IL-23 and IL-1β are required for GM-CSF production by γδT17 cells and conventional αβ Th17 cells.40, 41 In models of autoimmunity in which GM-CSF is a key pathogenic molecule, such as experimental autoimmune encephalomyelitis, γδ T cells have been identified as the major source of GM-CSF.42 Whereas conventional αβ Th17 cells evolve to produce IFNγ during the development of the disease, γδT17 cells are less likely to produce IFNγ and will more likely evolve to produce GM-CSF.42 As for γδT17, recruitment of IL-23-driven, GM-CSF-producing Th17 cells requires CCR2.43