NFKB1 and major depressive disorder: A clinical study by Savitz et al. [60] found that cytomegalovirus infection exacerbates depressive symptoms in patients with MDD by enhancing NF‐κB activity, with reductions in viral antibody titers or cluster of differentiation (CD) 8+ T cell activity correlating with reduced depressive symptomatology and NF‐κB signaling.