CXCL9 and psoriasis: This elevated IFN-γ could trigger macrophages to release high levels of other inflammatory cytokines and pro-inflammatory mediators, including chemokine (C-X-C motif) ligand 9 and 10 (CXCL9, CXCL10), which could in turn recruit T helper type 1 (Th1) and type 1 T cytotoxic (Tc1) cells to the psoriatic tissues and promote the progression of psoriasis (20).