The crosstalk between the HPA-axis, nervous and immune systems. Neuroendocrine hormones, neuropeptides and cytokines produced by immune and neuroendocrine cells are recognized by common receptors expressed in both systems. The released neuroendocrine mediators act on immune cells influencing their function. In turn, molecules produced and released by immune cells, such as cytokines and neuropeptides, affect the response of neuroendocrine system. VIP and substance P influence the expression of immunoregulatory cytokines. While an increase in VIP and decrease in substance P lead to a modulatory cytokine environment, decrease in VIP and increase in substance P lead to an inflammatory cytokine environment, which are associated with the different clinical forms of Chagas disease.