Cytokines, neurophysiology, neuropsychology, and psychiatric symptoms.

Figures & data

Figure 1. The balance between Th1 (cell-mediated) and Th2 (humoral) response of the adaptive (specific) immune system. IL, interleukin; IFN-γ, interferon gamma; Th1 , T helper 1; Th2, T helper 2.

Table I Expression of some selected cytokines and their receptors on neurons and glial cells. Th, T helper cell; C, cytokine; R, receptor; IFN, interferon; TNF-α, tumor necrosis factor alpha; IL, interleukin; AIDS, acquired immune deficiency syndrome; CNS, central nervous system; HPA, hypothalamus-pituitary-adrenal; BBB, blood-brain barrier; ACTH, adrenocorticotropic hormone.

Figure 2. The essential amino acid tryptophan is converted either into the neurotransmitter serotonin, or into the neuroactive metabolite kynurenine, which is further degraded to quinolinic acid. The rate-limiting enzyme in the kynurenine pathway, indoleamine2,3-dioxygenase (IDO), and kynurenine hydroxylase (KYNHydrox) are activated by the cytokine interferon gamma (IFN-γ).