Increased serum sCTLA‐4 concentrations have been reported in several autoimmune diseases,15, 18 and a reduced PD‐1/PD‐L1 signaling has been detected in the synovial microenvironment of patients with rheumatoid arthritis (RA), leading to the recent development of drugs stimulating this endogenous immune‐inhibitory pathway.19, 20. This evidence concerns the gene PDCD1 and rheumatoid arthritis.