IL17A and psoriasis: Biological drugs target various cytokine pathways related to the pathogenesis of psoriasis, such as tumor necrosis factor α (TNF-α) (adalimumab, certolizumab, etanercept, infliximab), the p40 subunit of IL-12 and IL-23 (ustekinumab), IL-17A (ixekizumab, secukinumab), IL-17 receptor (brodalumab), and the p19 subunit of IL-23 (guselkumab, risankizumab, and tildrakizumab) [12].