Th17 cells produce the effector cytokines IL-17 and IL-22, which activate signal transducer and activator of transcription (STAT) 3 signaling in keratinocytes, resulting in the synthesis of proinflammatory mediators, chemokines, and cytokines like IL-6, IL-8, GM-CSF, CXCL10, and CCL20, which drive the proliferation of epidermal keratinocytes to develop psoriasis lesions [62]. The gene discussed is IL22; the disease is psoriasis.