IL17A and rheumatoid arthritis: Paulissen et al. found that co‐culture of primary human Th17 cells with FLSs from RA patients led to more IL‐17A production, and this autocrine IL‐17 production as well as the induction of IL‐6, IL‐8 and MMP‐1 and MMP‐3 was effectively prevented by co‐blockade of COX‐2 and TNF‐α (Paulissen et al., 2013).