Elderly patients that have high Th1/Th1 levels and alterations in this ratio, or increased levels of Interleukin (IL)-18, transforming growth factor (TGF)-β, chemokine of regulated on activation, normal T cell expressed and secreted (RANTES), and urokinase plasminogen activator receptor (uPAR), are associated with a higher risk of depression development [31,48]. The gene discussed is PLAUR; the disease is major depressive disorder.