JAK2 and psoriasis: In addition, baricitinib mainly acts on JAK1 and JAK3 and downregulates cytokines such as interferon-γ, IL-12, IL-17, and IL-23,502,503 and ruxolitinib acts on JAK1 and JAK2, thereby inhibiting the phosphorylation of STAT3 and promoting Th17 cell apoptosis504; both of them are first-generation JAK inhibitors and are effective for the treatment of psoriasis.