Stress is one of the most important life events. Thus, the ability to cope with, it protects against its noxious effects. An extensive network of central nervous system and endocrine system processes could be delineated in the modulation of the immune system in response to stressors. The relationship between these systems is bi-directionalThe effect of stress on the immune function and its interesting physiological and pathological consequences fit well into the emerging field of psychoneuroimmunology or neuroimmunomodulation and reinforce continuing efforts to elucidate the neural and neurohumoral mechanisms by which the environment can affect the organism's immune system.