“…Besedovsky and Del Rey [4] have suggested that, in addition to the affected cell subpopulation, the effects of NA also depend on the stimulus that triggers the immune response and, above all, on the activation stage at which macrophages and lymphocytes are exposed to neurotransmitters [5]. The processes directly or indirectly affected by sympathetic neurotransmitters are mainly the phagocytic process and antigenic presentation, the expression of adhesion molecules, the activation of lymphoid cells, the production of cytokines and chemokines, the Th1/Th2 balance, and the generation of cytotoxic cells [4,6,[8][9][10][11]. NA can also play a very important role in recirculation and leukocyte trafficking between lymphoid organs and blood [1,4,9,11], modulating chemotactic capacity and accumulation of phagocytes in inflammation sites as well [8,12,13].…”