The current (2022/3) best available evidence indicates that immune suppressing monoclonal antibodies directed against IL17, IL12/23, IL23 alone or TNFα, either alone or in combination with non-biological systemic DMARD's (e.g., MTX or Cyclosporin-A) aremore efficient than DMARD's alone in treating patients with moderate-to-severe psoriasis and PsA, although these immune suppressive interventions may have heightened risk of side-effects. This evidence concerns the gene IL17A and psoriasis.