IL17A and psoriasis: IL-23 regulates Th17 cells and promotes secretion of IL-17 and IL-22 through activation of JAK2 and TYK2 [11, 12••] 1) which are important for the disease process of psoriasis and PsA so tofacitinib (pan JAKi, which includes JAK2 inhibition) and deucravacitinib (TYK 2 inhibitor) are likely countering IL-23 activation by inhibiting JAK2 and TYK2, respectively, and effective in psoriasis and PsA (Table 3 and 1).