NOS2 and psoriasis: TNF‐α, IL‐1β, IL‐23, IL‐17, IL‐22, Cox2, and iNOS are all inflammatory cytokines involved in the pathogenesis of psoriasis,32, 33 and CXCL1, CXCL8, and CCL20 are antimicrobial peptides and chemokines produced by keratinocytes.34