IFNγ and IL-17 double-positive cells have been observed in the CNS during EAE and fate mapping of IL-17 producing T cells has revealed Th17 cell plasticity to an IFNγ+ Th1-like phenotype.52–55 Future studies are needed to further elucidate the function of the Th17/Th1 plasticity in the pathogenesis of autoimmune diseases. This evidence concerns the gene IL17A and autoimmune disease.