S100A9 and psoriasis: The Luminex assays confirmed that proinflammatory cytokines involved in the pathogenesis of psoriasis and PsA, including IL-1β, TNF-α, IL-23, IL-17A, CCL2, CCL3, CXCL1, S100A9, RANKL, and MMP12, were highly elevated in Spry1-cKO skin (Figure 2G and Supplemental Figure 2D).