Consequently, exposure of keratinocytes to the IFN-γ/IL-17A/IL-22 cytokine combination represents a reliable psoriasis-like in vitro model (Kim et al., 2014; An et al., 2018; Kim et al., 2018; Shi et al., 2018; Zhang et al., 2018; Li et al., 2020). The gene discussed is IL22; the disease is psoriasis.