TNF and psoriasis: Furthermore, the transcriptional signature from affected skin revealed upregulation of key human psoriasis genes, including Lcn2 and Defb4, cytokines Tnf, Il1b, and Il36a/g, and chemokine ligands Ccl2, Cxcl9, and Ccl20 (Fig. 1k, Supplementary data 1-2).