Serum concentration of HMGB1, TLR4, IL‐23, and IL‐17A were all positively correlated with psoriasis patients' PASI (r = 0.66, 0.68, 0.65, and 0.65, respectively, all p < .001, Table 3, Figure 3A–D). This evidence concerns the gene HMGB1 and psoriasis.