Similarly, another study showed increases in pro-inflammatory cytokines interleukin-1b (IL-1b), interleukin-6 (IL-6), but not in tumor necrosis factor alpha (TNF-a) in the cerebrospinal fluid (CSF) of 24 CRPS patients ages 17–60 years, compared 16 controls, [32]. Here, IL6 is linked to complex regional pain syndrome.