Abrogation of GM-CSF production by either the stromal cells or ILCs is able to prevent Th17 cell-mediated arthritis, while GM-CSF from arthritogenic Th cells is contributory to but not mandatory for arthritis development, at variance with a crucial role of Th17 cell-derived GM-CSF in mouse EAE (Codarri et al., 2011, El-Behi et al., 2011). The gene discussed is CSF2; the disease is Arthritis.