TNF and major depressive disorder: Furthermore, high TNF-α (P=0.044, P=0.176 after adjustment), high IL-1β (P=0.012, P=0.048 after adjustment), increased IL-6 (P=0.010, P=0.040 after adjustment), and increased IL-17 (P=0.010, P=0.040 after adjustment) were correlated with increased depression severity grade (Figure 4A-L).