As shown in Figure 4A–C, RA patients have significantly elevated serum levels of soluble PD-1, PDL-2, and Tim3 compared to normal controls (sPD1: 450.5 ± 89.01, n = 31 vs. 111.1 ± 32.92, n = 92 p < 0.0001; sPD-L2: 17.9 ± 1.566, n = 47 vs. 12.78 ± 0.2314, n = 92 p < 0.0001; sTIM3: 4.288 ± 0.3015, n = 40 vs. 3.675 ± 0.08441, n = 92 p = 0.0104). This evidence concerns the gene PDCD1 and rheumatoid arthritis.