Although new biological drugs targeting T cell activation molecules such as TNFα (such as etanercept, adalimumab, and infliximab), IL12 and IL23 (such as ustekinumab), IL23 (such as guselkumab, tildrakizumab, and risankizumab), IL17A (such as secukinumab and ixekizumab), or IL17 receptor A (such as brodalumab) have shown to be safe and efficacious in recent psoriasis clinical trials, however, lack of long-term efficacy and rapid regain of psoriasis upon removal of these drugs suggest that preventing adaptive immune activation alone is not sufficient to treat psoriasis. This evidence concerns the gene IL17A and psoriasis.