One possible explanation for the difference observed from the CSF and serum is that IL‐2, IL‐6, and IL‐10 might have a limited input in central nervous system (CNS) during the inflammatory process; as one previous study has shown, these cytokines are at similar levels in the CSF of ALS patients and control subjects (Tateishi et al., 2010). This evidence concerns the gene IL2 and amyotrophic lateral sclerosis.