Cytokines are chemical messengers that primarily signal the immune system, but also play a role as neuromodulators. They can be defined as either pro-inflammatory or anti-inflammatory. Cytokine imbalances may be involved in autoimmune disorders, atopic conditions as well as neuropsychiatric disorders.Cytokines are signaling proteins and glycoproteins that mediate and regular immunity, inflammation and hematopoiesis.  They are also involved in cell growth and differentiation, cell death, angiogenesis, normal development and neuromodulations.Cytokines are critical to the functional both innate (cell-mediated) and adaptive (antigen specific/humoral) immune systems.  They are known as either pro-inflammatory or anti-inflammatory.  Pro-inflammatory cytokines include interferon-gamma (INFγ), interleukin-2 (IL2) and interleukin-12 (IL12); whereas interleukin-4 (IL4) and interleukin-5 (IL5) are anti-inflammatory.Generally pro-inflammatory cytokines are secreted from T-helper 1 (Th1) cells and anti-inflammatory cytokines are secreted from T-helper 2 (Th2) cells.  Under normal circumstances the Th1 and Th2 systems should be in balance.