In contrast, the significantly decreased IL-2 in sera of ALS patients at a more pronounced disease stage (42 months disease duration) demonstrated in our study strengthens potential down-regulation of this cytokine on differentiation and/or maintenance of all T cell subsets, including regulatory T cell populations, such as T helper cells, that might lead to a Th1/Th2 imbalance toward the development of an autoimmune disorder [84]. Here, IL2 is linked to amyotrophic lateral sclerosis.