Evolving role of immunology in chronic pain medicine: tissue necrosis factor and interleukin modulatory treatments

Our immune system acts to protect us in times of stress and traumatic injury. As part of the immune response, the body produces various cytokines, which mediate or modulate immune functions. Such cytokines include tumor necrosis factor (TNF) and interleukin 6 (IL-6) and IL-17. These cytokines can also act on the nervous system to influence pain perception. TNF-α triggers an inflammatory response and two forms of programmed cell death, apoptosis and necroptosis, depending on the pathological state. For individuals with chronic conditions relating to immune deficiency, the actions of these cytokines can present as chronic pain states, significantly altering quality of life. One attractive potential solution for treating this immune linked pain is by altering signaling pathways of pain-enhancing cytokines. Infliximab and etanercept are TNF inhibitors that are currently on the market for use in the treatment of chronic pain. Secukinumab and tocilizumab serve as IL inhibitors, utilized for a similar purpose. These novel immunotherapies have shown efficacy in numerous clinical studies with acceptable side effect profiles. In this review, we summarize the pharmacological profiles of these drugs and discuss their usage in treating chronic pain.