TNF and complex regional pain syndrome: For example, IL-1β, IL-6, and TNF-α play a crucial role in central sensitization, a process that has been repeatedly linked to the development and maintenance of chronic pain.21,42,44,51 Furthermore, fibromyalgia has been characterized by increased levels of IL-6, IL-8, and TNF-α,34 whereas IL-1β, IL-6, and TNF-α are elevated in patients with complex regional pain syndrome.1,28,48,50 Despite evidence among adult samples, there is a dearth of research examining proinflammatory cytokines in youth with chronic pain.