Their findings indicated lower chitinase-3-like-1 (YKL-40)—a glycoprotein that is upregulated under inflammatory conditions—concentrations in PSP compared to the controls, reduced monocyte chemotactic protein-1 (MCP-1)—a chemokine that is associated with microglial activation—in PDD relative to PSP, and a positive correlation between interleukin 6 IL-6 concentration and motor disability specifically in PSP [79]. Here, CHI3L1 is linked to supranuclear palsy, progressive, 1.