In 2017, Al-Mossawi and colleagues observed a significant prevalence of GM-CSF + Th17 cells in patients with SpA compared to healthy donors and RA controls and also a high percentage of cells producing GM-CSF independently of IL-17A (GM-CSF + IL-17A — cells in both CD4 and CD8 cells) [147]. This evidence concerns the gene IL17A and rheumatoid arthritis.