In patients affected by rheumatoid arthritis (RA), which have lower p53 mRNA levels and higher percentages of circulating T helper 17 (Th17) cells compared to healthy controls, the inhibition of p53-MDM2 interaction by Nutlin-3a induced Treg differentiation under the effect of Th17 polarizing conditions (3). Here, TP53 is linked to rheumatoid arthritis.