The blockade of RA development in TonEBP-haplodeficient mice27,30 led us to examine the role of myeloid TonEBP in a mouse model of inflammatory arthritis based on myeloid-specific TonEBP knockout; these mice are referred to as TonEBPfl/flLysM-cre mice. This evidence concerns the gene NFAT5 and rheumatoid arthritis.