DPP4 and rheumatoid arthritis: This finding was confirmed when analyzing the percentages of IL-1R1+CD161+CD26+CD45RO+ cells of living CD4+ cells in the same set of experiments (PsA: mean 11.20%, SEM 2.84% vs. HCs: mean 5.76%, SEM 0.74%; p < 0.05, Figure 2D) with no differences for axSpA (mean 4.93%, SEM 0.68%) and RA (mean 3.86%, SEM 0.71%).