IL6 and amyotrophic lateral sclerosis: Blood levels of cytokines have been studied widely, including tumor necrosis factor-α (TNF-α) (123–125) interleukin-1β (IL-1β), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, and IL-13 which were reported to be increased, while interferon–γ (IFN-γ) was decreased in ALS patients in cross-sectional studies.