IL18 and psoriasis: QRT-PCR further confirmed that pro-inflammatory factors, including IL17A, tumor necrosis factor (TNF), CXCL8 (IL8), IL18, high mobility group box protein 1 (HMGB1), cathelicidin (LL37), S100A8, and S100A9, were all highly expressed in CXCR4hi neutrophils, compared to CXCR4lo neutrophils, with expression levels being overall higher in psoriasis CXCR4hi neutrophils than healthy controls (Fig. 2k).