CCL2 and depressive symptom measurement: The levels of M-CSF and GM-CSF in plasma of patients with ulcerative colitis with symptoms of anxiety/depression were significantly higher than those in patients with ulcerative colitis without symptoms of anxiety/depression [M-CSF:118.20(64.85, 154.10) vs. 65.16(47.28, 83.81), P = 0.0057; GM-CSF: 2.49 ± 0.16 vs. 1.69 ± 0.05, P = 0.0001], while there was no significantly difference in MCP-1 level (pg/mL) between the two groups [139.3(98.4, 176.9) vs. 144.5(107.9, 192.8), P = 0.7983] (Fig. 5A).