IL17A and Arthritis: Here, we have shown that in vitro stimulation of SKG FLSs with IL-17 increases FLS-derived production of neutrophil-recruiting chemokines and GM-CSF, as previously reported with RA synoviocytes (Fossiez et al., 1996, Varas et al., 2015) and that loss of GM-CSF production by radio-resistant stromal cells including FLSs prevents arthritis development.