In the four cytokines RANTES, SDF-1α, MIP-1β, and IL-17, only the causal effect of RANTES on psoriasis vulgaris was significant in all the 3 MR methods: IVW (β = 0.325, S.E. = 0.119, p = 0.006), weighted median (β = 0.348, S.E. = 0.153, p = 0.022), and MR-PRESSO (β = 0.325, S.E. = 0.106, p = 0.028; Table 1 and Figures 1, 2). Here, CCL4 is linked to psoriasis vulgaris.