Moreover, our mRNA-based predictions of the expression of certain ligands or receptors in particular cell types are supported by immunohistochemical studies of diseased human tissue (even though such studies are limited), including elevated epithelial CCL20 in psoriasis [(Homey et al., 2000); Figure 3A] and endothelial CX3CL1 in IgAN kidney [(Cox et al., 2012); Figure 3G]. This evidence concerns the gene CCL20 and psoriasis.