IMQ is a ligand for Toll like receptors (TLR7 and TLR8) and when topically applied produces psoriasis-like skin lesions in mice which display many of the same characteristics as those observed in psoriasis in humans; elevations of IL-23/IL-17[15] and the dependency upon IL-22 to develop the lesions [20]. The gene discussed is IL23A; the disease is psoriasis.