IL2 and major depressive disorder: The serum concentration of several cytokines was significantly increased in MDD vs. control group (Figure 5), as follows: IL-1β (84.11 ± 9.67 pg/mL vs. 46.41 ± 3.54 pg/mL), IL-2 (1479.13 ± 33.28 pg/mL vs. 985.47 ± 24.16 pg/mL), TNF-α (1323.47 ± 21.44 pg/mL vs. 956.43 ± 18.56 pg/mL), IFN-γ (346.92 ± 19.35 pg/mL vs. 264.78 ± 14.53 pg/mL), G-CSF (184.63 ± 12.45 pg/mL vs. 112.34 ± 9.51 pg/mL).