Nervous system has a direct effect on immune system
The nervous system has a direct effect on the immune system due to the nerve supply to the important immune system organs!
Sympathetic activity has been shown to release immune regulatory cells into the blood circulation, which alters immune function. This was reported by Drs. Murray, Irwin, and Reardon. The authors stated: Growing evidence suggests that immune function is regulated in part by the sympathetic nervous system. Sympathetic nerve endings densely innervate lymphoid tissue such as the spleen, lymph nodes and the thymus, and lymphoid cells have beta 2 adregenergic receptors.
J Am Osteopathy Assoc 1974 73:362.