Interestingly, in RA patients with high disease activity and compared to patients with low disease activity, we observed a decreased HDAC activity (1009.3 ± 113.1 vs 2230.7 ± 254.3 pmol/min/mg; p = 0.01) (Figure 1C), an enhanced HAT activity (215.2 ± 57.2 vs 115.6 ± 42.5 ng/h/mg; NS) and a decreased ratio of HDAC/HAT activity (13.1 ± 8.2 vs 23.7 ± 12.6; NS). This evidence concerns the gene HDAC9 and rheumatoid arthritis.