The expression of T17 cell genes [KLRB1 (CD161) (41), IL17A, IL17F, and IL26 (42, 43)], a cytokine that represents a particularly T17-specific abnormality and positively associates with psoriasis severity (CXCL13) (44–47), and Treg genes (FOXP3, IL2RA (CD25), and TIGIT) was increased in pretreatment psoriasis lesional skin T-cells compared to control skin T-cells (Figure 4A, p < 0.05). This evidence concerns the gene IL17F and psoriasis.