PTK2B and rheumatoid arthritis: Quantitative analysis shows that p-PYK2 in PBMCs stimulated by PMA, but not by medium, was significantly up-regulated in healthy control (1.10 ± 0.32 VS 0.77 ± 0.29), RA (1.12 ± 0.35 VS 0.81 ± 0.30) and SLE (1.47 ± 0.36 VS 1.08 ± 0.34) patients, respectively (Figure 4B).