These natural immune mediators stimulate the  overproliferation of key T lymphocyte subsets such as Th1, Th17 and Th22, releasing additional cytokines and chemokines such as IL‐17, IL‐22, TNF‐α, and IFN‐γ, triggering a cascade response in psoriasis.1, 6. The gene discussed is IL17A; the disease is psoriasis.