Serum LCN2 levels were significantly decreased in psoriasis patients with itch after biological treatment (74.11 ± 40 ng/ml vs. 39.86 ± 25.69 ng/ml, P < 0.05) (Figure 6(a)), but there was no significant difference in serum LCN2 levels with psoriasis patients without itch after treatment (Figure 6(b)). The gene discussed is LCN2; the disease is psoriasis.