Proinflammatory cytokines, such as TNF-a, IL-1, and IL-6, are the major mediators between the brain, HPA axis, and immune system and continuous prolonged upregulation of proinflammatory cytokines can lead to depression and HPA axis suppression, which may trigger exacerbation of asthma [39–41]. The gene discussed is IL6; the disease is depressive disorder.