Based on subgroup analysis of psoriasis types, study types, regions, and laboratory measurements, we know that IL-17 has P = 0.001<0.05 for plaque psoriasis and P = 0.054 >0.05 for other types of psoriasis, indicating that the serum level of IL-17 in plaque psoriasis is more different than other types of psoriasis. Here, IL17A is linked to psoriasis vulgaris.