Extensive bidirectional interactions exist between the endocrine system and the immune system.[16] Cortisol has major immunosuppressive effects,[17][18] and dopamine has immunomodulatory functions.[19] On the other hand, cytokines produced during inflammation activate the HPA axis at all three levels, sensible to negative feedback.[20] Moreover cytokines stimulate hepcidin release from the liver, which is eventually responsible for the anemia of chronic disease.[21]