We also found that some cytokines, such as IL-8, chemokine (C-C motif) ligand 27 (CCL27), C-X-C motif chemokine 1 (CXCL1), CXCL9, CXCL10 and IFN-α2, which were not significantly different in HC and PBC saliva, were significantly enriched in PBC serum (Figure 2B). The gene discussed is CXCL9; the disease is primary biliary cholangitis.