For the treatment of psoriasis there is an on-going effort to increase the focus on the blockade of the type 17 inflammatory response, for example, by inhibition of IL-23p19 (refs 21, 56) or IL-17 (refs 18, 19, 20), which in recent clinical trials exhibiting even higher efficacy than ustekinumab30. Here, IL23A is linked to psoriasis.