IL17A and arthritic joint disease: On day 13 after pristane injection, mRNA expression of Il17 and the Th17-associated cytokine, Il22, was approximately 60–80-fold higher in CD4+ T cells from inguinal than mesenteric LNs (Fig. 3a), which drains the intestine but not the joints, and whose T cells do not transfer arthritis (Fig. 3b).