A potential role for brain cytokine elevations in depression has been confirmed in studies using rodent models of the disorder showing that psychosocial stressors, such as social defeat, increased plasma IL-6, and IL-1β levels and up-regulated expression of these cytokines in the PFC and hippocampus (Audet et al., 2010, 2011). The gene discussed is IL1B; the disease is major depressive disorder.