IL17A and rheumatoid arthritis: Furthermore, the fecal transplantation from RA patients to germ-free arthritis-prone SKG mice induces the Th17 profile in the gut mucosa and severe RA, and when SKG dendritic cells were cultivated with Prevotella copri, there was an increased IL-17 response to RA autoantigens, suggesting that the gut microbes could induce autoreactive cells in the gut mucosa [14].