Moreover, a previous meta-analysis failed to identify significantly elevated IL-4 levels in DN MDD patients compared to HCs [62], and a meta-analysis on FE DN individuals did not find higher levels of IL-4 in the patient group compared to HCs (g = −1.71; 95% CI, −4.73 to 1.31; p = 0.27; I2 = 97%) [20]. The gene discussed is IL4; the disease is major depressive disorder.