As IFN-γ is produced by T cells but not in significant amounts by any CNS resident cells, including microglia [49, 50], it has been proposed that, in neurodegenerative diseases, activated T cells would infiltrate into the parenchyma of the CNS [51–54] releasing their own inflammatory mediators, including IFN-γ [55, 56]. Here, IFNG is linked to neurodegenerative disease.