IL20 and psoriasis: For instance, excellent basic science results in the field of cytokines in psoriasis have been generated for IFN-α, IFN-γ, IL-20, or IL-22, but their in vivo neutralization with monoclonal antibodies in clinical trials did not improve psoriasis severity (4–7), indicating that those cytokines, despite their presence in the lesions, are not suitable for patients' treatment.