This review focuses on the powerful pain facilitatory effects produced by the immune system.
Immune cells, activated in response to infection, inflammation, or trauma, release proteins
called proinflammatory cytokines. These proinflammatory cytokines signal the central
nervous system, thereby creating exaggerated pain as well as an entire constellation of
physiological, behavioral, and hormonal changes. These changes are collectively referred
to as the sickness response. Release of proinflammatory cytokines by immune cells in the …