The neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), and the systemic immune–inflammation index (SII) were measured in patients with psoriasis initiating TNF-α inhibitors (n = 131), IL-17/IL-17R inhibitors (n = 65), or IL-23/IL-12/23 inhibitors (n = 50). Here, IL17RA is linked to psoriasis.