S100A8 and S100A9 are messengers in the crosstalk between epidermis and dermis modulating a psoriatic milieu in human skin

► Upregulated S100A8 and/or S100A9 in psoriasis epidermis induce cytokine production. ► Upregulated S100A8 and/or S100A9 in psoriasis epidermis induce migration of immune cells. ► Upregulated S100A8 and/or S100A9 in psoriasis epidermis induce angiogenesis. ► S100A8 and/or S100A9 may play a role in the crosstalk between epidermis and dermis in psoriasis.