Xu et al. (2023) found that patients with MDD in China had blood IL-4 levels that were twice as high as those seen in HCs (16.4 ± 71.84 pg/ml)10, while our research found that patients with MDD in Bangladesh had IL-4 levels that were three times higher than those found in controls (272.81 ± 23.94 pg/ml). The gene discussed is IL4; the disease is major depressive disorder.