There is an increasing body of evidence that the nervous system is capable of modulating the immune response. Receptors for neuromodulators and neurohormones have been found on human T lymphocytes. Activation of these receptors can be stimulatory or inhibitory depending on the neuroactive substance. The immune system may be able to communicate with the nervous system using neuromodulators and neurohormones secreted by lymphocytes. Sympathetic innervation of lymphoid tissues is not restricted to blood vessels and smooth muscle, but directly supplies lymphocytes and blood precursor cells. It is theorized that spinal fixations may adversely affect the immune response through somatosympathetic reflexes. Spinal manipulation can correct the spinal fixations and may eliminate the adverse affects of somatosympathetic reflexes.
Fidelibus JC J Manipulative Physiol Ther 1989; 12 (4) Aug: 289-292