ALS astrocytes secrete toxic factors [20, 21, 23], so to investigate this further, we performed a secretome analysis by measuring the presence of 10 inflammatory cytokines (IFN-γ, TNF-α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70 and IL-13) in the media from immature (APCs d25/d+0) and more mature astrocytes (maturation week 4) (Fig. 2F). Here, IL4 is linked to amyotrophic lateral sclerosis.