CTSZ and primary biliary cholangitis: Cathepsin Z was expressed in hepatocytes, Kupffer cells, endothelial cells, and a small portion of infiltrating mononuclear cells, mainly in macrophages and monocytes, in both non-diseased liver (NL) and early-stage PBC, whereas cathepsin Z was minimally expressed in bile ducts (Fig. 3Aa–c).