IL17A and psoriasis: In Europe, for moderate to severe psoriasis, systemic drugs are the treatments of choice subdivided in a first line of conventional drugs (methotrexate, cyclosporine A and retinoids) and a second line of biologic drugs approved for psoriasis and psoriatic arthritis (TNF-α inhibitors [infliximab, etanercept, adalimumab], IL-12 and 23 blockers [ustekinumab and guselkumab] and anti-IL17 [secukinumab, ixekizumab and brodalumab]) or for arthropathic psoriasis (golimumab, a TNF-α inhibitor) [4].