IL6 and major depressive disorder: The plasma levels of proinflammatory cytokines, including IL-1β、IL-6 and TNF-α were significantly higher in UC patients with symptoms of anxiety/depression, while the level of anti-inflammatory cytokine TGF-β1 was evidently lower in UC patients with symptoms of anxiety/depression compared to UC patients without symptoms of anxiety/depression (P < 0.05, Fig. 1C).