BDNF and major depressive disorder: This study observed significant reductions in MCP-1, BDNF, IL-7, and IL-10 levels in individuals of Bangladeshi descent diagnosed with MDD than controls34–36.While studies have demonstrated associations between MDD severity and concentrations of pro-inflammatory cytokines such as IL-2, IL-6, and MCP-1 in the blood of Bangladeshi patients37–39, research on concentration of anti-inflammatory cytokines like IL-4 in MDD patients from the same population is currently lacking.