IL17F and psoriasis: However, looking on the effects of cytokines highly relevant in the pathogenesis of psoriasis, i.e., IL-17A, IL-17F, IL-1α, or TNF, on S100A8 or S100A9 expression in keratinocytes we found strong effects on mRNA induction for both genes most pronounced for IL-17A > IL-17F > IL-1α > TNF.