ T cells infiltrate in the skin producing IL-17A and IL-22 in the IL-23-induced psoriasis model.87,88 Thus, it seems that the CCL20/CCR6 axis plays a vital role in the pathogenesis of psoriasis.