CCL17 and psoriasis: Across five patients with psoriasis, we reported a sub-cluster of DCs (IRF4+ cDC2) that displays elevated expression of CCL17, CCL22, and IL12B, markers of cDC2s that have recently been shown to drive psoriatic inflammation in mice and humans through the recruitment of inflammatory T cells (Kim et al., 2018; Zaba et al., 2010).