BRF2 and rheumatoid arthritis: To investigate whether any of the other ARE-BP included in our study would be required for ITF2357 effects on IL6, IL8, CXCL2 or PTGS2 mRNA expression, we performed knockdown of AUF1, BRF1, BRF2, KHSRP and HuR in RA FLS, achieving 80–95% silencing efficiency (Fig. 4a).