TNF and amyotrophic lateral sclerosis: Although cytokine data are inconsistent across studies, a meta-analysis by Chen et al. reported that granulocyte-colony stimulating factor, interleukin-2 (IL-2), IL-15, IL-17, monocyte chemotactic protein-1, macrophage inflammatory protein-1α, tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor levels in the cerebrospinal fluid were significantly elevated in patients with ALS when compared with controls [9].