PDCD1 and rheumatoid arthritis: The study identified the following percentages of total T cells expressing CD3: CD3+CD279+ (4.7 (9.33), (N = 46) vs. 2 (5.7), (N = 27), p = 0.025) and CD3+TIGIT+ (40 (31.8), (N = 47) vs. 22.5 (18.6), (N = 27), p = 0.0001) were expanded in RA patients compared to healthy volunteers.