CXCL10 and major depressive disorder: The results showed that no significant relationship was observed between the severity of SI and serum IL-17C (r = −0.159, P = 0.409), CXCL10 (r = −0.145, P = 0.453), and TNF-β (r = −0.131, P = 0.497) levels in MDD patients with SI.