IL17A and psoriasis: In particular, we studied the tofacitinib effect on JAK/STAT pathway and downstream inflammatory molecules in human keratinocyte cultures activated with proinflammatory molecules related to psoriasis, including IFN-γ, IL-22, IL-17, and TNF-γ, as well as in vivo in the imiquimod- (IMQ-) induced murine model of psoriasis.